Pablo Sarricolea Espinoza

Spatial analysis of rainfall daily trends and concentration in Chile

Chile has a great diversity of climates. In average, the rainfall differs between 0.7 mm (Iquique, North) and 1,814.8 mm (Valdivia, South) according to the main meteorological stations. The small rainfall amount in the North concentrates on few days, with only 3 days per year. In Central Chile, there are among 16 to 42 rainy days and in the South more than 150 days. In order to understand the correlation between precipitation totals (grouped into 1-mm size classes) and the number of rain days, climatologists use the Concentration Index (CI). In the present study, this index was calculated for 17 meteorological stations across Chile for the period between 1965-2005, also using other indicators: Coefficient of Variation, Temporal irregularity and the relation of precipitation with teleconnections. The results of the CI show a high variation among the regions (from 0.51 to 0.76). The highest one was recorded in La Serena (30o S), with values higher than 0.70. From La Serena, the CI decreases gradually, reaching values of about 0.60 in the Atacama Region (North) and further South in the Biobio Region. The concentration of rainfall has increased in the last sub-period (1985-2005), as inter-seasonal variability.

El estudio de la Isla de Calor Urbana de Superficie del Área Metropolitana de Santiago de Chile con imágenes Terra-MODIS y Análisis de Componentes Principales

In order to understand the patterns and intensities of the Surface Urban Heat Islands (SUHIs) of Santiago emission temperatures were calculated using 53 Terra MODIS satellite images and then factor reduction was performed using Principal Components Analysis (PCA). In addition, intensity maps of SUHIs were created. Results show that the maximum temperature (with intensities measuring above 5°C) within the SUHI tends to be located in the central municipalities of Santiago, as well as in the municipalities of Huechuraba and Quilicura. Furthermore, PCA reveals four typical patterns, which explain 90.6% of cases: consolidated SUHI, piedmont SUHI and high income wedge, no SUHI and high intensity SUHI in the south. It has been hypothesized that the lack of a SUHI to the drain effect, which is linked to the katabatic breeze, causing the SUHI to move toward the west sector of the city.

Variabilidad y cambios climáticos observados y esperados en el Altiplano del norte de Chile

This study analyses temperature, rainfall irregularity and droughts in the Altiplano of Northern Chile at different temporal and spatial scales using data from meteorological stations and high spatial resolution climatic coverage, in respect to current and future scenarios included in the Fifth IPCC report. The aim of this work is to analyze and evaluate climate variability and climate change affecting this region. Our work confi rms an increase in temperature, and offers regional scale precision as to the predicted reduction in rainfall, as well as its predicted increase in variability. We identifi ed territories with distinct responses to climate change in the Altiplano, considering spatial and temporal variability in temperature, rainfall and extreme events (storms and droughts). Our results indicate a high coeffi cient of variation in annual rainfall and an opposite response when the concentration index for daily precipitation is considered.