Aplicación de Sistemas de Información Geográfica al análisis de eventos climáticos extremos en la Región Semiárida Pampeana (provincia de Buenos Aires, Argentina)

Abstract

Rainfall is one of the main input to the water balance of a region or of a natural system. The  variability  often  causes  severe  floods  or  droughts  that  may  affect  the  population,  the economic activities, the access to water and the land coverages. The occurrence of Geographic Information Systems (GIS) facilitates the analysis of large volumes of data and spatiotemporal studies. On the other hand, the development of satellites with sensors that record data at different spatial, temporal, spectral and radiometric resolutions allowed us to observe the Earth surface periodically to complement studies on the environment. Based on these tools, the objectives of this study were to analyze the spatial response of water  bodies of the Pampas  Region and its possible relation to extreme rainfall events (period 1960-2010). Due to its vast spatial extension, the studied area was subdivided considering the different precipitation patterns. Thus, a cluster analysis of monthly precipitation data from 33 meteorological stations belonging to the National Weather Service (SMN, Argentina) for the period 1960-2010 was applied. As a result six sub regions were obtained: Extremely Humid, Very Wet, Moderately Wet, Wet, Dry and Very Dry. The extreme precipitation events were studied by applying the Standardized Precipitation Index (IEP) and Continuous Wavelet Transformation. Both methods permitted to analyze dry, wet and normal events in each sub regions. After determination of these extreme events, it was proceeded to select a water body belonging to each sub region. Each one water body was monitored during extreme rainfall events in order to determine variations in physical (color, reflectivity, Suspended particular  matter)  and  morphometric  characteristics.  For  this  study  45  satellite  images  (18 Landsat 5 TM, 12 Landsat, 8 OLI- TIRS and 15 Spot 5) were digitally processed for monitoring water bodies during the studied period. As a result, it was found that the physical response of water  bodies  was  different  depending on the region and its behavior allowed us to infer the effects of rainfall variability