The Experts below are selected from a list of 489 Experts worldwide ranked by ideXlab platform
Fuzhong Weng - One of the best experts on this subject based on the ideXlab platform.
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vegetation indices derived from FengYun 3d mersi ii data
International Geoscience and Remote Sensing Symposium, 2020Co-Authors: Xiuzhen Han, Fuzhong Weng, Yang Han, He HuangAbstract:The MEdium Resolution Spectral Imager-II (MERSI-II) onboard FY-3D satellite is used to retrieve surface vegetation parameters. MERSI TOA reflectances are corrected to surface reflectance and then used to compute normalized differential vegetation index (NDVI) and enhanced vegetation index (EVI) at the canopy levels. MERSI-II VI products are also compared with MODIS data and show a good consistency.
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multisource assessments of the FengYun 3d microwave humidity sounder mwhs on orbit performance
IEEE Transactions on Geoscience and Remote Sensing, 2020Co-Authors: Wanlin Kan, Fuzhong Weng, Yang Han, Li GuanAbstract:The microwave humidity sounder (MWHS) onboard the FengYun-3D satellite is providing the data for profiling atmospheric temperature and moisture and has become an important data source for improving the weather forecasts. In this article, three data sources are utilized for assessing the MWHS on-orbit performance, including Global Navigation Satellite System Occultation Sounder (GNOS), ECMWF (European Centre for Medium-Range Weather Forecasts) Re-Analysis (ERA)-Interim reanalysis, and Advanced Technology Microwave Sounder (ATMS) data. GNOS-retrieved atmospheric profiles and the reanalysis data are used as inputs to the community radiative transfer model (CRTM) for simulating the MWHS brightness temperatures at the top of the atmosphere in July 2018 for characterizing the instrument performance. Since ATMS is a well-calibrated microwave sounding instrument onboard both Suomi NPP and NOAA-20 satellites, its measurements are also collocated with MWHS data for a consensus analysis using the simultaneous nadir overpasses (SNOs) method. In comparing GNOS simulations, MWHS upper air temperature sounding channels (3–6) have relatively larger biases (less than 2.5 K) than the water vapor sounding channels. However, the standard deviation of the difference between observations and simulations (O-B) is larger for water vapor sounding channels. For ERA simulations, MWHS sounding channels exhibit negative biases similar to GNOS results but the standard deviation of O-B at the water vapor channels is much smaller. When compared with ATMS water vapor channels, MWHS biases are mostly negative and agree with those from ERA simulation. Thus, the large uncertainty in simulating MWHS water vapor sounding channels from GNOS could result from the poor input water vapor profiles and high water vapor variability in the lower troposphere.
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estimation and correction of geolocation errors in FengYun 3c microwave radiation imager data
IEEE Transactions on Geoscience and Remote Sensing, 2016Co-Authors: Fei Tang, Hu Yang, Fuzhong WengAbstract:Microwave Radiation Imager (MWRI) onboard the FengYun (FY)-3C satellite provides measurements of the Earth's atmosphere and surface at 10.65, 18.7, 23.8, 36.5, and 89.0 GHz with dual polarization. While FY MWRI data have been widely distributed to the user community, their geolocation accuracy has not been documented. In this paper, the coastline inflection method is used to estimate MWRI geolocation errors. Three coastal regions where MWRI brightness temperature exhibits a large contrast are selected for the geolocation analysis. A total of 720 MWRI data points are identified that cross the coastlines. The latitudes and longitudes at these data points are compared with the fine-resolution database of the Global Self-consistent, Hierarchical, High-resolution Shoreline (GSHHS). It is found that the mean geolocation errors in along- and cross-track directions are approximately 5–6 km at 89 GHz. This magnitude of errors is more than 30% of the field-of-view size at 89 GHz. Such a geolocation error must be corrected so that the MWRI data can be more useful for quantitative remote sensing. Thus, the mean geolocation errors are further utilized to adjust the satellite attitude angles (e.g., pitch, roll, and raw). After the attitude angle correction, the MWRI geolocation is very accurate at 89 GHz, and errors in other MWRI channels may be corrected through their co-registration relationships to the 89-GHz channel.
