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Journal articles on the topic 'Tropical Cyclones'
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1
Chaudhuri, Sutapa, and Anindita De Sarkar. "Severity of Tropical Cyclones atypical during El Nino – A Statistical Elucidation." Asian Journal of Water, Environment and Pollution 6, no. 4 (January 2009): 79–85. http://dx.doi.org/10.3233/ajw-2009-6_4_11.
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Tropical cyclones are one of nature's most violent manifestations and potentially the deadliest of all meteorological phenomena. The casualty associated with major cyclones in the Indian sub-continent gives an idea about its enormous destructive capability. The effect of El Nino over Indian Ocean is not fully understood yet. The present study is an attempt to establish a relationship between El Nino and severity of tropical cyclones. The rationale of the present study is to view whether a persistent cyclonic disturbance leads to the development of a tropical cyclone or severe tropical cyclone during an El Nino year. Statistical techniques are adopted to attain the objectives. The results of the study reveal that in the El Nino year cyclonic disturbances may turn to tropical cyclones but turning to its severity is absolutely unusual.
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Surinati, Dewi, and Dwi Ayu Kusuma. "KARAKTERISTIK DAN DAMPAK SIKLON TROPIS YANG TUMBUH DI SEKITAR WILAYAH INDONESIA." OSEANA 43, no. 2 (October 30, 2018): 1–12. http://dx.doi.org/10.14203/oseana.2018.vol.43no.2.16.
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CHARACTERISTICS AND IMPACTS OF TROPICAL CYCLONES GROWING AROUND INDONESIAN TERRITORY. Tropical cyclone is a cyclonic originates from tropical oceans and driven principally by heat transfer from the ocean. Tropical cyclone is an atmospheric phenomenon characterized by the emergence of low air pressure that triggers the occurrence of strong winds due to the process of heat transfer from the equator to the latitude. This phenomenon can not be prevented, so that it has great potential to impact on the damage in the area it through. Tropical cyclones can be characterized through their life cycle, scale of power and how it impacts in the area it through. The Cempaka and Dahlia tropical cyclone occuring in 2017 greatly influenced territory of Indonesia. The effect of the cyclone causes extreme weather in Indonesia, especially in areas close to where cyclones are formed.
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Zy Misa Harivelo, Rakotoarimanana, Rakotoarimanana Zy Harifidy, Pandin Moses Glorino Rumambo, and Waloejo Christrijogo Sumartono. "Analysis of tropical cyclones 2000-2020 in Madagascar." Disaster Advances 15, no. 3 (February 25, 2022): 13–20. http://dx.doi.org/10.25303/1503da1320.
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Madagascar is among the ten countries most exposed to cyclonic disasters in the world due to its geographical position. The country faces serious problems directly related to tropical cyclones every year. This research aims to analyze the cyclones in Madagascar from 2000 to 2020 focusing on the impact of the cyclone based on human losses and costs. The findings showed that during the past 20 years, 39 significant cyclones have affected Madagascar. On an average, 02 cyclones per year hit the country but its frequency has been decreasing since 2014. Cyclone Eline, Gafilo and Ivan were considered the most dangerous and have caused serious damages to the country. The number of victims caused by the cyclone, Eline, in 2000 were numerous while the cyclone Ivan in 2008 led many people to homelessness. In addition, the cyclone Gafilo in 2004 was recorded as the deadliest, costliest and has provoked many injuries including missing people. The number of victims, homeless, injured, missing and the cost of damage increase depending on the intensity of the cyclone. The East, North-East, West and Southwest coasts are most often hit by cyclones. Despite the frequency and damage of cyclones in the country, the actions carried out to reduce or mitigate the impacts of cyclones are still not sustainable, which makes the populations more vulnerable.
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Tang, Brian, and Kerry Emanuel. "A Ventilation Index for Tropical Cyclones." Bulletin of the American Meteorological Society 93, no. 12 (December 1, 2012): 1901–12. http://dx.doi.org/10.1175/bams-d-11-00165.1.
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An important environmental control of both tropical cyclone intensity and genesis is vertical wind shear. One hypothesized pathway by which vertical shear affects tropical cyclones is midlevel ventilation—or the flux of low-entropy air into the center of the tropical cyclone. Based on a theoretical framework, a ventilation index is introduced that is equal to the environmental vertical wind shear multiplied by the nondimensional midlevel entropy deficit divided by the potential intensity. The ventilation index has a strong influence on tropical cyclone climatology. Tropical cyclogenesis preferentially occurs when and where the ventilation index is anomalously low. Both the ventilation index and the tropical cyclone's normalized intensity, or the intensity divided by the potential intensity, constrain the distribution of tropical cyclone intensification. The most rapidly intensifying storms are characterized by low ventilation indices and intermediate normalized intensities, while the most rapidly weakening storms are characterized by high ventilation indices and high normalized intensities. Since the ventilation index can be derived from large-scale fields, it can serve as a simple and useful metric for operational forecasts of tropical cyclones and diagnosis of model errors.
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Lloyd, Ian D., and Gabriel A. Vecchi. "Observational Evidence for Oceanic Controls on Hurricane Intensity." Journal of Climate 24, no. 4 (February 15, 2011): 1138–53. http://dx.doi.org/10.1175/2010jcli3763.1.
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Abstract The influence of oceanic changes on tropical cyclone activity is investigated using observational estimates of sea surface temperature (SST), air–sea fluxes, and ocean subsurface thermal structure during the period 1998–2007. SST conditions are examined before, during, and after the passage of tropical cyclones, through Lagrangian composites along cyclone tracks across all ocean basins, with particular focus on the North Atlantic. The influence of translation speed is explored by separating tropical cyclones according to the translation speed divided by the Coriolis parameter. On average for tropical cyclones up to category 2, SST cooling becomes larger as cyclone intensity increases, peaking at 1.8 K in the North Atlantic. Beyond category 2 hurricanes, however, the cooling no longer follows an increasing monotonic relationship with intensity. In the North Atlantic, the cooling for stronger hurricanes decreases, while in other ocean basins the cyclone-induced cooling does not significantly differ from category 2 to category 5 tropical cyclones, with the exception of the South Pacific. Since the SST response is nonmonotonic, with stronger cyclones producing more cooling up to category 2, but producing less or approximately equal cooling for categories 3–5, the observations indicate that oceanic feedbacks can inhibit intensification of cyclones. This result implies that large-scale oceanic conditions are a control on tropical cyclone intensity, since they control oceanic sensitivity to atmospheric forcing. Ocean subsurface thermal data provide additional support for this dependence, showing weaker upper-ocean stratification for stronger tropical cyclones. Intensification is suppressed by strong ocean stratification since it favors large SST cooling, but the ability of tropical cyclones to intensify is less inhibited when stratification is weak and cyclone-induced SST cooling is small. Thus, after accounting for tropical cyclone translation speeds and latitudes, it is argued that reduced cooling under extreme tropical cyclones is the manifestation of the impact of oceanic conditions on the ability of tropical cyclones to intensify.
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SINGH, CHARAN, SUNIT DAS, R. B. VERMA, B. L. VERMA, and B. K. BANDYOPADHYAY. "Rainfall estimation of landfalling tropical cyclones over Indian coasts through satellite imagery." MAUSAM 63, no. 2 (December 16, 2021): 193–202. http://dx.doi.org/10.54302/mausam.v63i2.1377.
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One of the most significant impacts of landfalling tropical cyclones is caused by the copiousrainfall associated with it. The main emphasis of present study is to provide some guidance to the operational forecastersfor indicating the possible rainfall over the areas likely to be affected by the cyclones after landfall. Study of 14 pastlandfalling cyclones reveals that the maximum rainfall occurred in the first forward quadrant of tropical cyclonemovement, followed by the second quadrant and the areas near the track of the cyclones. Isohyetal analysis of 24 hoursrainfall for each cyclone reveals that occurrence of heavy rainfall is generally confined up to 150 kms radius from thestorm centre and rainfall is found to generally extend up to 300 kms with gradual decrease in amount. The rainfallreceiving areas are mostly covered with convective clouds with cloud top temperatures of -80 to -60 ºC, prior to and afterthe landfall of the systems. In 93% of tropical cyclones out of the 14 cases studied, 70 % convection lay to the right of thetrack. To examine the rainfall asymmetry due to asymmetry in distribution of convection, cloud top temperatures derivedfrom satellite infrared imagery data have been taken as the proxy of strong convection. It is also revealed in the study thatthe slow moving tropical cyclones cause heavy rain rather than fast moving tropical cyclones. The Bay of Bengalcyclones which crossed coast as cyclonic storm and very severe cyclonic storm caused 71.4% rainfall within the range 0-10 cm, 22.8% rainfall in the range 11-20 cm and 4.3% rainfall within the range 21-30 cm in the area of radius of 300 kmsfrom the centre of the cyclonic storms. For the Arabian Sea tropical cyclones, in general, about 70% rainfall occurredwithin the range 16-25 cm in 24 hours.
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Hulme, Andrew L., and Jonathan E. Martin. "Synoptic- and Frontal-Scale Influences on Tropical Transition Events in the Atlantic Basin. Part II: Tropical Transition of Hurricane Karen." Monthly Weather Review 137, no. 11 (November 1, 2009): 3626–50. http://dx.doi.org/10.1175/2009mwr2803.1.
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Abstract A finescale simulation of the tropical transition of Atlantic Hurricane Karen in October 2001 is examined to determine the processes leading to the development of upshear convection and its effects on the process of tropical transition. The analysis shows that, as in marine extratropical cyclones, the area upshear of the pretransition cyclone is characterized by reduced stability. Lower-tropospheric frontogenesis leads to an intense burst of convection there and instigates three important processes that combine to produce a full-fledged tropical cyclone. First, the convection generates intense low-level vorticity on the western half of the cyclone, which quickly dominates the cyclone’s vorticity field eventually organizing the circulation into a small-scale, intense vortex. Second, the diabatically enhanced circulation hastens the isolation of the cyclone’s developing warm core by intensifying cold air advection on the northern and western sides of the storm and by placing evaporatively cooled air into the boundary layer to the south of the cyclone. Third, upshear convection vertically redistributes potential vorticity (PV) from the tropopause to the surface and introduces a component to the upper-level winds, which advects strong, shear-inducing PV gradients away from the column above the cyclone. These three processes transform the initial extratropical cyclone into a frontless vortex with tropical storm–force winds and a warm core in a low-shear environment. These features are sufficient, given a warm enough ocean surface, to allow self-amplification of the storm as a tropical cyclone. The results further blur the distinction between tropical and extratropical cyclones as many of the processes identified as important to transition are similar to those that characterize ordinary marine cyclones and the extratropical occlusion process with the key distinctions being that here the convection is stronger and the initial upper-level feature is weaker. Thus, tropical transition of strong extratropical precursors follows the canonical midlatitude cyclone life cycle with upshear convection serving as the catalyst that both induces and organizes processes that favor tropical cyclogenesis in the postmature phase.
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Wu, Liguang, Haikun Zhao, Chao Wang, Jian Cao, and Jia Liang. "Understanding of the Effect of Climate Change on Tropical Cyclone Intensity: A Review." Advances in Atmospheric Sciences 39, no. 2 (January 21, 2022): 205–21. http://dx.doi.org/10.1007/s00376-021-1026-x.
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AbstractThe effect of climate change on tropical cyclone intensity has been an important scientific issue for a few decades. Although theory and modeling suggest the intensification of tropical cyclones in a warming climate, there are uncertainties in the assessed and projected responses of tropical cyclone intensity to climate change. While a few comprehensive reviews have already provided an assessment of the effect of climate change on tropical cyclone activity including tropical cyclone intensity, this review focuses mainly on the understanding of the effect of climate change on basin-wide tropical cyclone intensity, including indices for basin-wide tropical cyclone intensity, historical datasets used for intensity trend detection, environmental control of tropical cyclone intensity, detection and simulation of tropical cyclone intensity change, and some issues on the assessment of the effect of climate change on tropical cyclone intensity. In addition to the uncertainty in the historical datasets, intertwined natural variabilities, the considerable model bias in the projected large-scale environment, and poorly simulated inner-core structures of tropical cyclones, it is suggested that factors controlling the basin-wide intensity can be different from individual tropical cyclones since the assessment of the effect of climate change treats tropical cyclones in a basin as a whole.
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Yanase, Wataru, and Hiroshi Niino. "Parameter Sweep Experiments on a Spectrum of Cyclones with Diabatic and Baroclinic Processes." Journal of the Atmospheric Sciences 76, no. 7 (June 18, 2019): 1917–35. http://dx.doi.org/10.1175/jas-d-18-0232.1.
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Abstract A wide range of environments that prevail over the globe generate various types of cyclones such as tropical, extratropical, and hybrid cyclones. In this paper, idealized numerical experiments are used to explore a spectrum of cyclones ranging from the diabatic type to the baroclinic type in a parameter space consisting of three environmental factors: temperature, vertical shear, and planetary vorticity. The experiments reproduce not only typical dynamics of tropical and extratropical cyclones but also their modified dynamics, which are consistent with theoretical studies; tropical cyclones are suppressed by vertical shear, while extratropical cyclones are intensified by condensational heating. The experiments also reproduce hybrid cyclones in environments with high temperature and large baroclinicity. The hybrid cyclones show multiscale dynamics in which synoptic-scale baroclinic systems spawn smaller-scale tropical cyclone–like convective cores. The spectrum of cyclones is found to be nonmonotonic in the parameter space because of a two-sided effect of the vertical shear: moderate shear weakens a tropical cyclone by tilting the small-scale vortex to the downshear, while strong shear develops a large-scale vortex of an extratropical cyclone or a hybrid cyclone through warm-air advection from the south. The indices based on the energetics and the symmetric and asymmetric structures overview the different types of cyclones in the parameter space. These parameter sweep experiments provide useful information on what environment is favorable for cyclones, particularly for intermediate environments where cyclone mechanisms are yet to be fully defined.
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Scherrmann, Alexander, Heini Wernli, and Emmanouil Flaounas. "Origin of low-tropospheric potential vorticity in Mediterranean cyclones." Weather and Climate Dynamics 4, no. 1 (January 25, 2023): 157–73. http://dx.doi.org/10.5194/wcd-4-157-2023.
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Abstract. Mediterranean cyclones are extratropical cyclones, typically of smaller size and weaker intensity than other cyclones that develop over the main open ocean storm tracks. Nevertheless, Mediterranean cyclones can attain high intensities, even comparable to the ones of tropical cyclones, and thus cause large socioeconomic impacts in the densely populated coasts of the region. After cyclogenesis takes place, a large variety of processes are involved in the cyclone’s development, contributing with positive and negative potential vorticity (PV) changes to the lower-tropospheric PV anomalies in the cyclone center. Although the diabatic processes that produce these PV anomalies in Mediterranean cyclones are known, it is still an open question whether they occur locally within the cyclone itself or remotely in the environment (e.g., near high orography) with a subsequent transport of high-PV air into the cyclone center. This study introduces a Lagrangian method to determine the origin of the lower-tropospheric PV anomaly, which is applied climatologically to ERA5 reanalysis and to 12 monthly simulations, performed with the integrated forecasting system (IFS) model. We define and quantify so-called “cyclonic” and “environmental” PV and find that the main part of the lower-tropospheric PV anomaly (60 %) is produced within the cyclone, shortly prior (−12 h) to the cyclones' mature stage. Nevertheless, in 19.5 % of the cyclones the environmental PV production near the mountains surrounding the Mediterranean Basin plays a significant role in forming the low-tropospheric PV anomaly and therefore in determining the intensity of these cyclones. The analysis of PV tendencies from the IFS simulations reveals that the major PV production inside the cyclone is typically due to convection and microphysics, whereas convection and turbulent momentum tendencies cause most of the positive PV changes in the environment.
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Patandean, Candra Febryanto. "Influence of Enso to Variability of Rain Chain at Tropical Cyclon in Southern East Nusa Tenggara." Jurnal Ilmiah Ilmu Administrasi Publik 9, no. 2 (February 4, 2020): 277. http://dx.doi.org/10.26858/jiap.v9i2.12305.
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The Region of East Nusa Tenggara province which is geographically situated around Equator is an area immediately adjacent to place where the growth of tropical cyclones. This research to determine the variability of tropical cyclones that have happened, how the influence of ENSO on the variability of tropical cyclones, and how the impact of tropical cyclones on rainfall in East Nusa Tenggara. In this study, the rainfall data used is represented by 8 stations observations in the region of NTT, namely Kupang, Rote, Sabu, Waingapu, Ruteng, Maumere, Larantuka, and Alor, with period of 19 years ie the assessment year 1996-2014. The data was obtained from Era Interim ECMWF. Tropical cyclone data was obtained from JTWC-Japan and TCWC-Australia, covering a maximum sustained wind data, position, and lifetime cyclone. Rainfall data obtained from Climatological Station of Lasiana-Kupang. Results of the analysis showed that during the study period the total incidence of tropical cyclones in the south of East Nusa Tenggara many as 113 cases, with an average of 6 events cyclones per year and were distributed mainly in the winter between November and April. The results also show that ENSO influence on tropical cyclone variability indirectly to the parameter of tropical cyclones.
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Enz, Bernhard M., Jan P. Engelmann, and Ulrike Lohmann. "Use of threshold parameter variation for tropical cyclone tracking." Geoscientific Model Development 16, no. 17 (September 6, 2023): 5093–112. http://dx.doi.org/10.5194/gmd-16-5093-2023.
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Abstract. Assessing the capacity of numerical models to produce viable tropical cyclones, as well as assessing the climatological behavior of simulated tropical cyclones, requires an objective tracking method. These make use of parameter thresholds to determine whether a detected feature, such as a vorticity maximum or a warm core, is strong enough to indicate a tropical cyclone. The choice of parameter thresholds is generally subjective. This study proposes and assesses the parallel use of many threshold parameter combinations, combining a number of weaker and stronger values. The tracking algorithm succeeds in tracking tropical cyclones within the model data, beginning at their aggregation stage or shortly thereafter and ending when they interact strongly with extratropical flow and transition into extratropical cyclones or when their warm core decays. The sensitivity of accumulated cyclone energy to tracking errors is assessed. Tracking errors include the faulty initial detection and termination of valid tropical cyclones and systems falsely identified as tropical cyclones. They are found to not significantly impact the accumulated cyclone energy. Thus, the tracking algorithm produces an adequate estimate of the accumulated cyclone energy within the underlying data.
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Wang, Jie, Sirui Zhu, Jiaming Liu, Xun Wang, Jiarui Wang, Jiayuan Xu, Peiling Yao, and Yijie Yang. "Frequency, Intensity and Influences of Tropical Cyclones in the Northwest Pacific and China, 1977–2018." Sustainability 15, no. 5 (February 21, 2023): 3933. http://dx.doi.org/10.3390/su15053933.
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China is part of the western Pacific region, which is the source of the most frequent tropical cyclones in the world. These cause severe disasters each year, including huge economic losses and casualties. To better understand their frequency and intensity, remote sensing tropical cyclone data were obtained for the entire Northwest Pacific region for the period 1977–2018. MATLAB and ArcGIS were used to analyse the frequency and intensity of tropical cyclones and their characteristics in various regions of China. At the same time, the influence factors of tropical cyclone characteristics such as El Niño and SST were analyzed by correlation analysis and Geographical detector. The annual frequency of tropical cyclones in the Northwest Pacific showed a fluctuating state, but the overall trend was decreasing. In particular, since 1994, the overall frequency decreased significantly but rebounded in recent years, while the intensity did not change significantly. It was found that cyclone intensity is lower when the frequency is higher, and vice versa. 85% of tropical cyclones occurred in summer and autumn, with the highest intensities in autumn, when the maximum average wind speed peaks at 37 m/s. The area with the most frequent tropical cyclones was 5–20° N, 125–155° E. A total of 314 tropical cyclones arrived in China during the study period, an average of about 7.5 per year. Their frequency and intensity gradually decreased as they moved from coastal to inland areas. Both SST and El Niño are significantly related to the formation and development of tropical cyclones, and the contribution of multiple factors interaction to the variation characteristics of tropical cyclones is significantly higher than that of single factors. Understanding the characteristics of the Pacific tropical cyclones is an important step in planning disaster prevention framework.
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Venkat Ratnam, M., S. Ravindra Babu, S. S. Das, G. Basha, B. V. Krishnamurthy, and B. Venkateswararao. "Effect of tropical cyclones on the stratosphere–troposphere exchange observed using satellite observations over the north Indian Ocean." Atmospheric Chemistry and Physics 16, no. 13 (July 15, 2016): 8581–91. http://dx.doi.org/10.5194/acp-16-8581-2016.
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Abstract. Tropical cyclones play an important role in modifying the tropopause structure and dynamics as well as stratosphere–troposphere exchange (STE) processes in the upper troposphere and lower stratosphere (UTLS) region. In the present study, the impact of cyclones that occurred over the north Indian Ocean during 2007–2013 on the STE processes is quantified using satellite observations. Tropopause characteristics during cyclones are obtained from the Global Positioning System (GPS) radio occultation (RO) measurements, and ozone and water vapour concentrations in the UTLS region are obtained from Aura Microwave Limb Sounder (MLS) satellite observations. The effect of cyclones on the tropopause parameters is observed to be more prominent within 500 km of the centre of the tropical cyclone. In our earlier study, we observed a decrease (increase) in the tropopause altitude (temperature) up to 0.6 km (3 K), and the convective outflow level increased up to 2 km. This change leads to a total increase in the tropical tropopause layer (TTL) thickness of 3 km within 500 km of the centre of cyclone. Interestingly, an enhancement in the ozone mixing ratio in the upper troposphere is clearly noticed within 500 km from the cyclone centre, whereas the enhancement in the water vapour in the lower stratosphere is more significant on the south-east side, extending from 500 to 1000 km away from the cyclone centre. The cross-tropopause mass flux for different intensities of cyclones is estimated and it is found that the mean flux from the stratosphere to the troposphere for cyclonic storms is 0.05 ± 0.29 × 10−3 kg m−2, and for very severe cyclonic storms it is 0.5 ± 1.07 × 10−3 kg m−2. More downward flux is noticed on the north-west and south-west side of the cyclone centre. These results indicate that the cyclones have significant impact in effecting the tropopause structure, ozone and water vapour budget, and consequentially the STE in the UTLS region.
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Flaounas, Emmanouil, Suzanne L. Gray, and Franziska Teubler. "A process-based anatomy of Mediterranean cyclones: from baroclinic lows to tropical-like systems." Weather and Climate Dynamics 2, no. 1 (March 29, 2021): 255–79. http://dx.doi.org/10.5194/wcd-2-255-2021.
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Abstract. In this study, we address the question of the atmospheric processes that turn Mediterranean cyclones into severe storms. Our approach applies online potential vorticity (PV) budget diagnostics and piecewise PV inversion to WRF model simulations of the mature stage of 100 intense Mediterranean cyclones. We quantify the relative contributions of different processes to cyclone development and therefore deliver, for the first time, a comprehensive insight into the variety of cyclonic systems that develop in the Mediterranean from the perspective of cyclone dynamics. In particular, we show that all 100 cyclones are systematically influenced by two main PV anomalies: a major anomaly in the upper troposphere, related to the baroclinic forcing of cyclone development, and a minor anomaly in the lower troposphere, related to diabatic processes and momentum forcing of wind. Among the diabatic processes, latent heat is shown to act as the main PV source (reinforcing cyclones), being partly balanced by PV sinks of temperature diffusion and radiative cooling (weakening cyclones). Momentum forcing is shown to have an ambiguous feedback, able to reinforce and weaken cyclones while in certain cases playing an important role in cyclone development. Piecewise PV inversion shows that most cyclones develop due to the combined effect of both baroclinic and diabatic forcing, i.e. due to both PV anomalies. However, the stronger the baroclinic forcing, the less a cyclone is found to develop due to diabatic processes. Several pairs of exemplary cases are used to illustrate the variety of contributions of atmospheric processes to the development of Mediterranean cyclones: (i) cases where both baroclinic and diabatic processes contribute to cyclone development; (ii) cases that mainly developed due to latent-heat release; (iii) cases developing in the wake of the Alps; and (iv) two unusual cases, one where momentum forcing dominates cyclone development and the other presenting a dual-surface pressure centre. Finally, we focus on 10 medicane cases (i.e. tropical-like cyclones). In contrast to their tropical counterparts – but in accordance with most intense Mediterranean cyclones – most medicanes are shown to develop under the influence of both baroclinic and diabatic processes. In discussion of medicane-driving processes, we highlight the need for a physical definition of these systems.
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Sinha, Mourani, Somnath Jha, and Anupam Kumar. "A Comparison of Wave Spectra during Pre-Monsoon and Post-Monsoon Tropical Cyclones under an Intense Positive IOD Year 2019." Climate 11, no. 2 (February 12, 2023): 44. http://dx.doi.org/10.3390/cli11020044.
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The impact of Indian Ocean Dipole (IOD) events on the generation and intensity of tropical cyclones under the influence of monsoons is explored. The standardized sea surface temperature (SST) anomalies are computed for the pre-monsoon and post-monsoon months for the Bay of Bengal (BOB) and Arabian Sea (AS) from 1971 to 2020 and relationships are analyzed with the frequency of tropical cyclones for the neutral, positive and negative IOD years. Ocean states are sensitive to cyclonic conditions exhibiting a complex spectral distribution of the wave energy. Due to a tropical cyclone, the surface waves remain under high wind forcing conditions for prolonged periods generating a huge amount of energy. The spectral wave model SWAN (Simulating WAves Nearshore) is used to generate the energy density spectra during FANI (26 April–5 May 2019), which was a pre-monsoon extreme severe cyclonic storm, and BULBUL (5–12 November 2019), which was a post-monsoon very severe cyclonic storm in the BOB region. This study aims to estimate the intensity of wave energy during tropical cyclones in the pre- and post-monsoon months for 2019 (an extremely positive IOD year).
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Zhu, Jiong, and Jian Cheng Kang. "Relationship between Sea Temperature Change and Tropical Cyclones Based on Argo." Advanced Materials Research 250-253 (May 2011): 2782–86. http://dx.doi.org/10.4028/www.scientific.net/amr.250-253.2782.
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The relationship between sea water temperature with depth and the maximum cyclone wind speed was analyzed, the temperature was acquired before 24h of the cyclones occurred by using of data of Argo floats and cyclones in 2005, and taking advantage of inverse distance weighted interpolation method. The results showed that: (1) the Tropical Cyclone’s intensity had a strong correlation with the sea water temperature in the depth of about 42m or so. (2) Under the conditions of similar latitude, according to the energy conservation law, the maximum intensity of cyclones wind was a linear function of sea water temperature, depth, and continuous change in the overall rate, which was verified through the actual observation data.
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Mulyana, Erwin, M. Bayu Rizky Prayoga, Ardila Yananto, Samba Wirahma, Edvin Aldrian, Budi Harsoyo, Tri Handoko Seto, and Yaya Sunarya. "Tropical cyclones characteristic in southern Indonesia and the impact on extreme rainfall event." MATEC Web of Conferences 229 (2018): 02007. http://dx.doi.org/10.1051/matecconf/201822902007.
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The southern region of Indonesia is one of the places where tropical cyclones grow in the southern hemisphere. During 1983-2017 there were 51 tropical cyclones occurring in the region. This study aims to understand the characteristic of tropical cyclones in southern Indonesia and their variations, both spatially and temporally, and their effect on extreme rain events in Indonesia. Historical data analysis results show that tropical cyclones in southern Indonesia generally occur in November-April with a lifetime of 7-8 days. The result of data analysis shows that the central pressure value of tropical cyclone in latitude 0°-10°S is more than 960 hPa. The value tends to be higher than the central value pressure of tropical cyclone in latitude 10°S-20°S, which has the range of values about 920-960 hPa. This study also explains that there are 9 tropical cyclones in 35 years back that grow or move closer to the Indonesian archipelago in latitude 0°-10°S. The event of tropical cyclone Dahlia at the end of 2017 also affect the enormously increase of rainfall in Gunungkidul, Yogyakarta region with the increase of rain reaches 750% from the historical average.
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Bell, Ray, Jane Strachan, Pier Luigi Vidale, Kevin Hodges, and Malcolm Roberts. "Response of Tropical Cyclones to Idealized Climate Change Experiments in a Global High-Resolution Coupled General Circulation Model." Journal of Climate 26, no. 20 (October 4, 2013): 7966–80. http://dx.doi.org/10.1175/jcli-d-12-00749.1.
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Abstract The authors present an assessment of how tropical cyclone activity might change owing to the influence of increased atmospheric carbon dioxide concentrations, using the U.K. High-Resolution Global Environment Model (HiGEM) with N144 resolution (~90 km in the atmosphere and ~40 km in the ocean). Tropical cyclones are identified using a feature-tracking algorithm applied to model output. Tropical cyclones from idealized 30-yr 2×CO2 (2CO2) and 4×CO2 (4CO2) simulations are compared to those identified in a 150-yr present-day simulation that is separated into a five-member ensemble of 30-yr integrations. Tropical cyclones are shown to decrease in frequency globally by 9% in the 2CO2 and 26% in the 4CO2. Tropical cyclones only become more intense in the 4CO2; however, uncoupled time slice experiments reveal an increase in intensity in the 2CO2. An investigation into the large-scale environmental conditions, known to influence tropical cyclone activity in the main development regions, is used to determine the response of tropical cyclone activity to increased atmospheric CO2. A weaker Walker circulation and a reduction in zonally averaged regions of updrafts lead to a shift in the location of tropical cyclones in the Northern Hemisphere. A decrease in mean ascent at 500 hPa contributes to the reduction of tropical cyclones in the 2CO2 in most basins. The larger reduction of tropical cyclones in the 4CO2 arises from further reduction of the mean ascent at 500 hPa and a large enhancement of vertical wind shear, especially in the Southern Hemisphere, North Atlantic, and northeast Pacific.
