Estimation of radius of 15m/s on Tropical Cyclone using Microwave Satellite data

KMA/NMSC is developing an algorithm for retrieving sea surface wind(SSW) speed under rain-free and rain conditions using the low frequency bands (6.9 GHz and 10.7 GHz) of passive microwave satellite observations such as GCOM-W1/AMSR-2 and GPM/GMI. According to the algorithm Sea surface roughness is proportioned to sea surface wind speed and reflectance of sea surface depends on sea surface roughness. Long microwave (under 10GHz) that transmit cloud and water vapor can observe the brightness temperature by sea surface roughness. Using these principle SSW can be produced from the low frequency bands (6.9 GHz and 10.7 GHz) of passive microwave satellite data.

From the SSW of GCOM-W/AMSR-2 and GPM/GMI, the maximum wind speed(MWS) and radius of 15 m/s and 25m/s wind speed are estimated. In addition to GCOM-W/AMSR-2 and SSW of GPM/GMI, METOP/ASCAT, DMSP/SSMIS and CORIOLIS/WINDSAT are used to estimate MSW and radius of 15 m/s and 25m/s wind speed.

The newly developed radius of 15 m/s wind speed based on AMSR2, GMI, ASCAT, WINDSAT and SSMIS microwave data has been adopted operationally in NMSC/KMA for analyzing the TCs since December 2015.