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1
Goll, James G., Lindsay J. Wilkinson, and Dolores M. Snell. "Teaching Chemistry Using October Sky." Journal of Chemical Education 86, no. 2 (February 2009): 177. http://dx.doi.org/10.1021/ed086p177.
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Yeop, Noorhasimah, and Azni Zain Ahmed. "Classification of the Sky in Shah Alam, Malaysia Using Measured Sky Radiance and Luminance." Applied Mechanics and Materials 204-208 (October 2012): 2740–43. http://dx.doi.org/10.4028/www.scientific.net/amm.204-208.2740.
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This study aims at classifying the sky at Shah Alam, Malaysia (3° 3.82´N, 101° 29.50´ E). Measurements of sky luminance and sky radiance were made at a chosen location in Shah Alam. The measurements were done by using a sky scanner. This equipment tracked 145 points of sky hemisphere. Field measurements were made during the periods of October to December 2010 and between January, July and August 2011. The luminance and radiance data were converted to illuminance and irradiance. The sky ratio and Perez clearness index were then calculated. It was confirmed that the sky at Shah Alam is mostly of the partly cloudy or intermediate type. During the measurement period, the maximum mean monthly hourly irradiation was more than 200 W/m2 and the maximum mean monthly hourly illuminance exceeded 20klux.
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Nguyen Thi Khanh Phuong. "Determination of luminance distribution under tropical sky conditions." Vestnik MGSU, no. 9 (September 2019): 1096–105. http://dx.doi.org/10.22227/1997-0935.2019.9.1096-1105.
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Introduction. Natural illumination calculations depend on the sky luminance distribution. The most often used diagram of sky luminance in handbooks and guidelines is the luminance distribution in the cloudy sky proposed by Moon and Spencer. This concept actually includes the tropical areas of Vietnam, where the overcast sky and clear sky does not typically occur. To improve the calculation of natural illumination, it is necessary to determine the luminance distribution in the real sky.
Materials and methods. In solving the research problem, the real sky types for Hanoi were identified using the 15 international standard sky types with their descriptions by lighting climate, which is provided using the method by R. Kittler. The descriptions are derived from the data on diffuse horizontal illumination Dv, extraterrestrial horizontal illumination Ev and light turbidity coefficient Tv. For a specific sky type, the standard parameters were selected for calculating the luminance distribution of the real sky.
Results. The obtained results show that the typical sky type of Hanoi is the partly cloudy sky, no gradation towards zenith, with slight bleaching towards the Sun (type VI). The sky types from October to December are partly cloudy with the obscured Sun (type IX) and partly cloudy with the more luminant circumsolar area (type X). The study shows that the state of cloud coverage has a great influence on the level of diffuse horizontal illumination and luminance distribution under tropical sky conditions.
Conclusions. It is revealed that the typical sky type for Hanoi is neither overcast nor clear sky. A typical sky with statistic dominance of cirrus and stratus clouds under effect of high solar radiation of Vietnamese tropical climate gives a high level of diffuse horizontal illuminance. The results show that the difference in luminance distribution between the CIE standard overcast sky and Kittler’s intermediate sky can be resolved at the angles of sky point elevation above horizon γ is higher than 50° with the relative errors below 10 %. In other words, the luminance distribution β of the considered sky type is significant for a system of side natural illumination.
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Horner, Scott D., Marvin E. Germain, Thomas P. Greene, Fred H. Harris, Mark S. Johnson, Kenneth J. Johnston, David G. Monet, et al. "The Full-Sky Astrometric Mapping Explorer – Distances and Photometry of 40 Million Stars." International Astronomical Union Colloquium 176 (2000): 76–77. http://dx.doi.org/10.1017/s025292110005716x.
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The Full-sky Astrometric Mapping Explorer (FAME) is designed to perform an all-sky, astrometric survey with unprecedented accuracy. It will create a rigid astrometric catalog of 4 × 107 stars with 5 < mV < 15. For bright stars, 5 < mV < 9, FAME will determine positions and parallaxes accurate to < 50 μas, with proper motion errors < 50 μas/yr. For fainter stars, 9 < mV < 15, FAME will determine positions and parallaxes accurate to < 500 μas, with proper motion errors < 500 μas/yr. It will also collect photometric data on these 4 × 107 stars in four Sloan Digital Sky Survey colors. NASA selected FAME to be one of five MIDEX missions funded for a concept study. In October 1999, NASA selected FAME for launch in 2004 as the MIDEX-4 mission in its Explorer program.
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Sakai, T., T. Nagai, T. Kobayashi, A. Yamazaki, A. Uchiyama, and Y. Mano. "Multiwavelength and polarization lidar measurements of Asian dust layers over Tsukuba, Japan: a case study." Atmospheric Chemistry and Physics Discussions 7, no. 4 (July 13, 2007): 10179–203. http://dx.doi.org/10.5194/acpd-7-10179-2007.
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Abstract. Elastic and polarization lidar was used to measure the vertical profiles of aerosol backscattering coefficients at wavelengths of 355, 532, 735, and 1064 nm, and the depolarization ratio at 532 nm in order to study the aerosol properties in the free troposphere over Tsukuba, Japan, in 2006. An elevated dust layer was observed at altitudes between 3 and 8.5 km on 1 April during the Asian dust period. The wavelength exponents of the aerosol backscattering coefficient (k) were –0.1 to 0.5, and the depolarization ratio (δp) was 25% for the dust layer, suggesting the predominance of supermicrometer-sized (coarse mode) nonspherical particles. An aerosol layer observed at altitudes between 1.5 and 5 km on 19 October during the less-dust period exhibited the values of k=1.0 to 1.6 and δp=1 to 13%, suggesting the predominance of submicrometer-sized (fine mode) particles. In those layers, the values of k and δp varied with height; they were also negatively correlated, suggesting that the proportion of the coarse nonspherical particles to total particles varied. The particle size distributions estimated from the observed values and the theoretical computation revealed number mode radii of 0.3 &mum; for the coarse mode and 0.1 &mum; for the fine mode, assuming bimodal distribution. These results were consistent with those obtained from the sky-radiometer measurements, although they revealed another mode in the larger radius. The column volume concentration derived from the lidar was 48% lower than that derived from the sky-radiometer on 1 April and 16% lower on 19 October. The optical thickness derived from the lidar was 12% lower than that obtained from the sky-radiometer on 1 April and 29% higher on 19 October. Further case study is necessary to validate the method for estimating aerosol properties based on the lidar measurement.
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Anggaraditya, Putu Bagus. "A history of the King in the sky: Balinese Kite Festival." Bali Tourism Journal 1, no. 1 (July 28, 2017): 3. http://dx.doi.org/10.36675/btj.v1i1.4.
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‘Pelangi’ (Persatuan Layang-Layang Bali) or Bali Kite Association, held a kite flying festival from early July until the end of October 2017. It aims to preserve culture, stimulate creativity and grow bond and togetherness among societies as well as become a tourist attraction. Government supports the festival as means of cultural preservation as well as a tourist attraction for domestic and foreign. However, as time goes by, the land to play kite is getting narrower due to development. Therefore, attention and participation by local government and society are needed to maintain the availability of land for the sake of the preservation of this cultural festival.
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Tedlow, Richard S. "The Sky above and the Mud below: Two Books about Steve Jobs." Business History Review 94, no. 4 (2020): 835–52. http://dx.doi.org/10.1017/s0007680520000756.
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Steve Jobs was the most charismatic businessperson in the modern era. When he died, on October 5, 2011, Apple was inundated with condolence messages from all over the United States and from around the world. These notes were sent not only to Apple headquarters in Cupertino, California, but to Apple retail stores. The stores posted them on their windows. In addition, bouquets of flowers were brought to the stores. Think of this—flowers in front of hundreds of stores in dozens of countries because of Jobs's death. No one knows how many notes were received at Apple and in the stores. According to the “Remembering Steve” page on Apple.com, “Over a million people from all over the world have shared their memories, thoughts, and feelings about Steve.” As he was dying, people made a pilgrimage to his home in Palo Alto. His daughter has written that “a few people he didn’t know came to the doors wanting to see him … , wandering into the garden. … A stranger in a sari begged to talk with him. A man came in through the gate and said he had flown in from Bulgaria just to see my father.” After Jobs's death, California governor Jerry Brown declared October 16 to be “Steve Jobs Day.” The president of United States and the First Lady, Barack and Michelle Obama, posted a condolence note. Nothing remotely like this outpouring had ever taken place on the occasion of the death of an American CEO.
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Dworak, Richard, Yinghui Liu, Jeffrey Key, and Walter N. Meier. "A Blended Sea Ice Concentration Product from AMSR2 and VIIRS." Remote Sensing 13, no. 15 (July 29, 2021): 2982. http://dx.doi.org/10.3390/rs13152982.
