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Dissertations / Theses on the topic 'Tropical Cyclone'
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1
Budzko, David C. "North Pacific tropical cyclones and teleconnections." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2005. http://handle.dtic.mil/100.2/ADA432435.
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Blackerby, Jason S. "Accuracy of Western North Pacific tropical cyclone intensity guidance /." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2005. http://library.nps.navy.mil/uhtbin/hyperion/05Mar%5FBlackberry.pdf.
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Vogl, Stefanie. "Tropical Cyclone Boundary-Layer Models." Diss., lmu, 2009. http://nbn-resolving.de/urn:nbn:de:bvb:19-102740.
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Fu, Bing. "An observational analysis of tropical cyclogenesis in the Western North Pacific." Thesis, University of Hawaii at Manoa, 2003. http://hdl.handle.net/10125/7030.
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Stenger, Robert A. "Assessment of tropical cyclone structure variability." Thesis, Monterey, California: Naval Postgraduate School, 2013. http://hdl.handle.net/10945/37723.
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Approved for public release; distribution is unlimitedThe landfall of large hurricanes in densely populated areas has increased the awareness that tropical cyclone struc-ture plays an important role in the destructive potential of a storm. A unique set of H*Wind analyses of Atlantic tropical cyclones during the 2003-2005 seasons is studied to better understand the internal and external mechanisms that lead to significant variability in surface wind structure. Secondary eyewall formation, asymmetric convection, land interaction, and environmental vertical wind shear were generally found to be mechanisms for radius of maximum wind increases, intensity decreases, and size of the radius of 34-kt wind increases. Two modes of size changes were documented that may lead to 100 km increases in 12-24 h, or near-zero size changes when a sharper than average outer wind structure profi les are generated. The statistical relationships among the radius of maximum wind, intensity, and outer-core wind structure from this sample may provide perturbed vortex initial conditions for an ensemble model to predict structure changes.
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Ramstrom, William D. (William Douglas). "Tropical cyclone momentum and energy fluxes." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/59095.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2001.Includes bibliographical references (leaves 82-84).
Many modeling studies of tropical cyclones use the bulk aerodynamic formulae to determine angular momentum and enthalpy fluxes at the sea surface. These results show that the intensification of a hurricane is very sensitive to the values of the coefficients defined in these formulae (Emanuel, 1995). Using these formulae allows the model to make bulk estimates of these fluxes as a function of wind speed, without having to consider the full complexity of the physics of the air-sea interface. Generally, a complete treatment of fluxes would require modeling a number of small-scale physical processes, e.g. wave field response to the duration and fetch of the wind, sea spray processes, and convective stability of the boundary layer. The coefficients to these equations, Cd and Ck, have been empirically determined in previous studies, either by direct measurements on platforms and ships (Large and Pond, 1981), or by budget analyses from airborne data. However, these studies do not provide results for the high winds speeds encountered in strong hurricanes. Previous work has suggested that the coefficients do not remain constant, but rather are a function of wind speed. Producing values for these coefficients at high wind speeds will improve the accuracy of the numerical models. Recent advances in dropsonde technology (Hock and Franklin, 1999) provide improved range and accuracy from earlier methods, with reliable measurements of wind and thermodynamic variables down to within 10m of the surface. Three cases of strong hurricanes have been selected for this study, allowing analysis of these coefficients for conditions with up to 65 ms- 1 surface winds. The values of the drag coefficient, Cd, are demonstrated to reach a maximum value at about hurricane force, then maintain that value with higher wind speeds. The values of Ck, the heat flux coefficient, do not show variation with wind speed. These coefficients are calculated both at the standard 10m, so that they may be compared with existing literature, and at the top of the boundary layer, so that models which do not explicitly resolve the physics of the boundary layer may nonetheless make use of this data. The budget calculations in this study have shown that the 10m drag coefficient has a value of 0.0026 to 0.0030 for wind speeds in the 40-60 ms- 1 range. Eddy fluxes of total energy and entropy are also shown to be significant. With this effect added, budget calculations have shown that the 10m enthalpy transfer coefficient ranges from 0.0029 to 0.0036 under these conditions for Floyd and Georges. Thus, the ratio of Ck/Cd is slightly larger than 1.0. At the gradient wind level, Cd is 0.0019 ± 0.0010 and Ck is approximately 0.0018.
by William Douglas Ramstrom.
S.M.
7
Sippel, Jason Allen. "The multiple vortex nature of tropical cyclogenesis." Texas A&M University, 2004. http://hdl.handle.net/1969.1/1424.
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This thesis contains an observational analysis of the genesis of Tropical Storm Allison (2001). Using a paradigm of tropical cyclone formation as the superposition of potential vorticity (PV) anomalies, the importance of different scales of PV merger to various aspects of Allisons formation is discussed. While only the case of Allison is discussed in great detail, other studies have also documented PV superposition on various scales, and superposition could be important for most tropical cyclones. Preceding Allisons genesis, PV superposition on the large scale destabilized the atmosphere and increased low-level cyclonic vorticity. This presented a more favorable environment for the formation of MCV-type PV anomalies and smaller, surface-based, meso-β-scale vortices. Although these vortices eventually merged to form a more concentrated vortex with stronger surface pressure gradients, the merger happened well after landfall of Allison and no strengthening ensued. The unstable, vorticity-rich environment was also favorable for the development of even smaller, meso-γ-scale vortices that accompanied deep convective cells within one of Allisons meso-β-scale vortices. The observations herein suggest that the meso-γ- scale convective cells and vortices are the respective source of PV production and building blocks for the meso-β-scale vortices. Finally, this thesis discusses issues related to the multiple vortex nature of tropical cyclone formation. For instance, the tracking of developing tropical cyclones is
greatly complicated by the presence of multiple vortices. For these cases, the paradigm of a single cyclone center is inappropriate and alternative tracking methods are
introduced.
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Zhu, Hongyan. "A minimal three-dimensional tropical cyclone model." Diss., [S.l. : s.n.], 2002. http://edoc.ub.uni-muenchen.de/archive/00000260/.
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Shin, Seol Eun. "Convective instability changes and tropical cyclone intensification." Diss., lmu, 2007. http://nbn-resolving.de/urn:nbn:de:bvb:19-72966.
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Sherman, Brett T. "Synoptic patterns related to tropical cyclone recurvature/." Thesis, Monterey, California. Naval Postgraduate School, 1988. http://hdl.handle.net/10945/23131.