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estimation and correction of geolocation errors in FengYun 3c microwave radiation imager data
IEEE Transactions on Geoscience and Remote Sensing, 2016Co-Authors: Fei Tang, Hu Yang, Xiaolei Zou, Fuzhong WengAbstract:Microwave Radiation Imager (MWRI) onboard the FengYun (FY)-3C satellite provides measurements of the Earth's atmosphere and surface at 10.65, 18.7, 23.8, 36.5, and 89.0 GHz with dual polarization. While FY MWRI data have been widely distributed to the user community, their geolocation accuracy has not been documented. In this paper, the coastline inflection method is used to estimate MWRI geolocation errors. Three coastal regions where MWRI brightness temperature exhibits a large contrast are selected for the geolocation analysis. A total of 720 MWRI data points are identified that cross the coastlines. The latitudes and longitudes at these data points are compared with the fine-resolution database of the Global Self-consistent, Hierarchical, High-resolution Shoreline (GSHHS). It is found that the mean geolocation errors in along- and cross-track directions are approximately 5–6 km at 89 GHz. This magnitude of errors is more than 30% of the field-of-view size at 89 GHz. Such a geolocation error must be corrected so that the MWRI data can be more useful for quantitative remote sensing. Thus, the mean geolocation errors are further utilized to adjust the satellite attitude angles (e.g., pitch, roll, and raw). After the attitude angle correction, the MWRI geolocation is very accurate at 89 GHz, and errors in other MWRI channels may be corrected through their co-registration relationships to the 89-GHz channel.
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polarization signature from the FengYun 3 microwave humidity sounder
Frontiers in Earth Science, 2014Co-Authors: Xiaolei Zou, Xu Chen, Fuzhong WengAbstract:Microwave Humidity Sounders (MHS) onboard NOAA-15, -16, -17, -18, -19, and EUMETSAT MetOp-A/B satellites provide radiance measurements at a single polarization state at any of five observed frequencies. The Microwave Humidity Sounder (MWHS) onboard the FengYun-3 (FY-3) satellite has a unique instrument design that provides dual polarization measurements at 150 GHz. In this study, the MWHS polarization signal was investigated using observed and modeled data. It is shown that the quasi-polarization brightness temperatures at 150 GHz display a scan angle dependent bias. Under calm ocean conditions, the polarization difference at 150 GHz becomes non-negligible when the scan angle varies from 10° to 45° and reaches a maximum when the scan angle is about 30°. Also, the polarization state is sensitive to surface parameters such as surface wind speed. Under clear-sky conditions, the differences between horizontal and vertical polarization states at 150 GHz increase with decreasing surface wind speed. Therefore, the polarization signals from the cross-track scanning microwave measurements at window channels contain useful information about surface parameters. In addition, the availability of dual polarization measurements allows a one-to-one conversion from antenna brightness temperature to sensor brightness temperature if a cross-polarization spill-over exists.
Xiaolei Zou - One of the best experts on this subject based on the ideXlab platform.
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estimation and correction of geolocation errors in FengYun 3c microwave radiation imager data
IEEE Transactions on Geoscience and Remote Sensing, 2016Co-Authors: Fei Tang, Hu Yang, Xiaolei Zou, Fuzhong WengAbstract:Microwave Radiation Imager (MWRI) onboard the FengYun (FY)-3C satellite provides measurements of the Earth's atmosphere and surface at 10.65, 18.7, 23.8, 36.5, and 89.0 GHz with dual polarization. While FY MWRI data have been widely distributed to the user community, their geolocation accuracy has not been documented. In this paper, the coastline inflection method is used to estimate MWRI geolocation errors. Three coastal regions where MWRI brightness temperature exhibits a large contrast are selected for the geolocation analysis. A total of 720 MWRI data points are identified that cross the coastlines. The latitudes and longitudes at these data points are compared with the fine-resolution database of the Global Self-consistent, Hierarchical, High-resolution Shoreline (GSHHS). It is found that the mean geolocation errors in along- and cross-track directions are approximately 5–6 km at 89 GHz. This magnitude of errors is more than 30% of the field-of-view size at 89 GHz. Such a geolocation error must be corrected so that the MWRI data can be more useful for quantitative remote sensing. Thus, the mean geolocation errors are further utilized to adjust the satellite attitude angles (e.g., pitch, roll, and raw). After the attitude angle correction, the MWRI geolocation is very accurate at 89 GHz, and errors in other MWRI channels may be corrected through their co-registration relationships to the 89-GHz channel.
