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13th European Conference on Antennas and Propagation (EuCAP)

作者： Lyras, Nikolaos K. Kourogiorgas, Charilaos I. Kapsis, Theodore Panagopoulos, Athanasios D. NTUA Sch Elect & Comp Engn Athens Greece STFC RAL Space Didcot Oxon England

ISBN: (纸本)9788890701887

Optical satellite communication systems are severely affected by the cloud coverage. Therefore, for the evaluation of system's availability cloud Free Line of Sight statistics of the optical ground stations (OGSs) must be estimated. The elevation angles and the altitude of the OGSs should be considered for the accurate prediction and reliable evaluation of the optical satellite network performance. In this paper, new simple engineering expressions for the estimation of CFLOS in terms of the elevation angle of the slant path, the altitude of the OGS, and the CFLOS of the corresponding vertical link are presented. Additionally, a new selection algorithm of the OGSs for the formation of an OGS Network (OGSN) that would achieve a CFLOS threshold but also mitigating the turbulence effects, is proposed. The proposed models are evaluated numerically and some interesting conclusions are drawn.

关键词： Free Space Optics Satellite Communications Feeder Links cloud Free Line Of Sight cloud coverage

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Monthly and Seasonal CFLOS Statistics for Optical GEO Feeder Links Design 9th

Monthly and Seasonal CFLOS Statistics for Optical GEO Feeder...

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9th European-Alliance-for-Innovation (EAI) International Conference on Wireless and Satellite Systems (WiSATS)

作者： Lyras, Nikolaos K. Kourogiorgas, Charilaos I. Panagopoulos, Athanasios D. Liolis, Konstantinos P. Natl Tech Univ Athens Sch Elect & Comp Engn Athens Greece SES SA Betzdorf Luxembourg

ISBN: (纸本)9783319765716;9783319765709

A methodology for the generation of seasonal and monthly cloudfree-line of sight (CFLOS) statistics for single optical satellite slant paths and joint CFLOS statistics for multiple spatially separated optical satellite links is proposed and evaluated with numerical results. It is assumed that the blockage of the satellite link is considered with the occurrence of clouds. The reported methodology is based on the stochastic dynamic modeling of Integrated Liquid Water Content (ILWC) and uses as inputs monthly statistical parameters of the logarithm of (ILWC) to produce CFLOS statistics. This methodology is an extension of an existing model that captures very well both the seasonal and monthly variability of clouds. The proposed model takes into account the temporal and spatial correlation of clouds, the elevation angle and the altitude of the ground station among others. The numerical results are concentrated on for hypothetical satellite links with optical gateways located in North and South hemisphere respectively are presented. The numerical results are compared with the corresponding annual results.

关键词： Optical satellite communications cloud-Free-Line of Sight probability CFLOS cloud coverage Seasonal and monthly variability

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Effects of Carbon Dioxide and clouds on Temperature 6th

Effects of Carbon Dioxide and Clouds on Temperature

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6th International Conference on Information Technology and Quantitative Management (ITQM)

作者： Lee, Hyunsoo Cheong, Hee-Woon Ft Hays State Univ Hays KS 67601 USA Hoseo Univ Grad Sch Management Technol Asan 31499 South Korea

With the observed rise in temperature, many researchers have tried to identify the causes of such climate change to help mitigate its effects. The objective of this study is to determine whether, under the same carbon dioxide (CO2) concentrations, CO2 with lower cloud coverage would raise the temperature at a greater rate than CO2 with higher cloud coverage. The hypothesis was tested through big data analysis and modeling. The relationships between the temperature and the CO2 emissions, the temperature and the cloud coverage, and the CO2 emissions and the cloud coverage were identified using the Pearson's correlation test. The data analysis concluded that the relationship between the temperature and the CO2 emission is positively proportional with a significant correlation. The relationship between the cloud coverage and the temperature and the relationship between the CO2 emissions and the cloud coverage were determined to be negatively proportional with significant correlations. For modeling, the temperature increased more rapidly as cloud coverage shrank. The results supported the hypothesis that the cloud coverage mitigates warming effects created by CO2 emissions. (C) 2018 The Authors. Published by Elsevier B.V.

关键词： cloud coverage Carbon dioxide Temperature

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Effects of Carbon Dioxide and clouds on Temperature

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Procedia Computer Science 2018年 139卷 95-103页

作者： Hyunsoo Lee Hee-Woon Cheong Fort Hays State University KS 67601 USA Graduate School of Management of Technology Hoseo Univerisity Asan 31499 Korea

With the observed rise in temperature, many researchers have tried to identify the causes of such climate change to help mitigate its effects. The objective of this study is to determine whether, under the same carbon dioxide (CO 2 ) concentrations, CO 2 with lower cloud coverage would raise the temperature at a greater rate than CO 2 with higher cloud coverage. The hypothesis was tested through big data analysis and modeling. The relationships between the temperature and the CO 2 emissions, the temperature and the cloud coverage, and the CO 2 emissions and the cloud coverage were identified using the Pearson’s correlation test. The data analysis concluded that the relationship between the temperature and the CO 2 emission is positively proportional with a significant correlation. The relationship between the cloud coverage and the temperature and the relationship between the CO 2 emissions and the cloud coverage were determined to be negatively proportional with significant correlations. For modeling, the temperature increased more rapidly as cloud coverage shrank. The results supported the hypothesis that the cloud coverage mitigates warming effects created by CO 2 emissions.