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Relative vorticity fields calculated from the U. S. Navy operational Global Band Analysis are used to relate synoptic and storm parameters to the track of tropical cyclones in the western North Pacific Ocean. In this preliminary study, synoptic patterns are developed, described and discussed from the perspective of a pattern recognition technique to assist the forecasters at the Joint Typhoon Warning Center, Guam. The focus is on track turning motions to the left and right of the persistence track and on trying to accurately predict the point of the turn or recurvature in relation to the time evolution of the vorticity patterns. The developmental sample of storms indicates that there is potential for using synoptic patterns in the Global Band Analysis to guide the selection of the appropriate track aid in the 48-60 hour time range. (Author)
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Tang, Brian Hong-An. "Midlevel ventilation's constraint on tropical cyclone intensity." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/62321.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2010.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (p. 185-195).
Midlevel ventilation, or the flux of low-entropy air into the inner core of a tropical cyclone (TC), is a hypothesized mechanism by which environmental vertical wind shear can constrain a TC's intensity. An idealized framework is developed to assess how ventilation affects TC intensity via two pathways: downdrafts outside the eyewall and eddy fluxes directly into the eyewall. Three key aspects are found: ventilation has a detrimental effect on TC intensity by decreasing the maximum steady state intensity, imposing a minimum intensity below which a TC will unconditionally decay, and providing an upper ventilation bound beyond which no steady TC can exist. Based on the idealized framework, a ventilation index is derived that is equal to the environmental vertical wind shear times the midlevel entropy deficit divided by the potential intensity. The ventilation index has a strong influence on the present-day climatology of tropical cyclogenesis and the distribution of TC intensification. Additionally, changes in the ventilation index are also examined in general circulation models (GCMs) between the late 20th century and the late 22nd century. Individual GCMs indicate potential regional shifts in preferred locations of tropical cyclogenesis and changes in TC intensity statistics due to shifts in the seasonal ventilation index, but a statistically significant projection cannot be given. The GCMs do show a robust increase in the midlevel entropy deficit and potential intensity nearly everywhere in the tropics. Lastly, an axisymmetric model with parameterized ventilation is used to examine the sensitivity of TC intensity to the strength and location of the ventilation and to examine the findings of the idealized framework. Increasing the strength of the ventilation and placing the ventilation at lower to middle levels results in a greater decrease in the quasi-steady intensity, whereas upper-level ventilation has little effect on the intensity. For strong ventilation, an oscillatory intensity regime materializes and is tied to transient convective bursts and strong downdrafts into the boundary layer. The sensitivity of TC intensity to ventilation can be viewed in the context of a modified thermal wind relation or the fractional Carnot efficiency of the inner-core.
by Brian Hong-An Tang.
Ph.D.
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Tao, Cheng. "Climatology of overshootings in tropical cyclones and their roles in tropical cyclone intensity changes using TRMM data." FIU Digital Commons, 2015. http://digitalcommons.fiu.edu/etd/2457.
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The climatology of overshooting convection in tropical cyclones (TCs) is examined using Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR). The percentage of TC convective systems with overshooting convection is highest over the North Indian Ocean basin, while the northwest Pacific basin contains the highest population of both TC convective systems and convection with overshooting tops. Convective systems in the inner core region are more capable of penetrating 14 km and the associated overshooting convection are featured with much stronger overshooting properties compared with those in the inner rainband and outer rainband regions. In the inner core region of TCs, convection associated with precipitating systems of higher intensity and intensification rates has a larger probability of containing overshooting tops.
To identify the relative importance of shallow/moderate versus deep/very deep convection in the rapid intensification (RI) of TCs, four types of precipitation-convection are defined based on the 20 dBZ radar echo height (Z20dBZ). Distributions of four types of precipitation-convection, and their contributions to total volumetric rain and total latent heating are quantified. It is shown that RI is closely associated with increased and widespread shallow precipitation around the storm center, while moderately deep and very deep convection (or overshooting convection) does not increase until in the middle of RI. This is further confirmed by the study of rainfall and convection evolution with respect to the timeline of RI events. Statistically, the onset of RI follows a significant increase in the areal coverage of rainfall, shallow precipitation, and cyan of 37 GHz color composites upshear-left, which in turn could be used as potential parameters to forecast RI. Very deep convection is most frequent 12-24 hours before RI onset and concentrates upshear-left, but it quickly decreases in the following 24 hours. The percent occurrence of very deep convection is less than 1% for RI storms. The tilt of vortex is large prior to, and near the RI onset, but rapidly decreases in the middle of RI, suggesting that the vertical alignment is a result instead of a trigger of RI.
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Spollen, Rachael A. "Meteorological and model traits knowledge bases for North Indian Ocean tropical cyclones." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2002. http://library.nps.navy.mil/uhtbin/hyperion-image/02sep%5FSpollen.pdf.
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Thesis (M.S. in Meteorology and Physical Oceanography)--Naval Postgraduate School, September 2002.Thesis advisor(s): Russell L. Elsberry, Patrick A. Harr, Mark A. Boothe. Includes bibliographical references (p. 119-120). Also available online.
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Dorics, Theodore G. "An assessment of NOGAPS performance in the prediction of tropical Atlantic circulation formation." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2002. http://library.nps.navy.mil/uhtbin/hyperion-image/02Jun%5FDorics.pdf.
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Ford, Debra M. "Forecasting tropical cyclone recurvature using an empirical othogonal [sic] function representation of vorticity fields." Thesis, Monterey, California : Naval Postgraduate School, 1990. http://handle.dtic.mil/100.2/ADA238489.
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Thesis (M.S. in Meteorology and Oceanography)--Naval Postgraduate School, September 1990.Thesis Advisor(s): Elsberry, Russell L. ; Harr, Patrick A. "September 1990." Description based on title screen as viewed on December 16, 2009. DTIC Identifier(s): EOF (empirical orthogonal functions). Author(s) subject terms: Tropical cyclones, recurvature, empirical orthogonal functions. Includes bibliographical references (p. 73-74). Also available in print.
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Schmidt, Christoph Wolf Dieter Jakob. "Tropical-cyclone evolution in a minimal axisymmetric model." Diss., lmu, 2011. http://nbn-resolving.de/urn:nbn:de:bvb:19-134427.
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Jones, Colin G. "Tropical cyclone forecasting with a limited area model." Thesis, University of East Anglia, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386034.
