Detection of ice mass changes in the Patagonia from GRACE data

MARÍA JOSÉ MILICICH; AYELEN PEREIRA; MARÍA CRISTINA PACINO; RENE FORSBERG

Ciudad de Buenos Aires

Otro; Asamblea Científica de la IAG (International Association of Geodesy): Geodesy for the Planet Earth; 2009

International Association of Geodesy (IAG)

Gravimetric satellite missions introduce a new concept in the gravitational field modeling, since they provide valuable information about the geodynamic behavior of our planet. The satellite campaign GRACE allows to obtain monthly variations of the gravity field for a certain region; furthermore, we can derive these changes in terrestrial water storage (groundwater, snow, ice) and postglacial rebound, for example. Recent investigations in Greenland and Antarctica show that large ice masses are melting annually, increasing the sea level in about 2 cm per decade. Also, some researches were carried out in Glaciology using GRACE data, connecting the postglacial rebound and the Earth´s internal structure with a global approach. The Patagonia is located in the southernmost part of Argentina and Chile, between 40º S and 56º S parallels. This region is characterized by the presence of a big continental ice extension (the third greater of the world after the Antarctica and Greenland), located in the Andes Patagónicos in the border between Argentina and Chile. The continental ice lies throughout 350 Km and 49 glaciers descend from them. In Argentina, they have an extension of 3,000 Km2. Through GRACE it is possible to monitor the melting glaciers and the impact in the regional climatic change. The main objective of this research is to analyze the temporal ice mass variations in the Patagonian region from the monthly global gravity solutions provided by the four different GRACE processing centers: JPL, CSR, GFZ and BGI. Time series of ice mass variations are shown together with trend and amplitude maps for the period 2002-2008. The observed mass changes in the zone under study are caused mainly by the postglacial rebound, the water, snow and ice redistribution, among others; and partly also by the climatic change that is generating a great retrocession and loss of mass in most of the Patagonian glaciers (the Upsala glacier has backed down more than 8 Km in the last 25 years, for example). In a next stage, the detected variations will be compared and verified with satellite images series and GPS surveys. Furthermore, the connection between ice mass loss and postglacial rebound signals will be analyzed.