Dynamics of Atmosphere and Hydrosphere

Mass re-distribution of near-surface geophysical fluids in Atmosphere, Oceans, and continental Hydrosphere are reflected in the observations from various geodetic and geophysical measurement techniques. The broad-band spectrum of atmosphere-hydrosphere dynamics with periods ranging from hours to decades requires the consideration of various modeling approaches for either correcting for the high-frequency variability in raw observations in order to avoid aliasing effects, or for jointly interpreting measurements from different observation techniques covering several years or even decades.To describe atmospheric variations of surface pressure and winds with high temporal resolution, we rely on data from the European Centre for Medium-Range Weather Forecasts (ECMWF). For present-day applications, operational analyses and 10-day forecasts are available.

For studies covering time-frames of more than a few years, we use re-analysis data-sets from ERA-40 or ERA Interim. In addition, dedicated simulation studies from the coupled chemistry climate models WACCM and CESM are available for analysis.The continental part of the global hydrological cycle is simulated with the Land Surface Discharge Model (LSDM). The water masses stored in the soil, snow/ice, rivers and lakes load the Earth surface and cause elastic deformations of the Earth's crust. Modeled water storage data from the LSDM can be used to simulate load-induced time-variable variations of the Earth gravity field in order to separate relevant climatological signals from systematic and random errors of the various geodetic observation techniques.For interpreting and correcting oceanic bottom pressure and sea level variations in geodetic observables, we primarily rely on simulations with the Ocean Model for Circulation and Tides (OMCT), which is maintained and developed at GFZ since 2007. Data from an OMCT configuration forced with ECMWF operational data are currently applied as a standard background model for the de-aliasing of non-tidal and short-term atmosphere-ocean variability in the GRACE and GOCE gravity field processing. Simulations from alternate general ocean circulation models are also considered for further studies.Simultaneously geodetic observations are assimilated into the numeric ocean model OMCT. Thus, for example, satellite gravimetry observations can be used to improve the modelled high frequency mass redistributions in the world ocean and consequently derive a better state estimate for forecasts. 

 

Contact

Profile photo of  Dr. Henryk Dobslaw

Dr. Henryk Dobslaw
Earth System Modelling

Telegrafenberg
Building A 20, room 316
14473 Potsdam
tel. +49 331 288-1974