Evaluating short-term hydro-meteorological fluxes using daily GRACE data
Abstract
Atmospheric and terrestrial water budgets, which represent important boundary conditions for both climate modeling and hydrological studies, are linked by evapotranspiration (E) and precipitation (P). These fields are provided by numerical weather prediction models and atmospheric reanalyses and play an important role in the context of climate modeling for initialization and evaluation. Changes in terrestrial water storage as observed by the satellite gravity mission GRACE (Gravity Field and Climate Experiment) represent a new and completely independent data set for constraining the net flux deficit in atmospheric reanalyses. In this study daily GRACE gravity field changes are used to investigate high-frequency hydro-meteorological fluxes over the continents. Band-pass filtered water fluxes are derived from GRACE water storage time series by first applying a numerical differentiation filter and subsequent high-pass filtering to isolate fluxes at periods between 5 and 30 days. By comparison to the latest atmospheric reanalysis ERA5 of the European Centre for Medium-Range Weather Forecasts (ECWMF) we can show that daily GRACE gravity field models contain realistic high-frequency water flux information. Furthermore, GRACE-derived water fluxes can clearly identify improvements realized within ERA5 over its direct predecessor ERA-Interim with substantial differences detectable especially in equatorial and temperate climate zones. Regions of improvement are in good correspondence with rain gauge validation but GRACE also identifies three distinct regions (Sahel Zone, Okavango Catchment, Kimberley Plateau) with a slight degradation of net-fluxes in ERA5 with respect to ERA-Interim highlighting the potentially added value of non-standard daily GRACE gravity series for hydro-meteorological monitoring purposes.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.G52A..01E
- Keywords:
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- 1218 Mass balance;
- GEODESY AND GRAVITY;
- 1223 Ocean/Earth/atmosphere/hydrosphere/cryosphere interactions;
- GEODESY AND GRAVITY;
- 1225 Global change from geodesy;
- GEODESY AND GRAVITY;
- 1655 Water cycles;
- GLOBAL CHANGE