Volume 17, No. 1, January 2017, Pages 253-261 PDF(895 KB)
Evaluation of PM2.5 Surface Concentrations Simulated by Version 1 of NASA’s MERRA Aerosol Reanalysis over Israel and Taiwan
Simon Provençal1, Virginie Buchard2,3, Arlindo M. da Silva2, Richard Leduc1, Nathalie Barrette1, Emily Elhacham4, Sheng-Hsiang Wang5
1 Département de géographie, Université Laval, Quebec City, Quebec, Canada
2 Goddard Space Flight Center, National Aeronautics and Space Administration, Greenbelt, Maryland, USA
3 Goddard Earth Sciences Technology and Research, Universities Space Research Association, Columbia, Maryland, USA
4 Department of Geophysical, Atmospheric and Planetary Sciences, Tel Aviv University, Tel Aviv, Israel
5 Department of Atmospheric Sciences, National Central University, Taoyuan, Taiwan
- The concentration of PM2.5 in Israel is high and composed mostly of mineral dust.
- The evaluation in Israel was favorable despite a slight overestimation overall.
- The concentration in Taiwan is high and composed mostly of anthropogenic particles.
- The evaluation was most favorable during the summer in Taiwan.
Version 1 of the NASA MERRA Aerosol Reanalysis (MERRAero) assimilates bias-corrected aerosol optical depth (AOD) data from MODIS-Terra and MODIS-Aqua, and simulates particulate matter (PM) concentration data to reproduce a consistent database of AOD and PM concentration around the world from 2002 to the end of 2015. The purpose of this paper is to evaluate MERRAero’s simulation of fine PM concentration against surface measurements in two regions of the world with relatively high levels of PM concentration but with profoundly different PM composition, those of Israel and Taiwan. Being surrounded by major deserts, Israel’s PM load is characterized by a significant contribution of mineral dust, and secondary contributions of sea salt particles, given its proximity to the Mediterranean Sea, and sulfate particles originating from Israel’s own urban activities and transported from Europe. Taiwan’s PM load is composed primarily of anthropogenic particles (sulfate, nitrate and carbonaceous particles) locally produced or transported from China, with an additional contribution of springtime transport of mineral dust originating from Chinese and Mongolian deserts. The evaluation in Israel produced favorable results with MERRAero slightly overestimating measurements by 6% on average and reproducing an excellent year-to-year and seasonal fluctuation. The evaluation in Taiwan was less favorable with MERRAero underestimating measurements by 42% on average. Two likely reasons explain this discrepancy: emissions of anthropogenic PM and their precursors are largely uncertain in China, and MERRAero doesn’t include nitrate particles in its simulation, a pollutant of predominately anthropogenic sources. MERRAero nevertheless simulates well the concentration of fine PM during the summer, when Taiwan is least affected by the advection of pollution from China.
MERRAero; Evaluation; Fine particulate matter; Israel; Taiwan.