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An effective blended Sea-Ice Concentration (SIC) product has been developed that utilizes ice concentrations from passive microwave and visible/infrared satellite instruments, specifically the Advanced Microwave Scanning Radiometer-2 (AMSR2) and the Visible Infrared Imaging Radiometer Suite (VIIRS). The blending takes advantage of the all-sky capability of the AMSR2 sensor and the high spatial resolution of VIIRS, though it utilizes only the clear sky characteristics of VIIRS. After both VIIRS and AMSR2 images are remapped to a 1 km EASE-Grid version 2, a Best Linear Unbiased Estimator (BLUE) method is used to combine the AMSR2 and VIIRS SIC for a blended product at 1 km resolution under clear-sky conditions. Under cloudy-sky conditions the AMSR2 SIC with bias correction is used. For validation, high spatial resolution Landsat data are collocated with VIIRS and AMSR2 from 1 February 2017 to 31 October 2019. Bias, standard deviation, and root mean squared errors are calculated for the SICs of VIIRS, AMSR2, and the blended field. The blended SIC outperforms the individual VIIRS and AMSR2 SICs. The higher spatial resolution VIIRS data provide beneficial information to improve upon AMSR2 SIC under clear-sky conditions, especially during the summer melt season, as the AMSR2 SIC has a consistent negative bias near and above the melting point.
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Mims, Forrest M., Lin Hartung Chambers, and David R. Brooks. "Measuring Total Column Water Vapor by Pointing an Infrared Thermometer at the Sky." Bulletin of the American Meteorological Society 92, no. 10 (October 1, 2011): 1311–20. http://dx.doi.org/10.1175/2011bams3215.1.
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A 2-yr study affirms that the temperature indicated by an inexpensive ($20–$60) IR thermometer pointed at the cloud-free zenith sky (Tz) is a proxy for total column water vapor [precipitable water (PW)]. From 8 September 2008 to 18 October 2010 Tz was measured either at or near solar noon, and occasionally at night, at a field in south-central Texas. PW was measured by a MICROTOPS II sun photometer. The coefficient of correlation (r2) of PW and Tz was 0.90, and the rms difference was 3.2 mm. A comparison of Tz with PW from a GPS site 31 km northnortheast yielded an r2 of 0.79 and an rms difference of 5.8 mm. An expanded study compared Tz from eight IR thermometers with PW at various times during the day and night from 17 May to 18 October 2010, mainly at the Texas site, with an additional 10 days at Hawaii's Mauna Loa Observatory. The best results were provided by two IR thermometers that yielded an r2 of 0.96 and an rms difference with PW of 2.7 mm. The results of both the ongoing 2-yr study and the 5-month comparison show that IR thermometers can measure PW with an accuracy (rms difference/mean PW) approaching 10%, which is the accuracy typically ascribed to sun photometers. The simpler IR method, which works during both day and night, can be easily mastered by students, amateur scientists, and cooperative weather observers.
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Aleksandrov, Aleksandr Sergeevich. "CORRESPONDENCE BETWEEN L. N. ANDREEV AND I. I. YASINSKY." Russkaya literatura 3 (2021): 70–84. http://dx.doi.org/10.31860/0131-6095-2021-3-70-84.
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This article is devoted to the creative ties and relations between L. N. Andreev and I. I. Yasin-sky, as well as to the history of their personal contacts. The article outlines Yasinsky’s attitude to the personality and art of Andreev after the October Revolution of 1917. Their correspondence is reproduced in the Conclusion; the publication of the epistolary dialogue is accompanied by historical and literary commentaries.
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MASETTI, NICOLA, PIETRO PARISI, ELIANA PALAZZI, LOREDANA BASSANI, RAFFAELLA LANDI, ANGELA MALIZIA, FILOMENA SCHIAVONE, et al. "REVEALING THE NATURE OF NEW UNIDENTIFIED INTEGRAL SOURCES." International Journal of Modern Physics D 19, no. 06 (June 2010): 819–24. http://dx.doi.org/10.1142/s0218271810016701.
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Since its launch on October 2002, the INTEGRAL satellite has revolutionized our knowledge of the hard X–ray sky thanks to its unprecedented imaging capabilities and source detection positional accuracy above 20 keV. Nevertheless, many of the newly-detected sources in the INTEGRAL sky surveys are of unknown nature. However, the combined use of available information at longer wavelengths (mainly soft X–rays and radio) and of optical spectroscopy on the putative counterparts of these new hard X–ray objects allows pinpointing their exact nature. Continuing our long-standing program running since 2004 (and with which we identified more than 100 INTEGRAL objects) here we report the classification, through optical spectroscopy, of 25 unidentified high-energy sources, mostly belonging to the recently published 4-th IBIS survey.
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Nyassor, Prosper K., Ricardo Arlen Buriti, Igo Paulino, Amauri F. Medeiros, Hisao Takahashi, Cristiano M. Wrasse, and Delano Gobbi. "Determination of gravity wave parameters in the airglow combining photometer and imager data." Annales Geophysicae 36, no. 3 (May 4, 2018): 705–15. http://dx.doi.org/10.5194/angeo-36-705-2018.
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Abstract. Mesospheric airglow measurements of two or three layers were used to characterize both vertical and horizontal parameters of gravity waves. The data set was acquired coincidentally from a multi-channel filter (Multi-3) photometer and an all-sky imager located at São João do Cariri (7.4∘ S, 36.5∘ W) in the equatorial region from 2001 to 2007. Using a least-square fitting and wavelet analysis technique, the phase and amplitude of each observed wave were determined, as well as the amplitude growth. Using the dispersion relation of gravity waves, the vertical and horizontal wavelengths were estimated and compared to the horizontal wavelength obtained from the keogram analysis of the images observed by an all-sky imager. The results show that both horizontal and vertical wavelengths, obtained from the dispersion relation and keogram analysis, agree very well for the waves observed on the nights of 14 October and 18 December 2006. The determined parameters showed that the observed wave on the night of 18 December 2006 had a period of ∼43.8±2.19 min, with the horizontal wavelength of 235.66 ± 11.78 km having a downward phase propagation, whereas that of 14 October 2006 propagated with a period of ∼36.00±1.80 min with a horizontal wavelength of ∼195±9.80 km, and with an upward phase propagation. The observation of a wave taken by a photometer and an all-sky imager allowed us to conclude that the same wave could be observed by both instruments, permitting the investigation of the two-dimensional wave parameter. Keywords. Atmospheric composition and structure (airglow and aurora) – electromagnetics (wave propagation) – history of geophysics (atmospheric sciences)
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Henrard, Jacques. "7. Mécanique Céleste (Celestial Mechanics)." Transactions of the International Astronomical Union 21, no. 1 (1991): 15–27. http://dx.doi.org/10.1017/s0251107x00009767.
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During 1988–1990 Commission 7 has sponsored or co-sponsored several IAU conferences: Colloquium No. 109 “Application of Computer Technology to Dynamical Astronomy” (Gaithersburg, July 1988), Symposium No. 141 “Inertial Coordinate System on the Sky” (Pulkovo, October 1989), Colloquium No. 127 “Reference Frames” (Virginia Beach, October 1990), Colloquium No. 132 “Instability, Chaos and Predictability in Celestial Mechanics and Stellar Systems” (Delhi, October 1990). The colloquium No. 118 “Dynamics of Small Bodies in the Solar System” which was to be held in Nanjing in June 1989 had unfortunately to be postponed then cancelled. Other meetings of interest to the members of Commission 7 were the 2nd Alexander von Humbolt Colloquium on “Long Term Evolution of Planetary Systems” (Ramsau, March 1988), the Colloquium “Asteroids, Comets, Meteors III” (Uppsala, June 1989), the colloquium “Mécanique Céleste et Systèmes Hamiltoniens” (Luminy, May 1990) and the NATO Advanced Study Institute on “Predictability, Stability and Chaos in N-Body Dynamical Systems” (Cortina d’Ampezzo, August 1990).
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Kaifler, Bernd, and Natalie Kaifler. "A Compact Rayleigh Autonomous Lidar (CORAL) for the middle atmosphere." Atmospheric Measurement Techniques 14, no. 2 (March 2, 2021): 1715–32. http://dx.doi.org/10.5194/amt-14-1715-2021.