关键词： cloud coverage Carbon dioxide Temperature

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A literature review on estimating of PV-array hourly power under cloudy weather conditions

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RENEWABLE & SUSTAINABLE ENERGY REVIEWS 2016年 63卷 579-592页

作者： Gandoman, Foad H. Raeisi, Fatima Ahmadi, Abdollah Islamic Azad Univ Marvdasht Branch Dept Elect Engn Marvdasht Iran

The capacity of installed photovoltaic cells (PVs) has been remarkably increased globally over past few decades. In addition, changing cloud cover (Oktas-scale) is an important component that influences on solar radiation hourly and plays a key role in electrical output power of PVs. However, it is necessary for electrical utilities to use a powerful model in order to forecast PV power systems on electrical networks. Thus, forecasting power output of PV systems increase the quality of modern power systems. This paper presents a comprehensive review on short term forecasting of solar PV power output in modern electrical networks. Additionally, a new model based on hourly measurements has been proposed in this research and was reported during the past 20 years in Sanandaj (Applied Research Center of Kurdistan Weather), located in west of Iran (14 degrees.35'N, 46 degrees.35'E). The results show that the possibility of changing hourly and PV output power estimate based on Oktas analysis have been calculated with minimum fault. (C) 2016 Elsevier Ltd. All rights reserved.

关键词： cloud coverage PV output power Forecasting Short term Solar radiation

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Analysis of Carbon Dioxide and cloud Effects on Temperature in Northeast China

Analysis of Carbon Dioxide and Cloud Effects on Temperature ...

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4th International Conference on Information Technology and Quantitative Management (ITQM) - Promoting Business Analytics and Quantitative Management of Technology

作者： Lee, Hyunsoo Ft Hays State Univ 420 Custer DrCuster Hall 241 Hays KS 67601 USA

With the observed rise in temperature, many researchers have tried to identify the causes of such climate change to help mitigate its effects. The objective of this study is to determine whether, under the same carbon dioxide (CO2) concentrations, CO2 with lower cloud coverage would raise the temperature at a greater rate than CO2 with higher cloud coverage. The hypothesis was tested through data analysis and modeling. The relationships between the temperature and the CO2 emissions, the temperature and the cloud coverage, and the CO2 emissions and the cloud coverage were identified using Pearson's correlation test. The data analysis concluded that the relationship between the temperature and the CO2 emission is positively proportional with a significant correlation. The relationship between the cloud coverage and the temperature and the relationship between the CO2 emissions and the cloud coverage were determined to be negatively proportional with significant correlations. For modeling, the temperature increased more rapidly as cloud coverage shrank. The results supported the hypothesis that the cloud coverage mitigates warming effects created by carbon dioxide emissions. Further research is anticipated to reduce the uncertainties in the data along with specification of cloud types. (C) 2016 The Authors. Published by Elsevier B.V.

关键词： Carbon Dioxide Emissions cloud coverage Environmental Science

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Sky Status : A Local Analysis of Ground based Digital Images 5

Sky Status : A Local Analysis of Ground based Digital Images

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5th International Conference on Multimedia Computing and Systems (ICMCS)

作者： Moughyt, Salah Zaz, Youssef Fathi, Samia El Kadmiri, Omar Abdelemalek Essaidi Univ Elect & Microwave Grp Fac Sci Tetouan Morocco

ISBN: (纸本)9781509051465

cloud coverage obscures the sunlight, it can be identified as the major factor that significantly decreases the total irradiance received by photovoltaic panels, and then the power generation is intermittent. In this paper, and in order to predict the energy production by a solar installation, we analyze the acquired ground based images of the sky to extract its actual status (clear, partially cloudy, or totally cloudy). An embedded system is dedicated to simultaneously capture images and estimate the power generation. The accurate sky status is determined by comparing the brightness of the sun zone in the digital image to its surrounding area. The experimental results are promising and shows that the developed techniques can be easily embedded in solar plants to accurately predict the short time energy production.

