This paper reviews the data quality and impact of observations from the FY-3 satellite series used operationally in the ECMWF system. This includes data from the passive microwave radiometers MWHS-1, MWHS-2 and MWRI, ...This paper reviews the data quality and impact of observations from the FY-3 satellite series used operationally in the ECMWF system. This includes data from the passive microwave radiometers MWHS-1, MWHS-2 and MWRI, as well as observations from the radio occultation receiver GNOS. Evaluations against background equivalents show that the quality of the observations is broadly comparable to that of similar instruments on other polar-orbiting satellites, even though biases for the passive microwave observations can be somewhat larger and more complex for some channels. An observing system experiment shows that the FY-3 instruments jointly contribute significantly to the forecast skill in the ECMWF system. Positive impact of up to 2% is seen for most variables out to the day-2 forecasts over hemispheric scales, with significant benefits for total column water vapor or for temperature and wind in the stratosphere out to day 4.展开更多
The paper develops a passive sub-millimeter precipitation retrievals algorithm for Microwave Humidity and Temperature Sounder(MWHTS)onboard the Chinese Feng Yun 3C(FY-3C)satellite.The retrieval algorithm employs a num...The paper develops a passive sub-millimeter precipitation retrievals algorithm for Microwave Humidity and Temperature Sounder(MWHTS)onboard the Chinese Feng Yun 3C(FY-3C)satellite.The retrieval algorithm employs a number of neural network estimators trained and evaluated using the validated global reference physical model NCEP/WRF/ARTS,and works for seawater.NCEP data per 6 hours are downloaded to run the Weather Research and Forecast model WRF,and derive the typical precipitation data from the whole world.The Atmospheric Radiative Transfer Simulator ARTS is feasible for performing simulations of atmospheric radiative transfer.Rain detection algorithm has been used to generate level 2 products.Retrievals are reliable for surface precipitation rate higher than 0.1 mm/h at 15km resolution,which is in good agreement with those retrieved using the Precipitation retrieval algorithm version 1(ATMP-1)for Advanced Technology Microwave Sounder(ATMS)aboard Suomi NPP satellite.展开更多
The objective of this study was to retrieve daily composite soil moisture by jointly using brightness temperature observations from multiple operating satellites for near real-time application with better coverage and...The objective of this study was to retrieve daily composite soil moisture by jointly using brightness temperature observations from multiple operating satellites for near real-time application with better coverage and higher accuracy.Our approach was to first apply the single-channel brightness radiometric algorithm to estimate soil moisture from the respective brightness temperature observations of the SMAP,SMOS,AMSR2,FY3B,and FY3C satellites on the same day and then produce a daily composite dataset by averaging the individual satellite-retrieved soil moisture.We further evaluated our product,the official soil moisture products of the five satellites,and the ensemble mean (i.e.,arithmetic mean) of the five official satellite soil moisture products against ground observations from two networks in Central Tibet and Anhui Province,China.The results show that our product outperforms the individual released products of the five satellites and their ensemble means in the two validation areas.The root mean square error (RMSE ) values of our product were 0.06 and 0.09 m3/m3 in Central Tibet and Anhui Province,respectively.Relative to the ensemble mean of the five satellite products,our product improves the accuracy by 9.1% and 57.7% in Central Tibet and Anhui Province,respectively.This demonstrates that jointly using brightness temperature observations from multiple satellites to retrieve soil moisture not only improves the spatial coverage of daily observations but also produces better daily composite products.展开更多
China will continue its FY program by launching FY-2C atop LM-3A launch vehicle probably in October 2004. The geostationary meteorological satellite FY2C will be deployed to replace FY-2B launched on June 25, 2000.
