A Regional Modeling System for Weather and Climate Studies in
South America
Ana
Nunes
Universidade Federal do Rio de
Janeiro
Noon April 21 in Room 2155
Abstract:
A version of the NCEP Regional Spectral Model, coupled to the Noah
Land-Surface Model, was successfully implemented at the Federal
University of Rio de Janeiro in Brazil, as part of an integrated
modeling system for the analysis of vulnerability and risk caused by
severe weather or extreme climate events. Specifically for climate
studies, this regional modeling system employs a new boundary forcing
based on scale-selective bias correction and precipitation
assimilation. Similar to the spectral nudging technique for dynamical
downscaling, the scale-selective bias correction allows high-resolution
modes to develop, but maintains the large-scale features from the
boundary conditions, whereas the precipitation assimilation procedure
acts on the modeled deep-convection and drives the land-surface scheme
variables. In this newer version, the scale-selective bias correction
was applied only on the rotational part of the wind field, letting the
assimilation of satellite-based precipitation estimates to correct
moisture convergence. Thus, the two techniques can be used together to
improve the regional modeling system solutions, particularly in the
tropics and subtropics where moisture convergence can be difficult to
depict. Comparisons with the NCEP Climate Forecast System Reanalysis
outputs will be shown at resolutions of approximately 38- and 25-km of
the regional modeling system.
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