Analisi del clima e delle dinamiche climatiche nella Repubblica Dominicana e delle relative influenze sul territorio

In this thesis, we present the results of a climatic analysis carried out in the Dominican Republic to define the climate of the country, with emphasis on the identification of possible trends and corresponding land feedbacks, as a basis for a more adequate territory management. The study, which is articulated in climate classification, identification of climatic trends in a long term perspective and evaluation of territory vulnerability to desertification, is based on precipitation and air temperature monthly data from the meteorological network of the National Meteorlogical Office, integrated with some stations from the National Hydraulic Resources Institute of the Dominican Republic, a part from other data from the Ministry of Environment. The climatic classification is based on precipitation and air temperature from 115 stations (reference period 1971-2000), interpolated by means of Regression Kriging. In the regression model, the better combination of auxiliary variables derived from a Stepwise Regression analysis. The classification was carried out by means of the Thornthwaite method, based on potential evapotranspiration. After analyzing the quality of precipitation and air temperature series and omogenizing them, climate trends were estimated according to the Mann-Kendall test. The estimation of the vulnerability to desertification was carried out according to the ESA (Environmental Sensitive Areas) methodology, conveniently modified to adapt it to tropical contexts. The products of the investigation, which is innovative both in terms of the techniques used and in terms of the analysis carried out, are the following ones: 1. An up-to-date climatic map of the Dominican Republic; 2. The identification of the long term precipitation and air temperature trends in different areas of the country; 3. A map of the Index of Seisibility to Desertification of the Dominican Republic. The results give a synthesis of the climate of the Dominican Republic, consistent with its orography and the atmospheric dynamics typical of the Caribbean region. According to the analysis, 54% of the Dominican territory can be classified as dry or semi-dry, and hence quite vulnerable to inappropriate land use practices, with important implications in terms of water supplies. Trend analysis reveals that in the analysed period the Dominican Republic experimented changes both in precipitation and air temperature. This last shows an increase all over the country, which, in the case of the capital Santo Domingo, can be estimated, at a 95% confidence level, in 3.0±0.5ºC and 1.8±0.4ºC for the average annual minimum and maximum temperature respectively. Contrary to air temperature, precipitation does not show a uniform behavior in the national territory, being observed changes, both in totals amounts and pattern, which depend on the specific geographical region. A reduction in precipitation can be observed in the western portion of the country, at the border with Haiti, a zone typically dry, except the high mountainous areas and slopes with a nordeaters exposure. Increases in precipitation which can be observed in other areas of the country, such as the Caribbean coast, do not achieve the contemporary growth of air temperature be compensated, causing an increase in evapotranspiration which get us to foreseen a possible increase in aridity. In terms of vulnerability to desertification, 48% of the Dominican territory can be classified as critically sensible to desertification, pointing out that region-specific strategies of territory management are a priority in the Dominican Republic in a perspective of reduction of climate risks and territory vulnerability depending on human factors.