Analysis of the Long-Term Trend of Temperature, Precipitation, and Dominant Atmospheric Phenomena in Lake Urmia

Lake Urmia is one of the largest saline lakes in the world, which its level has gone through significant variations. To study the impact of climate change on the lake variations, 41 years (1979–2019) of the annual average of daily minimum and maximum temperature, precipitation, and prevailing atmospheric phenomena observed at three stations in the water catchment of Lake Urmia were used. Mann–Kendall test has been used to find any trend of temperature and precipitation. A Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model has been used to generate an ensemble backward trajectory in order to identify the source of severe dust events in the Lake Urmia basin. The result of this study shows that the eastern Mediterranean cyclogenesis contributes the most to precipitation in the Lake Urmia basin in winter and spring. Furthermore, an increasing trend of an annual anomaly for both minimum and maximum temperatures in this region was observed; however, the increasing trend for maximum temperature is stronger and reaches 0.64°C per decade. The long-term annual trend for precipitation is not significant, though there was an annual decreasing trend. Since the region is industrialized, the haze event is dominantly observed and it had an annual increasing trend. The frequency of snowfall has reduced due to regional warming but the number of showery precipitation has increased. The occurrence of thunderstorms has increased due to climate change in the region. By growing desertification in Iraq and Syria, more frequent dust events are expected. Despite the continuation of human activities in the Lake Urmia basin, significant precipitations in the lake catchment area in 2018 and 2019 have partially revived it. As a whole, the results show that the Lake Urmia basin is one of the hotspots susceptible to climate change impacts.