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Kastelein, Bryce. "VULNERABILITY TO TROPICAL CYCLONE RELATED MORTALITIES ON HISPANIOLA." Kent State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=kent1416264208.
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Kieu, Chanh Q. "Theoretical and numerical studies of tropical cyclone development." College Park, Md.: University of Maryland, 2008. http://hdl.handle.net/1903/8597.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2008.Thesis research directed by: Dept. of Atmospheric and Oceanic Sciences. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Petty, Kevin R. "The effects of synoptic factors on the intensities of tropical cyclones over the eastern North Pacific Ocean." The Ohio State University, 1997. http://catalog.hathitrust.org/api/volumes/oclc/39803779.html.
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Evans, Allen Clark. "The thermodynamic evolution of recurving Tropical Cyclone Bonnie (1998)." Tallahassee, Florida : Florida State University, 2009. http://etd.lib.fsu.edu/theses/available/etd-08102009-004539/.
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Thesis (Ph. D.)--Florida State University, 2009.Advisor: Robert E. Hart, Florida State University, College of Arts and Sciences, Dept. of Meteorology. Title and description from dissertation home page (viewed on May 25, 2010). Document formatted into pages; contains xvi, 117 pages. Includes bibliographical references.
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Ulses, Greg A. "Statistical post-processing of NOGAPS tropical cyclone track forecasts." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1998. http://handle.dtic.mil/100.2/ADA345053.
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Thesis (M.S. in Meteorology and Physical Oceanography) Naval Postgraduate School, March 1998."March 1998." Thesis advisor(s): Russell L. Elsberry. Includes bibliographical references (p. 63-64). Also available online.
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Woll, Stephen C. "Short term teleconnections associated with an individual tropical cyclone." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1993. http://handle.dtic.mil/100.2/ADA277210.
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Thesis (M.S. in Meteorology and Physical Oceanography) Naval Postgraduate School, December 1993.Thesis advisor(s): Murphree, James Thomas. "December 1993." Bibliography: p. 74-76. Also available online.
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Finta, Christopher A. "Observations of mesoscale convective systems during tropical cyclone genesis." Monterey, California. Naval Postgraduate School, 1997. http://hdl.handle.net/10945/8757.
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Approved for public release; distribution is unlimitedA better understanding of the role mesoscale convective systems (MCS) play in the formation stages of tropical cyclones will increase the ability to predict their occurrence and motion. This thesis employs high-resolution satellite imagery to observe the interaction between MCSs and their environment. Specifically, thirteen cases of tropical disturbances that eventually developed into tropical cyclones are analyzed to determine the role of MCSs in increasing the system organization. Following two conceptual models developed during the Tropical Cyclone Motion (TCM-93) mini-field experiment, each tropical cyclone is classified according to the relative importance of MCS activity to its development. Both conceptual models are verified through analysis and a third model is created to account for tropical cyclone developments that share features of the previous two models. An alternate approach is proposed for determining tropical system organization using only visible and infrared satellite imagery
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Jakus, Craig E. "The remote impacts of a Western Pacific tropical cyclone." Thesis, Monterey, California. Naval Postgraduate School, 1995. http://hdl.handle.net/10945/7568.
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The short term teleconnections arising from an individual tropical cyclone in tne western Pacific (typhoon Seth, October 1994) were examined using an operational global data assimilation system and numerical weather prediction model. During the data assimilation, the model's initial conditions were modified using a tropical cyclone bogusing procedure that either maintained or eliminated the individual storm. These different initial conditions were used in six extended-range forecasts of about 3.5 weeks duration. Three of these forecasts simulated the atmosphere with tne tropical cyclone and three without the storm. The ensemble average differences between the forecasts with the storm and those without it were used to infer the global teleconnection response to the tropical cyclone. This response was dominated by a strong and persistent Rossby wave train that extended from east Asia across the North Pacific into North America. This wave train was initiated when an anticyclonic circulation formed near Japan as the tropical cyclone approached the east Asian jet. The anticyclone formation was primarily the result of two factors: (1) vortex stretching; and (2) absolute vorticity advection as divergent outflow from the tropical cyclone crossed the large absolute vorticity gradient of the east Asian jet. The wave response was quasi-stationary. However, the basic wave train (i.e., the teleconnection pattern) developed within a week due to a relatively rapid eastward propagation of wave energy across the North Pacific and North America. In regions of strong jet flow, this propagation tended to parallel the flow while in regions of weaker flow, the propagation had stronger poleward or equatorward components. The wave train intensified well after the tropical cyclone and the initial wave formation process had dissipated.
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Lantz, Stephen W. "Incorporation of tropical cyclone avoidance into automated ship scheduling." Thesis, Monterey, California: Naval Postgraduate School, 2014. http://hdl.handle.net/10945/42670.
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Approved for public release; distribution is unlimitedThe U.S. Navy’s Combat Logistics Force (CLF) provides at-sea resupply to U.S. and allied vessels throughout the world. The CLF scheduling system anticipates demand and schedules 45 days in advance to meet that demand. Tropical cyclones (TCs) frequently disrupt these plans, requiring diversions and inefficient steaming speeds. We evaluate the impact of adding anticipated TC positions in an operational planning tool called the Replenishment At Sea Planner. Various scenarios are used to test the impact of different geographic representations of the TC obstacle in CLF operational planning. Open-ocean scenarios explore TC impact in ocean crossings, with no limitations caused by land masses, while near-shore scenarios examine the pinching effect of TC landfall. Shorter distances are traveled by CLF ships in the scenarios when the TC obstacle is forecasted, but the present position is excluded. The recommended TC representation is the 24-hour advanced position, with no extended duration. This representation produces the shortest total travel distances for both the open-ocean and near-shore scenarios.
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Shedd, Sandra Michael. "Tropical cyclone precipitation risk in the Southern United States." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/98676.
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Thesis: S.M. in Climate Physics and Chemistry, Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2015.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 81-83).
