[A-CG37] Satellite Earth Environment Observation

[ACG37-15] Comparison between the GSMaP cloud moving vector and a tracking method of individual precipitation clusters

*Hitoshi Hirose¹, Takuji Kubota¹, Tomoaki Mega², Tomoo Ushio² (1.Japan Aerospace Exploration Agency, 2.Osaka University, Japan)

Keywords:Remote Sensing, Precipitation Estimation, Precipitation Tracking

The Global Satellite Mapping of Precipitation (GSMaP) uses an algorithm called MVK to track precipitating clouds observed by PMW satellites to interpolate gaps in the PMW satellites observation network (Ushio et al. 2009). Forecast and Tracking the Evolution of Cloud Clusters (ForTraCC: Villa et al. 2008) is a method that tracks each precipitation cluster individually. The ForTraCC calculates the pseudo-center of gravity of precipitation clusters and predicts its destination based on its past movement history. The ForTraCC can track precipitation from middle and lower-levels clouds without being affected by upper-level clouds. To improve the cloud moving vector of the GSMaP by using the ForTraCC, this study compared the tracking performance of the GSMaP_MVK and the ForTraCC in tropical regions.
We calculated the movement of precipitating clouds after one hour by using the GSMaP_MVK and the ForTraCC, and compared their tracking performance by using passive microewave satellites as truth. The results showed that the ForTraCC was more accurate for shallow precipitation in the tropics. On the other hand, the GSMaP_MVK was more accurate in terms of RMSE because the ForTraCC does not account for temporal changes in rain rate. In addition, we corrected the GSMaP cloud moving vector by using the center-of-gravity moving vector of the ForTraCC. As a result, tracking accuracy of the GSMaP_MVK was improved especially for shallow precipitation in the tropics.