Abstract |
Space-borne precipitation radar observes three dimensional distribution of reflectivity. In numerical weather prediction system, a skillful assimilation of such observation data provides improvement of precipitation forecast. Therefore, Japan Meteorological Agency (JMA) has been developing the space-born radar assimilation. Then JMA started its first operational assimilation of space-borne radar data, introducing GPM/DPR in Meso-scale Analysis in March 2016. In the GPM/DPR assimilation, relative humidity profiles are retrieved from the DPR reflectivity profile using Bayesian theory. Then, the relative humidity profiles thus obtained are assimilated in 4DVAR system. This method, known as 1D+4DVAR, is also used for assimilation of ground-based weather radar at JMA. In the performance evaluation tests of the GPM/DPR assimilation, improvement of Typhoon and precipitation forecast was demonstrated. This impact of GPM/DPR assimilation will be presented in the seminar.
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