Numerical Downscaling of Extreme Events at South Brazil Coastal Region
Abstract
The south coastal region of Brazil is undergoing a series of extreme weather events. Mid-latitude cyclones, squall-lines, semi-stationary anti-cyclones over the Atlantic and strong mesoscale convective systems are among the events that are affecting this region. Understanding their behavior and improving the forecast capacity of these events is still a challenge problem for this high populated region. The major tools for the forecasting are the numerical weather prediction models. In this study, a state-of-the-art model is used to evaluate its skill on the modeling the major extreme events of this region. A total of twelve case studies were chosen to conduct the numerical simulations with the Ocean-Land-Atmosphere Model (OLAM). This model uses and icosahedrical global grid and resolve the Navier-Stokes equations with a finite volume integration. The model was setup with a global hexagonal grid and a refining approach with a local mesh positioned along the coast having a 6km grid spacing. This novel approach allows for a simultaneous consideration of the large scale and local scale features representation. In this initial stage, the 12 simulated case studies were evaluated comparing the model results for precipitation and wind fields with observations. The results show that OLAM is able to capture the major atmospheric dynamics and the precipitation distribution that occurred in each case study. At the present stage, a hybrid climate downscaling is under development that will combine a statistical downscaling to extract the major regional weather types and further dynamical downscaling with the OLAM model. This hybrid downscaling approach should provide an important tool for regional climate change projections for coastal regions.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.A31O2789R
- Keywords:
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- 3329 Mesoscale meteorology;
- ATMOSPHERIC PROCESSES;
- 3354 Precipitation;
- ATMOSPHERIC PROCESSES;
- 3355 Regional modeling;
- ATMOSPHERIC PROCESSES;
- 4313 Extreme events;
- NATURAL HAZARDS