Climate Change Research

Climate Change Research

Spatiotemporal Analysis of Annual Rainfall Indices Trends in Southern Zagros

Document Type : Original Article

Authors
Parisa Yosefi 1
Mohammad Naji 2
mostafa karimi ahmad abad 3
AliAkbar Shamsipour 3
Ghasem Azizi 4
1 PhD Candidate in Climatology, Department of Physical Geography, Faculty of Geography, Tehran University, Tehran, Iran
2 PhD Candidate in Climatology, Department of Physical Geography, Faculty of Earth Sciences, University of shahid beheshti,Tehran, Iran
3 Associate professor of Climatology, Department of Physical Geography, Faculty of Geography, Tehran University, Tehran, Iran
4 Professor of Climatology, Department of Physical Geography, Faculty of Geography, Tehran University, Tehran, Iran,
10.30488/ccr.2025.534109.1292
Abstract
Changes in climatic indices, particularly precipitation, provide valuable insights into the trend in climatic conditions. The southern Zagros region, due to its complex mountainous-plain characteristics and the high dependency of agricultural activities and water resources on rainfall, requires a comprehensive understanding of rainfall patterns and their temporal variations. This study aimed to investigate precipitation trends using eight annual precipitation indices across 61 meteorological stations over the 1978 to 2020. The trends were analyzed using the non-parametric Mann-Kendall test to evaluate rainfall changes and identify statistically significant changes. The results indicated that, precipitation trends, particularly in terms of the number of rainy and rainless days, generally tend toward a decrease in rainfall and an increase in drought conditions across the region. Specifically, 89% of the stations showed an increase in the number of rainless days, with 37% of stations exhibiting statistical significance. Furthermore, over 90% of the stations exhibited a decrease in the number of rainy days (>0.1 mm), with 42% showing statistically significant reductions. Light (0.1–10 mm) and moderate (10–20 mm) precipitation displayed decreasing trends at most stations. In some stations, a non-significant increasing trend in heavy and very heavy rainfall precipitation was observed, indicating an increase in the frequency of short-term, intense precipitation events. Overall, the annual precipitation trend declined at most stations, and maximum 24-hour precipitation also decreased in approximately 80% of the stations. These results highlight substantial alterations in regional precipitation patterns, and suggest an increased likelihood of droughts and flash floods, and emphasize the critical need for effective water resource management and mitigation strategies in the southern Zagros region
Keywords
Drought Iran Mann
Kendall test Precipitation changes Water resources management

Subjects

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