University of Oulu

Jamali M, Gohari A, Motamedi A, Haghighi AT. Spatiotemporal Changes in Air Temperature and Precipitation Extremes over Iran. Water. 2022; 14(21):3465.

Spatiotemporal changes in air temperature and precipitation extremes over Iran

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Author: Jamali, Mohammad1; Gohari, Alireza1; Motamedi, Armita1;
Organizations: 1Department of Irrigation, College of Agriculture, Isfahan University of Technology, Isfahan 84156-83111, Iran
2Water, Energy and Environmental Engineering Research Unit, University of Oulu, P.O. Box 4300, FIN-90014 Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 2.7 MB)
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Language: English
Published: Multidisciplinary Digital Publishing Institute, 2022
Publish Date: 2023-01-03


In this study, a comprehensive trend analysis was employed to study the spatiotemporal changes in precipitation characteristics with air temperature increasing over time. The nonparametric Mann–Kendall test and the quantile regression methods were applied to detect the plausible temporal trends in 11 extreme rainfall indices and three air temperature indices employed in this study. The results showed there was little evidence to suggest that increases in the maximum of 3-h and 24-h precipitation at higher temperatures resulted in similar increases in the annual precipitation, with most stations throughout Iran showing drying features with higher temperatures. Generally, most regions over Iran scaled negatively, implying a reduction in the annual precipitation ranging from −2.64 to −0.44 mm/°C at higher temperatures. The linear tendencies of the maximum 24-h precipitation ranged from −0.4 to 0.23 mm/°C. The annual precipitation of the stations located at Urmia Lake, Caspian Sea, and the Eastern Border Basins showed a decreasing trend (−3.70 to 1.11 mm/year), while the number of rainy days increased (−2.78 to 4.72), which showed the occurrence of lighter rainfall in these regions. The increasing trend in the maximum 24-h precipitation over Western and Central Iran implied a higher probability of extreme precipitation with a higher intensity. This study revealed that the shift in precipitation extremes shifted from fall to winter by increasing the elevation, but these effects have no statistical significance in Iran.

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Series: Water
ISSN: 2073-4441
ISSN-E: 2073-4441
ISSN-L: 2073-4441
Volume: 14
Issue: 21
Article number: 3465
DOI: 10.3390/w14213465
Type of Publication: A1 Journal article – refereed
Field of Science: 1172 Environmental sciences
Funding: The research presented in this paper received funding from Maa- ja vesitekniikan tuki ry (MVTT) grant No. 43588.
Copyright information: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (