[A-CG37] Satellite Earth Environment Observation

[ACG37-14] Polar extension of moving vector calculation using NEXRA data for the GSMaP PMW-IR combined algorithm

*Munehisa K. Yamamoto¹, Takuji Kubota¹, Ying-Wen Chen² (1.Earth Observation Research Center, Japan Aerospace Exploration Agency, 2.Atmosphere and Ocean Research Institute, The University of Tokyo)

Keywords:GSMaP, NEXRA, cloud/precipitation, moving vector

The Global Precipitation Measurement (GPM) project leads the global distribution of precipitation by combining observations from multiple microwave radiometers (PMWs) onboard low Earth orbit satellite. Since sampling gaps occur with PMW observation alone shorter than 3 hours, infrared (IR) images from geostationary meteorological satellites are used to interpolate precipitation areas and their moving vectors, and are combined with PMW observations, as a PMW-IR combined algorithm. When the zenith angle from geostationary Earth orbits is large such as high latitude areas, it is difficult to accurately capture cloud areas due to radiometric effect. Therefore, coverage of major PMW-IR combined satellite precipitation map products has been limited to the equatorial region below 60-degree latitude. The Global Satellite Mapping of Precipitation (GSMaP) product version 05 (algorithm version 8), released in December 2021, implemented precipitation estimation up to the poles only in the PMW observation area. However, it is expected that the PMW-IR combined algorithm fill the remaining PMWs sampling gaps in the polar regions.
This study examined the derivation of moving vectors using Nonhydrostatic Icosahedral Atmospheric Model-Local Ensemble Transform Kalman Filter (NICAM-LETKF) Japan Aerospace Exploration Agency (JAXA) Research Analysis (NEXRA), which is in regular operation together with GSMaP to extend the PMW-IR combined algorithm to the polar regions. The moving vectors of column water vapor and precipitation were calculated by modifying the current version of GSMaP moving vector calculation program to extend poleward and to allow the use of geophysical quantities other than IR. In this presentation, we will compare the results with other numerical weather forecast data used in previous studies and discuss issues for their use.