Sea ice has important effect on the marine ecosystem and people living in the surrounding regions in winter.However,the understanding on changes of sea ice in the Bohai and northern Huanghai Sea(BNHS),China is still l...Sea ice has important effect on the marine ecosystem and people living in the surrounding regions in winter.However,the understanding on changes of sea ice in the Bohai and northern Huanghai Sea(BNHS),China is still limited.Based on the images from Visible and InfraRed Radiometer(VIRR)onboard Chinese second generation polar-orbit meteorological series satellites FY-3A/B/C,the sea ice areas in the BNHS were extracted from December 2008 to March 2019,the spatio-temporal distribution charac-teristics of sea ice and the relationship between sea ice area and climatic factors were analyzed,then a preliminary sea ice forecast model based on the climatic factors was developed.The results showed that sea ice area in the BNHS in each December was relatively small and rather high sea ice occurrence probability appeared in the offshore areas in Liaodong Bay and northern Huanghai Sea.The sea ice area in January or February each year was the largest,and sea ice occurred in most of areas in Liaodong Bay and northern Huanghai Sea with rather high probability and in some areas in Bohai Bay and Laizhou Bay with relatively high probability.How-ever,the sea ice area in each March was the smallest,and sea ice was even melted completely occasionally,hence with relatively low occurrence probability in Liaodong Bay.As for the inter-annual variability of sea ice in the BNHS during the research period,the sea ice area was largest in winter 2010/11 and smallest in winter 2014/15,and annual sea ice area presented a decreasing trend.The at-mospheric temperature,western Pacific subtropical high(WPSH),Asia polar vortex(APV),Asian monsoon circulation(AMC)and Eurasian monsoon circulation(EMC)were very important climatic factors for sea ice formation and they had significant correlations with sea ice area.Therefore,a preliminary sea ice forecast model was constructed by using eight climatic factors including western Pacific subtropical high area index(WPSHAI),western Pacific subtropical high intensity index(WPSHII),western Pacific subtro-pical high northern boundary position index(WPSHNBPI),Asia polar vortex area index(APVAI),Asian zonal circulation index(AZCI),Asian meridional circulation index(AMCI),Eurasian zonal circulation index(EZCI)and mean minimum atmospheric tem-perature(MMAT).The model was confirmed to have a robust forecast effect by using F-test and validated sample data.The results are useful for monitoring sea ice with remote sensed data and forecasting sea ice conditions by climatic indices.展开更多
基金We acknowledge funding from the EUMETSAT Fellowship Programme for Heather LAWRENCE,Katrin LONITZ and David DUNCAN.
文摘This paper reviews the data quality and impact of observations from the FY-3 satellite series used operationally in the ECMWF system. This includes data from the passive microwave radiometers MWHS-1, MWHS-2 and MWRI, as well as observations from the radio occultation receiver GNOS. Evaluations against background equivalents show that the quality of the observations is broadly comparable to that of similar instruments on other polar-orbiting satellites, even though biases for the passive microwave observations can be somewhat larger and more complex for some channels. An observing system experiment shows that the FY-3 instruments jointly contribute significantly to the forecast skill in the ECMWF system. Positive impact of up to 2% is seen for most variables out to the day-2 forecasts over hemispheric scales, with significant benefits for total column water vapor or for temperature and wind in the stratosphere out to day 4.
文摘The paper develops a passive sub-millimeter precipitation retrievals algorithm for Microwave Humidity and Temperature Sounder(MWHTS)onboard the Chinese Feng Yun 3C(FY-3C)satellite.The retrieval algorithm employs a number of neural network estimators trained and evaluated using the validated global reference physical model NCEP/WRF/ARTS,and works for seawater.NCEP data per 6 hours are downloaded to run the Weather Research and Forecast model WRF,and derive the typical precipitation data from the whole world.The Atmospheric Radiative Transfer Simulator ARTS is feasible for performing simulations of atmospheric radiative transfer.Rain detection algorithm has been used to generate level 2 products.Retrievals are reliable for surface precipitation rate higher than 0.1 mm/h at 15km resolution,which is in good agreement with those retrieved using the Precipitation retrieval algorithm version 1(ATMP-1)for Advanced Technology Microwave Sounder(ATMS)aboard Suomi NPP satellite.
