Evaluation of drought impact on Frequency of dust phenomenon occurrence by SPI, PNI and ZSI indexes

Dust phenomenon is one the problem that is developed due to human interference and unreasonable utilities from natural resources and their destruction. In this review, the dust phenomenon frequency was done using selected synoptic stations statistical in Alborz and Qazvin provinces during 2000 to 2014 that annual frequency was evaluated by extraction of dust codes from meteorological data statistically. In order to study of velocity and direction of region winds, wind rose and storm rose of Karaj and Qazvin stations were drew and prevalent wind direction was determined that it showed prevalent wind is northwest and southeast at Karaj and Qazvin stations respectively. Study of the effect of drought on dust phenomenon event was done using SPI, PNI, ZSI indicator for annual scale and was evaluated via SPSS software. The drought result show that 2013 was the driest year at Karaj station and the SPI, PNI and ZSI values were obtained -1.64, 58 and -1.39 respectively. Also 2008 was the driest year at Qazvin station and SPI, PNI and ZSI values were calculated -2.34, 50 and -1.99 respectively. With studying of annual dust frequency with regard to 06 and 07 codes detected that totally 169 days was reported as day with dust at Karaj station that 2012 and 2014 had the most event frequency. Furthermore, totally 115 days with dust accrued at Qazvin station that 2011 with 23 days had the most event frequency.