LONG-TERM TRENDS IN TEMPERATURE-BASED AGROCLIMATIC INDICES IN ARGENTINA

FERNANDEZ LONG MARIA ELENA; MÜLLER, GABRIELA V.; BELTRAN-PRZEKURAT ADRIANA

Mendoza

Congreso; XI Congreso Argentino de Meteorología (CONGREMET XI); 2011

Centro Argentino de Meteorólogos

Changes in several temperature-based agroclimatic indices in the central-eastern of Argentina, most of them located within the Pampas region were analyzed for 39 meteorological stations. Trends of first (FFD), last (LFD) and number (NFD) of frost days, frost period (FP), start (SGS), end (EGS) and length (LGS) of the growing season, growing degree days (GDD), diurnal temperature range (DTR), chilling hours and lowest annual minimum temperature were computed for the period 1940-2007. Changes were observed for this period and were mostly indicative of a long-term minimum temperature warming throughout the region.During this period, generalized decreases in the NFD and in the FP (i.e., a delayed FFD and an earlier LFD) were found. Although the trends in the growing season indices were not as large as in the frost indices, they were consistent with the overall warming: an earlier SGS and a delayed in the EGS. The trends of the GDD showed a large variability between months with a generalized increased throughout the year. The DTR showed the largest number of stations with statistically significant negative trends from austral late-spring (November) to austral early fall (April). They could potential affect management decisions and crop yields. In particular, frost is still an important hazard in agricultural activities and within the context of our results longterm characterization of frost risk need to be considered at local and sub-regional scales.