Determination of dust storms by Hoffman index in Tehran, Iran and com-pare with remote sensing, and responsible organizations from March 2014 through March 2015
Abstract
Introduction: The occurrence of dust storms in recent years, has led to the use of data recorded in ground measurements stations to determine the sourc-es and investigate the occurrence of these storms in the past; however, it is as-sociated with the possibility of measurement errors or failures in some cases. Materials and methods: In this study, using the data records by synoptically stations, dust storms that occurred in Tehran during March 21, 2014 to March 20, 2015 were determined.
To verify the detected cases of dust storms through the index, satellite imag-ery was collected and analyzed on the days. For remote sensing, Modis Level 1 images were processed using the ENVI 5.3. In order to show dust, NDDI, BTD (32-31), and BTD (20-31) indices were used. Finally, the sensitivity and specificity of all two items were compared with the weather data announced on these days; using R software.
Results: Results indicate, compared to actual observations, that the sensitiv-ity of this method was 100% and its specificity was 98%.
Conclusion: Because the index used in this study consisted of three parame-ters of wind speed, PM10 concentration, and horizontal visibility, it minimized the possibility of mistakes due to the simultaneous use of all three parameters to show dust storms.