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Abstract. The Compact Rayleigh Autonomous Lidar (CORAL) is the first fully autonomous middle atmosphere lidar system to provide density and temperature profiles from 15 to approximately 90 km altitude. From October 2019 to October 2020, CORAL acquired temperature profiles on 243 out of the 365 nights (66 %) above Río Grande, southern Argentina, a cadence which is 3–8 times larger as compared to conventional human-operated lidars. The result is an unprecedented data set with measurements on 2 out of 3 nights on average and high temporal (20 min) and vertical (900 m) resolution. The first studies using CORAL data have shown, for example, the evolution of a strong atmospheric gravity wave event and its impact on the stratospheric circulation. We describe the instrument and its novel software which enables automatic and unattended observations over periods of more than a year. A frequency-doubled diode-pumped pulsed Nd:YAG laser is used as the light source, and backscattered photons are detected using three elastic channels (532 nm wavelength) and one Raman channel (608 nm wavelength). Automatic tracking of the laser beam is realized by the implementation of the conical scan (conscan) method. The CORAL software detects blue sky conditions and makes the decision to start the instrument based on local meteorological measurements, detection of stars in all-sky images, and analysis of European Center for Medium-range Weather Forecasts Integrated Forecasting System data. After the instrument is up and running, the strength of the lidar return signal is used as additional information to assess sky conditions. Safety features in the software allow for the operation of the lidar even in marginal weather, which is a prerequisite to achieving the very high observation cadence.
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Santos, Carlos Antonio Costa dos, Bernardo Barbosa da Silva, Tantravahi Venkata Ramana Rao, Prakki Satyamurty, and Antonio Ocimar Manzi. "Downward longwave radiation estimates for clear-sky conditions over northeast Brazil." Revista Brasileira de Meteorologia 26, no. 3 (September 2011): 443–50. http://dx.doi.org/10.1590/s0102-77862011000300010.
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The main objective of this paper is to assess the performance of nine downward longwave radiation equations for clear-sky condition and develop a locally adjusted equation using the observed vapor pressure and air temperature data. The radiation and atmospheric parameters were measured during the months of October 2005 to June 2006 at a micrometeorological tower installed at the experimental site in a banana orchard in the semiarid region of Northeast Brazil. The comparative statistics for the performance of the downward longwave radiation calculation models during daytime and nighttime compared to measured data have shown that the parameterizations with more physical foundations have the best results. The locally adjusted equation and Sugita and Brutsaert model developed in 1993 showed errors less than 1.0% in comparison with measured values. Downward longwave radiation is one of the most expensive and difficult component of the radiation budget to be monitored in micrometeorological studies. Hence, the locally adjusted equation can be used to estimate downward longwave energy, needed as input to some agricultural and hydrological models, in semi-arid regions of the Northeast Brazil, where this component is not monitored.
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Fechine, J., C. M. Wrasse, H. Takahashi, A. F. Medeiros, P. P. Batista, B. R. Clemesha, L. M. Lima, et al. "First observation of an undular mesospheric bore in a Doppler duct." Annales Geophysicae 27, no. 4 (April 1, 2009): 1399–406. http://dx.doi.org/10.5194/angeo-27-1399-2009.
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Abstract. On 1 October 2005, during the SpreadFEx campaign, a distinct mesospheric bore was observed over São João do Cariri (7.4° S, 36.5° W), Brazil by using airglow all-sky imagers. The event appeared both in the OI5577 and OH emissions, forming a well extended wave front which was followed by short waves from behind. Simultaneous wind and temperature data obtained by the meteor radar and the TIMED/SABER satellite instrument revealed that the bore event occurred during the Doppler ducting condition in the emission layers.
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Mateshvili, N., D. Fussen, G. Mateshvili, I. Mateshvili, F. Vanhellemont, E. Kyrölä, S. Tukiainen, et al. "Nabro volcano aerosol in the stratosphere over Georgia, South Caucasus from ground-based spectrometry of twilight sky brightness." Atmospheric Measurement Techniques Discussions 6, no. 3 (May 17, 2013): 4401–44. http://dx.doi.org/10.5194/amtd-6-4401-2013.
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Abstract. Ground-based spectral measurements of twilight sky brightness were carried out between October 2009 and August 2011 in Georgia, South Caucasus. The algorithm which allowed to retrieve the lower stratospheric and upper tropospheric aerosol extinction profiles was developed. The Monte-Carlo technique was used to correctly represent multiple scattering in a spherical atmosphere. The estimated stratospheric aerosol optical depths at a wavelength of 780 nm were: 3.0 × 10−3 ± 1 × 10 −3 (31 August 2009–15 January 2011) and 1.1 × 10−2 ± 3 × 10−3 (18 July 2011–03 August 2011, 10 observations). The first optical depth value corresponds to the background stratospheric aerosol level, the last one to the volcanically disturbed one after the Nabro eruption in June 2011. Reconsideration of measurements acquired soon after the Pinatubo eruption in 1991 allowed to model the phenomenon of the "second purple light", a twilight sky brightness enhancement at large solar zenith angles (97–102°). Monte-Carlo modeling reveals that the second purple light is caused by multiple scattering in the stratospheric aerosol layer. The modeling also shows that, assuming a hypothetical mesospheric aerosol layer with optical extinction comparable to typical noctilucent cloud values, a measurable twilight sky brightness increase at wavelength 440 nm follows at solar zenith angles 98–99&deg.
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Tiba, Chigueru, and Sérgio da Silva Leal. "Enhancement of UV Radiation by Cloud Effect in NE of Brazil." International Journal of Photoenergy 2017 (2017): 1–9. http://dx.doi.org/10.1155/2017/8107435.
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This paper reports a detailed analysis of ground-based measurements of cloud-enhanced global solar and UV radiation in NE Brazil in the city of Recife. It was found that (a) the phenomenon of UV enhancement, above clear sky model, is not uncommon and that it occurs on at least eight months; (b) the cumulative duration can reach 13 minutes; (c) there is a clear seasonal effect, and the probability of occurrence on a monthly basis shows two peaks, one in March and another in October; and (d) the most extreme UV radiation was 70.4 W/m2, approximately 6 W/m2 higher than the clear sky UV radiation. The extreme values should be taken into account in the study of effects related to the UV index and biological effects. Two statistical models also were elaborated, to estimate the UV solar radiation, in which the first is for all sky conditions and the second exclusively for situations where the global solar radiation is equal to or higher than 1367 W/m2, resulting from the enhancement effect caused by a particular configuration of the clouds. The statistical indicatives for both models presented, respectively, MBE% of 3.09 and 0.48% and RMSE% of 15.80 and 3.90%.
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Pazmiño, A. F., S. Godin-Beekmann, E. A. Luccini, R. D. Piacentini, E. J. Quel, and A. Hauchecorne. "Increased UV radiation due to polar ozone chemical depletion and vortex occurrences at Southern Sub-polar Latitudes in the period [1997–2005]." Atmospheric Chemistry and Physics 8, no. 17 (September 8, 2008): 5339–52. http://dx.doi.org/10.5194/acp-8-5339-2008.
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Abstract. The variability of total ozone and UV radiation from Total Ozone Mapping Spectrometer (TOMS) measurements is analyzed as a function of polar vortex occurrences over the southern subpolar regions during the 1997–2005 period. The analysis of vortex occurrences showed high interannual variability in the 40° S–60° S latitude band with a longitudinal asymmetry showing the largest frequencies over the 90° W–90° E region. The impact of vortex occurrences on UV radiation and ozone in clear sky conditions was determined from the comparison between the measurements inside the vortex and a climatology obtained from data outside the vortex over the studied period. Clear sky conditions were determined from TOMS reflectivity data. For measurements outside the vortex, clear sky conditions were selected for reflectivity values lower than 7.5%, while for measurements inside the vortex, a relaxed threshold was determined from statistically similar UV values as a function of reflectivity. UV changes and ozone differences from the climatology were analyzed in the 40° S–50° S and 50° S–60° S latitude bands during the spring period (September to November). The largest UV increases and ozone decreases, reaching ~200% and ~65%, respectively, were found in the 50° S–60° S latitude band in September and October. The heterogeneous ozone loss during vortex occurrences was estimated using a chemical transport model. The largest impact of vortex occurrences was found in October with mean UV increase, total ozone decrease and accumulated ozone loss in the 350–650 K range of, respectively, 47%, 30% and 57%. The region close to South America is the most affected by the Antarctic ozone depletion due to the combined effect of large number of vortex occurrences, lower cloud cover and large ozone decrease. This region would be the most vulnerable in case of cloud cover decrease, due to more frequent occurrence of ozone poor air masses during austral spring.
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Pazmino, A. F., S. Godin-Beekmann, E. A. Luccini, R. D. Piacentini, E. J. Quel, and A. Hauchecorne. "Increased UV radiation due to polar ozone chemical depletion and vortex occurrences at southern sub-polar latitudes in the period (1997–2005)." Atmospheric Chemistry and Physics Discussions 8, no. 2 (April 4, 2008): 6501–37. http://dx.doi.org/10.5194/acpd-8-6501-2008.
