Upper Air Temperature Profiles averaged monthly and zonally from 2002 to present derived from satellite observations

This dataset contains monthly and zonally averaged Upper Tropospheric and Lower Stratospheric (UTLS) temperature profiles derived from globally distributed GPS radio occultation (RO) measurements from EUMETSAT's Metop polar-orbiting satellites as well as other satellites carrying RO instruments. The atmospheric temperature distribution is an important characteristic for the Earth's climate system. Temperature changes are one of the most important indicators of global climate change, and any impacts on the temperature distribution may reveal the processes involved in those changes.

The dataset is produced by the EUMETSAT Radio Occultation Meteorology Satellite Application Facility (ROM SAF) and comprises the Climate Data Record (CDR, January 2002 to December 2023, ROM SAF product ID GRM-28-R2) and the Interim Climate Data Record (ICDR, January 2024 to present, ROM SAF product ID GRM-29-I2). The dry temperature profiles are retrieved using observed atmospheric refractivity profiles, and assuming hydrostatic equilibrium. Compared to other satellite observation techniques, RO observations have high vertical resolution, have a high long-term stability, and are not affected by clouds or the type of underlying surface (such as land and sea).

The retrieved dry temperature data are averaged in monthly and 5-degree latitude bands for altitudes below the mid-stratosphere. The variability (standard deviation) within such monthly bins is also provided, as well as associated quantities such as observation counts, sampling errors, and a mask (‘drymask’) indicating where the dry temperatures can safely be used as a measure of the physical temperature. In addition, dry temperature data are provided for collocated ECMWF reanalysis data (currently ERA5), sampled at the same times and locations as the observed data.