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Observed dimming effect during a forest fire in the southeastern United States and the role of aerosols
Author(s) -
Prabha Thara V.,
Hoogenboom Gerrit
Publication year - 2009
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2009gl038435
Subject(s) - environmental science , aerosol , weather research and forecasting model , atmospheric sciences , moderate resolution imaging spectroradiometer , atmosphere (unit) , radiative transfer , flux (metallurgy) , sensible heat , climatology , spectroradiometer , meteorology , satellite , geology , geography , physics , reflectivity , materials science , quantum mechanics , astronomy , metallurgy , optics
A surface dimming effect during a forest fire was observed in the incoming solar radiation measurements of the Georgia Automated Environmental Monitoring Network (AEMN). A combination of in situ AEMN and Moderate Resolution Imaging Spectroradiometer (MODIS) datasets were used to demonstrate the implications on the forecasts when aerosol radiative effects are not included in the Weather Research and Forecasting (WRF) model. The clear sky incoming radiative flux predicted by the model at the surface was overestimated when aerosol optical depths (AODs) exceeded 0.2, which in turn caused a positive temperature bias and a negative mixing ratio bias at the surface. These biases resulted from differences in the energy partitioning at the surface, where the main contribution was from enhanced sensible heat flux. The model atmosphere was also cooler and drier than the MODIS profiles, indicative of the aerosol induced warming below 6 km.