The ROM SAF radio occultation climate data records and trend analyses

Many studies have by now demonstrated the accuracy of GNSS Radio Occultation (RO) data, and their usefulness as a stable climate reference. Homogeneity of the data records are obtained by reprocessing of the data using uniform processing software throughout the length of the climate record. Version 1 of the ROM SAF Climate Data Record (CDR), based on Metop, CHAMP, GRACE, and COSMIC data, covers a continuous 15-year period from 2002 to 2016. The CDR is extended in time by an Interim CDR (ICDR) which is regularly updated nearly up to present time, and the combined time series is now long enough (20 years) to begin detection of climate trends. We here present results from recent climate applications of RO data: bending angle and temperature trends in the upper troposphere and stratosphere, including the first RO contribution to the IPCC 6th Assessment Report. Furthermore, we outline ROM SAF plans for generating RO climate data records. This includes calculating uncertainty estimates and generating homogenized water vapour climate data records based on a one-dimensional variational retrieval using detrended background data.

The Radio Occultation Meteorology Satellite Application Facility (ROM SAF) is a decentralized operational processing facility under EUMETSAT. The main objective of the ROM SAF is to generate and deliver operational radio occultation products from GNSS RO instruments onboard Metop, Metop-SG, Sentinel-6 Michael Freilich and other satellites for NWP and climate applications. The ROM SAF CDR and ICDR is publically available from: http://www.romsaf.org. Further information about the ROM SAF products and services are available at this website.