HR: 0830h
AN: A11E-0018    [PDF]
TI: Assessment of clear sky radiative forcing in the Caribbean region using an aerosol dispersion model and ground radiometry during the Puerto Rico Dust Experiment
AU: * Gass\'{o}, S
EM: santiago@climate.gsfc.nasa.gov
AF: GEST/University of Maryland,Baltimore County, Code 913, GSFC/NASA, Greenbelt, MD 20771
AU: Ji, Q
EM: ji@climate.gsfc.nasa.gov
AF: GEST/University of Maryland,Baltimore County, Code 913, GSFC/NASA, Greenbelt, MD 20771
AU: Westphal, D L
EM: westphal@nrlmry.navy.mi
AF: Aerosol and Radiation Modeling Section,Naval Research Laboratory, 7 Grace Hopper Street, Stop 2, Monterey, CA 93943
AU: Reid, J
EM: jreid@nrlmry.navy.mi
AF: Aerosol and Radiation Modeling Section,Naval Research Laboratory, 7 Grace Hopper Street, Stop 2, Monterey, CA 93943
AU: Tsay, S
EM: tsay@climate.gsfc.nasa.gov
AF: GEST/University of Maryland,Baltimore County, Code 913, GSFC/NASA, Greenbelt, MD 20771
AB: This study investigates the surface and top of the atmosphere solar radiative forcing by long-range transport of Saharan dust. The calculations of radiative forcing are based on measurements collected in the Puerto Rico Dust Experiment (PRIDE) carried out during July, 2000. The purpose of the experiment was the characterization of the Saharan dust plume, which frequently reaches the Caribbean region during the summer. The experiment involved the use of three approaches to study the plume: space and ground based remote sensing, airborne and ground based in-situ measurements and aerosol dispersion modeling. The diversity of measuring platforms provides an excellent opportunity for determination of the direct effect of dust on the clear sky radiative forcing. Specifically, comparisons of heating rates, surface and TOA fluxes derived from the Navy global aerosol dispersion model NAAPS (NRL Aerosol Analysis and Prediction System) and actual measurements of fluxes from ground and space based platforms are shown. In addition, the direct effect of dust on the clear sky radiative forcing is modeled. The extent and time of evolution of the radiative properties of the plume are computed with the aerosol concentrations modeled by NAAPS. Standard aerosol parameterizations, as well as in-situ composition and size distributions measured during PRIDE, are utilized to compute the aerosol optical depth, single scattering albedo and asymmetry factor. Radiative transfer computations are done with an in-house modified spectral radiative transfer code (Fu-Liou). The code includes gas absorption and cloud particles (ice and liquid phase) and it allows the input of meteorological data. The code was modified to include modules for the aerosols contribution to the calculated fluxes. This comparison study helps to narrow the current uncertainty in the dust direct radiative forcing, as recently reported in the 2001 IPCC assessment.
DE: 3359 Radiative processes
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting