Analysis of terrestrial water storage variability in South America derived from GRACE data

AYELEN PEREIRA; CECILIA CORNERO; MARÍA JOSÉ MILICICH; MARÍA CRISTINA PACINO

Potsdam

Otro; Asamblea Científica de la IAG (International Association of Geodesy); 2013

IAG (International Association of Geodesy)

The gravity does not remain constant but changes over time depending on the masses redistribution. These changes can be associated with continental water storage temporal variations which is the main component of the global hydrological cycle. The satellite gravity mission GRACE (Gravity Recovery And Climate Experiment) provides time-variable gravity field models that reflect the Earth?s gravity field variations at a resolution of ~400 km, which are mainly due to mass transport processes. The 26% of the Earth?s freshwater is found in SouthAmerica where three large river basins (the Amazon -the most extensive in the world-, the Orinoco and the La Plata) and the second fresh groundwater reservoir of the world (the Guaraní water-bearing system) are distinguished. Moreover, in the southernmost part of Argentina and Chile, there is region characterized by the presence of a large continental ice extension (the third greater of the world after Antarctica and Greenland). The continental ice lies throughout 350 Km and 49 glaciers descend from them. The aim of this work is to analyze the most significant terrestrial water storage changes over SouthAmerica for the period 2002-2012 in order to identify patterns of surface run-off and groundwater flows at continental and regional scales. The Equivalent Water Height ?EWH- of 10-day interval derived from GRACE data computed by GRGS/CNES processing center is applied in this research. The EWH variations show important features in coincidence with large hydrographical areas like the Amazon, Orinoco and La Plata basins, and the in the Patagonian Icefield region. The results are validated with GPCP?s (Global Precipitation Climatology Project) data sets, river level measurements and GLDAS (Global Land Data Assimilation System) model in the areas where the major variations occurred. Interannual variations of EWH from GRACE are related to extreme climatic events as the 2007 flood and 2009 drought that affected SouthAmerica. Significant agreement is also found at interannual time-scale between EWH and river level measurements in basins that are dominated by surface reservoirs.