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polarization signature from the FengYun 3 microwave humidity sounder
Frontiers in Earth Science, 2014Co-Authors: Xiaolei Zou, Xu Chen, Fuzhong WengAbstract:Microwave Humidity Sounders (MHS) onboard NOAA-15, -16, -17, -18, -19, and EUMETSAT MetOp-A/B satellites provide radiance measurements at a single polarization state at any of five observed frequencies. The Microwave Humidity Sounder (MWHS) onboard the FengYun-3 (FY-3) satellite has a unique instrument design that provides dual polarization measurements at 150 GHz. In this study, the MWHS polarization signal was investigated using observed and modeled data. It is shown that the quasi-polarization brightness temperatures at 150 GHz display a scan angle dependent bias. Under calm ocean conditions, the polarization difference at 150 GHz becomes non-negligible when the scan angle varies from 10° to 45° and reaches a maximum when the scan angle is about 30°. Also, the polarization state is sensitive to surface parameters such as surface wind speed. Under clear-sky conditions, the differences between horizontal and vertical polarization states at 150 GHz increase with decreasing surface wind speed. Therefore, the polarization signals from the cross-track scanning microwave measurements at window channels contain useful information about surface parameters. In addition, the availability of dual polarization measurements allows a one-to-one conversion from antenna brightness temperature to sensor brightness temperature if a cross-polarization spill-over exists.
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environmental data records from FengYun 3b microwave radiation imager
IEEE Transactions on Geoscience and Remote Sensing, 2012Co-Authors: Hu Yang, Xiaolei Zou, Ran YouAbstract:Microwave Radiation Imagers (MWRIs) onboard the FengYun (FY)-3A/B satellites of China Meteorological Administration were launched on May 28, 2008, and November 5, 2010, respectively. They both observe the Earth atmosphere and land surface at 10.65, 18.7, 23.8, 36.5, and 89.0 GHz with dual polarization. After extensive on-orbit calibrations, the MWRI Level-1 data were collocated in space and time with the data from Aqua Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E), F18 Special Sensor Microwave Imager Sounder (SSMIS), and Tropical Rainfall Measuring Mission Microwave Imager for cross-calibration. A forward radiative transfer model was used to simulate the clear sky brightness temperatures at the MWRI frequencies over ocean. The differences between MWRI observations and model simulations, referred to as “O-A,” and the double difference results from pairs of MWRI and AMSR-E were examined. Comparing to the biases between AMSR-E/SSMIS measurements and model simulations, the biases for MWRI are small and stable. Atmospheric and surface geophysical parameters are retrieved from MWRI observations using the heritage algorithms. It is shown that these environmental data records from MWRI are comparable with those similar data products from AMSR-E and SSMIS. Their biases from each other seemed to be minimal.
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quality assessments of chinese FengYun 3b microwave temperature sounder mwts measurements
IEEE Transactions on Geoscience and Remote Sensing, 2012Co-Authors: Xiang Wang, Xiaolei ZouAbstract:Following the successful launch of the first polar-orbiting morning-configured satellite, FY-3A, on May 27, 2008, in a new FengYun three (FY-3) series, the second afternoon-configured polar-orbiting satellite (FY-3B) was launched on November 5, 2010. The four-channel Microwave Temperature Sounder (MWTS) was onboard both FY-3A/B satellites, with designed channel frequency similar to channels 3, 5, 7, and 9 of the Advanced Microwave Sounding Unit-A (AMSU-A). This study assesses the quality of the brightness temperature measurements from FY-3B MWTS by comparing them with numerical weather prediction (NWP) model simulations and NOAA-18 AMSU-A measurements with the same frequencies. A strong latitudinal-dependent bias is found for both MWTS channel 3 and AMSU-A channel 7. At channel 4, the brightness temperatures are contaminated within a small latitudinal zone ( ~ 30°-40°N) of the Northern Hemisphere. It is also found that the MWTS channel 4 bias is strongly asymmetric across the scan and the fourth field of view (FOV4) of channel 4 is globally and systematically warmer than its neighboring FOVs. These anomalous biases may arise from sidelobe effect and interferences of the signal transmitted from some unknown sources. A quality control algorithm is developed to remove the anomalous data at MWTS channel 4 for its applications in NWP.
