Upper tropospheric humidity gridded data derived from satellite observations

Upper Tropospheric Humidity (UTH) is of key importance to the Earth’s greenhouse effect and understanding of climate change. It is considered an Essential Climate Variable (ECV), because it controls key atmospheric processes, including those involved in water vapour and cloud feedbacks, that can amplify the climate system’s response to increases in other greenhouse gases.

The Upper Tropospheric Humidity is defined as the integrated amount of Water Vapour in the atmospheric layer between ~500 hPa and ~100 hPa. The UTH Thematic Climate Data Record (TCDR) and Interim Climate Data Record (ICDR) are derived from observations from the AMSU-B and MHS microwave humidity sounder instruments on board the NOAA- and MetOp- satellite series. Instantaneous satellite observations are used to derive a spatially and -temporally averaged data record. The data are available as twice daily (one for the ascending and the other for the descending passes) averages on a regular latitude/longitude grid. Additionally, the daily mean UTH is provided as a weighted average of ascending and descending orbits for all the grid points with valid ascending and descending observations.

The TCDR component of this dataset is brokered to the CDS and was originally produced on behalf of EUMETSAT Satellite Application Facility on Climate Monitoring (CMSAF) by the Met Office. The ICDR component has been delivered directly to the CDS and was originally produced on behalf of the C3S by the Met Office. Besides, UTH, Total Column Water Vapour and Tropospheric Humidity Profiles are part of the Water Vapour ECV data from satellites in the CDS, see related datasets.