Urmia Lake dust storms occurrences: investigating the relationships with changes in water zone and land cover in the eastern part using remote sensing and GIS

摘要

Urmia Lake is the largest lake in the Middle East which has greatly decreased in recent years. It has had a great impact on the environmental properties of areas around the lake. This study aimed to identify the relationship among dust storms in the eastern part of Urmia Lake and the surrounding vegetation due to the annual and long-term variability of this water zone during the statistical period 1999-2019. Normalized difference water index (NDWI), normalized difference vegetation index (NDVI), Aerosol Optical Depth (AOD), and Dust Storm Index (DSI) were used due to trend and correlation analysis models and T-student analysis. The study results found that, first, the decreasing trend of Urmia Lake, directly and significantly, has led to an increase in dust concentration (AOD) in the lake's eastern part. On the other hand, changes in the water level of Lake Urmia have led to a general decreasing trend in vegetation in the region which led to an increase in the frequency of DSI in the region. The model developed showed that changes in the water zone of Urmia Lake as a very powerful driver leads to an increase in the intensity and frequency of dust storms in the eastern part of the lake and intensifies the dust conditions in the region. The synergistic resultant of these two drivers was maximized in years when both lake area and vegetation were at a minimum at the same time (2011-2016). The estimated scenario of this model is that if the decreasing trend of Urmia Lake intensifies in the study area, more frequent and severe dust storms will occur in the region.