The Enhancement and Monitoring of Dust Events Based on Visible and Infrared Remote Sensing Techniques

In recent years, the frequency of dust pollution events in the Southwest of Iran are increased which caused huge damage and imposed a negative impacts on air quality, airport traffic and people daily life in local areas. In this study, two methods based on the analysis of satellite visible and infrared measurements have developed to enhancement and monitoring of dust events from origin source to local areas. In order to do this work, two dust cases using MODIS observation and METEOSAT data are investigated in two parts A and B.In part A, a method to modify the initial state of model in the numeric analysis using discrepancies between dynamic fields and the Water vapor (WV) satellite imagery are presented. Results from superposition of vorticity fields and satellite WV images shows a close relationship in the circulation systems of extratropical cyclones. but, a mismatch between the vorticity fields and the imagery can indicate a model analysis or forecasting error. In part B,the magnitude of the difference in Brightness Temperature (BTD) in selected bands of MODIS and NDVI, MNDVI indices used to infer the signature of dust. Initial results show that MNDVI index cannot detect dust over water completely. Thus we used the algorithm of combining BTD of dust between the wavelengths 8.5μm (MODIS band-29) and 11μm (MODIS band-31) with negative values of bands -31 and 32 BTDs. In this study for extraction of dust areas, (BT8.5-BT11) – (BT11-BT12) values larger than obtained threshold and (BT11-BT12) smaller than zero are used.The use of thermal infrared spectrum algorithm detects dust well.The aerosol optical depth (AOD), ground-based observations and surface visibility are used to validation of output product .Comparing the results with synoptic maps and output of a Dust Regional Atmospheric Model (DREAM 8b) showed that using enhancement algorithms is a more reliable way than other MODIS products or model outputs to detect dust.Finally, using backward trajectories of NOAA HYSPLIT model showed how the dust transports from the source to other areas.