Prospects for improving AMV spatial coverage between geostationary and polar AMVs: LeoGeo and Dual-Sentinel

Historically there has been a gap in spatial coverage between AMVs provided from polar-orbiting satellites and geostationary satellites. In the use of AMVs at ECMWF, this has partly been filled with Dual-Metop AMVs from EUMETSAT and by accepting geostationary AMVs from higher zenith angles. Here we examine LeoGeo AMVs from CIMSS and Dual-Sentinel AMVs from EUMETSAT which both provide additional AMV data in the gap region. Our evaluation in the ECMWF system finds that the LeoGeo AMVs had very small background departure statistics but assimilation experiments showed some negative effects on the model geopotential height field. Dual-Sentinel AMVs showed similar departure statistics to the Dual-Metop AMVs, demonstrated a largely neutral result when assimilated in addition to Dual-Metop, and a positive result when assimilated in the absence of Dual-Metop.