| Observing the intensity and structure of tropical cyclones can provide more accurate wind speed structure at the sea surface of tropical cyclones,which is helpful for disaster prediction and assessment,and also helps to study the mechanism of sudden changes in tropical cyclone intensity.Based on 615 tropical cyclones’ sea surface wind speed images of the soil moisture active passive(SMAP)satellite L-band microwave radiometer from April 2015 to December 2021,this paper proposes an estimating method about tropical cyclone intensity and multiple structural parameters including center,the radius of maximum wind(RMW),the radius of 34 knots wind(R34),the radius of 50 knots wind(R50)and the radius of 64 knots wind(R64)and then compare the result with data from Synthetic Aperture Radar(SAR),the International Best Track Archive for Climate Stewardship(IBTr CAS)and the Stepped Frequency Microwave Radiometer(SFMR).It is found that the parameters which are calculated by the model have good consistency with the corresponding test data,indicating that our model solves the problem of positioning and intensity determination in observing tropical cyclones by SMAP radiometer.Using the relevant parameters estimated by the model,we combined the cloud top brightness temperature data provided by the FY4 A geostationary satellite and the threedimensional precipitation data provided by the Global Precipitation Measurement(GPM)Dual-frequency precipitation radar(DPR)to study the influence of tropical cyclone intensity changes on internal convection intensity,and the number of overshooting tops,the ratio of cloud top height and the proportion of convective precipitation are used as indirect observations of convective intensity.It is found that the change of intensity causes changes in the azimuth and radial distribution of overshooting tops,as well as changes in cloud top height,precipitation rate and the proportion of convective precipitation. |
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