GACP Projects
Aerosol Research Activities at the Naval Research Laboratory, Marine Meteorology Division, relevant to the "NASA NRA for Investigations to Addressthe Radiative Impact of Aerosols on the Earth's Climate"
Douglas L. Westphal
Abstract: The Marine Meteorology Division (MMD) of the Naval Research Laboratory is the lead research agency for development of global Numerical Weather Prediction models for the armed services. The MMD also develops regional and LES numerical models as well as techniques for global and regional data assimilation of surface, upper-air, aircraft, and satellite data. In conjunction with the Navy's Fleet Numerical Meteorology and Oceanographic Center (FNMOC), MMD does operational processing of AVHRR, DMSP, GOES, Meteosat, and GMS data. Research is underway at MMD to adapt these methods, techniques, and data to aerosol analysis and prediction.
Of particular interest to the NASA NRA, are our plans for a multi-year, global simulation of SO2, sulfate, desert dust, sea salt and smoke using a global aerosol model driven by the observed weather as provided by the Navy's Operational Global Atmospheric Prediction System (NOGAPS). The global weather is re-analyzed at 6-hour intervals by assimilating observations to produce global, 24-level, 0.75-degree resolution datasets of winds, temperature, precipitation, boundary layer depth, stress, surface heat fluxes, etc. The operational NOGAPS fields, interpolated to a 1.0-degree grid have been archived since January 1996 and will be available through the length of the proposal period and beyond.
The 6-hourly NOGAPS fields drive our global, semi-lagrangian, three-dimensional model of aerosols (similar to Christensen, Atm. Env, 1997) which predicts the global distribution of aerosols and diagnoses relevant radiative properties at hourly intervals. Our long-term Navy objective is to use the global analyses for initialization and boundary conditions for our regional aerosol model, hence our greatest interest lies in analyses of current conditions, though retrospective studies will be conducted to take advantage of special datasets collected during field programs and intercomparison with other models.
The current major uncertainties in the model are in the source terms for dust and smoke. We propose to use GSFC's TOMS absorbing aerosol index and land-use datasets to determine the source areas of dust. We will use data from the AVHRR, DMSP and GOES satellites to locate fires.
Despite the lack of feedback of aerosol radiative effects on model dynamics, the model suite is suitable for studying the predictability of the frequency and other characteristics of observed aerosol phenomena. For example, we will determine the ability of a combined dynamical/aerosol model with 0.75 degree resolution to predict the onset and location of dynamical forcing of dust outbreaks as well as the duration, size, and evolution of the dust plumes. This study of the predictability of dust outbreaks will help to determine the credibility of fully coupled climate simulations.