Hu Yang - One of the best experts on this subject based on the ideXlab platform.
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estimation and correction of geolocation errors in FengYun 3c microwave radiation imager data
IEEE Transactions on Geoscience and Remote Sensing, 2016Co-Authors: Fei Tang, Hu Yang, Fuzhong WengAbstract:Microwave Radiation Imager (MWRI) onboard the FengYun (FY)-3C satellite provides measurements of the Earth's atmosphere and surface at 10.65, 18.7, 23.8, 36.5, and 89.0 GHz with dual polarization. While FY MWRI data have been widely distributed to the user community, their geolocation accuracy has not been documented. In this paper, the coastline inflection method is used to estimate MWRI geolocation errors. Three coastal regions where MWRI brightness temperature exhibits a large contrast are selected for the geolocation analysis. A total of 720 MWRI data points are identified that cross the coastlines. The latitudes and longitudes at these data points are compared with the fine-resolution database of the Global Self-consistent, Hierarchical, High-resolution Shoreline (GSHHS). It is found that the mean geolocation errors in along- and cross-track directions are approximately 5–6 km at 89 GHz. This magnitude of errors is more than 30% of the field-of-view size at 89 GHz. Such a geolocation error must be corrected so that the MWRI data can be more useful for quantitative remote sensing. Thus, the mean geolocation errors are further utilized to adjust the satellite attitude angles (e.g., pitch, roll, and raw). After the attitude angle correction, the MWRI geolocation is very accurate at 89 GHz, and errors in other MWRI channels may be corrected through their co-registration relationships to the 89-GHz channel.
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estimation and correction of geolocation errors in FengYun 3c microwave radiation imager data
IEEE Transactions on Geoscience and Remote Sensing, 2016Co-Authors: Fei Tang, Hu Yang, Xiaolei Zou, Fuzhong WengAbstract:Microwave Radiation Imager (MWRI) onboard the FengYun (FY)-3C satellite provides measurements of the Earth's atmosphere and surface at 10.65, 18.7, 23.8, 36.5, and 89.0 GHz with dual polarization. While FY MWRI data have been widely distributed to the user community, their geolocation accuracy has not been documented. In this paper, the coastline inflection method is used to estimate MWRI geolocation errors. Three coastal regions where MWRI brightness temperature exhibits a large contrast are selected for the geolocation analysis. A total of 720 MWRI data points are identified that cross the coastlines. The latitudes and longitudes at these data points are compared with the fine-resolution database of the Global Self-consistent, Hierarchical, High-resolution Shoreline (GSHHS). It is found that the mean geolocation errors in along- and cross-track directions are approximately 5–6 km at 89 GHz. This magnitude of errors is more than 30% of the field-of-view size at 89 GHz. Such a geolocation error must be corrected so that the MWRI data can be more useful for quantitative remote sensing. Thus, the mean geolocation errors are further utilized to adjust the satellite attitude angles (e.g., pitch, roll, and raw). After the attitude angle correction, the MWRI geolocation is very accurate at 89 GHz, and errors in other MWRI channels may be corrected through their co-registration relationships to the 89-GHz channel.
