Detection of climate change using precipitation extreme indices (Case study: Najaf Abad city, Esfahan Province)

Extreme weather and climate events have received increased attention in the last few years, due to the often-large loss of human life and exponentially increasing costs associated with them. These events have profound impacts on economies and livelihoods of many regions of the world. In this regard, diagnosis of extreme events in terms of intensity, duration, and frequency is crucial in order to frame mitigation and adaptation strategies to counter the impacts due to climate. The purpose of this research is to analyze the trend of changes in precipitation extreme indices to reveal the occurrence of climate change in Najaf Abad using 20-year daily statistics of Najaf Abad synoptic station from 2003 to 2022. For this purpose, the extreme indices of precipitation and the non-parametric Mann-Kendall test were used to investigate the changes. The results showed that the precipitation extreme indices present different patterns of intensity, duration and frequency of precipitation. PRCPTOT, CDD, CWD, R10mm, R20mm, R95p, Rx5day and SDII indices are decreasing and Rnnmm, R99p and Rx1day indices are increasing. But in general, due to the high dispersion and low amount of rainfall, the regional rainfall pattern cannot be clearly identified. The results of the analysis of the threshold indices of precipitation showed that the precipitation does not follow a regular trend and is irregular. The results of this research can provide solutions to workers and managers in line with correct management and use of other capacities to deal with possible situations. In addition, the combination of the results with long-term meteorological data and the perception of local communities affected by climate change can be examined and become a model for managers to make more appropriate and relevant decisions and plans.