This thesis works to evaluate the new rainfall algorithm that is used to simulate longterm tropical cyclone precipitation (TCP) climatology throughout the southeastern United States. The TCP climatology is based on a fleet of synthetic tropical cyclones developed using National Center for Atmospheric Research/National Centers for Environmental Prediction reanalysis data from 1980 to 2010 and the Coupled Hurricane Intensity Prediction System (CHIPS) model. The climatology is compared to hourly rainfall estimates from the WSR-88D Next Generation Weather Radar (NEXRAD-II) system. In general the synthetic TCP estimates show good agreement with radar-based observations. The rainfall algorithm appears to perform better at coastal locations versus inland ones, and in general has better agreement in the eastern locations considered in this study. In addition, the spatial dependence of radar rainfall estimates was addressed, and in general more extreme TCP-events exhibited a greater degree of event total precipitation variation at grid box-scale. Finally, preliminary work incorporating streamflow measurements as a metric for assessing TCP risk using the synthetic rainfall climatology was begun. Correlation between both grid box-specific and basin-average radar-based event TCP and surface streamflow measurements (from the U.S. Geological Survey National Water Information System) varied greatly, and was generally moderate, and future work should incorporate more thorough streamflow modeling in order to evaluate these comparisons.
by Sandra Michael Shedd.
S.M. in Climate Physics and Chemistry
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Murphy, Maurice D. "Tropical cyclone preparedness and response : opportunities for operations research." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/45397.
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Thesis (S.M.)--Massachusetts Institute of Technology, Sloan School of Management, Operations Research Center, 2008.Includes bibliographical references (p. 79-87).
This thesis explores how operations research methods can be applied in the emergency response community by looking at two recent tropical storm disasters; tropical cyclone Yemyin in Pakistan, June 2007 and super typhoon Durian in the Philippines, Nov 2006. The case studies are used to highlight three common problem areas; determining the scope of the disaster, agency coordination, and relief logistics. The thesis identifies some operational models and applicable research and suggests that these ideas should be formulated as emergency management decision making tools particularly for use in the developing world.
by Maurice D. Murphy.
S.M.
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Luitel, Beda Nidhi. "Prediction of North Atlantic tropical cyclone activity and rainfall." Thesis, University of Iowa, 2016. https://ir.uiowa.edu/etd/2113.
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Among natural disasters affecting the United States, North Atlantic tropical cyclones (TCs) and hurricanes are responsible for the highest economic losses and are one of the main causes of fatalities. Although we cannot prevent these storms from occurring, skillful seasonal predictions of the North Atlantic TC activity and associated impacts can provide basic information critical to our improved preparedness. Unfortunately, it is not yet possible to predict heavy rainfall and flooding associated with these storms several months in advance, and the lead time is limited to few days at the most. On the other hand, overall North Atlantic TC activity can be potentially predicted with a six- to nine-month lead time.
This thesis focuses on the evaluation of the skill in predicting basin-wide North Atlantic TC activity with a long lead time and rainfall with a short lead time. For the seasonal forecast of TC activity, we develop statistical-dynamical forecasting systems for different quantities related to the frequency and intensity of North Atlantic TCs using only tropical Atlantic and tropical mean sea surface temperatures (SSTs) as covariates. Our results show that skillful predictions of North Atlantic TC activity are possible starting from November for a TC season that peaks in the August-October months.
The short term forecasting of rainfall associated with TC activity is based on five numerical weather prediction (NWP) models. Our analyses focused on 15 North Atlantic TCs that made landfall along the U.S. coast over the period of 2007-2012. The skill of the NWP models is quantified by visual examination of the distribution of the errors for the different lead-times, and numerical examination of the first three moments of the error distribution. Based on our results, we conclude that the NWP models can provide skillful forecasts of TC rainfall with lead times up to 48 hours, without a consistently best or worst NWP model.
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Fenlason, Joel W. "Accuracy of tropical cyclone induced winds using TYDET at Kadena AB." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2006. http://library.nps.navy.mil/uhtbin/hyperion/06Mar%5FFenlason.pdf.
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Bower, Caroline A. "Prediction of tropical cyclone formation in the western North Pacific using the Navy global model." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Mar%5FBower.pdf.
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Thesis (M.S. in Meteorology)--Naval Postgraduate School, March 2004.Thesis advisor(s): Patrick A. Harr, Russell L. Elsberry. Includes bibliographical references (p. 117-118). Also available online.
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Malvig, Steven C. "Analysis of a non-developing tropical circulation system during the Tropical Cyclone Structure (TCS08) field experiment." Thesis, Monterey, California : Naval Postgraduate School, 2009. http://edocs.nps.edu/npspubs/scholarly/theses/2009/Dec/09Dec%5FMalvig.pdf.
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Thesis (M.S. in Meteorology and Oceanography)--Naval Postgraduate School, December 2009.Thesis Advisor: Harr, Patrick. Second Reader: Elsberry, Russell. "December 2009." Description based on title screen as viewed on January 27, 2010. Author(s) subject terms: Electra Doppler Radar (ELDORA), Tropical Cyclone Structure (TCS08), TCS08, tropical cyclone formation, Tropical Circulation System (TCS), TCS025. Includes bibliographical references (p. 75-76). Also available in print.
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Fisher, Michael Robert. "Western North Pacific tropical cyclone wind structure and structure changes." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1996. http://handle.dtic.mil/100.2/ADA319513.
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Thesis (M.S. in Meteorology and Physical Oceanography) Naval Postgraduate School, September 1996.Thesis advisor(s): Russell L. Elsberry, Lester E. Carr III. "September 1996." Includes bibliographical references (p. 39). Also available online.
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Kelley, Owen A. "The association of tall eyewall convection with tropical cyclone intensification." Fairfax, VA : George Mason University, 2008. http://hdl.handle.net/1920/3073.
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Thesis (Ph.D.)--George Mason University, 2008.Vita: p. 320. Thesis director: Michael Summers. Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Computational Sciences and Informatics. Title from PDF t.p. (viewed July 3, 2008). Includes bibliographical references (p. 291-319). Also issued in print.
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Klima, Kelly. "Does Tropical Cyclone Modification Make Sense? A Decision Analytic Perspective." Research Showcase @ CMU, 2011. http://repository.cmu.edu/dissertations/101.
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Recent dramatic increases in damages caused by tropical cyclones (TCs) and improved understanding of TC physics have led the Department of Homeland Security to fund research on intentional hurricane modification. Here I present a decision analytic assessment of whether hurricane modification is potentially cost effective in South Florida.
First, for a single storm I compare hardening buildings to lowering the wind speed of a TC by reducing sea surface temperatures with wind-wave pumps. I find that if it were feasible and properly implemented, modification could reduce net wind losses from an intense storm more than hardening structures. However, hardening provides "fail safe" protection for average storms that might not be achieved if the only option were modification. The effect of natural variability is larger than that of either strategy.