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monitoring snow cover using chinese meteorological satellite data over china
Remote Sensing of Environment, 2014Co-Authors: Juntao Yang, Lingmei Jiang, Jiancheng Shi, Ruijing Sun, Hu YangAbstract:Snow cover plays an important role in hydrological processes and global climate change research. Geostationary satellites with high temporal resolution provide multiple observations in one day, which highlights their potential for monitoring real-time snow-cover information. In this paper, data from the Chinese meteorological satellites FengYun-2D (FY-2D), FengYun-2E (FY-2E) and FengYun-3B (FY-3B) was used for snow-cover mapping over China. A new method of detecting snow-cover information is proposed, that combines the Visible and Infrared Spin Scan-Radiometer (VISSR) on board the geostationary satellites FY-2D and FY-2E and the Microwave Radiation Imager (MWRI) on board the polar orbiting satellite FY-3B. The snow cover estimated from FengYun satellites was compared by the Moderate Resolution Imaging Spectroradiometer (MODIS) snow-cover products (MOD10A1 and MYD10A1), and Interactive Multisensor Snow and Ice Mapping System (IMS) snow-cover products. The FengYun satellite snow-cover images and IMS snow-cover products were validated with meteorological station observations for the 2010–2011 and 2011–2012 winter seasons. The influence of elevation and land-cover types on the accuracy of snow retrievals was also analyzed. The results showed that the combined use of FY-2D and FY-2E VISSR data reduced cloud obscuration by 30.47% compared to the MODIS products. The validation demonstrated that the accuracy of the final multi-sensor snow-cover images was 91.28%, which is similar to that for IMS snow-cover products. This work indicates that combined data from geostationary satellites and passive microwave remote sensing monitored snow cover over China to a high level of accuracy.
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environmental data records from FengYun 3b microwave radiation imager
IEEE Transactions on Geoscience and Remote Sensing, 2012Co-Authors: Hu Yang, Xiaolei Zou, Ran YouAbstract:Microwave Radiation Imagers (MWRIs) onboard the FengYun (FY)-3A/B satellites of China Meteorological Administration were launched on May 28, 2008, and November 5, 2010, respectively. They both observe the Earth atmosphere and land surface at 10.65, 18.7, 23.8, 36.5, and 89.0 GHz with dual polarization. After extensive on-orbit calibrations, the MWRI Level-1 data were collocated in space and time with the data from Aqua Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E), F18 Special Sensor Microwave Imager Sounder (SSMIS), and Tropical Rainfall Measuring Mission Microwave Imager for cross-calibration. A forward radiative transfer model was used to simulate the clear sky brightness temperatures at the MWRI frequencies over ocean. The differences between MWRI observations and model simulations, referred to as “O-A,” and the double difference results from pairs of MWRI and AMSR-E were examined. Comparing to the biases between AMSR-E/SSMIS measurements and model simulations, the biases for MWRI are small and stable. Atmospheric and surface geophysical parameters are retrieved from MWRI observations using the heritage algorithms. It is shown that these environmental data records from MWRI are comparable with those similar data products from AMSR-E and SSMIS. Their biases from each other seemed to be minimal.
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the FengYun 3 microwave radiation imager on orbit verification
IEEE Transactions on Geoscience and Remote Sensing, 2011Co-Authors: Hu Yang, Fuzhong Weng, Gaofeng Liu, Ming Bai, Qiaoyuan QianAbstract:The Microwave Radiation Imager (MWRI) on board the FengYun-3A/B satellites observes the Earth atmosphere at 10.65, 18.7, 23.8, 36.5, and 89.0 GHz with each having dual polarization. Its calibration system is uniquely designed with a main reflector viewing both cold and hot calibration targets. Two quasi-optical reflectors are used to reflect the radiation from the hot load and cold space to the main reflector. In the MWRI calibration process, a radiation loss in the beam transmission path must be taken into account. The loss factor in the hot load transmission path is derived using the antenna pattern data measured on ground and satellite data observing over the Amazon forest where the scene temperature is steady and close to the hot load. The instrument nonlinearity factors at different channels are also evaluated over a wide range of brightness temperatures and compared with the results from the ground vacuum test. After a cross-calibration with Windsat data, atmospheric products are derived from MWRI brightness temperatures with the accuracy similar to those from the legacy sensors (e.g., the Special Sensor Microwave/Imager).
Peng Zhang - One of the best experts on this subject based on the ideXlab platform.