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Fang, Wei, Wenhe Lu, Jiaxin Li, and Liyao Zou. "A Novel Tropical Cyclone Track Forecast Model Based on Attention Mechanism." Atmosphere 13, no. 10 (September 30, 2022): 1607. http://dx.doi.org/10.3390/atmos13101607.
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Tropical cyclones are one of the most powerful and destructive weather systems on Earth. Accurately forecasting the landing time, location and moving paths of tropical cyclones are of great significance to mitigate the huge disasters it produces. However, with the continuous accumulation of meteorological monitoring data and the application of multi-source data, traditional tropical cyclone track forecasting methods face many challenges in forecasting accuracy. Recently, deep learning methods have proven capable of learning spatial and temporal features from massive datasets. In this paper, we propose a new spatiotemporal deep learning model for tropical cyclone track forecasting, which adopts spatial location and multiple meteorological factors to forecast the tracks of tropical cyclones. The model proposes a multi-layer ConvGRU to extract the nonlinear spatial features of tropical cyclones, while Spatial and Channel Attention Mechanism (CBAM) is adopted to overcome the large-scale problem of high response isobaric surface affecting the tropical cyclones. Meanwhile, this model utilizes a Deep and Cross framework to combine the traditional CNN model with the multi-ConvGRU model. Experiments were conducted on the China Meteorological Administration Tropical Cyclone Best Track Dataset (CMA) from 2000 to 2020, and the EAR-Interim dataset provided by the European Centre for Medium-Range Weather Forecasts (ECMWF). The experimental results show that the proposed model is superior to the deep learning tropical cyclone forecasting methods.
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Serele, Charles, Michel Kouadio, and Francois Kayitakire. "Mitigating proximate impacts of tropical cyclone landfalls in the Southwest Indian Ocean." Western Indian Ocean Journal of Marine Science 22, no. 2 (December 20, 2023): 147–61. http://dx.doi.org/10.4314/wiojms.v22i2.11.
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The occurrence and impacts of tropical cyclones in the Southwest (SW) Indian Ocean were investigated over five cyclone seasons (November to April) between 2018/19 and 2022/23. Data describing cyclone characteristics, affected populations and economic losses from cyclone landfalls in Madagascar and Mozambique were extracted from the African Risk Capacity (ARC)’s Tropical Cyclone Explorer (TCE) software. Of 56 cyclones that formed in the region, 27 landfalls occurred with an average of 2.8 per season in Madagascar and 2.6 in Mozambique, mainly in January and February of each year. Most cyclone landfalls in Madagascar were categorized as moderate tropical storms (MTS, 43 %) and intense tropical cyclones (ITC, 22 %). In Mozambique, landfalls were mostly ITC (31 %) followed by MTS (23 %). Landfalls of very intense tropical cyclones (VITC) were more common in Mozambique (15 %) than Madagascar (7 %). An average of 1.8 million and 775,000 people per season were exposed to strong cyclone winds in Madagascar and Mozambique, respectively, with economic losses from cyclones per season averaging $544 million in Madagascar and $170 million in Mozambique. The African Risk Capacity (ARC), a specialized agency of the African Union, has implemented a parametric insurance solution to mitigate the proximate effects of cyclones damage on vulnerable populations. Four modules to estimate losses caused by cyclone events are described; the hazard-, vulnerability / damage-, - exposure- and insurance modules. Initial outcomes of the ARC’s parametric cyclone insurance policy in Madagascar and Mozambique are discussed. Since its launch in 2020, the ARC’s parametric cyclone insurance policy including its Replica partner allocated a total payout of $12.2 million to Madagascar following the landfalls of cyclones BATSIRAI in 2022 and FREDDY in 2023.
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Destantyo Nugroho, Anendha, and Nur Habib Muzaki. "Study of surface and vertical sea temperatures during the process of tropical cyclone formation in the territory of Indonesia (case study 2019-2021)." IOP Conference Series: Earth and Environmental Science 989, no. 1 (February 1, 2022): 012006. http://dx.doi.org/10.1088/1755-1315/989/1/012006.
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Abstract A tropical cyclone is an atmospheric phenomenon that has a system of low air pressure that forms over the oceans in the warm tropics. Tropical cyclones can form in oceans with sea surface temperatures above 26.5°C. In addition to the sea surface temperature which must be more than 26.5°C, the depth of warm sea water temperature strongly supports the formation of tropical cyclones in the territory of Indonesia. In this study, research was conducted on the surface and vertical temperatures of the sea during the formation of tropical cyclones or when cyclone seeds occurred in the case of tropical cyclones that occurred in 2019-2021 in the territory of Indonesia. The data used is processed using Ocean Data View 4.1 to determine the distribution of surface and vertical sea temperatures. Based on the results on this study, the vertical distribution of sea surface temperatures during the formation of tropical cyclones in Indonesia has an average sea temperature higher than 26.5°C which reaches a depth of 64 meters to 70 meters. Then the sea surface temperature during the tropical cyclone formation process averaged 28 °C to 29 °C.
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Lau, Yui-Yip, Tsz-Leung Yip, Maxim A. Dulebenets, Yuk-Ming Tang, and Tomoya Kawasaki. "A Review of Historical Changes of Tropical and Extra-Tropical Cyclones: A Comparative Analysis of the United States, Europe, and Asia." International Journal of Environmental Research and Public Health 19, no. 8 (April 8, 2022): 4499. http://dx.doi.org/10.3390/ijerph19084499.
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Tropical cyclones are highly destructive weather systems, especially in coastal areas. Tropical cyclones with maximum sustained winds exceeding 74 mph (≈119 kph) are classified as typhoons in the Northwest Pacific, whilst the term ‘hurricanes’ applies to other regions. This study aims to investigate the general characteristics of the most devastating and catastrophic tropical cyclones in the USA Europe, and Asia. To achieve the study objectives, the three most devastating typical tropical cyclones in each region were selected. The tropical cyclones were examined based on various features, such as the number of deaths, minimum pressure, highest wind speed, total financial losses, and frequency per year. In contrast to Europe and Asia, the USA has recorded the highest number of catastrophic tropical cyclones. The damage induced by hurricanes Katrina, Harvey, and Maria in the USA totalled approximately USD USD 380 billion. In addition, the present research highlights the demand to improve the public attitude and behaviour toward the impact of climate change along with the enhancement of climate change alleviation strategies. The number of intense tropical cyclones is expected to rise, and the tropical cyclone-related precipitation rate is expected to increase in warmer-climate areas. Stakeholders and industrial practitioners may use the research findings to design resilience and adaptation plans in the face of tropical cyclones, allowing them to assess the effects of climate change on tropical cyclone incidents from an academic humanitarian logistics viewpoint in the forthcoming years.
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Cheung, N. K. W. "The roles of ENSO on the occurrence of abruptly recurving tropical cyclones over the Western North Pacific Ocean Basin." Advances in Geosciences 6 (January 30, 2006): 139–48. http://dx.doi.org/10.5194/adgeo-6-139-2006.
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Abstract. The abruptly recurving tropical cyclones over the Western North Pacific Ocean Basin during El Niño and La Niña events are studied. Temporal and spatial variations of these anomalous tracks under different phases of ENSO are shown. The anomalies of the pressure field in relation to ENSO circulation for the occurrence of the abruptly recurving cyclone tracks are investigated using fuzzy method. These are supplemented by wind field analyses. It is found that the occurrence of recurving-left (RL) and recurving-right (RR) tropical cyclones under the modification of the steering currents, including the re-adjustment of the westerly trough, the expansion or contraction of the sub-tropical high pressure, the intensifying easterly flow and the strengthening of the cross-equatorial flow, can be in El Niño or La Niña events. Evidently, there is a higher chance of occurrence of anomalous tropical cyclone trajectories in El Niño rather than La Niña events, but there is not any pronounced spatial pattern of anomalous tropical cyclone tracks. By analyzing the pressure-field, it is seen RL (RR) tropical cyclones tend to occur when the subtropical high pressure is weak (strong) in El Niño and La Niña events. More importantly, how the internal force of tropical cyclones changed by the steering current, which relies upon the relative location of tropical cyclones to the re-adjustment of the weather systems, shows when and where RL and RR tropical cyclones occur in El Niño and La Niña events.
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Bousquet, Olivier, Guilhem Barruol, Emmanuel Cordier, Christelle Barthe, Soline Bielli, Radiance Calmer, Elisa Rindraharisaona, et al. "Impact of Tropical Cyclones on Inhabited Areas of the SWIO Basin at Present and Future Horizons. Part 1: Overview and Observing Component of the Research Project RENOVRISK-CYCLONE." Atmosphere 12, no. 5 (April 23, 2021): 544. http://dx.doi.org/10.3390/atmos12050544.
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The international research program “ReNovRisk-CYCLONE” (RNR-CYC, 2017–2021) directly involves 20 partners from 5 countries of the south-west Indian-Ocean. It aims at improving the observation and modelling of tropical cyclones in the south-west Indian Ocean, as well as to foster regional cooperation and improve public policies adapted to present and future tropical cyclones risk in this cyclonic basin. This paper describes the structure and main objectives of this ambitious research project, with emphasis on its observing components, which allowed integrating numbers of innovative atmospheric and oceanic observations (sea-turtle borne and seismic data, unmanned airborne system, ocean gliders), as well as combining standard and original methods (radiosoundings and global navigation satellite system (GNSS) atmospheric soundings, seismic and in-situ swell sampling, drone and satellite imaging) to support research on tropical cyclones from the local to the basin-scale.
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SINGH, DEVENDRA, R. C. BHATIA, and S. K. SRIVASTAVA. "Satellite analysis of tropical cyclones using NOAA-16 AMSU measurements over Indian region." MAUSAM 55, no. 1 (January 19, 2022): 149–54. http://dx.doi.org/10.54302/mausam.v55i1.962.