Second, for multiple storms over a given return period, I investigate TC wind and storm surge damage reduction by hardening buildings and by wind-wave pumps. The coastal areas examined experience more surge damages for short return periods, and more wind damages for long periods. Surge damages are best reduced through a surge barrier. Wind damages are best reduced by a portfolio of techniques including wind-wave pumps, assuming they work and are correctly deployed. Damages in areas outside of the floodplain will likely be dominated by wind damages, and hence a similar portfolio will likely be best in these areas.
Since hurricane modification might become a feasible strategy for reducing hurricane damages, to facilitate an informed and constructive discourse on implementation, policy makers need to understand how people perceive hurricane modification. Therefore using the mental models approach, I identified Florida residents’ perceptions of hurricane modification techniques. First, hurricane modification was perceived as a relatively ineffective strategy for damage reduction. Second, hurricane modification was expected to lead to changes in path, but not necessarily strength. Third, reported anger at hurricane modification was weaker when path was unaltered and the damages equal to or less than projected. Fourth, individuals who recognized the uncertainty inherent in hurricane prediction reported more anger at scientists across modification scenarios.
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Chen, Sue. "Modeling interaction of a tropical cyclone with its cold wake." Thesis, Monterey, California: Naval Postgraduate School, 2014. http://hdl.handle.net/10945/43889.
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Approved for public release; distribution is unlimitedThis dissertation examines the tropical cyclone (TC) intensity response to its cold wake first with five idealized cold wakes using an uncoupled version of the Coupled Ocean/Atmosphere Mesoscale Modeling System for Tropical Cyclone (COAMPS-TC) and then with simulated cold wakes from the coupled version. These simulations reveal a new dynamical pathway induced by the ocean cold wake that acts in concert with the conventional thermodynamic pathway to modulate the TC structure and intensity change. Wakes with a long trailing part or an irregular shape below the eyewall region force a dynamic response that tends to offset the negative feedback effect of reduced enthalpy flux. In particular, a low-level jet-like feature referred to as the wake jet is found at the top of the atmospheric boundary layer above the trailing cold wake. Significant wake cooling underneath the eye also tends to damp the vorticity gradient in the eyewall region, which forces the eyewall to transition from an unstable ring vortex to a stable Rankine-like vortex.
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Chavas, Daniel Robert. "Tropical cyclone size in observations and in radiative-convective equilibrium." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/82308.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2013.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 147-154).
Tropical cyclone size remains an unsolved problem in tropical meteorology, yet size plays a significant role in the damage caused by tropical cyclones due to wind, storm surge, and inland freshwater flooding. This work explores size, defined as the radius of vanishing wind, in observations and at equilibrium in an idealized numerical model. First, a climatology of size is created from the QuikSCAT database of near-surface wind vectors for the years 1999-2008. Globally, the distribution of the outer radius is found to be log-normal, with statistically significant variation across ocean basins, but with minimal correlation with various dynamic and thermodynamic parameters. Second, the sensitivity of the structure of a numerically-simulated axisymmetric tropical cyclone at statistical equilibrium to the set of relevant model, initial, and environmental external parameters is explored. The analysis is performed in a highly-idealized state of radiative-convective equilibrium (RCE). The non-dimensional equilibrium radial wind profile is found to be modulated primarily by a single nondimensional parameter given by the ratio of the storm radial length scale to the parameterized eddy radial length scale. The relevant storm length scale is shown to be the ratio of the potential intensity to the Coriolis parameter, matching the prediction for the "natural" storm length scale in prevailing axisymmetric tropical cyclone theory. The outer storm circulation is further modulated by a second non-dimensional parameter that represents the non-dimensional Ekman suction rate. Third, size is explored in three-dimensional "tropical cyclone world" simulations, with preliminary results confirming the relevant length scale obtained in axisymmetry. Ultimately, the results of the equilibrium storm analysis are insufficient to explain the observed distribution of tropical cyclone size, but they provide the first steps toward a more fundamental understanding of the dynamics of size.
by Daniel Robert Chavas.
Ph.D.
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Yu, Bo. "Surface Mean Flow and Turbulence Structure in Tropical Cyclone Winds." FIU Digital Commons, 2007. http://digitalcommons.fiu.edu/etd/25.
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Hurricanes are one of the deadliest and costliest natural hazards affecting the Gulf coast and Atlantic coast areas of the United States. An effective way to minimize hurricane damage is to strengthen structures and buildings. The investigation of surface level hurricane wind behavior and the resultant wind loads on structures is aimed at providing structural engineers with information on hurricane wind characteristics required for the design of safe structures. Information on mean wind profiles, gust factors, turbulence intensity, integral scale, and turbulence spectra and co-spectra is essential for developing realistic models of wind pressure and wind loads on structures. The research performed for this study was motivated by the fact that considerably fewer data and validated models are available for tropical than for extratropical storms. Using the surface wind measurements collected by the Florida Coastal Monitoring Program (FCMP) during hurricane passages over coastal areas, this study presents comparisons of surface roughness length estimates obtained by using several estimation methods, and estimates of the mean wind and turbulence structure of hurricane winds over coastal areas under neutral stratification conditions. In addition, a program has been developed and tested to systematically analyze Wall of Wind (WoW) data, that will make it possible to perform analyses of baseline characteristics of flow obtained in the WoW. This program can be used in future research to compare WoW data with FCMP data, as gust and turbulence generator systems and other flow management devices will be used to create WoW flows that match as closely as possible real hurricane wind conditions. Hurricanes are defined as tropical cyclones for which the maximum 1-minute sustained surface wind speeds exceed 74 mph. FCMP data include data for tropical cyclones with lower sustained speeds. However, for the winds analyzed in this study the speeds were sufficiently high to assure that neutral stratification prevailed. This assures that the characteristics of those winds are similar to those prevailing in hurricanes. For this reason in this study the terms tropical cyclones and hurricanes are used interchangeably.
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Wallace, Kenneth A. "A probabilistic approach to Tropical Cyclone Conditions of Readiness (TCCOR)." Thesis, Monterey, Calif. : Naval Postgraduate School, 2008. http://edocs.nps.edu/npspubs/scholarly/theses/2008/Sept/08Sep%5FWallace.pdf.
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Thesis (M.S. in Meteorology and Oceanography)--Naval Postgraduate School, September 2008.Thesis Advisor(s): Harr, Patrick. "September 2008." Description based on title screen as viewed on November 4, 2008. Includes bibliographical references (p. 47-48). Also available in print.
