Lidar measurements during a haze episode in Penang, Malaysia and validation of the ECMWF MACC-II model

Haze is a phenomenon which occurs when there is a great amount of tiny particulates suspended in the atmosphere. During the period of March 2014, a long period of haze event occurred in Penang, Malaysia. The haze condition was measured and monitored using a ground-based Lidar system. By using the measurements obtained, we evaluated the performance of the ECMWF MACC-II model. Lidar measurements showed that there was a thick aerosol layer confined in the planetary boundary layer (PBL) with extinction coefficients exceeding values of 0.3 km−1. The model however has underestimated the atmospheric conditions in Penang. Backward trajectories analysis was performed to identify aerosols sources and transport. It is speculated that the aerosols came from the North-East direction which was influenced by the North-East monsoon wind and some originated from the central eastern coast of Sumatra along the Straits of Malacca.