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The first Advanced Microwave Sounding Unit (AMSU) was launched aboard NOAA-15 satellite on 13 May 1998. AMSU measurements are now also available from NOAA-16 and NOAA-17 satellites. The AMSU is well suited for the observation of tropical cyclones because the ice clouds that cover tropical cyclones do not significantly affect its measurements. In this paper the intensity of three tropical cyclones formed over Bay of Bengal and Arabian Sea in the month of October 1999, May and September 2001 were studied using AMSU measurements. The upper tropospheric warm core thermal anomalies over the tropical cyclone areas were computed from temperature profiles using the NOAA-15 and NOAA-16 AMSU-A measurements. It has been observed that the magnitude of the warm core temperature anomaly at about 250 hPa was an indicator of the intensity of tropical cyclones in all three cases. The order of the temperature anomaly was about 6oC in case of super tropical cyclone, 1999 while in other two cases the order of the temperature anomaly were of about 3oC for moderate tropical cyclones, 2001. Therefore, it may be stated that the AMSU data appeared to offer substantial opportunities for improvements in tropical cyclone analysis and forecasting.
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Pham, Thi Thanh Hoa, Ba Thuy Nguyen, Van Huong Nguyen, and Van Khiem Mai. "Distribution characteristics of tropical cyclones affecting the Vietnam region during 1992–2022." Vietnam Journal of Marine Science and Technology 24, no. 4 (December 10, 2024): 335–48. https://doi.org/10.15625/1859-3097/21326.
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This research investigates the distribution characteristics of tropical cyclones affecting the Vietnam region, including the mainland and the East Vietnam Sea, from 1992 to 2022. The tropical cyclone activity showed an increasing trend, mainly in the numbers of tropical depressions and typhoons with the sustained maximum wind speed ranging from level 12 to 15 on the Beaufort Wind Scale; however, this trend did not meet the statistical 99% confidence level. The number of tropical cyclones directly affecting the mainland of Vietnam accounted for approximately 32%. Over the East Vietnam Sea, tropical cyclones presented a peak in September and a slump in February. Occurrence frequencies and probabilities were significantly high over the in-shore and off-shore regions from Quang Ninh to Phu Yen, over the North and Center of East Vietnam Sea, where the maximum frequencies could be 0.9 tropical cyclone/year over the Gulf of Tonkin higher than 1.1 tropical cyclone/year passing a grid of 1o longitude-latitude over the north East Vietnam Sea. Meanwhile, the southern offshore areas from Phu Yen - Ca Mau, Ca Mau - Kien Giang, and Thailand Gulf were less influenced by tropical cyclones. The frequency and probability of typhoons were below 0.1 tropical cyclone/year and 0.2%, respectively.
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Chen, Cheng, Lei Wang, Ruozhou Chen, Fangliang Xing, and Jun Chen. "Temporal-spatial characteristics and path analysis of maritime cyclones in Guangdong coastal areas in the South China Sea." Earth Sciences Research Journal 22, no. 4 (October 1, 2018): 319–25. http://dx.doi.org/10.15446/esrj.v22n4.77361.
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This study was conducted to analyze the maritime cyclone characteristics in Guangdong coast in the years of 1949 to 2016, including inter-annual variation, the intensity of tropical cyclones, generating location and time, and path direction. The temporal-spatial characteristics were also studied. Results show there were 183 tropical cyclones landed in Guangdong coast in the past 68 years, with an average of 2.7 each year, which more than 60 percent were a typhoon. Most of the tropical cyclones were generated in the northwest Pacific, spanning from April to December. The path directions were mainly north, northwest, and west. The strengths of the tropical cyclones were reduced from central Guangdong coast to the east and the west sides, and the section of Zhanjiang city to Shenzhen city was the most vulnerable to tropical cyclones. Tropical cyclones that generated in the South China Sea tend to attack the west of the Guangdong coast, while the ones that produced in the northwest Pacific tend to attack the east of the Guangdong coast. In the study area, the tropical cyclones frequently occurred from July to September and became strongest in September. There are a most common landing section and path direction for each month. Finally, based on the statistical data and research results, the tropical cyclone paths in Guangdong coast were preliminarily analyzed.
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Toman, Ivan, and Branko Grisogono. "Preliminarna analiza mogućeg slučaja jadranske ciklone tropskih karakteristika od 21. siječnja 2023." Hrvatski meteorološki časopis 56, no. 56 (June 10, 2024): 77–82. http://dx.doi.org/10.37982/hmc.56.1.5.
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This short article addresses a preliminary study of transient subsynoptic cyclonic behavior over a broader area of the Adriatic Sea. The January 2023 case presented here shows a transition from an extratropical Mediterranean cyclone into a partially tropical-like cyclonic system (TLC) over the south and central Adriatic Sea. The warm barotropic core, cyclonic “eye” and relatively symmetric precipitation bands around the vortex were the main TLC properties of this system. In the short analysis of the event, the assumption is made that size limitations of the Adriatic basin prevented development of the system into a full-strength “medicane”. Hence, such vigorous small-scale cyclones just might be named “adricanes”. Presentation of this case contributes to the relatively scarce research of these rare Adriatic TLC events. The criteria for cyclonic system classification as TLC or extra- tropical are also discussed, with the supporting idea of a spectrum between fully tropical and fully extratropical cyclones (instead of binary classification), where the particular system can fall anywhere in between, depending on the ratio of tropical and extratropical properties it possesses.
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Mauk, Rachel G., and Jay S. Hobgood. "Tropical Cyclone Formation in Environments with Cool SST and High Wind Shear over the Northeastern Atlantic Ocean*." Weather and Forecasting 27, no. 6 (December 1, 2012): 1433–48. http://dx.doi.org/10.1175/waf-d-11-00048.1.
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Abstract Tropical cyclones with nontropical characteristics are being identified more frequently over the North Atlantic Ocean in recent years. These systems present forecasting challenges because of their hybrid structure. The authors analyze environmental conditions preceding the formation of 20 late-season northeastern Atlantic tropical cyclones identified during the 1975–2005 seasons. A recent tropical storm, Grace (2009), is discussed as a case study. Seventeen of the 20 systems originated from nontropical systems (surface low, frontal weak, and frontal strong). Three tropical cyclones experienced nontropical influences during development despite originating from tropical waves. Ambient sea surface temperatures, relative vorticity, vertical temperature profiles, and wind shear are investigated to identify conditions conducive to tropical cyclone formation. Tropical cyclones developing from nontropical precursors form in environments distinct from the classical tropical cyclone environment. For 17 systems, sea surface temperatures are cooler than 26°C. Stability analysis suggests that convection is shallow. Wind shear decreases for the 850–300-hPa layer in comparison to the 850–200-hPa layer. Most systems still experience shear in excess of 8 m s−1 for the 850–300-hPa layer. It is suggested that late-season tropical cyclones in this region are shallower in vertical extent than typical tropical cyclones, which reduces the impact of strong wind shear in the 850–200-hPa layer.
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Khaldun, Muhammad Hafidz Ibnu, Yuli Naulita, and Alan Frendy Koropitan. "Percampuran Turbulen Di Tenggara Samudera Hindia Saat Siklon Tropis Marcus Menggunakan Data ARGO Float." Journal of Marine and Aquatic Sciences 6, no. 2 (December 23, 2020): 293. http://dx.doi.org/10.24843/jmas.2020.v06.i02.p17.
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Tropical cyclones are a phenomenon that occurs because of the interaction between oceans and atmospheric circulation. The southeastern Indian Ocean is one of the areas that has a high activity of tropical cyclones. Tropical cyclones that cross waters can result in mixing of water masses. The mixing process produces water mass entrainment between lower and upper layers which decreases temperature in the upper layer. The purpose of this study was to estimate the strength of turbulent mixing caused by tropical cyclones using Argo Float data. The result of this study shows the turbulent mixing caused by tropical cyclones was very strong in the surface layer. Turbulent mixing is not found before the cyclone and increases when the cyclone occurs. The increase in turbulent mixing was recorded at a depth of 50 m which had an energy dissipation value ranging from 6.86x10-8 - 1.93x10-4 W/Kg and a turbulent mixing value with a range of 1.0x10-3 - 2.51x10-1 m2 s-1. This study concluded that the turbulent mixing in the surface layer is caused by tropical cyclones which is the main factor triggering the increase in the dissipation of kinetic and turbulent energy at the sites.
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Conrado, Eduardo Traversi de Cai, Rosmeri Porfírio da Rocha, Michelle Simões Reboita, and Andressa Andrade Cardoso. "Cyclone Classification over the South Atlantic Ocean in Centenary Reanalysis." Atmosphere 15, no. 12 (December 21, 2024): 1533. https://doi.org/10.3390/atmos15121533.
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Since the beginning of the satellite era, only three tropical cyclones have been recorded over the South Atlantic Ocean. To investigate the potential occurrence of such systems since the 1900s, ERA20C, a centennial reanalysis, was utilised. This study first evaluates the performance of ERA20C in reproducing the climatology of all cyclone types over the southwestern South Atlantic Ocean by comparing it with a modern reanalysis (ERA5) for the period 1979–2010. Despite its simpler construction, ERA20C is able to reproduce key climatological features, such as frequency, location, seasonality, intensity, and thermal structure of cyclones similar to ERA5. Then, the Cyclone Phase Space (CPS) methodology was applied to determine the thermal structure at each time step for every cyclone between 1900 and 2010 in ERA20C. The cyclones were then categorised into different types (extratropical, subtropical, and tropical), and systems exhibiting a warm core at their initial time step were classified as tropical cyclogenesis. Between 1900 and 2010, 96 cases of tropical cyclogenesis were identified over the South Atlantic. Additionally, throughout the lifetime of all cyclones, a total of 1838 time steps exhibited a tropical structure, indicating that cyclones can acquire a warm core at different stages of their lifecycle. The coasts of southeastern and southern sectors of northeast Brazil emerged as the most favourable for cyclones with tropical structures during their lifecycle. The findings of this study highlight the occurrence of tropical cyclones in the South Atlantic prior to the satellite era, providing a foundation for future research into the physical mechanisms that enabled these events.
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Basheer Ahammed, K. K., Arvind Chandra Pandey, Bikash Ranjan Parida, Wasim, and Chandra Shekhar Dwivedi. "Impact Assessment of Tropical Cyclones Amphan and Nisarga in 2020 in the Northern Indian Ocean." Sustainability 15, no. 5 (February 22, 2023): 3992. http://dx.doi.org/10.3390/su15053992.