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Abstract. The variability of total ozone and UV radiation from Total Ozone Mapping Spectrometer (TOMS) measurements is analyzed as a function of polar vortex occurrences over the southern subpolar regions during the 1997–2005 period. The analysis of vortex occurrences showed high interannual variability in the 40° S–60° S latitude band with a longitudinal asymmetry showing the largest frequencies over the 90° W–90° E region. The impact of vortex occurrences on UV radiation and ozone in clear sky conditions was determined from the comparison between the measurements inside the vortex and a climatology obtained from data outside the vortex over the studied period. Clear sky conditions were determined from TOMS reflectivity data. For measurements outside the vortex, clear sky conditions were selected for reflectivity values lower than 7.5%, while for measurements inside the vortex, a relaxed threshold was determined from statistically similar UV values as a function of reflectivity. UV changes and ozone differences from the climatology were analyzed in the 40° S–50° S and 50° S–60° S latitude bands during the spring period (September to November). The largest UV increases and ozone decreases, reaching 200% and 65%, respectively, were found in the 50° S–60° S latitude band in September and October. The heterogeneous ozone loss during vortex occurrences was estimated using a chemical transport model. The largest impact of vortex occurrences was found in October with mean UV increase, total ozone decrease and accumulated ozone loss in the 350 K–650 K range of respectively 47%, 32% and 63%. The region close to South America is the most affected by the Antarctic ozone depletion due to the combined effect of large number of vortex occurrences, lower cloud cover and large ozone decrease. This region would be the most vulnerable in case of cloud cover decrease linked to climate change, due to more frequent occurrence of ozone poor air masses during austral spring.
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Chen, Liu, Zhang, Liu, Chen, Qian, Xu, and Xie. "Retrieval of the Fraction of Radiation Absorbed by Photosynthetic Components (FAPARgreen) for Forest using a Triple-Source Leaf-Wood-Soil Layer Approach." Remote Sensing 11, no. 21 (October 23, 2019): 2471. http://dx.doi.org/10.3390/rs11212471.
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The fraction of absorbed photosynthetically active radiation (FAPAR) is generally divided into the fraction of radiation absorbed by the photosynthetic components (FAPARgreen) and the fraction of radiation absorbed by the non-photosynthetic components (FAPARwoody) of the vegetation. However, most global FAPAR datasets do not take account of the woody components when considering the canopy radiation transfer. The objective of this study was to develop a generic algorithm for partitioning FAPARcanopy into FAPARgreen and FAPARwoody based on a triple-source leaf-wood-soil layer (TriLay) approach. The LargE-Scale remote sensing data and image simulation framework (LESS) model was used to validate the TriLay approach. The results showed that the TriLay FAPARgreen had higher retrieval accuracy, as well as a significantly lower bias (R2 = 0.937, Root Mean Square Error (RMSE) = 0.064, and bias = −6.02% for black-sky conditions; R2 = 0.997, RMSE = 0.025 and bias = −4.04% for white-sky conditions) compared to the traditional linear method (R2 = 0.979, RMSE = 0.114, and bias = −18.04% for black-sky conditions; R2 = 0.996, RMSE = 0.106 and bias = −16.93% for white-sky conditions). For FAPAR that did not take account of woody components (FAPARnoWAI), the corresponding results were R2 = 0.920, RMSE = 0.071, and bias = −7.14% for black-sky conditions, and R2 = 0.999, RMSE = 0.043, and bias = −6.41% for white-sky conditions. Finally, the dynamic FAPARgreen, FAPARwoody, FAPARcanopy and FAPARnoWAI products for a North America region were generated at a resolution of 500 m for every eight days in 2017. A comparison of the results for FAPARgreen against those for FAPARnoWAI and FAPARcanopy showed that the discrepancy between FAPARgreen and other FAPAR products for forest vegetation types could not be ignored. For deciduous needleleaf forest, in particular, the black-sky FAPARgreen was found to contribute only about 23.86% and 35.75% of FAPARcanopy at the beginning and end of the year (from January to March and October to December, JFM and OND), and 75.02% at the peak growth stage (from July to September, JAS); the black-sky FAPARnoWAI was found to be overestimated by 38.30% and 28.46% during the early (JFM) and late (OND) part of the year, respectively. Therefore, the TriLay approach performed well in separating FAPARgreen from FAPARcanopy, which is of great importance for a better understanding of the energy exchange within the canopy.
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Sahai, Y., F. Becker-Guedes, P. R. Fagundes, A. J. de Abreu, R. de Jesus, V. G. Pillat, J. R. Abalde, et al. "Observations of the F-region ionospheric irregularities in the South American sector during the October 2003 "Halloween Storms"." Annales Geophysicae 27, no. 12 (December 8, 2009): 4463–77. http://dx.doi.org/10.5194/angeo-27-4463-2009.
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Abstract. The response of the ionospheric F-region in the South American sector during the super geomagnetic storms on 29 and 30 October 2003 is studied in the present investigation. In this paper, we present ionospheric sounding observations during the period 29–31 October 2003 obtained at Palmas (a near equatorial location) and Sao Jose dos Campos (a location under the southern crest of the equatorial ionospheric anomaly), Brazil, along with observations during the period 27–31 October 2003 from a chain of GPS stations covering the South American sector from Imperatriz, Brazil, to Rio Grande, Argentina. Also, complementary observations that include sequences of all-sky images of the OI 777.4 and 630.0 nm emissions observed at El Leoncito, Argentina, on the nights of 28–29 (geomagnetically quiet night) and 29–30 (geomagnetically disturbed night) October 2003, and ion densities observed in the South American sector by the DMSP F13, F14 and F15 satellites orbiting at about 800 km on 29 and 30 October 2003 are presented. In addition, global TEC maps derived from GPS observations collected from the global GPS network of International GPS Service (IGS) are presented, showing widespread and drastic TEC changes during the different phases of the geomagnetic disturbances. The observations indicate that the equatorial ionospheric irregularities or plasma bubbles extend to the Argentinean station Rawson (geom. Lat. 33.1° S) and map at the magnetic equator at an altitude of about 2500 km.
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Lehner, Manuela, C. David Whiteman, and Sebastian W. Hoch. "Diurnal Cycle of Thermally Driven Cross-Basin Winds in Arizona’s Meteor Crater." Journal of Applied Meteorology and Climatology 50, no. 3 (March 1, 2011): 729–44. http://dx.doi.org/10.1175/2010jamc2520.1.
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Abstract Cross-basin winds produced by asymmetric insolation of the crater sidewalls occur in Arizona’s Meteor Crater on days with weak background winds. The diurnal cycle of the cross-basin winds is analyzed together with radiation, temperature, and pressure measurements at the crater sidewalls for a 1-month period. The asymmetric irradiation causes horizontal temperature and pressure gradients across the crater basin that drive the cross-basin winds near the crater floor. The horizontal temperature and pressure gradients and wind directions change as the sun moves across the sky, with easterly winds in the morning and westerly winds in the evening. A case study of 12 October 2006 further illustrates the obtained relation between these parameters for an individual day. The occurrence of an elevated cross-basin flow on 23 October 2006 is shown to relate to the presence of an elevated inversion layer.
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Bageston, J. V., C. M. Wrasse, D. Gobbi, H. Takahashi, and P. B. Souza. "Observation of mesospheric gravity waves at Comandante Ferraz Antarctica Station (62° S)." Annales Geophysicae 27, no. 6 (June 26, 2009): 2593–98. http://dx.doi.org/10.5194/angeo-27-2593-2009.
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Abstract. An airglow all-sky imager was operated at Comandante Ferraz Antarctica Station (62.1° S, 58.4° W), between April and October of 2007. Mesospheric gravity waves were observed using the OH airglow layer during 43 nights with good weather conditions. The waves presented horizontal wavelengths between 10 and 60 km and observed periods mainly distributed between 5 and 20 min. The observed phase speeds range between 5 m/s and 115 m/s; the majority of the wave velocities were between 10 and 60 m/s. The waves showed a preferential propagation direction towards the southwest in winter (May to July), while during spring (August to October) there was an anisotropy with a preferential propagation direction towards the northwest. Unusual mesospheric fronts were also observed. The most probable wave source could be associated to orographic forcing, cold fronts or strong cyclonic activity in the Antarctica Peninsula.
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Sharpee, B. D., E. R. O'Neill, and T. G. Slanger. "Astronomical sky spectra from the 29-31 October 2003 geomagnetic superstorms: Observations of O+(2Do-4So) and other emissions." Journal of Geophysical Research: Space Physics 113, A12 (December 2008): n/a. http://dx.doi.org/10.1029/2007ja013010.
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Maddy, Eric S., Thomas S. King, Haibing Sun, Walter W. Wolf, Christopher D. Barnet, Andrew Heidinger, Zhaohui Cheng, et al. "Using MetOp-A AVHRR Clear-Sky Measurements to Cloud-Clear MetOp-A IASI Column Radiances." Journal of Atmospheric and Oceanic Technology 28, no. 9 (September 1, 2011): 1104–16. http://dx.doi.org/10.1175/jtech-d-10-05045.1.
