Water storage temporal estimates in the La Plata Basin from GRACE monthly models

AYELEN PEREIRA; SILVIA MIRANDA; MARÍA CRISTINA PACINO; RENE FORSBERG

Foz do Iguasu

Congreso; American Geophysical Union (AGU) Meeting of the Americas; 2010

American Geophysical Union (AGU)

Aquatic environments perform important functions in nature such as the control of climate, floods and nutrients, and they provide goods and services for humanity. To monitor these environments at large spatial scales , the satellite gravity mission GRACE provides time-variable gravity field models that reflect the Earth´s gravity field variations due to mass transport processes like continental water storage variations. GRACE can map water storage changes to heights of a few millimeters on a spatial resolution of 400 Km. The La Plata Basin is one of the largest in South America with an area of 3.100.000 Km2. This basin covers 5 countries: Brazil, Argentina, Paraguay, Bolivia and Uruguay; and it is a sample of the abundance, variety and quality of natural resources and the possibilities offered in connection with the production of goods and services. The main rivers in Argentina that are part of this hydrographic system are the Paraná (its basin is the biggest one with an area of 1.510.000 Km2), Uruguay and Paraguay. Also in the La Plata basin lies a big part of the second fresh groundwater reservoir of the world (the Guaraní Water-bearing System), thus knowing its behavior is of extreme importance for being a great environmental, economic and strategic resource. Temporal and spatial variations of water storage in the area covered by the basin are difficult to measure using ground data because of the hydrographic system´s size; but with the present advance of technologies represented by GRACE data it is possible to detect the monthly spatial changes in the distribution of water masses in these regions. In this work the GRACE capability to monitor the water storage over La Plata Basin is analyzed for the period 2002- 2009, using the solutions provided by the 4 different GRACE processing centers: CSR, JPL, GFZ and BGI. The time series of water storage variations from GRACE are shown together with the corresponding trend maps. Afterward the calculated hydrological signal is used to estimate four mass change models over this hydrographic system´s area using a generalized inversion method on the gravity trends. Results from ENVISAT altimetry data are compared with GRACE solutions. Also, GRACE monthly mass grids from the NASA are presented with hydrometric heights from the National Hydric Information System (SINH) in Argentina.