基金supported by the National Key Research and Development Program of China(Grant No.2016YFC0402701)the National Natural Science Foundation of China(Grants No.51879067 and 51579131)+4 种基金the Natural Science Foundation of Jiangsu Province(Grant No.BK20180022)the Six Talent Peaks Project in Jiangsu Province(Grant No.NY-004)the Fundamental Research Funds for the Central Universities of China(Grants No.2018842914 and 2018B04714)the China National Flash Flood Disaster Prevention and Control Project(Grant No.126301001000150068)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(Grant No.KYCX18_0572)
文摘The objective of this study was to retrieve daily composite soil moisture by jointly using brightness temperature observations from multiple operating satellites for near real-time application with better coverage and higher accuracy.Our approach was to first apply the single-channel brightness radiometric algorithm to estimate soil moisture from the respective brightness temperature observations of the SMAP,SMOS,AMSR2,FY3B,and FY3C satellites on the same day and then produce a daily composite dataset by averaging the individual satellite-retrieved soil moisture.We further evaluated our product,the official soil moisture products of the five satellites,and the ensemble mean (i.e.,arithmetic mean) of the five official satellite soil moisture products against ground observations from two networks in Central Tibet and Anhui Province,China.The results show that our product outperforms the individual released products of the five satellites and their ensemble means in the two validation areas.The root mean square error (RMSE ) values of our product were 0.06 and 0.09 m3/m3 in Central Tibet and Anhui Province,respectively.Relative to the ensemble mean of the five satellite products,our product improves the accuracy by 9.1% and 57.7% in Central Tibet and Anhui Province,respectively.This demonstrates that jointly using brightness temperature observations from multiple satellites to retrieve soil moisture not only improves the spatial coverage of daily observations but also produces better daily composite products.
文摘China will continue its FY program by launching FY-2C atop LM-3A launch vehicle probably in October 2004. The geostationary meteorological satellite FY2C will be deployed to replace FY-2B launched on June 25, 2000.
基金supported by the National Research and Development Program of China(Nos.2020YFA0608203 and 2016YFC1402003)the FengYun Application Pioneering Project of China Meteorological Administration(No.FYAPP2021)+1 种基金the National Natural Science Foundation of China(No.42001362)the NUIST-Reading Research Institute Pump-Priming Application.
文摘Sea ice has important effect on the marine ecosystem and people living in the surrounding regions in winter.However,the understanding on changes of sea ice in the Bohai and northern Huanghai Sea(BNHS),China is still limited.Based on the images from Visible and InfraRed Radiometer(VIRR)onboard Chinese second generation polar-orbit meteorological series satellites FY-3A/B/C,the sea ice areas in the BNHS were extracted from December 2008 to March 2019,the spatio-temporal distribution charac-teristics of sea ice and the relationship between sea ice area and climatic factors were analyzed,then a preliminary sea ice forecast model based on the climatic factors was developed.The results showed that sea ice area in the BNHS in each December was relatively small and rather high sea ice occurrence probability appeared in the offshore areas in Liaodong Bay and northern Huanghai Sea.The sea ice area in January or February each year was the largest,and sea ice occurred in most of areas in Liaodong Bay and northern Huanghai Sea with rather high probability and in some areas in Bohai Bay and Laizhou Bay with relatively high probability.How-ever,the sea ice area in each March was the smallest,and sea ice was even melted completely occasionally,hence with relatively low occurrence probability in Liaodong Bay.As for the inter-annual variability of sea ice in the BNHS during the research period,the sea ice area was largest in winter 2010/11 and smallest in winter 2014/15,and annual sea ice area presented a decreasing trend.The at-mospheric temperature,western Pacific subtropical high(WPSH),Asia polar vortex(APV),Asian monsoon circulation(AMC)and Eurasian monsoon circulation(EMC)were very important climatic factors for sea ice formation and they had significant correlations with sea ice area.Therefore,a preliminary sea ice forecast model was constructed by using eight climatic factors including western Pacific subtropical high area index(WPSHAI),western Pacific subtropical high intensity index(WPSHII),western Pacific subtro-pical high northern boundary position index(WPSHNBPI),Asia polar vortex area index(APVAI),Asian zonal circulation index(AZCI),Asian meridional circulation index(AMCI),Eurasian zonal circulation index(EZCI)and mean minimum atmospheric tem-perature(MMAT).The model was confirmed to have a robust forecast effect by using F-test and validated sample data.The results are useful for monitoring sea ice with remote sensed data and forecasting sea ice conditions by climatic indices.