Authors

• Negar Shamsaei ¹
• Rasoul Mahdavi ²
• Asadolah khoorani ³
• Hamid Gholami ⁴

¹ PhD student in Desert Management and Control, Department of Natural Resources Engineering, Faculty of Agricultural and Natural Resources Engineering, University of Hormozgan, Bandar Abbas, Iran.

² Associate Professor, Department of Natural Resources Engineering, Faculty of Agricultural and Natural Resources Engineering, University of Hormozgan, Bandar Abbas, Iran

³ Associate Professor, Department of Geographical Sciences, Faculty of Humanities, University of Hormozgan, Bandar Abbas, Iran

⁴ Professor,Department of Natural Resources Engineering, Faculty of Agricultural and Natural Resources Engineering, University of Hormozgan, Bandar Abbas, Iran.

Abstract

Abstract
Background and Objectives
Climate change, especially changes in temperature and precipitation, is one of the most essential topics in environmental sciences. Due to its scientific and practical dimensions, including environmental and economic-social effects, climate change is increasingly important because human systems dependent on climatic elements such as water resources, agriculture, and industries are designed and operated based on climate stability. On the other hand, the impact of climate change on water resources is significant and requires further investigation. This impact is particularly concerning in arid and semi-arid regions like the southern parts of the country, especially Hormozgan Province. Therefore, when we can analyze the current climatic conditions in the region and predict the availability of water in the coming years, we can make more effective long-term decisions to sustainably utilize the province’s natural resources and prevent its ecological decline.
Methodology
Due to its location on a dry belt and desert strip, Hormozgan province is faced with a fragile natural environmental ecosystem and climate conditions and long drought periods (Figure 1). Since the available potential water includes several parameters, it is considered a suitable indicator for the long-term study of climate change and desertification. Therefore, in this study, while evaluating various CMIP6 models, changes in temperature, precipitation, potential evapotranspiration, and available potential water index in two periods of the near future (2031-2060) and the far future (2071-2100) compared to the observation period (1993-2023) was investigated under shared socio-economic pathways o SSP2-4.5 and SSP5-8.5. In order to conduct this research, first, the daily temperature and precipitation data for the six study meteorological stations in the observation were obtained from http://data.irimo.ir. Also, the precipitation and average temperature output based on 14 CMIP6 models for the base period (1993-2014), the near future, and the far future were extracted from the ESGF database (Table 1). In the following, two shared socio-economic pathway scenarios were used: the SSP2-4.5, which considers the world with socio-economic development under normal conditions, with medium vulnerability and radiative forcing level, and also the SSP5-8.5, which considers the upper limit of fossil fuel consumption. The climate models were fine-scaled using the linear scaling bias correction (LSBC) for the temperature and the delta change factor (DCF) method for precipitation. To evaluate the performance of the models, RMSE, MSE, MAE, R, and R2 criteria were considered. Also, the IWM method was used to ensemble the selected models for better understanding and reducing uncertainty. Then, the changes in temperature, precipitation, potential evapotranspiration, and available potential water were predicted in the two future periods and compared with those in the observation period. The trend of changes in the available potential water index in these periods was also investigated using the non-parametric Mann-Kendall test and Sen’s slope estimator (table 4).
Result
The results showed that the ensemble of models exerted a suitable accuracy for simulating temperature and precipitation. The forecast results showed that the precipitation in the near future will decrease by 10 and 14.5% based on the SSP2-4.5 and SSP5-8.5 scenarios, respectively (Figure 3). In the far future, the precipitation will decrease by 5.5 and 32.6%, respectively, compared to the base period using such scenarios. In total, it is expected that the average precipitation will decrease by 12.2% in the near future period and 20.7% in the far future period in Hormozgan province. Meanwhile, the temperature will increase, and this increase in the near and far future periods will be 1.7 and 3.3 °C, respectively, compared to the observation period (Figure 4).
Conclusion
Based on this, the amount of potential evapotranspiration increases, while the amount of available potential water decreases. In the near future period, the rate of potential evapotranspiration and the shortage of available water will increase by an average of 5.02 and 8.9%, respectively. In the far future period, they will increase by 12.5 and 17.3%, respectively (Figure 6). Examining the time series of these variables also confirms the results. The findings of this research can be used as a strategic tool for policymakers and managers of water resources in Hormozgan province.

Keywords

• Bias Correction
• CMIP6
• potential available water
• precipitation
• temperature