Recent climatic changes in western Patagonia

Abstract

Climatological data of long, reliable records between Puerto Montt (41°S) and Ushuaia (55°S) have been analyzed for detecting climatic trends, with special emphasis on western Patagonia. The data consist of mean annual values of temperature at 15 stations and precipitation at 5 stations collected since the beginning of this century. Temperature data show surface cooling at 41° and 42°S between the 1950's and 1970's on both sides of the Andes. However, the troposphere shows warming above the 2 km level at the same latitude. Between 43° and 45°S the surface temperature data show no significant trend during the last 100 years. South of 46°S a surface warming of 0.4 to 1.4°C since the beginning of the century can be observed. An important precipitation decrease of up to 1400 mm in the last 70 years has been observed at 52°-53°S on the Pacific side of the Andes. The generalized glacier retreat observed during this century in Patagonia is thought to be a response both to tropospheric warming and precipitation decrease.