Acceleration of terrestrial water storage changes from GRACE data
Abstract
Gravity Recovery and Climate Experiment (GRACE) satellite has been producing scientific results on mass variations since its launch in 2002, particularly land water storage on seasonal and inter-annual timescales as the soil moisture reflects the time integration of fluxes of precipitation, evapo-transpiration and runoff. For example, in Amazon Basin (e.g. Tapley et al., 2004), Alaska glacial melting (e.g. Tamisiea et al., 2005), ENSO precipitation anomalies (Morishita and Heki, 2008), and seasonal land water storage with global hydrological model (Syed et al., 2008). If climate changes have trends of time scale longer than inter-annual, we can expect to see quadratic trends in land water time series now that over six years have passed since GRACE"fs launch and the time span is becoming long enough to study such trends, which signify the temporal acceleration in gravity, and hence climatic, changes. To look for such accelerations, we compute time series of equivalent water thicknesses in global land regions from monthly GRACE data of gravity anomaly, and model the changes with quadratic functions in addition to seasonal components. We repeat similar calculations for the GLDAS global hydrological model data as well. We found that the geographic distribution of the quadratic trends shows good agreement between GRACE and GLDAS, prominent in East Africa, East Europe, Ural Mountains, eastern North America and southern South America. Amplitudes of the signals are generally larger in GRACE than the corresponding GLDAS model. We also compare and verify such acceleration terms with trends in meteorological data of precipitation and evapo-transpiration.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2008
- Bibcode:
- 2008AGUFM.G13A0642O
- Keywords:
-
- 1217 Time variable gravity (7223;
- 7230);
- 1225 Global change from geodesy (1222;
- 1622;
- 1630;
- 1641;
- 1645;
- 4556);
- 1240 Satellite geodesy: results (6929;
- 7215;
- 7230;
- 7240);
- 1616 Climate variability (1635;
- 3305;
- 3309;
- 4215;
- 4513);
- 1866 Soil moisture