Evaluating Spatial and Temporal Variations of Aerosol Optical Depth and Biomass Burning over Southeast Asia Based on Satellite Data Products

Abstract

Many severe air quality problems in the major cities of Southeast Asia (SEA) are related to atmospheric aerosols, and these are mainly caused by smoke haze from biomass burning. To better understand the cause and effect relationships for the tempo-spatial distributions of atmospheric aerosols in SEA, a variety of satellite-based Moderate Resolution Imaging Spectroradiometer (MODIS) products of aerosol optical depth (AOD), precipitation, burned area (BA) and fire pixel counts (FC, derived from the active fire product) were collected and processed to evaluate the spatial and temporal variations among atmospheric aerosol, climate factors, and biomass burning in SEA during 2002-2011. High AOD zones (HAZs) located in the continental and maritime portion of SEA are identified through hotspot analysis of AOD maps. The peak AOD, BA and FC months are concentrated in the dry seasons of each HAZ. Although BA and FC are mostly identified in Indochina, the HAZ located in maritime SEA has a comparable level of AOD which may be contributed by the fire-related emissions from peatland in Indonesia. Compared to the commonly used fire-effected area dataset (MCD45 product), BA derived from a hybrid approach (MCD64 product) that considers both active fire (AF) and land change information has higher correlation coefficients with AOD in both HAZs. Linear regression models are then developed for the Indochina and the maritime HAZs, to estimate the level of AOD from the MODIS monthly fire datasets. In general the empirical models can better explain the temporal trends of AOD in HAZs by using AF-based products. The links between regional aerosol and local burning in Indochina SEA are relatively complex due to the cross-boundary transport of aerosol from Southern China.

Public health impacts of the severe haze in Equatorial Asia in September–October 2015: demonstration of a new framework for informing fire management strategies to reduce downwind smoke exposure

“…We use the Level 3 qualityassured products from both instruments, processed at 1°horizontal resolution. Both products are frequently employed to characterize smoke aerosol in Southeast Asia (Reid et al 2013, Chang et al 2015. By using two different aerosol products, we overcome some of the uncertainty associated with representing smoke optical properties in the retrievals (Zender et al 2012).…”

Satellite-Surface Perspectives of Air Quality and Aerosol-Cloud Effects on the Environment: An Overview of 7-SEAS/BASELInE

“…However, the emissions over SEA have garnered less attention than those in other tropical regions . Biomass-burning activities significantly contribute to regional pollutant emissions (Carmichael et al, 2009;Tsay et al, 2013;Chang et al, 2015). The resultant poor air quality and haze episodes cause significant pollution levels, such as PM, that far exceed regional air quality standards (Chew and Bhatia, 2008;Lyu et al, 2015).…”

Investigation of Biomass Burning Chemical Components over Northern Southeast Asia during 7-SEAS/BASELInE 2014 Campaign

“…Aerosols originate from both natural (e.g., oceans, volcanic eruptions, wind-blown dust, and forest fires) and anthropogenic (e.g., industrial activities, traffic emissions, fossil-fuel and open burning) sources. Biomass burning (BB) is a significant source of trace gases and particulate matters (PM) in the troposphere (Chang et al, 2015;Tian et al, 2015). Over Southeast Asia, this activity usually peaks in the dry season Hyer and chew, 2010;Permadi and Kim Oanh, 2013;Mahmud, 2013), which includes both forest fires and open burning of crop residues for preparation of planting areas (Chantara et al, 2012;Kim Oanh and Leelasakultum, 2011).…”