Climate regionalization and trends based on daily temperature and precipitation extremes in the south of the Pampas (Argentina).

FERRELLI, F.; BRENDEL, A.S.; ALIAGA, V.S.; PICCOLO, M.C.; PERILLO, G.M.E.

Cuadernos de Investigación Geográfica

Universidad de La Rioja

Lugar: LA RIOJA; Año: 2019 vol. 45

The south of Pampas (36° 32?- 40° 44? S; 63° 24?- 60° 30? W), as most of Argentina, is asemiarid region. Its economy is based on rain-fed agriculture and livestock. Traditionally, the climate hasbeen studied considering the analyses of monthly and annual climate parameters, but there is evidence thatin this type of areas, the short-term climatic events have a substantial impact on the climate. Therefore, thisstudy aimed at developing a climate regionalization from the analysis of daily temperature and precipitationextremes in the south of the Pampas for the period 1970-2017. Subsequently, it focuses on analyzing bothtrends and breakpoints of these events in the different sub-climates. To do so, we applied a Cluster-basedPrincipal Component Analyses with a Ward hierarchical supervised method to generate a climateregionalization considering 29 daily extreme climatic indices and the elevation. We identify four subregions,and we analyzed trends during 1970-2017, and in the two-time series defined by applyingbreakpoints. Both minimum and maximum temperatures and precipitation had structural changes in thelast 15 years, exposing the region to warming and dryness trends. The maximum temperature increases0.5ºC, while precipitation decreases 30 mm. The short-term climate variability allows us to identify areasclimatically more detailed and to conclude that the south of the Pampas is characterized by its highdependency on short-term climatic events.