Assimilation of EUMETSAT IASI 3D wind product in the Navy Global Environmental Model

The primary function of the Infrared Atmospheric Sounding Interferometer (IASI) instrument on board the Metop polar-orbiting satellites is to measure radiances. Recently, the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) developed the capability to estimate wind profiles using optical flow techniques from IASI 3D retrievals of temperature, humidity, and ozone on pressure surfaces. This wind product provides vector winds on 25 levels between 10 hPa and 1000 hPa for the high-latitude (45 degrees poleward) northern and southern hemispheres at approximately 100 km horizontal spacing. Since wind observations from satellites are important for numerical weather prediction models, we expect this new wind product to be of great value for weather forecasting. EUMETSAT's IASI wind product differs from traditional Atmospheric Motion Vectors (AMV) derived from other satellite products in two important ways: 1) AMVs only provide winds at one level (e.g., cloud top) whereas IASI provides wind profiles, and 2) AMV algorithms rely on estimates of wind height whereas the assigned heights of the IASI wind profiles are obtained from the retrieval algorithm.

We have developed the capability to assimilated EUMESAT’s IASI 3D wind product in the Navy Global Environmental Model (NAVGEM) and will present our evaluation of the impact of this new wind product on NAVGEM forecasts. EUMETSAT’s IASI wind product is expected to become operational in 2024 for the EPS-SG (EUMETSAT Polar System-Second Generation) and the technology is being developed for upcoming geostationary sounders such as MTG-IRS (Meteosat Third Generation Infrared Sounder).

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