Variation in climatic parameters affecting water access can play a key role in the sustainable development of agriculture and the environment. Reference evapotranspiration (ET₀), after precipitation, is the most important parameter affecting access to water resources in the arid and semiarid areas like Iran. In this study, data were collected from 50 synoptic weather stations for a period of 30 years (1988–2017) in the area with high population density and critical agricultural regions of Iran. Trend analysis of ET₀ and climatic parameters including maximum and minimum temperature (T_max and T_min), sunshine duration (SD), relative humidity (RH), wind speed (WS), and air pressure (P) were investigated. Also, the effects of climatic parameters on ET₀ were analyzed using dimensionless sensitivity coefficients. The aridity index (AI) was also evaluated using precipitation and ET₀ data in the study area. Results showed that on an annual time scale, ET₀ had a significant increasing trend (p ≤ 0.05) in 77.1% of the studied stations. In the seasonal time scale, the most increasing trend of ET₀ was observed in winter. The results of sensitivity analysis showed that T_max, RH, and WS were the most effective variables on ET₀. The trend analysis of AI revealed that 92% of the stations had a significant (p ≤ 0.05) increasing trend over the study period. The spatial distribution of the annual AI indicated that only 10% of the study area meets the atmospheric evaporation demand, and in 90% of the study area, the annual ET₀ was greater than the annual precipitation. These areas were highly affected by aridity and thus required additional water for crop production. These results indicated that climate change in Iran has increased ET₀ and aridity, thereby increasing the water requirement for plants in agricultural lands. Hence, the optimum use of water resources for agricultural purposes is a suitable way to deal with the crisis of water shortage and aridity in Iran.

影响取水的气候参数的变化在农业和环境的可持续发展中可以发挥关键作用。在降水之后，参考蒸散量 (ET ₀ ) 是影响伊朗等干旱和半干旱地区水资源获取的最重要参数。在这项研究中，从伊朗人口密度高和农业关键地区的 50 个天气气象站收集了 30 年（1988-2017 年）的数据。ET ₀和气候参数的趋势分析，包括最高和最低温度（T _max和T _min)、日照时间 (SD)、相对湿度 (RH)、风速 (WS) 和气压 (P)。此外，还使用无量纲敏感系数分析了气候参数对 ET ₀的影响。还使用研究区的降水和 ET ₀数据评估了干旱指数 (AI) 。结果表明，在年时间尺度上， 77.1%的研究台站的ET ₀有显着增加的趋势（p ≤ 0.05）。在季节性时间尺度上，ET _{0 的}增加趋势最大出现在冬季。敏感性分析结果表明，T _max、RH 和 WS 是对 ET ₀最有效的变量. AI 趋势分析显示，92% 的站点 在研究期间具有显着的（p ≤ 0.05）增加趋势。年AI的空间分布表明，只有10%的研究区满足大气蒸发需求，90%的研究区年ET ₀大于年降水量。这些地区受干旱影响很大，因此需要额外的水来进行作物生产。这些结果表明伊朗的气候变化增加了 ET ₀和干旱，从而增加了农业用地植物的需水量。因此，为农业目的优化利用水资源是应对伊朗缺水和干旱危机的合适途径。