GEOS-IT

Goddard Earth Observing System (GEOS) for Instrument Teams

Introduction

The GEOS-IT product is a stable meteorological dataset that is generated for NASA’s instrument teams. Like the GEOS-FPIT dataset that it replaces, the time period for GEOS-IT covers from 1998 to the present, which includes the active years of the NASA EOS instruments supported by GMAO.

GEOS-IT retains many characteristics of GEOS-FPIT, including the spatial resolution (about 50km) and the use of a three-dimensional variational data assimilation algorithm. The GEOS-5.29.4 system release is used, which allows the instrument teams to benefit from many model enhancements, leading to more realistic representations of moisture, temperature, land surface, etc., and analysis changes that introduce the most modern new satellite observations into the system.

At this time, GEOS-IT is not publicly available, but is available to approved instrument teams through the NASA GES DISC. Certain input observations are intentionally withheld because the instrument teams producing those products are using GEOS-IT in their algorithms. The GMAO produces other atmospheric assimilation products that are not subject to this data withholding, such as the near real-time high-resolution GEOS-FP product (which includes forecasts) and the MERRA-2 reanalysis product, which covers the time period 1980 to the present with an unchanging GEOS system. In addition, an interim atmospheric reanalysis called MERRA-21C covering the GEOS-IT time period using an ensemble-based system of higher-resolution is expected to become available in 2025.

• Questions about GEOS-IT or a request to access the data may be sent to robert.a.lucchesi@nasa.gov.