PESSACG Natalia Liz
congresos y reuniones científicas
Performance and evaluation of sensitivity experiments with a Regional Climate Model for extreme climate events.
Trieste, Italia
Workshop; Fifth ICTP Workshop on the Theory and Use of Regional Climate Models; 2010
Institución organizadora:
The Abdus Salam International Centre for Theoretical Physics (ICTP)
The CLARIS LPB project (A Europe-South America Network for Climate Change Assessment and Impact Studies in La Plata Basin) aims at predicting the climate change impact on hydroclimate and extreme events over La Plata Basin. As the first step to reach this goal, a group of regional climate models (RCMs) forced by 1989-2008 ERAinterim reanalysis have simulated the South American continent with 50km of horizontal resolution. Fifth-generation Pennsylvania-State University-NCAR nonhydrostatic Mesoscale Model (MM5) is one of the models that simulated this period. The goal of this study was analyzed the capability of MM5 to represent climatic conditions, in particular precipitation, associated with extreme climatic events over South America, and study the sensitivity of the this model to model’s physics and model’s configuration with the objective to find the best configuration of the model.We focused our analysis in November and December 1986. Experiments achieved reproduce the variability between both months in La Plata Basin (LPB) and South Atlantic Convergence Zone (SACZ) region linked with the positive and negative phase of see-saw pattern in South America (SASS). Kain Fritsch convective scheme presented troubles for simulating precipitation in LPB region, that problem is associated with the deficiencies that this scheme presents for representing the circulation at low layers. These deficiencies were solved with the nudging option, and this also improves the simulation of precipitation in LPB region. Simulations presented high levels of uncertainties, with ranges of precipitation bigger in SACZ than in LPB. And also, the level of uncertainties is bigger in wet months than in dry months. Finally, precipitation distributions showed that all simulations are overestimating the weak events of precipitation and underestimating the extreme events.