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Masters, Forrest James. "Measurement, modeling and simulation of ground-level tropical cyclone winds." [Gainesville, Fla.] : University of Florida, 2004. http://purl.fcla.edu/fcla/etd/UFE0005860.
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Long, Dana Marie. "Excitation of Low-Level Energy Wave Accumulations and Tropical Cyclone Formation." Thesis, Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7282.
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A spectral shallow water model is used at the 850 mb level to investigate the effects of cyclonic vorticity on heating in the lower troposphere and how this in turn causes an increase in cyclonic vorticity generation, creating a nonlinear vorticity feedback mechanism.
The model is initialized with NCEP-NCAR reanalysis data from the period 1990-2003 and then used to simulate a heating forcing function centered in east Africa. The model is simulated using a Gaussian damped basic state, a zonally symmetric basic state, and a zero basic state. The heating forcing function is applied to these different basic states with a scaled mass sink to simulate heating in the atmosphere. The heating forcing function creates a vorticity feedback mechanism that increases cyclonic vorticity.
The analysis of these different basic states shows that the Gaussian damped basic state reduces the amplitude of the observational fields at the poles, increases the observational fields in the tropical region and increases the stability of the model at shallow depths. The zero basic state does have a significant effect on cyclonic vorticity generation, but does not improve the capability of the wave to propagate westward into the Atlantic Ocean. The zonally symmetric basic state succeeds in increasing the amount of cyclonic vorticity generated. The zonally symmetric basic state, once the vorticity non-feedback region is extended, is also very effective at increasing the amount of cyclonic vorticity generated and increasing the propagation of this wave westward into the Atlantic Ocean. The analysis suggests that the vorticity feedback mechanism created by the heating forcing function is affected by cyclonic vorticity when a zero and zonally symmetric basic state are used.
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Hoarau, Thomas. "Couplage aérosols-microphysique pour la simulation des cyclones tropicaux : Cas du cyclone Dumile (2013)." Thesis, La Réunion, 2018. http://www.theses.fr/2018LARE0012/document.
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La prévision de l'intensité des cyclones tropicaux est aujourd'hui un enjeu scientifique majeur. Parmi de nombreux facteurs multi-échelle, l'impact de la microphysique nuageuse et des aérosols sur les variations d'intensité a été récemment mis en évidence. Cette problématique a motivé l'évaluation du schéma microphysique à 2-moments LIMA en milieu tropical et le développement d'un couplage avec le schéma d'aérosols ORILAM au sein du modèle atmosphérique Meso-NH. L'intérêt de ce développement numérique est d'inclure l'émission des aérosols marins en fonction des vents cycloniques et des paramètres océaniques. L'application de ce couplage aérosols-microphysique à la simulation du cyclone tropical Dumile (2013) montre que le modèle couplé tend à améliorer la représentation de l'intensité, la trajectoire, la structure microphysique du cyclone tropical et les précipitations associées, en comparaison avec les observations. La production secondaire des cristaux de glace est également un thème de recherche actif en microphysique nuageuse. Ainsi, une paramétrisation du processus de rupture collisionnelle de la glace a été implémentée dans le schéma microphysique LIMA. L'impact de ce processus a été testé sur le développement d'un orage des moyennes latitudes et sur le cyclone tropical Dumile. Les deux cas d'étude ont des réponses similaires vis-à-vis de ce processus : une augmentation de la concentration et de la masse des cristaux de glace et une diminution des cumuls de précipitations. La poursuite de ces travaux pourrait permettre de déterminer si ce processus de formation secondaire peut améliorer la modélisation de la couverture cirriforme des cyclones tropicauxIntensity forecast of tropical cyclones is a major scientific issue. Among many factors, the impact of cloud microphysics and aerosols on intensity variations has been recently underlined. This issue motivated the evaluation of the 2-moment microphysical scheme LIMA in a tropical context and the development of a coupling with the aerosol scheme ORILAM into the atmospheric model Meso-NH. The interest of this numerical development is to represent the emission of sea salt aerosols depending on cyclonic winds and oceanic parameters. The application of this aerosols-microphysics coupling to the simulation of tropical cyclone Dumile (2013) shows that the coupled model tends to improve the representation of the intensity, the track, the microphysical structure of the tropical cyclone and the associated precipitation, when comparing with observations. The secondary production of ice crystals is also an active research topic in cloud microphysics. A parameterization of the collisional ice break-up process is thus implemented into the microphysical scheme LIMA. The impact of this process has been analyzed on a mid-latitude storm and on tropical cyclone Dumile. Both case studies display similar results regarding this process: an increase of ice crystals concentration and mass, and a decrease of precipitation. The continuation of this work could allow to determine if this process of secondary formation could improve the cirrus modelling in tropical cyclones
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zhu, zhenduo. "Mechanisms Governing the Eyewall Replacement Cycle in Numerical Simulations of Tropical Cyclones." FIU Digital Commons, 2014. http://digitalcommons.fiu.edu/etd/1389.
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Eyewall replacement cycle (ERC) is frequently observed during the evolution of intensifying Tropical Cyclones (TCs). Although intensely studied in recent years, the underlying mechanisms of ERC are still poorly understood, and the forecast of ERC remains a great challenge. To advance our understanding of ERC and provide insights in improvement of numerical forecast of ERC, a series of numerical simulations is performed to investigate ERCs in TC-like vortices on a f-plane. The simulated ERCs possess key features similar to those observed in real TCs including the formation of a secondary tangential wind maximum associated with the outer eyewall. The Sawyer-Eliassen equation and tangential momentum budget analyses are performed to diagnose the mechanisms underlying the secondary eyewall formation (SEF) and ERC. Our diagnoses reveal crucial roles of outer rainband heating in governing the formation and development of the secondary tangential wind maximum and demonstrate that the outer rainband convection must reach a critical strength relative to the eyewall before SEF and the subsequent ERC can occur. A positive feedback among low-level convection, acceleration of tangential winds in the boundary layer, and surface evaporation that leads to the development of ERC and a mechanism for the demise of inner eyewall that involves interaction between the transverse circulations induced by eyewall and outer rainband convection are proposed. The tangential momentum budget indicates that the net tendency of tangential wind is a small residual resultant from a large cancellation between tendencies induced by the resolved and sub-grid scale (SGS) processes. The large SGS contribution to the tangential wind budget explains different characteristics of ERC shown in previous numerical studies and poses a great challenge for a timely correct forecast of ERC. The sensitivity experiments show that ERCs are strongly subjected to model physics, vortex radial structure and background wind. The impact of model physics on ERC can be well understood with the interaction among eyewall/outer rainband heating, radilal inflow in the boundary layer, surface layer turbulent processes, and shallow convection in the moat. However, further investigations are needed to fully understand the exhibited sensitivities of ERC to vortex radial structure and background wind.
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Updike, Aaron Jeffrey. "A Modeling Study of the Principal Rainband in Hurricane Matthew (2016) and the Influence of Remote Terrain on Hurricane Structure During its Intensification in the Southern Caribbean." Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/90391.
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Hurricane Matthew (2016) was a category 5 hurricane that interacted with remote terrain over northern South America in the early stages of its life cycle. Because tropical cyclone (TC) precipitation and convection are known to be crucial factors in the understanding and forecasting of TC intensity, this study investigates how this terrain impacted Hurricane Matthew's rainband structure. Remote terrain is hypothesized to play a role in the strength of TC rainband convection by modifying the thermodynamic environment such that subsiding dry air advects over an extremely moist ocean surface layer leading to increased moist static instability. To investigate this hypothesis, this study utilizes the Advanced Research Weather and Research Forecasting Model (WRF-ARW) to create a high-resolution (2-km horizontal grid spacing) control simulation (CTL) of Hurricane Matthew and a second experimental simulation with a 50% reduction of terrain height over the topography of northern South America (T50). This study focuses on a particular convective rainband positioned downstream of the terrain that displayed prolonged robust convection during the initial stages of Hurricane Matthew's life cycle. Results indicate that characteristics of this robust rainband are consistent with prior research on an inner core rainband called a principal rainband. This rainband does not display differences in intensity in the two simulations but is located closer to the TC center and more persistent in the control simulation. In the region downstream of the topography, significantly (p < 0.05) drier conditions exist in the control simulation, which is consistent with the hypothesis that downslope motion would lead to a drier air mass. TC structural changes are also apparent, with a weaker TC in the reduced topography simulation. This research emphasizes the potentially important role of terrain distant from the TC center with possible influences on TC rainband convection and warm core structure. Conclusions of this research are limited due to the small sample size of a single case study. An ensemble modeling study and additional cases are needed for a more thorough conclusion on the impact of remote terrain on TC structure.Master of Science
Predicting the intensity of hurricanes remains a monumental challenge for hurricane forecasters. Many factors can influence the intensity of hurricanes, including the strength, frequency, and spatial distribution of hurricane rainbands (band of precipitation). The hypothesis for this study is that terrain distant from the hurricane center can alter the hurricane environment and cause more frequent and stronger rainbands to form. To assess this hypothesis, I use a weather model to simulate Hurricane Matthew (2016) while it was interacting with remote terrain over northern South America on September 30 - October 1, 2016. Then I use the same model, but with terrain height reduced by 50% over northern South America and analyze the similarities and differences in the hurricane structure and rainband patterns. The results of this study suggest that terrain did not alter the peak rain rates in the hurricane rainbands but may have caused more frequent, widespread, and prolonged precipitation. Also, differences in hurricane structure were apparent when comparing the two model simulations. The reduced terrain simulation produced a weaker hurricane, lending some evidence to support the hypothesis that terrain may have played a role in altering the hurricane structure. These results demonstrate the potential importance of distant terrain on forecasting hurricane precipitation and intensity.
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Suzuki-Parker, Asuka. "An assessment of uncertainties and limitations in simulating tropical cyclone climatology and future changes." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/41062.
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The recent elevated North Atlantic hurricane activity has generated considerable interests in the interaction between tropical cyclones (TCs) and climate change. The possible connection between TCs and the changing climate has been indicated by observational studies based on historical TC records; they indicate emerging trends in TC frequency and intensity in some TC basins, but the detection of trends has been hotly debated due to TC track data issues. Dynamical climate modeling has also been applied to the problem, but brings its own set of limitations owing to limited model resolution and uncertainties.
The final goal of this study is to project the future changes of North Atlantic TC behavior with global warming for the next 50 years using the Nested Regional Climate Model (NRCM). Throughout the course of reaching this goal, various uncertainties and limitations in simulating TCs by the NRCM are identified and explored.
First we examine the TC tracking algorithm to detect and track simulated TCs from model output. The criteria and thresholds used in the tracking algorithm control the simulated TC climatology, making it difficult to objectively assess the model's ability in simulating TC climatology. Existing tracking algorithms used by previous studies are surveyed and it is found that the criteria and thresholds are very diverse. Sensitivity of varying criteria and thresholds in TC tracking algorithm to simulated TC climatology is very high, especially with the intensity and duration thresholds. It is found that the commonly used criteria may not be strict enough to filter out intense extratropical systems and hybrid systems. We propose that a better distinction between TCs and other low-pressure systems can be achieved by adding the Cyclone Phase technique.
Two sets of NRCM simulations are presented in this dissertation: One in the hindcasting mode, and the other with forcing from the Community Climate System Model (CCSM) to project into the future with global warming. Both of these simulations are assessed using the tracking algorithm with cyclone phase technique.
The NRCM is run in a hindcasting mode for the global tropics in order to assess its ability to simulate the current observed TC climatology. It is found that the NRCM is capable of capturing the general spatial and temporal distributions of TCs, but tends to overproduce TCs particularly in the Northwest Pacific. The overpredction of TCs is associated with the overall convective tendency in the model added with an outstanding theory of wave energy accumulation leading to TC genesis. On the other hand, TC frequency in the tropical North Atlantic is under predicted due to the lack of moist African Easterly Waves. The importance of high-resolution is shown with the additional simulation with two-way nesting.
The NRCM is then forced by the CCSM to project the future changes in North Atlantic TCs. An El Nino-like SST bias in the CCSM induced a high vertical wind shear in tropical North Atlantic, preventing TCs from forming in this region. A simple bias correction method is applied to remove this bias. The model projected an increase both in TC frequency and intensity owing to enhanced TC genesis in the main development region, where the model projects an increased favorability of large-scale environment for TC genesis. However, the model is not capable of explicitly simulating intense (Category 3-5) storms due to the limited model resolution. To extrapolate the prediction to intense storms, we propose a hybrid approach that combines the model results and a statistical modeling using extreme value theory. Specifically, the current observed TC intensity is statistically modeled with the General Pareto distribution, and the simulated intensity changes from the NRCM are applied to the statistical model to project the changes in intense storms. The results suggest that the occurrence of Category 5 storms may be increased by approximately 50% by 2055.
