Evaluation of PM forecasting model using Lidar and satellite data over East Asia

Abstract:

East Asian economies have experienced rapid growth over three decades, and the region is one of the world's most populated places. Asian dust and anthropogenic aerosols are considerable over East Asia. They are frequently transported to Korea during the late winter and spring. Trans-boundary dust is transported either as isolated or mixed with anthropogenic aerosols. Consequently, Asian dust and atmospheric aerosols have become an emerging issue resulting in high particulate matter (PM) episode in Korea. The PM forecasting model which has been developed and opened to public since 2007 is an effective tool to protect the public health by detecting the PM episode event and notifying it to the public in advance. Validation of forecasting models using measurements such as surface observations is necessary to assess their reliability, but they are not able to detect spatial and vertical distribution. Vertical profile is crucial to understand the long-range transport of PM.

In this study, long-range transports of aerosols were investigated by a integrated analysis of ground-based / space-borne Lidar observations and a numerical forecasting model for the PM episode in 2013. The numerical forecasting using the CMAQ model (Community Multiscale Air Quality) was compared with LIDAR (LIght Detection and Ranging) which is located in Seoul National University (37.46°N, 126.95°E) and CALIOP onboard CALIPSO satellite. Vertical profiles of CALIOP which are the Attenuated backscatter coefficient(532nm), the Depolarization ratio (532nm) and Ratio of attenuated backscatter coefficients (1064nm/532nm) were compared with those calculated from CMAQ output. Altitudinal distribution of extinction coefficient from CMAQ was also compared with vertical distribution of LIDAR extinction coefficient at Seoul.

Results showed that long-range transports of aerosols originated from China to Korea were observed by the CALIOP and the CMAQ model could depict the long-range transport of PM to identify the PM episode in Korea. Further details of model comparisons and meteorological and chemical characteristics during the haze event will be discussed in the presentation.