Retrievals of Aerosol Optical Depth and Angstrom Exponent for Identification of Aerosols at Kuching, Sarawak

Abstract

Anthropogenic and natural aerosols are important atmospheric constituents that significantly contribute to the Earth’s radiation budget but remain uncertainties due to the poor understanding of aerosol properties and its direct effects on scattering and absoprtion of solar radiation and the ability of aerosols to stay in atmosphere for a very short time. Different types of aerosols, representing biomass burning, urban or continental aerosols, maritime aerosols and dust particles will give different characterization and classification of aerosol properties. The data used in this study was obtained from Aerosol Robotic Network (AERONET).Two parameters were used for aerosol analysis which are Aerosol Optical Depth (AOD) at four wavelengths (440, 500, 675 and 870nm) and Angstrom exponent (α) derived from a multispectral log linear.

Monsoonal variations in aerosol optical properties and estimation of aerosol optical depth using ground-based meteorological and air quality data in Peninsular Malaysia

“…(2002bSmirnov at al. ( , 2003, Pace et al (2006), Kaskaotis et al (2007), Toledano et al (2007), Salinas et al (2009), andJalal et al (2012) were used to distinguish the aerosol types. The testing results indicate that the threshold criteria by Toledano et al (2007) were the most reliable, because of the minimal occurrence value of the indistinguishable aerosols (referred as mixed-type aerosols, MIXA).…”

“…The aerosol types are seasonally discriminated from scatter plots of Ångström exponent against the AOD. Threshold values in the scatter plot for aerosol classification have been previously reported by Smirnov et al (2002bSmirnov et al ( , 2003, Pace et al (2006), Kaskaotis et al (2007), Toledano et al (2007), Salinas et al (2009), andJalal et al (2012). The data selection criteria proposed by Tan et al (2014a) are used in this study.…”

“…Salinas et al (2009) suggested that the determination of DA and BMA does not correspond entirely to the range of threshold used in our study, in which the amount of MIXA (approximately 43 % of the total occurrence) was large. Jalal et al (2012) efficiently identified aerosol types using an alternative threshold criterion. Using their threshold, we find a low amount of MIXA of approximately 21 %.…”

“…Similar studies have performed this analysis using AERONET data. These data sets have been applied at different locations, such as the Persian Gulf (Smirnov et al, 2002a); several oceanic regions (Smirnov et al, 2002b); Brazil, Italy, Nauru, and Saudi Arabia (Kaskaoutis et al, 2007); Spain (Toledano et al, 2007); Singapore (Salinas et al, 2009); Kuching (Jalal et al, 2012); and the multi-filter rotating shadowband radiometer in central Mediterranean (Pace et al, 2006). The scatter plot of Ångström 440−870 against AOD_500 or AOD_440 was used to characterize the aerosol type.…”

Moderate Imaging Resolution Spectroradiometer (MODIS) Aerosol Optical Depth Retrieval for Aerosol Radiative Forcing

“…As resulting by the occurrence of dry season which usually occurs during June until September yearly and also comes from haze episodes and also from urbanization. Study by [12] classified that In Kuching area dominant aerosols occurred in Kuching area urban and continental aerosols. It can be shown that at Julian Day 253 in 2015 there are extremely high value of AOD MODIS was retrieved with 6.0 while only 2.9 for AOD AERONET .…”