Evaluation of WRF-Chem model: A case study of the June 2013 Biomass-Burning Haze event

This study aims to identify the weather conditions that intensified the transboundary transport of forest fire emissions from Sumatra and Kalimantan during the June 2013 and September to October 2015 haze events. WRF-Chem is used to simulate the formation and transport of biomass-burning haze during the study periods of 15th to 27th June 2013 and 1st September to 30th October 2015. Particular attention is given to the 2015 haze event since the dry conditions during that period were intensified by the El Niño event. A 27-km spatial grid is used to observe the South-Southeast Asian synoptic weather patterns and their effects on the transport of biomass-burning emissions from Sumatra and Kalimantan to Peninsular Malaysia and Singapore. The emissions in WRF-Chem is specified according to the Fire Locating and Modeling of Burning Emissions (FLAMBE) database which is derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) fire products. Results show that the transport of the PM2.5 emissions was intensified by the presence of low pressure systems over the South China Sea. The model was evaluated by comparing the results with high-spectral resolution LIDAR data of Singapore as well as meteorological data for Malaysia during the haze episode