The change in weather types in two population centers in northwestern Iran (Urmia and Tabriz) around Lake Urmia with the Woś classification approach

ABSTRACT

In order to recognize the effect of the drying up of Lake Urmia on the climate, using the Woś classification method, the types of weather of the two cities of Tabriz and Urmia, were determined during 1980–2018. Then, eight weather types in the range of hot weather types without rain to cool and very cold weather types with low cloudiness and no precipitation showed an occurrence frequency of more than 61%. The highest number of weather types with 45 types in the cold season and 26 types in the hot season was determined in Tabriz and Urmia, respectively. Then, modified Mann–Kendall (MMK) and Sen's slope estimator tests were used to determine the changing trend of the weather types. Investigations showed that, the hot weather type without precipitation and the slightly cool weather type without precipitation and of course without clouds had an increasing trend respectively, and the cold types also showed a decreasing trend in favor of cool types. The intensity of these changes is much greater in Tabriz. In addition, using the Mann–Kendall test, it was also determined that the increasing trend of hot weather in Tabriz started in 2000 at the same time as the lake began to dry up.