Characterization of aerosol physical and optical properties from a combination of ground-based and hand-held Sun-photometer data of Singapore

Since October 2006, the Center for Remote Imaging, Sensing and Processing (CRISP) of the National University of Singapore has joined the Aerosol Robotic Network, AERONET, to monitoring aerosol optical properties in this region. This initiative complements the already existing activities on satellite remote sensing performed at CRISP. In Singapore, the sources of aerosols are mostly from fossil fuel burning (energy stations, incinerators, cars etc.) and from the industrial and urban areas. The proximity to the sea adds a possible oceanic source and depending on the time of the year, there can be a strong bio-mass component coming from forest fires from various regions of the neighboring countries. In this work, we present a survey of aerosol optical depth (AOD) and Angstrom exponent retrievals at several regions of Singapore. AOD measurements were performed with the help of AERONET´s CIMEL Sun-photometer (located at CRISP) and a versatile hand held Microtops II Sun-photometer. In order to identify the degree of geographical variability of aerosol optical properties, we collected data samples over selected sites across the island. Furthermore, we extracted concurrent data points from our own AERONET site in order to check for consistency and validation of our results. This study has enabled us to identify possible aerosol sources and understand the nature and physical characteristics of atmospheric aerosols across Singapore.