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Abstract High spatial resolution measurements from the Advanced Very High Resolution Radiometer (AVHRR) on the Meteorological Operation (MetOp)-A satellite that are collocated to the footprints from the Infrared Atmospheric Sounding Interferometer (IASI) on the satellite are exploited to improve and quality control cloud-cleared radiances obtained from the IASI. For a partial set of mostly ocean MetOp-A orbits collected on 3 October 2010 for latitudes between 70°S and 75°N, these cloud-cleared radiances and clear-sky subpixel AVHRR measurements within the IASI footprint agree to better than 0.25-K root-mean-squared difference for AVHRR window channels with almost zero bias. For the same dataset, surface skin temperatures retrieved using the combined AVHRR, IASI, and Advanced Microwave Sounding Unit (AMSU) cloud-clearing algorithm match well with ECMWF model surface skin temperatures over ocean, yielding total uncertainties ≤1.2 K for scenes with up to 97% cloudiness.
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Pecot, Stephen D., Stephen B. Horsley, Michael A. Battaglia, and Robert J. Mitchell. "The influence of canopy, sky condition, and solar angle on light quality in a longleaf pine woodland." Canadian Journal of Forest Research 35, no. 6 (June 1, 2005): 1356–66. http://dx.doi.org/10.1139/x05-069.
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Light transmittance estimates under open, heterogeneous woodland canopies such as those of longleaf pine (Pinus palustris Mill.) forests report high spatial and temporal variation in the quantity of the light environment. In addition, light quality, that is, the ratio of red to far-red light (R:FR), regulates important aspects of plant development including stem extension, specific leaf area, and seed germination. We conducted two experiments to document sources of variation in R:FR (using a LI-COR 1800 portable spectroradiometer with a cosine-corrected light sensor) in a 70- to 90-year-old natural longleaf pine woodland in southwest Georgia, USA. The first experiment compared instantaneous measurements of R:FR over a 3-day period (March) with annual estimates of canopy transmittance (using gallium arsenide phosphide photodiodes) across the range of observed overstory abundance. The second experiment examined the effect of wiregrass cover (above or below), sky condition (blue sky or overcast), and solar angle (four sampling periods between October and March) on R:FR using a multifactorial repeated measures design. We found that (1) R:FR was significantly (p < 0.0001) and strongly (R2 = 0.72) related to annual estimates of canopy transmittance (percent photosynthetic photon flux density, %PPFD); (2) R:FR and %PPFD showed significant negative relationships with increasing overstory stocking (R2 = 0.20, p = 0.028 for R:FR, and R2 = 0.87, p < 0.0001 for %PPFD); and (3) R:FR decreased with increasing solar angle from maximum zenith for the study site under blue skies, was greater under overcast skies (0.84 blue sky vs. 1.18 overcast sky), and decreased under wiregrass (Aristida stricta Michx.) canopies (1.10 above vs. 0.98 below).
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Wu, Fengquan, Jixia Li, Shifan Zuo, Xuelei Chen, Santanu Das, John P. Marriner, Trevor M. Oxholm, et al. "The Tianlai dish pathfinder array: design, operation, and performance of a prototype transit radio interferometer." Monthly Notices of the Royal Astronomical Society 506, no. 3 (July 7, 2021): 3455–82. http://dx.doi.org/10.1093/mnras/stab1802.
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ABSTRACT The Tianlai Dish Pathfinder Array is a radio interferometer designed to test techniques for 21 cm intensity mapping in the post-reionization universe as a means for measuring large-scale cosmic structure. It performs drift scans of the sky at constant declination. We describe the design, calibration, noise level, and stability of this instrument based on the analysis of about 5% of 6200 h of on-sky observations through 2019 October. Beam pattern determinations using drones and the transit of bright sources are in good agreement, and compatible with electromagnetic simulations. Combining all the baselines, we make maps around bright sources and show that the array behaves as expected. A few hundred hours of observations at different declinations have been used to study the array geometry and pointing imperfections, as well as the instrument noise behaviour. We show that the system temperature is below 80 K for most feed antennas and that noise fluctuations decrease as expected with integration time, at least up to a few hundred seconds. Analysis of long integrations, from 10 nights of observations of the North Celestial Pole (NCP), yielded visibilities with amplitudes of 20–30 mK, consistent with the expected signal from the NCP radio sky with ${\lt}10\,$ mK precision for 1 MHz × 1 min binning. Hi-pass filtering the spectra to remove smooth spectrum signal yields a residual consistent with zero signal at the $0.5\,$ mK level.
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Phillips, Michael. "Flames in the Night Sky : Blake, Paine and the Meeting of the Society of Loyal Britons, Lambeth, October 10th, 1793." XVII-XVIII. Revue de la société d'études anglo-américaines des XVIIe et XVIIIe siècles 44, no. 1 (1997): 93–110. http://dx.doi.org/10.3406/xvii.1997.1368.
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Virolainen, Yana A., Yury M. Timofeyev, Vladimir S. Kostsov, Dmitry V. Ionov, Vladislav V. Kalinnikov, Maria V. Makarova, Anatoly V. Poberovsky, et al. "Quality assessment of integrated water vapour measurements at the St. Petersburg site, Russia: FTIR vs. MW and GPS techniques." Atmospheric Measurement Techniques 10, no. 11 (November 22, 2017): 4521–36. http://dx.doi.org/10.5194/amt-10-4521-2017.
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Abstract. The cross-comparison of different techniques for atmospheric integrated water vapour (IWV) measurements is the essential part of their quality assessment protocol. We inter-compare the synchronised data sets of IWV values measured by the Bruker 125 HR Fourier-transform infrared spectrometer (FTIR), RPG-HATPRO microwave radiometer (MW), and Novatel ProPak-V3 global navigation satellite system receiver (GPS) at the St. Petersburg site between August 2014 and October 2016. As the result of accurate spatial and temporal matching of different IWV measurements, all three techniques agree well with each other except for small IWV values. We show that GPS and MW data quality depends on the atmospheric conditions; in dry atmosphere (IWV smaller than 6 mm), these techniques are less reliable at the St. Petersburg site than the FTIR method. We evaluate the upper bound of statistical measurement errors for clear-sky conditions as 0.29 ± 0.02 mm (1.6 ± 0.3 %), 0.55 ± 0.02 mm (4.7 ± 0.4 %), and 0.76 ± 0.04 mm (6.3 ± 0.8 %) for FTIR, GPS, and MW methods, respectively. We propose the use of FTIR as a reference method under clear-sky conditions since it is reliable on all scales of IWV variability.
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Borsdorff, Tobias, Joost aan de Brugh, Haili Hu, Otto Hasekamp, Ralf Sussmann, Markus Rettinger, Frank Hase, et al. "Mapping carbon monoxide pollution from space down to city scales with daily global coverage." Atmospheric Measurement Techniques 11, no. 10 (October 9, 2018): 5507–18. http://dx.doi.org/10.5194/amt-11-5507-2018.
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Abstract. On 13 October 2017, the European Space Agency (ESA) successfully launched the Sentinel-5 Precursor satellite with the Tropospheric Monitoring Instrument (TROPOMI) as its single payload. TROPOMI is the first of ESA's atmospheric composition Sentinel missions, which will provide complete long-term records of atmospheric trace gases for the coming 30 years as a contribution to the European Union's Earth Observing program Copernicus. One of TROPOMI's primary products is atmospheric carbon monoxide (CO). It is observed with daily global coverage and a high spatial resolution of 7×7 km2. The moderate atmospheric resistance time and the low background concentration leads to localized pollution hotspots of CO and allows the tracking of the atmospheric transport of pollution on regional to global scales. In this contribution, we demonstrate the groundbreaking performance of the TROPOMI CO product, sensing CO enhancements above cities and industrial areas and tracking, with daily coverage, the atmospheric transport of pollution from biomass burning regions. The CO data product is validated with two months of Fourier-transform spectroscopy (FTS) measurements at nine ground-based stations operated by the Total Carbon Column Observing Network (TCCON). We found a good agreement between both datasets with a mean bias of 6 ppb (average of individual station biases) for both clear-sky and cloudy TROPOMI CO retrievals. Together with the corresponding standard deviation of the individual station biases of 3.8 ppb for clear-sky and 4.0 ppb for cloudy sky, it indicates that the CO data product is already well within the mission requirement.
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Aghanim, N., Y. Akrami, F. Arroja, M. Ashdown, J. Aumont, C. Baccigalupi, M. Ballardini, et al. "Planck 2018 results." Astronomy & Astrophysics 641 (September 2020): A1. http://dx.doi.org/10.1051/0004-6361/201833880.
