Modelización de riesgos climáticos y sistemas de vigilancia y alerta en la Comunitat Valenciana

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The first aim of this Thesis is related to the development and implementation of different warning and alert systems within the Valencia Region: a meteorological real-time forecasting system based on the Regional Atmospheric Modeling System (RAMS) and a UV Index (UVI) forecasting system based on the Santa Barbara Disort Model Atmospheric Radiative Transfer (SBDART). Furthermore, we propose a methodology that provides a computational environment suitable for the management and coordination of the different processes involved in both systems. The main improvement in the UVI forecast is related to using the total ozone column data obtained from the model Global Forecast System (GFS), rather than the data derived from the Ozone Monitoring Instrument (OMI) used in the original system. The validation of the results obtained by the UVI forecast system for the year 2008 shows a high degree of agreement between the modeling and the observations, taking into account a difference of one unit in the UV Index. Besides, the use of total ozone column from the GFS shows a slight improvement over the forecast obtained with the original system. The second aim of the current Thesis is related to the modeling of climate risks typical within the Valencia Region. In this sense, we have selected a recent episode of heavy rain, which took place on the 11th and 12th October 2007. Using this event, numerical experiments have been performed using the RAMS model in order to evaluate the influence of different physical parameters in the simulation results. On the one hand, we have analyzed the role of the orography in this sort of events. On the other hand, we have dealt with the effect of using the different convective parameterizations currently implemented in the RAMS model (Kuo and Kain-Fritsch) in the forecast results. Sensitivity tests have been run with and without these parameterizations activated in a series of combinations of the different grids. From the various experiments carried out it is shown that RAMS is a suitable tool to capture and represent the main characteristics of torrential rains in the area of study. In addition, removing the orography for the inner grid results in a decrease in intensity in the first mountain ranges close to the coast. Consequently, the observed precipitation is diminished in relation to the simulation that takes into account this parameter, and the bulk of precipitation moves inland. Finally, it has also been shown that activating Kuo and Kain-Fritsch at different horizontal resolution domains produces different results in the different variables and physical processes analyzed. Comparing both convective schemes, Kuo produces in general better results than Kain-Fritsch. Similarly, the effect of activating the Kuo parameterization on higher horizontal resolution domains improves the total precipitation results. Instead, activating the Kain-Fritsch parameterization for these domains decreases the simulated precipitation.
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