Calendar Event Details
AEROCENTER: Virginie Buchard
Affiliation: GESTAR USRA
Event Date: Tuesday, November 25, 2014
Location: G133
Time: 11:00 AM
Evaluation of surface PM2.5 in MERRAero
MERRAero is the first aerosol reanalysis produced at NASA’s Global Modeling Assimilation Office (GMAO) using meteorological fields from the MERRA reanalysis. This reanalysis is based on a version of the GEOS-5 model radiatively coupled to Goddard Chemistry, Aerosol, Radiation, and Transport (GOCART) aerosols and includes assimilation of bias corrected Aerosol Optical Depth (AOD) from the MODIS sensor on both Terra and Aqua satellites. In this presentation, we use surface fine particulate matter (PM 2.5) measurements collected by the US Environmental Protection Agency (US EPA) and the IMPROVE networks in the United States as independent validation for MERRAero. Focusing on a 10 years period (from 2003-2012), we first, make an assessment of MERRAero AOD against independent ground-based retrievals from AERONET network. Over this period, MERRAero shows relatively good agreement with AERONET AOD at 550 nm. While we constrain the total column aerosol loading in MERRAero, the assimilation of AOD however, does not correct errors in either aerosol vertical placement or composition, implying that surface PM 2.5 is much harder to estimate. The model was able to better capture monthly mean measurements from IMPROVE network, composed essentially of rural stations. Comparisons with the EPA chemical speciation network provides much understanding of which species MERRAero predicts well and for which there is some discrepancy when compared with EPA.