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The European Space Agency’s Planck satellite, which was dedicated to studying the early Universe and its subsequent evolution, was launched on 14 May 2009. It scanned the microwave and submillimetre sky continuously between 12 August 2009 and 23 October 2013, producing deep, high-resolution, all-sky maps in nine frequency bands from 30 to 857 GHz. This paper presents the cosmological legacy of Planck, which currently provides our strongest constraints on the parameters of the standard cosmological model and some of the tightest limits available on deviations from that model. The 6-parameter ΛCDM model continues to provide an excellent fit to the cosmic microwave background data at high and low redshift, describing the cosmological information in over a billion map pixels with just six parameters. With 18 peaks in the temperature and polarization angular power spectra constrained well, Planck measures five of the six parameters to better than 1% (simultaneously), with the best-determined parameter (θ*) now known to 0.03%. We describe the multi-component sky as seen by Planck, the success of the ΛCDM model, and the connection to lower-redshift probes of structure formation. We also give a comprehensive summary of the major changes introduced in this 2018 release. The Planck data, alone and in combination with other probes, provide stringent constraints on our models of the early Universe and the large-scale structure within which all astrophysical objects form and evolve. We discuss some lessons learned from the Planck mission, and highlight areas ripe for further experimental advances.
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du Preez, D. Jean, Hassan Bencherif, Thierry Portafaix, Kévin Lamy, and Caradee Yael Wright. "Solar Ultraviolet Radiation in Pretoria and Its Relations to Aerosols and Tropospheric Ozone during the Biomass Burning Season." Atmosphere 12, no. 2 (January 20, 2021): 132. http://dx.doi.org/10.3390/atmos12020132.
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Biomass burning has an impact on atmospheric composition as well as human health and wellbeing. In South Africa, the biomass burning season extends from July to October and affects the aerosol loading and tropospheric ozone concentrations which in turn impact solar ultraviolet radiation (UVR) levels at the surface. Using ground-based observations of aerosols, tropospheric ozone and solar UVR (as well as modelled solar UVR) we investigated the impact of aerosols and tropospheric ozone on solar UVR in August, September, and October over Pretoria. Aerosol optical depth (AOD) and tropospheric ozone reached a peak between September and October each year. On clear-sky days, the average relative difference between the modelled and observed solar Ultraviolet Index (UVI) levels (a standard indicator of surface UVR) at solar noon was 7%. Using modelled UVR—which included and excluded the effects of aerosols and tropospheric ozone from biomass burning—aerosols had a larger radiative effect compared to tropospheric ozone on UVI levels during the biomass burning season. Excluding only aerosols resulted in a 10% difference between the modelled and observed UVI, while excluding only tropospheric ozone resulted in a difference of −2%. Further understanding of the radiative effect of aerosols and trace gases, particularly in regions that are affected by emissions from biomass burning, is considered important for future research.
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Qian, Yuanyuan, Yuhan Luo, Fuqi Si, Haijin Zhou, Taiping Yang, Dongshang Yang, and Liang Xi. "Total Ozone Columns from the Environmental Trace Gases Monitoring Instrument (EMI) Using the DOAS Method." Remote Sensing 13, no. 11 (May 27, 2021): 2098. http://dx.doi.org/10.3390/rs13112098.
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Global measurements of total ozone are necessary to evaluate ozone hole recovery above Antarctica. The Environmental Trace Gases Monitoring Instrument (EMI) onboard GaoFen 5, launched in May 2018, was developed to measure and monitor the global total ozone column (TOC) and distributions of other trace gases. In this study, some of the first global TOC results of the EMI using the differential optical absorption spectroscopy (DOAS) method and validation with ground-based TOC measurements and data derived from Ozone Monitoring Instrument (OMI) and TROPOspheric Monitoring Instrument (TROPOMI) observations are presented. Results show that monthly average EMI TOC data had a similar spatial distribution and a high correlation coefficient (R ≥ 0.99) with both OMI and TROPOMI TOC. Comparisons with ground-based measurements from the World Ozone and Ultraviolet Radiation Data Centre also revealed strong correlations (R > 0.9). Continuous zenith sky measurements from zenith scattered light differential optical absorption spectroscopy instruments in Antarctica were also used for validation (R = 0.9). The EMI-derived observations were able to account for the rapid change in TOC associated with the sudden stratospheric warming event in October 2019; monthly average TOC in October 2019 was 45% higher compared to October 2018. These results indicate that EMI TOC derived using the DOAS method is reliable and has the potential to be used for global TOC monitoring.
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Editors, The. "Forthcoming Conferences." Journal of Skyscape Archaeology 4, no. 1 (August 3, 2018): 151. http://dx.doi.org/10.1558/jsa.36100.
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SEAC 26th meeting27th August-1st September, 2018, Graz, Austriahttp://www.seac2018.org/
European Association of Archaeologists meeting5th-9th September, 2018: EAA 24th Annual Meeting, Barcelona, Spainhttps://www.e-a-a.org/
International Association of Landscape Archaeology17th-20th September, 2018: 5th biennial Landscape Archaeology Conference, Newcastle and Durham, United Kingdom http://www.ncl.ac.uk/mccordcentre/lac2018/
Archaeology Ireland: Pathways to the Cosmos15th September, 2018, Dublin Castle, Irelandhttps://www.eventbrite.ie/e/pathways-to-the-cosmos-tickets-45383757039
SIAC conference2nd week of October, 2018. "Water and Sky", VII Escuela Interamericana de Astronomía Cultural and VI Jornadas Interamericanas de Astronomía Cultural, Samaipata, Boliviahttp://siac.fcaglp.unlp.edu.ar/jornadas-bolivia.html
Theoretical Archaeology Group meeting40th Theoretical Archaeology Group Conference, 17th-19th December, 2018, University of Chester, Chester, UK
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Hudec, René, and Miloš Klíma. "Identification and Analyses in Optical Light of Gamma-Ray Sources with Astronomical Archival Plates." Advances in Astronomy 2010 (2010): 1–6. http://dx.doi.org/10.1155/2010/618975.
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The ESA INTEGRAL satellite (International Gamma Ray Laboratory) launched in October 2002 continues to deliver valuable data about the gamma-ray sky. Nearly 450 gamma-ray sources have been detected so far mainly by the IBIS onboard instrument, and others are expected in the future. The first 3.5 years of INTEGRAL public and Core Program data have revealed more than 400 sources and this number is expected to increase to more than 500 in the future (Bird et al. 2007). Alternative method to identify and to analyze INTEGRAL gamma-ray sources using optical light and astronomical archival plates is described, together with additional results from analyses of high-energy sources in these databases.
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LE COULTRE, P. "SEARCH FOR BURST SIGNALS FROM POINT SOURCES." International Journal of Modern Physics A 20, no. 29 (November 20, 2005): 6962–64. http://dx.doi.org/10.1142/s0217751x05030600.
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A sky survey for flaring point sources emitting high energy gamma rays has been performed with the L 3+ C underground muon spectrometer at LEP, CERN. Data were collected from mid July to October 1999 and from April to November 2000. No signal excesses in any direction have been found with muons above 20, 30, 50 and 100 GeV within one day and longer time windows. The steady muon flux sensitivity is of the order of a few times 10-9 cm-2 s-1 for muon energies above 20 GeV, and between 2 × 10-11 and 5 × 10-10 cm -2 s -1 for muon energies above 20 GeV depending on the source position.
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Pautet, P. D., M. J. Taylor, N. P. Chapagain, H. Takahashi, A. F. Medeiros, F. T. São Sabbas, and D. C. Fritts. "Simultaneous observations of equatorial F-region plasma depletions over Brazil during the Spread-F Experiment (SpreadFEx)." Annales Geophysicae 27, no. 6 (June 8, 2009): 2371–81. http://dx.doi.org/10.5194/angeo-27-2371-2009.
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Abstract. From September to November 2005, the NASA Living with a Star program supported the Spread-F Experiment campaign (SpreadFEx) in Brazil to study the effects of convectively generated gravity waves on the ionosphere and their role in seeding Rayleigh-Taylor instabilities, and associated equatorial plasma bubbles. Several US and Brazilian institutes deployed a broad range of instruments (all-sky imagers, digisondes, photometers, meteor/VHF radars, GPS receivers) covering a large area of Brazil. The campaign was divided in two observational phases centered on the September and October new moon periods. During these periods, an Utah State University (USU) all-sky CCD imager operated at São João d'Aliança (14.8° S, 47.6° W), near Brasilia, and a Brazilian all-sky CCD imager located at Cariri (7.4° S, 36° W), observed simultaneously the evolution of the ionospheric bubbles in the OI (630 nm) emission and the mesospheric gravity wave field. The two sites had approximately the same magnetic latitude (9–10° S) but were separated in longitude by ~1500 km. Plasma bubbles were observed on every clear night (17 from Brasilia and 19 from Cariri, with 8 coincident nights). These joint datasets provided important information for characterizing the ionospheric depletions during the campaign and to perform a novel longitudinal investigation of their variability. Measurements of the drift velocities at both sites are in good agreement with previous studies, however, the overlapping fields of view revealed significant differences in the occurrence and structure of the plasma bubbles, providing new evidence for localized generation. This paper summarizes the observed bubble characteristics important for related investigations of their seeding mechanisms associated with gravity wave activity.