关键词： component Image processing Sky image cloud coverage Solar energy Photovoltaic (PV) Sun irradiance Energy forecast

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Analysis of Carbon Dioxide and cloud Effects on Temperature in Northeast China

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Procedia Computer Science 2016年 91卷 690-699页

作者： Hyunsoo Lee Fort Hays State University 420 Custer Drive Custer Hall 241 Hays KS and 67601 United States

With the observed rise in temperature, many researchers have tried to identify the causes of such climate change to help mitigate its effects. The objective of this study is to determine whether, under the same carbon dioxide (CO 2 ) concentrations, CO 2 with lower cloud coverage would raise the temperature at a greater rate than CO 2 with higher cloud coverage. The hypothesis was tested through data analysis and modeling. The relationships between the temperature and the CO 2 emissions, the temperature and the cloud coverage, and the CO 2 emissions and the cloud coverage were identified using Pearson's correlation test. The data analysis concluded that the relationship between the temperature and the CO 2 emission is positively proportional with a significant correlation. The relationship between the cloud coverage and the temperature and the relationship between the CO 2 emissions and the cloud coverage were determined to be negatively proportional with significant correlations. For modeling, the temperature increased more rapidly as cloud coverage shrank. The results supported the hypothesis that the cloud coverage mitigates warming effects created by carbon dioxide emissions. Further research is anticipated to reduce the uncertainties in the data along with specification of cloud types.

关键词： Carbon Dioxide Emissions cloud coverage Environmental Science

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ASTER cloud coverage reassessment using MODIS cloud mask products

ASTER cloud coverage reassessment using MODIS cloud mask pro...

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Conference on Earth Observing Missions and Sensors - Development, Implementation, and Characterization

作者： Tonooka, Hideyuki Omagari, Kunjuro Yamamoto, Hirokazu Tachikawa, Tetsushi Fujita, Masaru Paitaer, Zaoreguli Ibaraki Univ Ibaraki 3168511 Japan ERSDAC Chuo Ku Tokyo 1040054 Japan AIST Tsukuba Ibaraki 3058567 Japan

ISBN: (纸本)9780819483928

In the Advanced Spaceborne Thermal Emission and Reflection radiometer (ASTER) Project, two kinds of algorithms are used for cloud assessment in Level-1 processing. The first algorithm based on the LANDSAT-5 TM Automatic cloud Cover Assessment (ACCA) algorithm is used for a part of daytime scenes observed with only VNIR bands and all nighttime scenes, and the second algorithm based on the LANDSAT-7 ETM+ ACCA algorithm is used for most of daytime scenes observed with all spectral bands. However, the first algorithm does not work well for lack of some spectral bands sensitive to cloud detection, and the two algorithms have been less accurate over snow/ice covered areas since April 2008 when the SWIR subsystem developed troubles. In addition, they perform less well for some combinations of surface type and sun elevation angle. We, therefore, have developed the ASTER cloud coverage reassessment system using MODIS cloud mask (MOD35) products, and have reassessed cloud coverage for all ASTER archived scenes (>1.7 million scenes). All of the new cloud coverage data are included in Image Management System (IMS) databases of the ASTER Ground Data System (GDS) and NASA's Land Process Data Active Archive Center (LP DAAC) and used for ASTER product search by users, and cloud mask images are distributed to users through Internet. Daily upcoming scenes (about 400 scenes per day) are reassessed and inserted into the IMS databases in 5 to 7 days after each scene observation date. Some validation studies for the new cloud coverage data and some mission-related analyses using those data are also demonstrated in the present paper.

关键词： ASTER MODIS MOD35 cloud mask cloud coverage ASTER GDS LP DAAC metadata

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Spatio-Temporal Variability of Western Central African Convection from Infrared Observations

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ATMOSPHERE 2012年第3期3卷 377-399页

作者： Vondou, Derbetini A. Univ Yaounde I Fac Sci Dept Phys Lab Environm Modeling & Atmospher Phys Yaounde 812 Cameroon

The present study has used Meteosat infrared brightness temperature images to investigate the regional and interannual variability of Central African cloudiness. Spatial and temporal variability were investigated using half-hourly data from the Meteosat-7 during June-July-August (JJA) of 1998-2002. The full domain of study (1.5 degrees E-17 degrees E, 1 degrees N-15 degrees N) was divided into six regions and statistics in each region were derived. Analysis of the dependence of cloud fraction to the brightness temperature threshold is explored both over land and ocean. Three diurnal cycle regimes (continental, oceanic, and coastal) are depicted according to the amplitude and peak time. Over regions of relatively flat terrain, results indicate enhancement of deep convection in the afternoon followed by a gradual decrease in the night. The diurnal cycle of convection is characterised by afternoon and early evening (around 15: 00-18: 00 LST) maxima located mainly downwind of the major mountain chains, and a more rapid nighttime decay. In terms of the harmonic amplitude, the diurnal signal shows significant regional contrast with the strongest manifestation over the Adamaoua Plateau and the weakest near the South Cameroon Plateau. This remarkable spatial dependence is clear evidence of orographic and heterogeneous land-surface impacts on convective development. Oceanic region exhibits weak activity of convective cloudiness with a maximum at noon. It is suggested that daytime heating of the land surface and moist environment may play a role in determining the spatial distribution of cloud fraction. This study further demonstrates the importance of the Cameroon coastline concavity and coastal mountains in regulating regional frequencies of convection and their initialization. The strength of the diurnal cycle of convective activity depends on mountain height, mean flow, coastal geometry.

关键词： convection cloud coverage diurnal cycle meteosat

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