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FengYun meteorological satellite products for earth system science applications
Advances in Atmospheric Sciences, 2021Co-Authors: Di Xian, Peng Zhang, Ruijing Sun, Ling Gao, Haizhen Zhang, Xu JiaAbstract:Following the progress of satellite data assimilation in the 1990s, the combination of meteorological satellites and numerical models has changed the way scientists understand the earth. With the evolution of numerical weather prediction models and earth system models, meteorological satellites will play a more important role in earth sciences in the future. As part of the space-based infrastructure, the FengYun (FY) meteorological satellites have contributed to earth science sustainability studies through an open data policy and stable data quality since the first launch of the FY-1A satellite in 1988. The capability of earth system monitoring was greatly enhanced after the second-generation polar orbiting FY-3 satellites and geostationary orbiting FY-4 satellites were developed. Meanwhile, the quality of the products generated from the FY-3 and FY-4 satellites is comparable to the well-known MODIS products. FY satellite data has been utilized broadly in weather forecasting, climate and climate change investigations, environmental disaster monitoring, etc. This article reviews the instruments mounted on the FY satellites. Sensor-dependent level 1 products (radiance data) and inversion algorithm-dependent level 2 products (geophysical parameters) are introduced. As an example, some typical geophysical parameters, such as wildfires, lightning, vegetation indices, aerosol products, soil moisture, and precipitation estimation have been demonstrated and validated by in-situ observations and other well-known satellite products. To help users access the FY products, a set of data sharing systems has been developed and operated. The newly developed data sharing system based on cloud technology has been illustrated to improve the efficiency of data delivery.
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wide field aurora imager onboard FengYun satellite data products and validation
Earth and Planetary Physics, 2021Co-Authors: Guangxing Ding, Xiaoxin Zhang, Zhongdong Yang, Bo Chen, Kefei Song, Shijie Liu, Liang Sun, Shuang Dai, Peng ZhangAbstract:New observations of auroras based on the wide-field aurora imager (WAI) onboard FengYun-3D (FY-3D) satellite are exhibited in this paper. Validity of the WAI data is analyzed by comparing auroral boundaries derived from WAI observations with results obtained from data collected by the Special Sensor Ultraviolet Spectrographic Imager (SSUSI) aboard the Defense Meteorological Satellite Program (DMSP F18). Dynamic variations of the aurora with the solar wind, interplanetary magnetic field (IMF) parameters, and the SYM-H index are also investigated. The comparison of auroral boundaries indicates that the WAI data are morphologically valid and suitable to the study of auroral dynamics. Effective responses to solar wind parameters indicate that the WAI data can be useful to monitor and predict the Earth’s space weather. Since the configuration of aurora is a good indicator of the solar wind–magnetosphere–ionosphere (SW-M-I) coupling system, and can reflect the disturbance of the space environment, the WAI will provide important data to help us to study the physical processes in space.
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an accurate and efficient radiative transfer model for simulating all sky images from FengYun satellite radiometers
Science China-earth Sciences, 2020Co-Authors: Bin Yao, Peng Zhang, Zhiqing Zhang, Chao Liu, Shiwen Teng, Byungju SohnAbstract:Forward radiative transfer models (RTM) are an indispensable tool for quantitative applications of satellite radiometers, e.g., for data calibration, instrument development, retrieval, and so on. In this study, we develop an accurate and efficient RTM for radiometers onboard FengYun satellites, namely FYRTM (RTM for FengYun Radiometers). Correlated k-distribution models are developed to improve the computational efficiency for gas absorption, and the effects of cloud and aerosol multiple scattering and emission are accelerated with pre-computed look-up tables. FYRTM is evaluated with a rigorous simulation based on discrete ordinate radiative transfer model (DISORT) as well as a popular fast forward model, i.e., the Community Radiative Transfer Model (CRTM). Results indicate that FYRTM-based simulations are two to three orders of magnitudes faster than the DISORT-based simulations. Compared to the rigorous model, FYRTM relative errors are within 2% at solar channels, and brightness temperatures (BT) differences are within 1 K at infrared channels. Compared with CRTM, FYRTM is computationally similar at solar channels, but three times faster at infrared channels. Furthermore, simulated reflectances/BTs using FYRTM are in a good agreement with the satellite observations. Overall, FYRTM is capable to simulate satellite observations under different atmospheric conditions, and can be extended to other radiometers onboard the FengYun satellites (both geostationary and polar-orbiting satellites). It is expected to play important roles in future applications with FengYun observations.
