Time-variant gravity measurements and GPS-radio-occultation observations will be prepared for the validation (and initialising) of complex Earth system models.

Geodetic satellite missions provide precise information on the current state of the Earth’s system: gravity observations from the GRACE mission allow estimates on mass re-distributions related to variations in terrestrial water storage, ice mass changes, and ocean dynamics. GPS radio-occultation (RO) observations obtained from different low-orbiting satellites provide near-realtime information on temperature and water vapour distributions in the atmosphere.

Within GeoClim, gravity and RO observations will be processed into Level-3 products that are readily applicable for Earth System Model validation and eventually initialization. GRACE-based products will include globally gridded mass anomalies for both oceans and continents, as well as time-series of mass variability averaged across the largest discharge basins and transport changes across selected ocean transects. From the RO observations, zonally averaged monthly mean temperature and water vapour climatologies will be developed for the upper troposphere lower stratosphere between 5 and 35 km height with vertical resolution of 200m. In addition, tropopause parameter (height, pressure, temperature) climatologies will be provided, together with derived quantities such as gravity wave parameters, temperature gradients and Brunt-Vaisäla frequencies.

In line with the three different development stages (DS) of the MiKlip consortium, preliminary versions of these Level-3 products will be prepared during the first phase (DS1) to develop suitable evaluation metrics and to validate the baseline MiKlip prediction system. Subsequent improvements in the processing will be performed during the second phase (DS2) together with uncertainty assessments of the observations in order to provide a quality-controlled data-set for the evaluation of the prototype MiKlip prediction system (DS2), the synthesis MiKlip system (DS3) and additional process studies as, for example, the hydrological model MCRA.

Goals

• Provision of time-series of geophysical parameters derived from observations of the satellite gravity mission GRACE: monthly mean anomalies of ocean bottom pressure, changes in continental ice masses, variations in terrestrial water storage
• Provision of time-series of meteorological parameters from GPS radio occultation observations: zonally averaged monthly mean climatologies of temperature and water vapor in the UTLS region, climatologies of tropopause parameters and additional derived quantities
• Validation of the MiKlip decadal prediction system in its different development stages, and evaluation of additional process studies