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The Northern Indian Ocean (NIO) is one of the most vulnerable coasts to tropical cyclones (TCs) and is frequently threatened by global climate change. In the year 2020, two severe cyclones formed in the NIO and devastated the Indian subcontinent. Super cyclone Amphan, which formed in the Bay of Bengal (BOB) on 15 May 2020, made landfall along the West Bengal coast with a wind speed of above 85 knots (155 km/h). The severe cyclone Nisarga formed in the Arabian Sea (ARS) on 1 June 2020 and made landfall along the Maharashtra coast with a wind speed above 60 knots (115 km/h). The present study has characterized both TCs by employing past cyclonic events (1982–2020), satellite-derived sea surface temperature (SST), wind speed and direction, rainfall dataset, and regional elevation. Long-term cyclonic occurrences revealed that the Bay of Bengal encountered a higher number of cyclones each year than the ARS. Both cyclones had different intensities when making landfall; however, the regional elevation played a significant role in controlling the cyclonic wind and associated hazards. The mountain topography on the east coast weakened the wind, while the deltas on the west coast had no control over the wind. Nisarga weakened to 30 knots (56 km/h) within 6 h from making landfall, while Amphan took 24 h to weaken to 30 knots (56 km/h). We analyzed precipitation patterns during the cyclones and concluded that Amphan had much more (1563 mm) precipitation than Nisarga (684 mm). Furthermore, the impact on land use land cover (LULC) was examined in relation to the wind field. The Amphan wind field damaged 363,837 km2 of land, whereas the Nisarga wind field affected 167,230 km2 of land. This research can aid in the development of effective preparedness strategies for disaster risk reduction during cyclone impacts along the coast of India.
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Dutta, B., B. Pathak, R. Hazarika, U. Bhattacharjee, S. Baruah, A. Kakoty, P. J. Sahu, et al. "Upper and Lower Atmosphere interaction during Tropical Cyclones." Journal of Physics: Conference Series 2957, no. 1 (February 1, 2025): 012022. https://doi.org/10.1088/1742-6596/2957/1/012022.
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Abstract Tropical Cyclones (TCs) are significant atmospheric phenomena in the earth’s lower atmosphere leading to interactions between various atmospheric layers as well as destroy lives and properties owing to associated extreme weather conditions. The densely populated coastal areas of India are worst affected by TCs attributed to the distinctive geo-climatic conditions. As such, the variations of the atmospheric parameters during four tropical cyclones occurring over Bay of Bengal (BoB), Andaman Sea and Arabian Sea: Gonu (Super cyclonic storm, 1st June, 2007 to 8th June, 2007), Hudhud (Extremely severe cyclonic storm, 7th October, 2014 to 14th October, 2014), Mora (Severe cyclonic storm, 28th May, 2017 to 31st May, 2017) and Ockhi (Very severe cyclonic storm, 29th November, 2017 to 4th December, 2017) have been investigated in this work to examine the upper and lower atmosphere interactions. The enhancement of Potential vorticity, followed by the downward propagation of Ozone Mixing Ratio (OMR) from lower stratosphere to the upper troposphere is noticed during Tropical cyclones. Further, anomalous depression in VTEC is also observed during the landfall of the cyclone under the geomagnetic quiet condition (Dst ≤ ±50). VTEC is reduced due to the effect of gravity waves instigated by the TC and neutral particles generated from the terminator of TCs and lightning electric fields. These simultaneous phenomena establish the Upper and Lower Atmosphere exchanges.
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Li, Jinxiao, Qing Bao, Yimin Liu, Lei Wang, Jing Yang, Guoxiong Wu, Xiaofei Wu, et al. "Effect of horizontal resolution on the simulation of tropical cyclones in the Chinese Academy of Sciences FGOALS-f3 climate system model." Geoscientific Model Development 14, no. 10 (October 12, 2021): 6113–33. http://dx.doi.org/10.5194/gmd-14-6113-2021.
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Abstract. The effects of horizontal resolution on the simulation of tropical cyclones were studied using the Chinese Academy of Sciences Flexible Global Ocean–Atmosphere–Land System Finite-Volume version 3 (FGOALS-f3) climate system model from the High-Resolution Model Intercomparison Project (HighResMIP) for the Coupled Model Intercomparison Project phase 6 (CMIP6). Both the low-resolution (about 100 km resolution) FGOALS-f3 model (FGOALS-f3-L) and the high-resolution (about 25 km resolution) FGOALS-f3 (FGOALS-f3-H) models were used to achieve the standard Tier 1 experiment required by HighResMIP. FGOALS-f3-L and FGOALS-f3-H have the same model parameterizations with the exactly the same parameters. The only differences between the two models are the horizontal resolution and the time step. The performance of FGOALS-f3-H and FGOALS-f3-L in simulating tropical cyclones was evaluated using observations. FGOALS-f3-H (25 km resolution) simulated more realistic distributions of the formation, movement and intensity of the climatology of tropical cyclones than FGOALS-f3-L at 100 km resolution. Although the number of tropical cyclones increased by about 50 % at the higher resolution and better matched the observed values in the peak month, both FGOALS-f3-L and FGOALS-f3-H appear to replicate the timing of the seasonal cycle of tropical cyclones. The simulated average and interannual variabilities of the number of tropical cyclones and the accumulated cyclone energy were both significantly improved from FGOALS-f3-L to FGOALS-f3-H over most of the ocean basins. The characteristics of tropical cyclones (e.g., the average lifetime, the wind–pressure relationship and the horizontal structure) were more realistic in the simulation using the high-resolution model. The possible physical linkage between the performance of the tropical cyclone simulation and the horizontal resolution were revealed by further analyses. The improvement in the response between the El Niño–Southern Oscillation and the number of tropical cyclones and the accumulated cyclone energy in FGOALS-f3 contributed to the realistic simulation of tropical cyclones. The genesis potential index and the vorticity, relative humidity, maximum potential intensity and the wind shear terms were used to diagnose the effects of resolution. We discuss the current insufficiencies and future directions of improvement for the simulation of tropical cyclones and the potential applications of the FGOALS-f3-H model in the subseasonal to seasonal prediction of tropical cyclones.
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Zhang, Wei. "Extreme Translation Events of Atlantic Tropical Cyclones." Atmosphere 12, no. 8 (August 12, 2021): 1032. http://dx.doi.org/10.3390/atmos12081032.
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Changes in the translational speed of tropical cyclones (e.g., sluggish tropical cyclones) are associated with extreme precipitation and flash flooding. However, it is still unclear regarding the spatial and temporal variability of extreme tropical cyclone translation events in the North Atlantic and underlying large-scale drivers. This work finds that the frequencies of extreme fast- and slow-translation events of Atlantic tropical cyclones exhibited a significant rising trend during 1980–2019. The extreme fast-translation events of Atlantic tropical cyclones are primarily located in the northern part of the North Atlantic, while the extreme slow-translation events are located more equatorward. There is a significant rising trend in the frequency of extreme slow-translation events over ocean with no trend over land. However, there is a significant rising trend in the frequency of extreme fast-translation events over ocean and over land. The extreme slow-translation events are associated with a strong high-pressure system in the continental United States (U.S.). By contrast, the extreme fast-translation events are related to a low-pressure system across most of the continental U.S. that leads to westerly steering flow that enhances tropical cyclone movement. This study suggests that it might be useful to separate tropical cyclone events into fast-moving and slow-moving groups when examining the translational speed of North Atlantic tropical cyclones, instead of examining regional or global mean translational speed.
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Reboita, Michelle Simões, Natan Chrysostomo de Oliveira Nogueira, Isabelly Bianca dos Santos Gomes, Lucas Lemos da Cunha Palma, and Rosmeri Porfírio da Rocha. "Assessment of a Tropical Transition over the Southwestern South Atlantic Ocean: The Case of Cyclone Akará." Journal of Marine Science and Engineering 12, no. 11 (October 29, 2024): 1934. http://dx.doi.org/10.3390/jmse12111934.
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Tropical cyclones are rare in the South Atlantic Ocean. Hurricane Catarina (2004), developed from a tropical transition, was the first documented case, followed by Iba (2019), which had a purely tropical genesis. In February 2024, the southeastern South Atlantic recorded its third tropical cyclone, Akará, initially a subtropical system. Due to the specific conditions required for tropical cyclones to develop in this ocean basin, the main purpose of this study is to describe the physical mechanisms that triggered the genesis of Akará’s precursor and its tropical transition. Data from various sources and methodologies, including the cyclone phase space diagram, are used in this study. Results show that the passage of a cold front created an environment with horizontal wind shear, contributing to most of the cyclonic relative vorticity in the genesis region. This was the primary driver of cyclogenesis at 1200 UTC on 15 February, along with other secondary processes. The tropical transition occurred as the vertical shear weakened, and turbulent heat fluxes from the ocean to the atmosphere increased, enhancing diabatic processes that warmed the atmosphere. This led to the tropical transition at 0600 UTC on 17 February.
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Xu, Jin, Xinyue Xue, Bo Yang, Wen Wang, Wenxiang Wu, and Xiaodong Ji. "Risk Assessment of Landfalling Tropical Cyclones in China Based on Hazard Risk Theory." Applied Sciences 14, no. 12 (June 12, 2024): 5126. http://dx.doi.org/10.3390/app14125126.
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As a frequent hazard, tropical cyclones have a great impact on the social and economic development of China, which is close to the origin of tropical cyclones in the western Pacific Ocean. The primary objective of this study was to construct a comprehensive risk assessment model for tropical cyclone hazards based on natural influencing factors, informing recommendations for hazard prevention and mitigation in affected regions. This research focused on tropical cyclones that made landfall in mainland China and Hainan from 1949 to 2023, utilizing hazard risk theory and classical extreme value theory. The wind speed and rainfall data during the peak cyclone periods (June to October) from 1997 to 2021 gathered from various meteorological stations, as well as altitude and vegetation cover data, were examined. Hierarchical analysis and ArcGIS spatial analysis methods were employed to study the characteristics of the spatiotemporal distribution of landfalling tropical cyclones and the comprehensive risk of tropical cyclone hazards, and the regions of China were delineated according to these methods. The results showed that, during the period from 1949 to 2023, the overall number of landfalling tropical cyclones decreased in a fluctuating manner, while the intensity of the cyclones increased. Furthermore, severe typhoons tended to occur more frequently in the summer than autumn with time, intensifying the challenge to resist short-term hazards. Moreover, the hazard-causing factors in areas affected by tropical cyclones displayed an increasing trend from north to south and from west to east. In detail, the regions sensitive to natural hazards were primarily located in the central part of Liaoning province, Tianjin, central and eastern Hebei province, Shandong province, eastern Henan province, central and northern Anhui province, Jiangsu province, and Shanghai, which are characterized by flat terrain and relatively low vegetation cover. Overall, the comprehensive risk of tropical cyclone hazards showed a geographical distribution that decreases from south to north and from east to west, with coastal cities in provinces such as Hainan, Guangdong, Guangxi, Fujian, and Zhejiang—including Haikou, Zhanjiang, Xiamen, Beihai, and Taizhou—exhibiting the highest levels of risk.