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the first FengYun satellite international user conference
Advances in Atmospheric Sciences, 2020Co-Authors: Di Xian, Peng Zhang, Meng Fang, Chang Liu, Xu JiaAbstract:2019年11月15-17日,由中国气象局、中国国家航天局主办的首届风云气象卫星国际用户大会在位于海南省海口市的海南大学召开。本次会议旨在建立一个风云气象卫星国际合作交流的平台,以便国际用户应用风云气象卫星数据开展应用,交换其应用技术和成果,并针对风云卫星全球应用,尤其是为“一带一路”地区提供服务等方面开展研讨。来自世界气象组织(WMO)、亚太空间合作组织(APSCO)、美国国家大气海洋局(NOAA)、欧洲气象卫星应用组织(EUMETSAT)、第六届中国气象卫星国际咨询委员会(ISCC)等组织的专家以及30个国家的风云气象卫星用户参加了本次会议。会议期间,中外参会代表和专家围绕风云气象卫星现状和规划、全球数据共享及应用服务、国际应用需求、全球天气监测及预报应用、全球生态环境监测应用等议题进行了交流和研讨。
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capability of FengYun 3d satellite in earth system observation
Journal of meteorological research, 2019Co-Authors: Zhongdong Yang, Peng Zhang, Songyan Gu, Xiuqin Hu, Shihao Tang, Leiku Yang, Na Xu, Zhaojun Zhen, Ling Wang, Qiong WuAbstract:From the viewpoint of earth system science, this paper discusses the observation capability of the second-generation of Chinese polar-orbiting, sun-synchronous operational meteorological satellite observation systems, FengYun-3 (FY-3), based on the function and performance test results from the FY-3D satellite observation system in orbit. The FY-3 series of satellites have numerous remote sensing instruments and a wide range of imaging and sounding electromagnetic spectrometers onboard. These instruments can obtain reflectivity data for land surface, soil, vegetation, water body, snow cover, ocean color, and sea ice on earth’s surface over a wide spectral range, as well as information on the absorption and scattering radiative transfer of molecules and particles (clouds and aerosols) in earth’s atmosphere. All of these data can be used to retrieve physical and chemical information about the land, ocean, and atmosphere of the earth system. Comprehensive observation of the earth system by the FY-3 meteorological satellites is preliminarily realized.
Yang Han - One of the best experts on this subject based on the ideXlab platform.
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vegetation indices derived from FengYun 3d mersi ii data
International Geoscience and Remote Sensing Symposium, 2020Co-Authors: Xiuzhen Han, Fuzhong Weng, Yang Han, He HuangAbstract:The MEdium Resolution Spectral Imager-II (MERSI-II) onboard FY-3D satellite is used to retrieve surface vegetation parameters. MERSI TOA reflectances are corrected to surface reflectance and then used to compute normalized differential vegetation index (NDVI) and enhanced vegetation index (EVI) at the canopy levels. MERSI-II VI products are also compared with MODIS data and show a good consistency.
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vegetation products derived from FengYun 3d medium resolution spectral imager ii
Journal of meteorological research, 2020Co-Authors: Xiuzhen Han, Shihao Tang, Jun Yang, Yang HanAbstract:The surface vegetation condition has been operationally monitored from space for many years by the Advanced Very High Resolution Radiometer (AVHRR) and the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments. As these instruments are close to the end of their design life, the surface vegetation products are required by many users from the new satellite missions. The MEdium Resolution Spectral Imager-II (MERSI-II) onboard the FengYun (FY) satellite (FY-3 series; FY-3D) is used to retrieve surface vegetation parameters. First, MERSI-II solar channel measurements at the red and near-infrared (NIR) bands at the top of atmosphere (TOA) are corrected to the surface reflectances at the top of canopy (TOC) by removing the contributions of scattering and absorption of molecules and aerosols. The normalized difference vegetation index (NDVI) at both the TOA and TOC is then produced by using the same algorithms as the MODIS and AVHRR. The MERSI-II enhanced VI (EVI) at the TOC is also developed. The MODIS technique of compositing the NDVI at various timescales is applied to MERSI-II to generate the gridded products at different resolutions. The MERSI-II VI products are consistent with the MODIS data without systematic biases. Compared to the current MERSI-II EVI generated from the ground operational system, the MERSI-II EVI from this study has a much better agreement with MODIS after atmospheric correction.
