Impact studies of AMSR-E ocean surface wind speed data in NWP at JMA

The impact of assimilation of Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E) ocean surface wind speed data was investigated in Japan Meteorological Agency (JMA) global four dimensional variational data assimilation system. Japan Aerospace Exploration Agency (JAXA) produces ocean surface wind speed data from AMSR-E measurements as a standard level 2 product using 37 GHz vertical and horizontal polarized channels in no rainy area. As a research product, all weather ocean surface wind speed data are also produced by including AMSR-E low frequency (6.925 and 10.65 GHz) information. AMSR-E all weather ocean surface wind speed data were utilized in this study. A case study of cyclone Nargis in Myanmar 2008 was performed to examine the impact of microwave imager radiance data and AMSR-E all weather ocean wind speed data. Although there were no significant improvements in the cyclone track forecast by adding all weather ocean wind speed data, the assimilation of the data inside the cyclone strengthened the intensity and the maximum wind speed in the forecast realistically.