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Wang Y.,Hefei University of Technology | Wang Y.,Chinese Academy of Sciences | Fu Y.,Hefei University of Technology | Fu Y.,Chinese Academy of Sciences | And 2 more authors.
IEEE Transactions on Geoscience and Remote Sensing | Year: 2014

Ice water path (IWP) is an important parameter to characterize tropical cyclones. The FY-3B satellite, with multiple passive microwave sensors onboard, offers a unique opportunity to monitor the variation of cloud IWP during the evolution of tropical cyclones. In this paper, by using the combined simultaneous measurements of the MicroWave atmospheric Humidity Sounder and MicroWave Radiometer Imager on FY-3B satellite, an improved IWP algorithm for tropical clouds is developed. The new algorithm seeks to better estimate ice-free background brightness temperature at 150 GHz using simultaneous observations at low microwave frequencies. This approach improves IWP retrieval accuracy particularly for high IWP clouds that often associated with tropical cyclones. The current algorithm was applied to FY-3B observations of two typhoons with different strengths, and the characteristics of IWP variation at the storms' different evolution stages were investigated. The results showed that IWP tends to vary ahead of the storm intensification or decay, suggesting that IWP can be potentially used to predict the change of storm intensity. © 1980-2012 IEEE.

Ce G.,South-Central University for Nationalities | Bing-sen X.,National Satellite Meteorology Center | Zhao-xiang L.,South-Central University for Nationalities
Chinese Astronomy and Astrophysics | Year: 2013

Solar flares are important events for the space weather. The predic- tion of relevant parameters of solar flares has practical significance for evaluating the effect of sudden ionospheric disturbance (SID). The data of soft X-ray flux observed by the GOES-8 satellite in the 23th solar cycle are used to predict the peak intensities and ending times of X-class flares with the method of data fit- ting. Using this method to analyze the X-class flares in the 23th solar cycle, it is possible to predict the peak flux of an X-class flare 17. minutes in advance at most. And the ending time of an X-class flare may be predicted about 60. minutes in advance at most. The predicted results indicate that the prediction method has certain effectiveness and applicability. © 2013 Elsevier B.V.

Yang C.-Y.,PLA University of Science and Technology | Lu Q.-F.,National Satellite Meteorology Center | Jing L.,Air Force Academy of Armaments
Jiefangjun Ligong Daxue Xuebao/Journal of PLA University of Science and Technology (Natural Science Edition) | Year: 2012

To study the practicability of dual-channel atmospheric motion vectors(AMVs) of FY-2C in operational forecast, the dual-channel AMVs were merged firstly, and then the merged AMVs were reassigned to the new heights with the 12 h wind fields forecasted by the T511 System as a reference, which could both increase the spatial density and improve the quality of AMVs obviously. On this basis, the impact of the AMVs without and with height reassignment on assimilation and forecasts by using the WRF model and its three-dimensional system were studied. It's found that the assimilation of the original AMVs enhanced the statistical errors of the initial wind field. However, the assimilation of the reassigned AMVs improved the quality of the initial wind field. Further more, the assimilation of either the original or the reassigned AMVs led to increasing errors of the initial field of height, temperature and humidity. However, the assimilation of the reassigned AMVs was much better than that of the original AMVs. The 48 h forecasts of the wind field were improved by assimilating the reassigned AMVs. With the extension of the validity period, the better wind field could drive the impact of assimilating the reassigned AMVs on other element fields to translate from a negative initial pattern to a positive forecasting pattern.

Yang S.,National Meteorological Information Center | Shi G.Y.,CAS Institute of Atmospheric Physics | Chen L.,National Satellite Meteorology Center | Wang B.,CAS Institute of Atmospheric Physics | Yang H.L.,Shenzhen National Climate Observatory
Scientific Online Letters on the Atmosphere | Year: 2011

Deep Blue (DB) is a new MODIS retrieval algorithm to retrieve aerosol properties over bright surfaces such as arid, semiarid and urban areas. It's expected to fill in data gaps over bright surface left by the standard algorithm based on Dark Target (DT) retrieval algorithm. DB has been employed in recent Collection 5.1 AOD product. This study presents a comparison between the DT approach and the more recent DB algorithm using international Aerosol Robotic Network (AERONET) data as reference, analyzes the improvement in DB AOD product over urban surface and discusses the influence of aerosol model variation on MODIS AOD retrieval. Results show that DB products perform better than DT products under clear condition, and a systematic AOD overestimation in DT products doesn't occur in DB products. DT and DB AOD products both appear strong seasonal pattern, with better performance in autumn and winter and worse performance in spring and summer, and the underestimated Aerosol Single Scattering Albedo (SSA) during spring and summer over Beijing in MODIS retrieval probably is the major factor inducing the AOD overestimation in these seasons. In comparison with DB AOD, DT AOD is more likely overestimated, unsuitable surface reflectance over Beijing may be the key factor, and it may play a more important role in MODIS DT AOD retrieval than unsuitable SSA. © 2011, the Meteorological Society of Japan.

Wang X.,National Satellite Meteorology Center | Guo Q.,National Satellite Meteorology Center
Hongwai Yu Haomibo Xuebao/Journal of Infrared and Millimeter Waves | Year: 2014

By using the self-developed calibration of inner blackbody corrected by lunar emission (CIBLE) results of Fengyun-2 (FY-2) satellite, tropical cyclones (TC) intensity was estimated objectively with Dvorak technology. Several strong and supper strong TCs happened in 2012 summer and autumn were selected, when FY-2 lay in the stages of the smooth variation of calibration and the acutely variation one occurred in satellite eclipse period, respectively. As the comparative datum, both MTSAT satellite calibration and FY-2E cross-calibration result were used for the analysis. The results show that CIBLE method can accurately describe the diurnal and annual variation of FY-2E on-orbit calibration slopes, which is the main contributor to the consistent estimations of TC intensity between CIBLE and MTSAT in each intensity stage. Particularly, during the autumn eclipse period, the diurnal variation of calibration slope greatly improves the accuracy of strong typhoon intensity determination even at night. The maximal error of the wind speed in typhoon center has been reduced by 14m/s, which is believed to be a significant promotion for the TC intensity prediction.

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