Upgrades of Polar AMVs Use In JMA’s Global NWP System
Atmospheric Motion Vectors (AMVs) provide important information on tropospheric wind fields for observation data sparse areas, such as ocean areas. AMVs derived from geostationary satellites and low earth orbit satellites imagery have been assimilated into Japan Meteorological Agency’s (JMA’s) numerical weather prediction (NWP) systems.
MODIS and AVHRR polar AMVs have been provided by NOAA/NESDIS and CIMSS for approximately twenty years. Those AMV data are operationally utilized in JMA’s global NWP system. However, there is concern about a loss of polar AMVs coverage in the near future due to the termination of MODIS and AVHRR observation. Therefore, it was necessary to immediately start using new AMVs in the polar regions of the NWP system.
Impacts on addition of a new data, i.e., Dual-Metop and VIIRS AMVs have been investigated in the NWP system. The addition of the new data enhances the AMV data coverage, especially for polar regions. In the investigation, one-month observing system experiments (OSEs) were performed with using the new AMVs instead of MODIS AMVs at high latitudes. The experiments showed positive impacts on the analysis and forecast fields of the troposphere over high latitudes. Based on these findings, Dual-Metop AMVs have been assimilated operationally into the NWP system at high latitudes (50° N and S to the poles) since June 2022. Operational assimilation of Suomi-NPP and NOAA-20 VIIRS polar AMVs will start in 2023 in the NWP system.
This presentation will introduce the OSEs results on the use of Dual-Metop and VIIRS AMVs in JMA’s global NWP system.
