Seminar

Abstract

Tropical areas over South America have faced severe environmental changes associated with the rapid economic expansion, such as deforestation and fire activities over the Amazon basin and cerrado areas and a sustained growing demographic density around large- and mega cities. Efforts on BRAMS (Brazilian development on the Regional Atmospheric modeling System, RAMS) aim to develop a tool able to address the main environmental issues in South America and their atmospheric forcing. Forming the basis of this tool was RAMS model originally developed at Colorado State University. RAMS is a limited-area non-hydrostatic, time-split compressible atmospheric model designed to simulate atmospheric circulation within a range of scales of planetary waves to down to meters. BRAMS, version 5.0, progressed RAMS for being tuned for the South America region and including a comprehensive set of new physical parameterizations, gaseous and aerosol-chemistry and transport schemes and a completely restructuring of the parallel computational design. BRAMS dynamic core contains an absolutely monotonic/highly accurate advection scheme for scalars and the local mass conservation was improved. The set of physical parameterizations includes NN PBL scheme, a scaled and aerosol aware convective parameterization, radiative transfer schemes with aerosol and cloud microphysics interactions. The gaseous chemical module, which virtually allows the use of any chemical mechanism, fully coupled with the meteorological component includes a detailed emissions pre-processor, plume-rise for biomass burning, aqueous/gases chemistry, photochemistry, scavenging (grid and sub-grid scales) and dry deposition. More recently, a modal aerosol scheme has been coupled, with representation for up to 16 aerosol populations, including organic carbon, black-carbon, mineral dust, sea salt, sulfate, nitrate and ammonium. The JULES/UK surface scheme also has been coupled to BRAMS, allowing a fully consistent simulation of carbon and another relevant biogeochemical cycles.

BRAMS has been used operationally at the Brazilian center for weather forecast since 2003 providing an on-line weather and air quality forecast on a 20 km grid-spacing and, more recently, since 2013, for weather forecast on 5 km covering the entire South America.

BRAMS have also been broadly used for applications mainly over South America, with strong emphasis over the Amazonia and the main South American mega cities. An overview of the model development and main applications will be shown.