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Aberson, Sim D. "The Impact of Dropwindsonde Data from the THORPEX Pacific Area Regional Campaign and the NOAA Hurricane Field Program on Tropical Cyclone Forecasts in the Global Forecast System." Monthly Weather Review 139, no. 9 (September 2011): 2689–703. http://dx.doi.org/10.1175/2011mwr3634.1.
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Four aircraft released dropwindsondes in and around tropical cyclones in the west Pacific during The Observing System Research and Predictability Experiment (THORPEX) Pacific Area Regional Campaign (T-PARC) in 2008 and the Dropwindsonde Observations for Typhoon Surveillance near the Taiwan Region (DOTSTAR); multiple aircraft concurrently participated in similar missions in the Atlantic. Previous studies have treated each region separately and have focused on the tropical cyclones whose environments were sampled. The large number of missions and tropical cyclones in both regions, and additional tropical cyclones in the east Pacific and Indian Oceans, allows for the global impact of these observations on tropical cyclone track forecasts to be studied. The study shows that there are unintended global consequences to local changes in initial conditions, in this case due to the assimilation of dropwindsonde data in tropical cyclone environments. These global impacts are mainly due to the spectral nature of the model system. These differences should be small and slightly positive, since improved local initial conditions should lead to small global forecast improvements. However, the impacts on tropical cyclones far removed from the data are shown to be as large and positive as those on the tropical cyclones specifically targeted for improved track forecasts. Causes of this unexpected result are hypothesized, potentially providing operational forecasters tools to identify when large remote impacts from surveillance missions might occur.
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Chen, Tsing-Chang, Shih-Yu Wang, and Ming-Cheng Yen. "Interannual Variation of the Tropical Cyclone Activity over the Western North Pacific." Journal of Climate 19, no. 21 (November 1, 2006): 5709–20. http://dx.doi.org/10.1175/jcli3934.1.
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Abstract An effort was made to search for relationships between interannual variations of population, lifetime, genesis locations, and intensity of named typhoons and numbered tropical depressions in the western North Pacific during the 1979–2002 period. To support this research task, climatological relationships of tropical cyclone characteristics were also investigated for these cyclones. Major findings of this study are summarized as follows:Climatology: Measured by the intensity scale of the Japan Meteorological Agency, three groups of tropical cyclones were identified in terms of population versus intensity: Group 1 [tropical depression (TD) + typhoon (TY)], Group 2 (strong + very strong TY), and Group 3 (catastrophic TY). This group division coincides with that formed in terms of lifetime of tropical cyclones versus intensity. Weak cyclones (Group 1) have a larger population than strong cyclones (Group 3), while the former group has shorter lifetime than the latter group. For genesis locations, the monsoon trough is established as a favorable region of tropical cyclone genesis because it provides an environment of large vorticity. Therefore, the northward latitudinal displacement of the maximum genesis frequency in the three groups of tropical cyclones follows that of the monsoon trough.Interannual variation: Any mechanism that can modulate the location and intensity of the monsoon trough affects the genesis location and frequency of tropical cyclones. In response to tropical Pacific sea surface temperature anomalies, a short wave train consisting of east–west oriented cells emanates from the Tropics and progresses along the western North Pacific rim. Population of the Group-1 tropical cyclones varies interannually in phase with the oscillation of the anomalous circulation cell northeast of Taiwan and south of Japan in this short wave train, while that of Group 3 fluctuates coherently with the tropical cell of this short wave train. Because these two anomalous circulation cells exhibit opposite polarity, the out-of-phase interannual oscillation between these two cells results in the opposite interannual variation of genesis frequency between tropical cyclones of Groups 1 and 3.
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Wang, S. T., Y. X. Lin, W. J. Wang, B. Y. Zhang, and D. H. Zhang. "APPLICATION OF GROUND-BASED GPS WATER VAPOR DATA IN THE ANALYSIS OF TROPICAL CYCLONE SON-TINH HITTING HAINAN ISLAND." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-3/W10 (February 8, 2020): 1049–52. http://dx.doi.org/10.5194/isprs-archives-xlii-3-w10-1049-2020.
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Abstract. Tropical cyclone as a disaster. In addition to bringing abundant precipitation to the island, the huge wind will affect the public facilities in the island. In serious cases, it directly endangers people's lives and property. Every year, the disastrous damage caused by tropical cyclone causes direct or indirect economic losses to Hainan Island.This paper studies this problem. Based on the tropical cyclone data provided by China Typhoon Network and the information provided by GPS satellite observation data and 16 meteorological observatories in Hainan Island, this paper takes the monitoring of tropical cyclone Son-Tinh No. 9 in 2018 as an example to analyze the changes of meteorological elements and precipitation during the influence period of tropical cyclone. The results show that: The changes of atmospheric pressure, temperature and relative humidity at the stations are very obvious for the transit of tropical cyclones. When the island is affected by tropical cyclones, these parameters will change significantly. Among them, the abnormal changes of atmospheric pressure and temperature can effectively express the time and extent of the influence of tropical cyclone. It can be used as one of the important indicators to judge tropical cyclone before and after landfall. Based on these obvious changes, the influence of the parameters of tropical cyclone Son-Tinh before and after landing on Hainan Island is analyzed. It can effectively analyze the disasters caused by tropical cyclones and provide some reference information.
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He, Hailun, Ruizhen Tian, Xinyan Lyu, Zheng Ling, Jia Sun, and Anzhou Cao. "Annual Review of In Situ Observations of Tropical Cyclone–Ocean Interaction in the Western North Pacific during 2023." Remote Sensing 16, no. 11 (May 31, 2024): 1990. http://dx.doi.org/10.3390/rs16111990.
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We present a review of in situ observations regarding the interactions between tropical cyclones and the ocean in the western North Pacific for the year 2023. A total of at least 13 tropical cyclones occurred during this period. According to the Japan Meteorological Agency, Typhoon Mawar recorded the yearly minimum pressure at 900 hPar. On average, each tropical cyclone captured 7.4 surface drifters and 25.2 Argo floats when the search radius is 300 km. During Guchol, the maximum in situ Lagrangian current reached 1.23 m/s, with sustained wind speeds of the tropical cyclone up to 31.7 m/s and a relative position of 174 km. Additionally, several Argo floats were active during tropical cyclones, with maximum sea surface temperature cooling reaching 0.66 °C. This annual review provides a comprehensive summary of the current state of in situ observations regarding tropical cyclone–ocean interaction. These findings serve as valuable references for both scientific research and operational forecasting.
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Lin, Szu Yu, Paul L. C. Chua, Lei Yuan, Nasif Hossain, Jinyu He, Lisa Yamasaki, Lina Madaniyazi, Chris Fook Sheng Ng, Aurelio Tobias, and Masahiro Hashizume. "A scoping review and thematic analysis of the effects of tropical cyclones on diarrheal diseases." Environmental Epidemiology 9, no. 1 (January 9, 2025): e366. https://doi.org/10.1097/ee9.0000000000000366.
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Background: Tropical cyclones pose significant health risks and can trigger outbreaks of diarrheal diseases in affected populations. Although the effects of individual hazards, such as rainfall and flooding, on diarrheal diseases are well-documented, the complex multihazard nature of tropical cyclones is less thoroughly explored. To date, no dedicated review comprehensively examines the current evidence and research on the association between tropical cyclones and diarrheal diseases. Methods: We performed a scoping review to map the literature on tropical cyclones and diarrheal diseases. A comprehensive literature search was performed across multiple online databases, including PubMed/MEDLINE, Web of Science, Scopus, Google Scholar, and ProQuest. We then performed a thematic analysis on the specific transmission pathways between tropical cyclones and diarrheal diseases as described in the literature. Results: A total of 96 studies were included and categorized in this scoping review. Of these, 23 studies quantitatively assessed the association between tropical cyclones and diarrheal diseases, with more than half reporting a positive association. Additionally, we identified 30 studies that detailed transmission pathways, which we used for thematic analysis. Significant variability was observed in the definition of tropical cyclone exposure, with studies using different criteria such as an event, wind speed, or rainfall. Most studies used pre-post comparison designs without concurrent control groups, which can introduce limitations affecting internal validity by not accounting for temporal confounders. Diarrheal diseases can either increase or decrease during and after tropical cyclones, depending on the specific pathogens and the different strengths of tropical cyclones. Conclusion: The variability in exposure definitions and study designs impedes the ability to quantitatively pool evidence. To improve the comparability and reliability of future research, we recommend that studies explore how different tropical cyclone exposure definitions impact results to identify the most appropriate metrics. We also suggest adopting more robust study designs, such as difference-in-difference or controlled interrupted time series for studying single tropical cyclone events, and case-crossover designs for studying multiple events. Additionally, studies examining specific causal pathways, such as integrating environmental sampling with health outcomes, should be explored to identify effective prevention strategies.
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Sánchez-Rivera, Gabriel, and Leticia Gómez-Mendoza. "Tropical cyclone effects on vegetation resilience in the Yucatan Peninsula, México, between 2000-2012." Investigaciones Geográficas, no. 77 (January 26, 2022): 203. http://dx.doi.org/10.14198/ingeo.18499.
