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|Title:||Dust storm detection and monitoring using multi-temporal Insat-3A-CCD data|
|Abstract:||Sand and dust on being agitated up by winds often trigger huge dust storms and cause conditions of near-zero visibility. The local climatic conditions get altered by the airborne particles, from dust storms, by intercepting sunlight and modifying the energy budget through their ensuing behaviour of cooling and heating of the atmosphere. It is, therefore, essential to evolve proficiency in monitoring dust storms and predicting their evolution. Many studies using MODIS and other satellite data sets have shown importance of satellite imagery to detect and monitor the dust storms. However, the geostationary platform is the most suitable one to study the dynamics behaviour of such events. In the present study we have used INSAT-3A-CCD data to characterize a massive dust storm event occurred during October 15-16, 2008 over the northern Arabian Sea. The dust storm generated by strong winds lifts particles of dust or sand into air and is characterized by high Aerosol Optical Depth (AOD), lower angstrom exponent (a) along with near zero visibility condition. Multi temporal INSAT–3A–CCD data for every hour have been used to study the characteristics and transport of this dust storm event. AOD and a estimation were carried out and estimated AOD and a were also compared with MODIS derived AOD at 550nm and a (550/865). Air mass back-trajectory analysis was also conducted, along with the Quickscat scatterometer derived wind vector data, to identify potential source regions of these aerosols. An increase of the AOD values by 150-300% and simultaneous decrease of the angstrom exponent by 50 to 60 % was observed for dust-affected regions.Average AOD at 550nm was found to be 1.03, whereas, angstrom exponent was found to be 0.26 in comparison to AOD (550nm) of 0.33 and a of 0.4 during non-dust days. Higher AOD associated with lower angstrom exponents typically signifies presence of larger particles. Diurnal variations in AOD were also noticed an increment during dust storm, with 50% increase from morning to noon and 33% fall from afternoon to evening in the AOD at 550nm. Back trajectory analysis indicated that the dust was generated from the desert regions of Afghanistan and Pakistan and migrated towards the Arabian Sea.|
|ISSN:||0975-2412 (Online); 0771-7706 (Print)|
|Appears in Collections:||BVAAP Vol.18(2) [December 2010]|
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