Climate Change and Climate Disaster

Investigating the changes of droughts in Iran with the approach of climate change

Document Type : Original Article

Authors

Zahra Hejazizadeh 1
bouhlol alijani 2
mohammad Saligheh 3
sanaz nadi 4

1 Kharazmi University Professor

2 Professor of Department Meteorology, Kharazmi University, Tehran

3 Department of Natural Geography, Faculty of Geographical Sciences, Kharazmi University, Tehran, Iran

4 phd. student

Abstract
In this research, the changes in Iran's drought were studied using the rainfall data of 100 synoptic stations and the Standard Precipitation Index (SPI) for the period from 1990 to 2020. Then, the atmospheric pattern affecting the occurrence of droughts was synoptic analyzed. The results showed that the number of years with drought and its severity in the country increased during the study period. The intensity and spatial extent of drought in the winter season has increased more than in the autumn season. In the 1990s, the extent of drought was greater than drought. With the beginning of the second decade (2000-2010), the intensity and spatial extent of drought and the number of droughts have increased. This trend has continued until 2016, so that the country's most severe droughts have occurred in the last decade. The increase in the extent of drought in the winter season (January and March) is more evident during the last decade. These conditions were caused by climate changes and variations in the behavior of circulation patterns. Also, the most severe droughts in the country occur in the cold period of the year,when the subtropical high pressure (STHP) extends to 30 degrees north latitude. In this case, the conditions of stability prevail due to the absence of conditions for the ascent and passage of rain waves. In general, droughts in the country have increased during the studied period, and the spatial extent of droughts is influenced by the location of the STHP.

Keywords

Drought
Trend
climate change
Subtropical high pressure
Iran

Subjects

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