USING MICROWAVE RADIANCES FOR THE GENERATION OF CLIMATE DATA RECORDS FOR PRECIPITATION, WATER VAPOUR, LIQUID WATER PATH AND EVAPORATION-RELATED QUANTITIES AT CM SAF

K. Fennig¹, A. Niedorf¹, T. Sikorski¹, H. Konrad¹, M. Schröder¹, S. Finkensieper¹

¹Deutscher Wetterdienst

The Satellite Application Facility on Climate Monitoring (CM SAF) develops, generates, archives and distributes high-quality satellite-derived products of the global energy and water cycle and related sustained services in support to understand our climate. Microwave remote sensing of the atmosphere plays an important role at CM SAF for the generation of the Global Interpolated RAinFall Estimation (GIRAFE) climate data record (CDR) for precipitation (Niedorf et al., 2024; Konrad et al., 2025) and the Hamburg Ocean Atmosphere Parameters and fluxes from Satellite data (HOAPS) CDR which covers atmospheric parameters total column water vapour, liquid water path, evaporation and related parameters (Andersson et al., 2010, 2017; new version pending). In support of these, as well as external activities, CM SAF produces a microwave imager fundamental CDR (FCDR) covering quality-controlled, intercalibrated radiances observed by SSM/I and SSMIS. For a more complete sampling and optimum stability, observations by other microwave imaging instruments are intercalibrated with the FCDR. In addition, for a further improved monitoring of precipitation in GIRAFE, observations by microwave sounding instruments – not covered by the CM SAF FCDR-related activities – are used.

Here, we give an overview of these CDRs, the constellations feeding into them, and the processing that is necessary to obtain stable timeseries from these diverse constellations. Special emphasis will be put on contrasting different approaches, for example statistical post-processing of Level-2 data as pursued in GIRAFE vs mimicking target sensor Level-1 data (the HOAPS approach for radiative transfer modelling via 1d-Var / RTTOV).

Andersson, A., et al.: The Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data – HOAPS-3, Earth Syst. Sci. Data, 2, 215–234, https://doi.org/10.5194/essd-2-215-2010, 2010.

Andersson, A. et al.: Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data – HOAPS 4.0, Satellite Application Facility on Climate Monitoring, https://doi.org/10.5676/EUM_SAF_CM/HOAPS/V002, 2017.

Konrad, H., et al.: GIRAFE v1: a global climate data record for precipitation accompanied by a daily sampling uncertainty, Earth Syst. Sci. Data, 17, 4097–4124, https://doi.org/10.5194/essd-17-4097-2025, 2025.

Niedorf, A. et al.: GIRAFE v1: CM SAF Global Interpolated RAinFall Estimation version 1, Satellite Application Facility on Climate Monitoring. https://doi.org/10.5676/EUM_SAF_CM/GIRAFE/V001, 2024.