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Samson, Guillaume. "Modélisation de la réponse océanique à un cyclone tropical et de sa rétroaction sur l'atmosphère." Toulouse 3, 2009. http://www.theses.fr/2009TOU30339.
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Les cyclones tropicaux dépendent fortement de l'océan superficiel dont ils extraient l'énergie thermique nécessaire à leur maintient. Ils cèdent en contrepartie une part importante de leur énergie cinétique à l'océan sous la forme de courants. La sensibilité de la réponse océanique à la vitesse de déplacement d'un cyclone idéalisé ext examinée. Les bilans de température et d'énergie cinétique de la couche mélangée mettent en évidence un mécanisme de résonnance entre les vents du cyclone et les courants dans la couche mélangée. Ils révèlent également pour les cyclones lents une forte interaction avec l'upwelling créé par la divergence des courants. La rétroaction de l'océan sur les cyclones est ensuite explorée avec l'étude du cyclone Ivan dans le bassin Indien sud-ouest. L'utilisation d'un modèle couplé permet de déterminer le rôle de l'océan sur l'évolution des flux de chaleur en surface, de la convection et de l'intensité du cyclone.
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Pei, Yongxian. "Quantification of Precipitation Asymmetries in Tropical Cyclones and Their Relationship to Storm Intensity Changes Using TRMM Data." FIU Digital Commons, 2017. https://digitalcommons.fiu.edu/etd/3548.
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The climatology of precipitation asymmetries in Tropical Cyclones (TCs) and their relationship to TC intensity changes using 16 years of data from the Tropical Rainfall Measuring Mission (TRMM) satellite. TC Inner core precipitation asymmetries were quantified using the Fourier wavenumber decomposition method upon the pixel level data of 3,542 TRMM TMI overpasses. Composites of wavenumber–1 and wavenumber 1–6 total precipitation asymmetries were constructed to show the distribution pattern under different storm motion speed, vertical wind shear and the combined effects of varying vertical wind shear and storm motion. Results indicate that motion–relative total precipitation asymmetry is located down–motion. The phase of motion–relative maximum asymmetry shifts cyclonically by adding the wavenumber–2–6 asymmetry to wavenumber–1. Shear is more dominant than motion on the distribution of precipitation asymmetry. The analysis of combined effects of motion and shear shows when shear is weak, and shear is to the left of motion, the precipitation asymmetry is explained more by storm motion. The main contributor to the general asymmetry pattern is from the moderate and heavy precipitation. The wavenumber 2–6 energy localizes the maximum heavy precipitation asymmetry.
The quantified wavenumber 1–6 asymmetries is also applied to differentiate between different intensity change categories and the asymmetry evolution of a rapidly intensifying storm. The precipitation asymmetry properties of rapid intensification (RI) and non–RI storms are examined. The dataset of 2,186 global tropical storms through category 2 hurricanes is divided by future 24–h intensity change and includes storms with at least moderately favorable environmental conditions. The normalized wavenumber 1–6 asymmetries, indicates quantitatively that the lower asymmetry of precipitation is most strongly correlated with future intensity change. The precipitation field of non–RI storms are more asymmetric than RI storms. The 595 sampled overpasses are classified into 14 categories in the timeline of an RI event from 48 hours before RI until RI ends. The decrease of normalized wavenumber 1–6 asymmetries in the inner core region of all four types of precipitation several hours before RI onset was quantitatively demonstrated to be critical for TC RI.
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Lambert, Tara Denise Barton. "Accuracy of Atlantic and Eastern North Pacific tropical cyclone intensity guidance." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2005. http://library.nps.navy.mil/uhtbin/hyperion/05Sep%5FLambert.pdf.
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Thesis (M.S. in Meteorology and Physical Oceanography)--Naval Postgraduate School, September 2005.Thesis Advisor(s): Russell L. Elsberry. Includes bibliographical references (p.115-117). Also available online.
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Hauke, Matthew D. "EVALUATING ATLANTIC TROPICAL CYCLONE TRACK ERROR DISTRIBUTIONS BASED ON FORECAST CONFIDENCE /." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2006. http://library.nps.navy.mil/uhtbin/hyperion/06Jun%5FHauke.pdf.
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Ortt, Derek. "Effects of Environmental Water Vapor on Tropical Cyclone Structure and Intensity." Scholarly Repository, 2007. http://scholarlyrepository.miami.edu/oa_theses/90.
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The tropical cyclone (TC) and environmental interaction is not fully understood. Previous studies have demonstrated that this interaction affects intensity change. The studies found that intensification is favored in low shear, moist environments, with high sea surface temperatures (SST). However, little precise quantification was provided, especially in terms of the impact of environmental water vapor on TC intensity change. This work addresses the TC interaction with the environmental water vapor. Results from a comprehensive statistical study show that TC intensification is more likely to occur in an anomalously moist environment than a dry environment. However, only a small amount of the total variance is explained. When assessing the effect of vertical wind shear along with environmental water vapor, more of the variance is explained. Water vapor not only affects TC intensity. Prior modeling studies have demonstrated impacts from environmental water vapor on TC structure. These impacts can also affect intensity change. Specifically, enhanced water vapor content within the TC enhances the rainbands, which can lead to an eyewall replacement cycle, causing a temporary weakening, followed by re-intensification. This thesis evaluates observational and high resolution MM5 model output from Hurricanes Katrina and Rita from the Hurricane Rainband and Intensity Experiment (RAINEX) to evaluate the effects of varying water vapor distributions on TC structure. While the two hurricanes were of similar intensity, they had different water vapor distributions and structures. Rita underwent an eyewall replacement cycle while under RAINEX surveillance while Katrina did not. Rita was also located within a dry environment and had a strong horizontal moisture gradient, while Katrina was in a moist environment and had a weak moisture gradient. Results suggest that a strong horizontal water vapor gradient, with a moist TC and dry outer environment may confine the hurricanes into a pattern that causes them to have high circularity, promoting the formation of a secondary eyewall. The dry outer environment had strong atmospheric stability and was less favorable for deep convection far from the center in the Rita case. The moist environment in the Katrina case was more unstable. This may have allowed for the rainbands to be farther from the center in a less circular pattern than Rita. The results presented in this thesis suggest that this pattern is less favorable for an eyewall replacement cycle.