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The resilience capacity of vegetation in the Yucatan Peninsula is influenced by the winds and rains of tropical cyclones. There are no recent long-term studies on cyclonic impacts on natural vegetation in the region despite their significant effects on infrastructure and biodiversity. The objective of this study was to identify the area impacted by 21 tropical cyclones between 2000 and 2012 and to quantify the recovery capacity of the vegetation by using standardized anomalies of the normalized vegetation index (aNDVI). MODIS images from NASA’s “Terra and Aqua” satellites were used to calculate the damaged areas by analyzing the frequency of pixels corresponding to each type of vegetation per impact zone. The results showed that in 67% of the tropical cyclones, the impacts on vegetation were negative —a decrease in aNDVI—but in 33% of the cyclones, positive effects were recorded —an increase in aNDVI—. The lapse rate of vegetation recovery varied in 52% of the cases; vegetation recovered between two and three weeks after each cyclonic event, while 38% of the cases recovered within four to five weeks of the cyclone landfall. Tropical forests suffered the most significant effects, followed by hydrophilic vegetation. The most destructive hurricanes were Emily, Wilma, and Dean. The rate of recovery laps ranged from 4 to 10 weeks after the hurricane hit. The results could improve assessments of vegetation vulnerability against severe hydrometeorological events and establish priority zones for prompt inspection.
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Evans, Clark, and Robert E. Hart. "Analysis of the Wind Field Evolution Associated with the Extratropical Transition of Bonnie (1998)." Monthly Weather Review 136, no. 6 (June 1, 2008): 2047–65. http://dx.doi.org/10.1175/2007mwr2051.1.
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Abstract Extratropical transition brings about a number of environmentally induced structural changes within a transitioning tropical cyclone. Of particular interest among these changes is the acceleration of the wind field away from the cyclone’s center of circulation along with the outward movement of the radial wind maximum, together termed wind field expansion. Previous informal hypotheses aimed at understanding this evolution do not entirely capture the observed expansion, while a review of the literature shows no formal work done upon the topic beyond analyzing its occurrence. This study seeks to analyze the physical and dynamical mechanisms behind the wind field expansion using model simulations of a representative transition case, North Atlantic Tropical Cyclone Bonnie of 1998. The acceleration of the wind field along the outer periphery of the cyclone is found to be a function of the net import of absolute angular momentum within the cyclone’s environment along inflowing trajectories. This evolution is shown to be a natural outgrowth of the development of isentropic conveyor belts and asymmetries associated with extratropical cyclones. Asymmetries in the outer-core wind field manifest themselves via the tightening and development of height and temperature gradients within the cyclone’s environment. Outward movement of the radial wind maximum occurs coincident with integrated net cooling found inside the radius of maximum winds. Tests using a secondary circulation balance model show the radial wind maximum evolution to be similar yet opposite to the response noted for intensifying tropical cyclones with contracting eyewalls.
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Schreck, Carl J., John Molinari, and Karen I. Mohr. "Attributing Tropical Cyclogenesis to Equatorial Waves in the Western North Pacific." Journal of the Atmospheric Sciences 68, no. 2 (February 1, 2011): 195–209. http://dx.doi.org/10.1175/2010jas3396.1.
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Abstract Tropical cyclogenesis is attributed to an equatorial wave when the filtered rainfall anomaly exceeds a threshold value at the genesis location. It is argued that 0 mm day−1 (simply requiring a positive anomaly) is too small a threshold because unrelated noise can produce a positive anomaly. A threshold of 6 mm day−1 is too large because two-thirds of storms would have no precursor disturbance. Between these extremes, consistent results are found for a range of thresholds from 2 to 4 mm day−1. Roughly twice as many tropical cyclones are attributed to tropical depression (TD)-type disturbances as to equatorial Rossby waves, mixed Rossby–gravity waves, or Kelvin waves. The influence of the Madden–Julian oscillation (MJO) is even smaller. The use of variables such as vorticity and vertical wind shear in other studies gives a larger contribution for the MJO. It is suggested that its direct influence on the rainfall in forming tropical cyclones is less than for other variables. The impacts of tropical cyclone–related precipitation anomalies are also presented. Tropical cyclones can contribute more than 20% of the warm-season rainfall and 50% of its total variance. The influence of tropical cyclones on the equatorial wave spectrum is generally small. The exception occurs in shorter-wavelength westward-propagating waves, for which tropical cyclones represent up to 27% of the variance. Tropical cyclones also significantly contaminate wave-filtered rainfall anomalies in their immediate vicinity. To mitigate this effect, the tropical cyclone–related anomalies were removed before filtering in this study.
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Sinclair, Victoria A., Mika Rantanen, Päivi Haapanala, Jouni Räisänen, and Heikki Järvinen. "The characteristics and structure of extra-tropical cyclones in a warmer climate." Weather and Climate Dynamics 1, no. 1 (January 3, 2020): 1–25. http://dx.doi.org/10.5194/wcd-1-1-2020.
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Abstract. Little is known about how the structure of extra-tropical cyclones will change in the future. In this study aqua-planet simulations are performed with a full-complexity atmospheric model. These experiments can be considered an intermediate step towards increasing knowledge of how, and why, extra-tropical cyclones respond to warming. A control simulation and a warm simulation in which the sea surface temperatures are increased uniformly by 4 K are run for 11 years. Extra-tropical cyclones are tracked, cyclone composites created, and the omega equation applied to assess causes of changes in vertical motion. Warming leads to a 3.3 % decrease in the number of extra-tropical cyclones, with no change to the median intensity or lifetime of extra-tropical cyclones but to a broadening of the intensity distribution resulting in both more stronger and more weaker storms. Composites of the strongest extra-tropical cyclones show that total column water vapour increases everywhere relative to the cyclone centre and that precipitation increases by up to 50 % with the 4 K warming. The spatial structure of the composite cyclone changes with warming: the 900–700 hPa layer averaged potential vorticity, 700 hPa ascent, and precipitation maximums associated with the warm front all move polewards and downstream, and the area of ascent expands in the downstream direction. Increases in ascent forced by diabatic heating and thermal advection are responsible for the displacement, whereas increases in ascent due to vorticity advection lead to the downstream expansion. Finally, maximum values of ascent due to vorticity advection and thermal advection weaken slightly with warming, whereas those attributed to diabatic heating increase. Thus, cyclones in warmer climates are more diabatically driven.
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Yen-Chu Chen, Delia, Kevin K. W. Cheung, and Cheng-Shang Lee. "Some Implications of Core Regime Wind Structures in Western North Pacific Tropical Cyclones." Weather and Forecasting 26, no. 1 (February 1, 2011): 61–75. http://dx.doi.org/10.1175/2010waf2222420.1.
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Abstract In this study, a tropical cyclone (TC) is considered to be compact if 1) the radius of maximum wind or the maximum tangential wind is smaller than what would be expected for an average tropical cyclone of the same intensity or the same radius of maximum wind, and 2) the decrease of tangential wind outside the radius of maximum wind is greater than that of an average TC. A structure parameter S is defined to provide a quantitative measure of the compactness of tropical cyclones. Quick Scatterometer (QuikSCAT) oceanic winds are used to calculate S for 171 tropical cyclones during 2000–07. The S parameters are then used to classify all of the cases as either compact or incompact according to the 33% and 67% percentiles. It is found that the early intensification stage is favorable for the occurrence of compact tropical cyclones, which also have a higher percentage of rapid intensification than incompact cases. Composite infrared brightness temperature shows that compact tropical cyclones have highly axisymmetric convective structures with strong convection concentrated in a small region near the center. Low-level synoptic patterns are important environmental factors that determine the degree of compactness; however, it is believed that compact tropical cyclones maintain their structures mainly through internal dynamics.
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Haryanto, Yosafat Donni, Nelly Florida Riama, Dendi Rona Purnama, and Aurel Dwiyana Sigalingging. "The Effect of the Difference in Intensity and Track of Tropical Cyclone on Significant Wave Height and Wave Direction in the Southeast Indian Ocean." Scientific World Journal 2021 (March 3, 2021): 1–11. http://dx.doi.org/10.1155/2021/5492048.
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This study aims to analyze the effect of the differences in intensity and track of tropical cyclones upon significant wave heights and direction of ocean waves in the southeast Indian Ocean. We used the tropical cyclone data from Japan Aerospace Exploration Agency (JAXA) starting from December 1997 to November 2017. The significant wave height and wave direction data are reanalysis data from Copernicus Marine Environment Monitoring Service (CMEMS), and the mean sea level pressure, surface wind speed, and wind direction data are reanalysis data from European Center for Medium-Range Weather Forecasts (ECMWF) from December 1997 to November 2017. The results show that the significant wave height increases with the increasing intensity of tropical cyclones. Meanwhile, the direction of the waves is influenced by the presence of tropical cyclones when tropical cyclones enter the categories of 3, 4, and 5. Tropical cyclones that move far from land tend to have higher significant wave height and wider affected areas compared to tropical cyclones that move near the mainland following the coastline
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Faranda, D., G. Messori, P. Yiou, S. Thao, F. Pons, and B. Dubrulle. "Dynamical footprints of hurricanes in the tropical dynamics." Chaos: An Interdisciplinary Journal of Nonlinear Science 33, no. 1 (January 2023): 013101. http://dx.doi.org/10.1063/5.0093732.
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Hurricanes—and more broadly tropical cyclones—are high-impact weather phenomena whose adverse socio-economic and ecosystem impacts affect a considerable part of the global population. Despite our reasonably robust meteorological understanding of tropical cyclones, we still face outstanding challenges for their numerical simulations. Consequently, future changes in the frequency of occurrence and intensity of tropical cyclones are still debated. Here, we diagnose possible reasons for the poor representation of tropical cyclones in numerical models, by considering the cyclones as chaotic dynamical systems. We follow 197 tropical cyclones which occurred between 2010 and 2020 in the North Atlantic using the HURDAT2 and ERA5 data sets. We measure the cyclones instantaneous number of active degrees of freedom (local dimension) and the persistence of their sea-level pressure and potential vorticity fields. During the most intense phases of the cyclones, and specifically when cyclones reach hurricane strength, there is a collapse of degrees of freedom and an increase in persistence. The large dependence of hurricanes dynamical characteristics on intensity suggests the need for adaptive parametrization schemes which take into account the dependence of the cyclone’s phase, in analogy with high-dissipation intermittent events in turbulent flows.