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Scambos, Ted A., Terry M. Haran, and Robert Massom. "Validation of Avhrr and Modis ice Surface temperature products using in Situ radiometers." Annals of Glaciology 44 (2006): 345–51. http://dx.doi.org/10.3189/172756406781811457.
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AbstractShip-borne and airborne infrared radiometric measurements during the Arise cruise of September–October 2003 permitted in Situ validation Studies of two Satellite-based ice Surface Skin temperature algorithms: the AVHRR Polar Pathfinder Ice Surface Temperature and the MODIS Sea Ice Surface Temperature. Observations of Sea ice from the Aurora Australis Ship’s rail using a KT-19.82 radiometer were conducted between 25 September and 21 October during clear-sky overflights by AVHRR (41 passes) and MODIS (17 passes) on their respective Satellite platforms. Data from both Sensors Show highly linear fits to 1 min integrated radiometer Spot measurements, Spanning the range 245–270 K with a ±1.4˚C, 1σ (AVHRR) and ±1.0˚C (MODIS) variation relative to a 1: 1 relationship. There was no Significant offset. Helicopter observations made with a KT-19.85 radiometer on three dates (8, 19 and 20 October) provided more data (236 gridcell Sites total), but over a more limited Sea-ice Skin temperature range (252–268 K), with higher variation (±1.7˚C, 1σ) due to mixed-pixel issues. Comparison of MODIS and AVHRR algorithms directly, with both images acquired during a helicopter flight, indicates very high correlation and near-unity Slope for the two Satellite-based algorithms. Ship air-temperature data during the validation indicated moderate to Strong inversions over Sea ice under clear Skies. These formed and decayed rapidly (tens of minutes) as clouds moved out of and into the zenith area.
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Moon, Hong-Kyu, Myung-Jin Kim, Hong-Suh Yim, Young-Jun Choi, Young-Ho Bae, Dong-Goo Roh, Jintae Park, and Bora Moon. "DEEP-South: Network Construction, Test Runs and Early Results." Proceedings of the International Astronomical Union 10, S318 (August 2015): 306–10. http://dx.doi.org/10.1017/s1743921315008455.
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AbstractKorea Microlensing Telescope Network (KMTNet) which consists of three identical 1.6 m wide-field telescopes with 18k × 18k CCDs, is the first optical survey system of its kind. The combination of fast optics and the mosaic CCD delivers seeing limited images over a 4 square degrees field of view. The main science goal of KMTNet is the discovery and characterization of exoplanets, yet it also offers various other science applications including DEep Ecliptic Patrol of SOUTHern sky (DEEP-South). The aim of DEEP-South is to discover and characterize asteroids and comets, including Near Earth Objects (NEOs). We started test runs last February after commissioning, and will return to normal operations in October 2015. A summary of early results from the test runs will be presented.
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Chen, Xiaoyan, Ali Luo, and Haifeng Yang. "Stellar population analysis of galaxies in SDSS and LAMOST Pilot Survey." Proceedings of the International Astronomical Union 9, S298 (May 2013): 399. http://dx.doi.org/10.1017/s1743921313006662.
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AbstractThe Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST, i.e. Guoshoujing Telescope) has finished its pilot survey (from October 2011 to June 2012). With about 3000 galaxy spectra collected during the pilot survey, we are planning to analyze the stellar populations of these galaxies in two different ways respectively. One is Lick indices (such as Hβ, Mgb, 〈Fe〉 etc., Worthey et al. 1994), which are not sensitive to the flux calibration, and another one is the full optical spectra fitting (Chen et al. 2009, 2010). Then we can evaluate the affects of flux calibration errors on stellar population analysis by comparing the results of the two methods′. Here we briefly show the early experiments aiming to test the consistency and/or difference between the two methods.
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Irie, H., T. Nakayama, A. Shimizu, A. Yamazaki, T. Nagai, A. Uchiyama, Y. Zaizen, S. Kagamitani, and Y. Matsumi. "Evaluation of MAX-DOAS aerosol retrievals by coincident observations using CRDS, lidar, and sky radiometer inTsukuba, Japan." Atmospheric Measurement Techniques 8, no. 7 (July 16, 2015): 2775–88. http://dx.doi.org/10.5194/amt-8-2775-2015.
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Abstract. Coincident aerosol observations of multi-axis differential optical absorption spectroscopy (MAX-DOAS), cavity ring-down spectroscopy (CRDS), lidar, and sky radiometer were conducted in Tsukuba, Japan, on 5–18 October 2010. MAX-DOAS aerosol retrieval (for aerosol extinction coefficient and aerosol optical depth at 476 nm) was evaluated from the viewpoint of the need for a correction factor for oxygen collision complexes (O4 or O2–O2) absorption. The present study strongly supports this need, as systematic residuals at relatively high elevation angles (20 and 30°) were evident in MAX-DOAS profile retrievals conducted without the correction. However, adopting a single number for the correction factor (fO4 = 1.25) for all of the elevation angles led to systematic overestimation of near-surface aerosol extinction coefficients, as reported in the literature. To achieve agreement with all three observations, we limited the set of elevation angles to ≤10° and adopted an elevation-angle-dependent correction factor for practical profile retrievals with scattered light observations by a ground-based MAX-DOAS. With these modifications, we expect to minimize the possible effects of temperature-dependent O4 absorption cross section and uncertainty in DOAS fit on an aerosol profile retrieval, although more efforts are encouraged to quantitatively identify a physical explanation for the need of a correction factor.
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Reade, John B. "On the scientific explanation of parhelia." Mathematical Gazette 87, no. 509 (July 2003): 243–49. http://dx.doi.org/10.1017/s0025557200172687.
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The cover picture shows a 22° halo seen in Preston on Sunday 28 October 2001 at 10 am. In contrast with a rainbow, the red band is on the inside rather than the outside, the colour bands are much thinner, and the arc is centred round the sun instead of being opposite to the sun. Also, it is not raining. Haloes occur on still sunny days when there is plenty of cirrus cloud. It is possible to see a full circle depending on how high the sun is in the sky. This never happens with a rainbow except when seen from an aeroplane. Sometimes the colours are particularly vivid at the 3 o’clock and 9 o’clock points. These vivid areas are called parhelia or mock suns. Sometimes the parhelia are all that can be seen.
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King, J. R. "A Visit to the Home of Lithium." Bulletin of the Royal College of Psychiatrists 9, no. 5 (May 1985): 90–92. http://dx.doi.org/10.1192/s0140078900001905.
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Late one October afternoon in 1984, I left the grey London drizzle behind and took off on a flight bound for Aarhus, major city on the east coast of Jutland, Denmark.Within twenty minutes the jet, appropriately called a Viking, had climbed above the turbulence of the clouds and was cruising through a serene dimension poised somewhere between the night sky, the sunset, and the purple rainclouds far below. Such a passage from turbulence into even stability is. I reflected, a familiar experience to the hundreds of thousands of people who have now benefited from tithium all over the world. But the introduction and acceptance of lithium therapy have been far from smooth, and would perhaps not have been possible at all were it not for the commitment and persistence of a few dedicated individuals.
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Liu, X. W., H. B. Yuan, Z. Y. Huo, M. S. Xiang, H. H. Zhang, Y. Huang, H. W. Zhang, H. B. Zhao, J. S. Yao, and H. Lu. "The Digital Sky Survey of the Galactic Anti-center (DSS-GAC)." Proceedings of the International Astronomical Union 10, H16 (August 2012): 348. http://dx.doi.org/10.1017/s174392131401120x.