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multisource assessments of the FengYun 3d microwave humidity sounder mwhs on orbit performance
IEEE Transactions on Geoscience and Remote Sensing, 2020Co-Authors: Wanlin Kan, Fuzhong Weng, Yang Han, Li GuanAbstract:The microwave humidity sounder (MWHS) onboard the FengYun-3D satellite is providing the data for profiling atmospheric temperature and moisture and has become an important data source for improving the weather forecasts. In this article, three data sources are utilized for assessing the MWHS on-orbit performance, including Global Navigation Satellite System Occultation Sounder (GNOS), ECMWF (European Centre for Medium-Range Weather Forecasts) Re-Analysis (ERA)-Interim reanalysis, and Advanced Technology Microwave Sounder (ATMS) data. GNOS-retrieved atmospheric profiles and the reanalysis data are used as inputs to the community radiative transfer model (CRTM) for simulating the MWHS brightness temperatures at the top of the atmosphere in July 2018 for characterizing the instrument performance. Since ATMS is a well-calibrated microwave sounding instrument onboard both Suomi NPP and NOAA-20 satellites, its measurements are also collocated with MWHS data for a consensus analysis using the simultaneous nadir overpasses (SNOs) method. In comparing GNOS simulations, MWHS upper air temperature sounding channels (3–6) have relatively larger biases (less than 2.5 K) than the water vapor sounding channels. However, the standard deviation of the difference between observations and simulations (O-B) is larger for water vapor sounding channels. For ERA simulations, MWHS sounding channels exhibit negative biases similar to GNOS results but the standard deviation of O-B at the water vapor channels is much smaller. When compared with ATMS water vapor channels, MWHS biases are mostly negative and agree with those from ERA simulation. Thus, the large uncertainty in simulating MWHS water vapor sounding channels from GNOS could result from the poor input water vapor profiles and high water vapor variability in the lower troposphere.
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FengYun 3d mersi true color imagery developed for environmental applications
Journal of meteorological research, 2019Co-Authors: Xiuzhen Han, Feng Wang, Yang HanAbstract:Many techniques were developed for creating true color images from satellite solar reflective bands, and the so-derived images have been widely used for environmental monitoring. For the newly launched FengYun-3D (FY-3D) satellite, the same capability is required for its Medium Resolution Spectrum Imager-II (MERSI-II). In processing the MERSI-II true color image, a more comprehensive processing technique is developed, including the atmospheric correction, nonlinear enhancement, and image splicing. The effect of atmospheric molecular scattering on the total reflectance is corrected by using a parameterized radiative transfer model. A nonlinear stretching of the solar band reflectance is applied for increasing the image contrast. The discontinuity in composing images from multiple orbits and different granules is eliminated through the distance weighted pixel blending (DWPB) method. Through these processing steps, the MERSI-II true color imagery can vividly detect many natural events such as sand and dust storms, snow, algal bloom, fire, and typhoon. Through a comprehensive analysis of the true color imagery, the specific natural disaster events and their magnitudes can be quantified much easily, compared to using the individual channel data.
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cloud and precipitation features of super typhoon neoguri revealed from dual oxygen absorption band sounding instruments on board FengYun 3c satellite
Geophysical Research Letters, 2015Co-Authors: Yang HanAbstract:A new methodology is developed to detect the cloud structures at different vertical levels using the dual oxygen absorption bands located near 60 GHz and 118 GHz, respectively. Observations from Microwave Temperature Sounder (MWTS) and Microwave Humidity Sounder (MWHS) on board the recently launched Chinese FengYun-3C satellite are used to prove the concept. It is shown that a paired oxygen MWTS and MWHS sounding channel with the same peak weighting function altitude allows for detecting the vertically integrated cloud water path above that level. A cloud emission and scattering index (CESI) is defined using dual oxygen band measurements to indicate the amounts of cloud liquid and ice water paths. The CESI distributions from three paired channels reveal unique three-dimensional structures of clouds and precipitation within Super Typhoon Neoguri that occurred in July 2014.