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AbstractAs an integral component of the LAMOST Experiment for Galactic Understanding and Evolution (LEGUE; Deng et al. 2012), the LAMOST Galactic anti-center spectroscopic survey (Liu et al. in preparation) will survey over three thousand square degree sky area centered on the Galactic anti-center (150d ≤ l ≤ 210d, −30d ≤ b ≤ +30d) and obtain low resolution (R ~ 1800) optical spectra for a statistically complete sample of more than three million stars down to a limiting magnitude of 18.5 in r band, distributed in a spatially contiguous area and probing a significant volume of the Galactic thin/thick disks, halo and their interface. Sample stars of the LAMOST survey of the Galactic anti-center are derived from a recently completed CCD imaging photometric survey utilizing the newly built 1.0/1.2m Schmidt Telescope at the Xuyi Station of the Purple Mountain Observatory. The Xuyi imaging survey (Yuan et al., in preparation; Zhang et al. 2012) provides high quality photometry (~2 per cent) in the SDSS g, r and i bands and astrometry (~0.1 arcsec) for about a hundred million stars down to a limiting magnitude of about 19 (10 sigma) for over six thousand square degree sky area (3h ≤ RA ≤ 9h, −10d ≤ Dec ≤ +60d) that envelopes the LAMOST spectroscopic survey area of the Galactic anti-center, plus an extension to the M 31 and M 33 region.This Digital Sky Survey of the Galactic Anti-center (DSS-GAC) with the Xuyi Schmidt and LAMOST telescopes will yield for the first time optical photometry and spectra for millions of stars in the Galactic disk(s), the defining component of the Milky Way as a typical spiral galaxy that contains most Galactic baryonic material and angular momentum. DSS-GAC will deliver classification, extinction, radial velocity and stellar parameters (Teff, log g, [Fe/H], probably also [α/Fe], and in some cases, [C/Fe]), for each sample star. Together with the accurate proper motions and distances to be obtained with the forthcoming GAIA mission, DSS-GAC offers a unique opportunity for major breakthroughs in studies of the Galactic structure, formation and evolution. In particular, DSS-GAC will generate a huge data set to 1) study the stellar populations, chemical composition and kinematics of the thin and thick disks and their interface with the halo; 2) Understand how resilient galaxy disks are to gravitational interactions/perturbations and study the temporal and secular evolution of the disks; 3) identify tidal streams and debris of disrupted dwarfs and clusters; 4) probe the gravitational potential and dark matter distribution; 5) map the three-dimensional distribution and extinction of the interstellar medium; 6) search for rare objects (e.g. stars of peculiar chemical composition, hyper-velocity stars); and 7) ultimately advance our understanding of the formation and evolution of stars and galaxies.Following a two-year commissioning, the LAMOST pilot survey was initiated in October, 2011 and completed in June, 2012. In total, about 370,000 spectra of 270,000 stars have been obtained for DSS-GAC, with 70 per cent of the spectra reaching a spectral S/N ratio per resolution element at 7150 Å higher than 20. The formal LAMOST DSS-GAC survey will commence in September, 2012, and is expected to complete in five years.
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Irie, H., T. Nakayama, A. Shimizu, A. Yamazaki, T. Nagai, A. Uchiyama, Y. Zaizen, S. Kagamitani, and Y. Matsumi. "Evaluation of MAX-DOAS aerosol retrievals by coincident observations using CRDS, lidar, and sky radiometer in Tsukuba, Japan." Atmospheric Measurement Techniques Discussions 8, no. 1 (January 27, 2015): 1013–54. http://dx.doi.org/10.5194/amtd-8-1013-2015.
Full textAbstract:
Abstract. Coincident aerosol observations of Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS), Cavity Ring Down Spectroscopy (CRDS), lidar, and sky radiometer were conducted in Tsukuba, Japan on 5–18 October 2010. MAX-DOAS aerosol retrieval (for aerosol extinction coefficient and aerosol optical depth at 476 nm) was evaluated from the viewpoint of the need for a correction factor for oxygen collision complexes (O4 or O2-O2) absorption. The present study strongly supports this need, as systematic residuals at relatively high elevation angles (20 and 30°) were evident in MAX-DOAS profile retrievals conducted without the correction. However, adopting a single number for the correction factor (fO4 = 1.25) for all of the elevation angles led to systematic overestimation of near-surface aerosol extinction coefficients, as reported in the literature. To achieve agreement with all three observations, we limited the set of elevation angles to ≤ 10° and adopted an elevation-angle-dependent correction factor for practical profile retrievals with scattered light observations by a ground-based MAX-DOAS. With these modifications, we expect to minimize the possible effects of temperature-dependent O4 absorption cross section and uncertainty in DOAS fit on an aerosol profile retrieval, although more efforts are encouraged to quantitatively identify a physical explanation for the need of a correction factor.
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Pigatto, Luisa, Nha Il-Seong, Jürgen Hamel, Kevin Johnson, Rajesh K. Kochhar, Tsuko Nakamura, Wayne Orchiston, Bjørn R. Pettersen, Sara J. Schechner, and Shi Yunli. "DIVISION XII / COMMISSION 41 / WORKING GROUP HISTORICAL INSTRUMENTS." Proceedings of the International Astronomical Union 4, T27A (December 2008): 423. http://dx.doi.org/10.1017/s1743921308025994.
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The Historical Instruments Working Group (WG-HI) and Commission 41 started planning an interdisciplinary conference titled Astronomy and its instruments before and after Galileo since January 2007. This conference, as an IYA2009 initiative, aims “to highlight mankind's path toward an improved knowledge of the sky using mathematical and mechanical tools as well as monuments and buildings, giving rise, in doing so, to scientific astronomy”. Commission 46 and Commission 55 also support this conference, to be held on the Isle of San Servolo, Venice (Italy), 27 September – 3 October 2009. As a fact of history, it was in Venice that Galileo was advised and got material (glass) to make his telescope, and in Venice he presented an working instrument to Venetian Doge in August 1609. The conference is co-sponsored by IAU as a Joint Symposium with the INAF – Astronomical Observatory of Padova, Italy.
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Poliukhov, A. A., and D. V. Blinov. "Aerosol Effects on Temperature Forecast in the COSMO-Ru Model." Meteorologiya i Gidrologiya, no. 1 (2021): 29–39. http://dx.doi.org/10.52002/0130-2906-2021-1-29-39.
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Aerosol effects on the forecast of surface temperature, as well as temperature at the levels of 850 and 500 hPa over Europe and the European part of Russia are studied using various aerosol climatologies: Tanre, Tegen, and MACv2. The numerical experiments with the COSMO-Ru model are performed for the central months of the seasons (January, April, July, and October) in 2017. It is found that a change in the simulated surface air temperature over land can reach 1C when using Tegen and MACv2 data as compared to Tanre. At 850 and 500 hPa levels, the changes do not exceed 0.4C. At the same time, it is shown that a decrease in the root-mean-square error of 2-m air temperature forecast at individual stations reaches 0.5C when using Tegen and MACv2 data and 1C for clear-sky conditions in Moscow.
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Hidayat, Muhammad, Arwin Juli Rakhmadi, and Abu Yazid Raisal. "Measuring the Apparent Magnitude of Planet Mars on August 1st and October 2nd, 2018 at the Falak Observatory at Muhammadiyah University of North Sumatera." Indonesian Review of Physics 3, no. 1 (May 30, 2020): 6. http://dx.doi.org/10.12928/irip.v3i1.1838.
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The Bright stars that were seen by the eyes are the received quantity of the energy flux sent from the celestial body. The energy flux is inversely proportional to the distant quadrant which means that the light of the stars that are visible to our eyes cannot be compared to the actual brightness or even weaker than the others and the visible star lights the apparent magnitude. The purpose of this study is to measure the apparent magnitude of Mars. This research methodology is quantitative, by taking number of images/videos of Mars and then the data is processed by using IRIS software. The results of the analysis is using IRIS software that shows the value of the apparent magnitude of Mars on August 1st, 2018 is (-1.56 ± 0.33) and October 2nd 2018 is (-1.84 ± 0.08). This was taken by selecting the best image result in clear night sky.
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Ranith, R., L. Senthilnathan, M. Machendiranathan, T. Thangaradjou, and A. Saravanakumar. "Seasonal and inter-annual variability of the sea surface temperature and mixed layer depth in the southern Bay of Bengal." Advances in Oceanography and Limnology 4, no. 1 (May 22, 2013): 70. http://dx.doi.org/10.4081/aiol.2013.5337.
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Argo float data supplemented with satellite measurements was used to study the seasonal and inter-annual variation in wind speed, sea surface temperature (SST) and mixed layer depth (MLD) of the southern Bay of Bengal from 2003 through 2010. Due to persistence of wind, clear sky and high insolation an increase in SST by about 2°C is evident during summer months (March-May) and is followed by shallowed MLD with a minimum depth of 9.3 m during summer 2004. MLD reached the maximum depth during monsoon season (November-December) and often extends to post monsoon (February) owing to strong monsoon wind, cloudy sky and SST plummeted by 3°C. During the inter-monsoon period (August-October) the MLD shallowed and maintained a depth of 20–30 m all through the study period. High wind accompanied with moderate temperature (SST) due to the south west monsoon leads to decreased MLD with an average depth of 44 m in July. Analysis of wind speed, SST and MLD suggested that out of various meteorological parameters wind speed and induced mixing are highly influential in MLD formation. Reduced occurrence and amplitude of MLD deepening noticed in recent years can be attributed to the evident climate change scenarios. Large scale upper ocean variability observed from the present study has innumerable antagonistic consequences on the marine ecosystem which is evident from various events of seagrass burns and coral bleaching which have occurred in the last decade.