Irrigation water use associated with agricultural activities and urban green spaces provides substantial cooling effects and ameliorates heat in central Arizona. In this arid and semiarid area, evaluating the effect of irrigation on land surface temperature (LST) for different types of land use can improve decision making related to water resources management. In this work, we improved the simulation of urban and agricultural irrigation in the Variable Infiltration Capacity model through remotely sensed vegetation and irrigation parameters applied at high spatiotemporal resolution. We then conducted a multiyear (2004–2013) assessment of simulated LST with respect to ground observations and remotely sensed products finding overall good agreement. Overall, results show that irrigation of about 2 mm/day is required to reduce average daily LST by 1°C across the region. Numerical experiments with the validated model also reveal that irrigation leads to LST reductions of higher magnitude and greater spatial variability in croplands than in urban areas. Furthermore, we found that the role of interannual variations in cropping practices is more critical than year-to-year differences in climatic conditions for the evaluation of irrigation cooling capacity. Thus, remotely sensed vegetation products can serve a valuable purpose in quantifying LST reductions and irrigation requirements to achieve a target of heat amelioration.

中文翻译：

---

亚利桑那州中部农业和城市环境中灌溉冷却能力的多年评估

与农业活动和城市绿地相关的灌溉用水提供了显着的冷却效果并改善了亚利桑那州中部的热量。在这个干旱和半干旱地区，评估灌溉对不同土地利用类型的地表温度 (LST) 的影响可以改进与水资源管理相关的决策。在这项工作中，我们通过在高时空分辨率下应用的遥感植被和灌溉参数改进了可变渗透能力模型中城市和农业灌溉的模拟。然后，我们针对地面观测和遥感产品对模拟 LST 进行了多年（2004-2013 年）评估，发现总体一致。总体，结果表明，需要约 2 毫米/天的灌溉量才能将整个地区的平均每日 LST 降低 1°C。经验证模型的数值实验还表明，与城市地区相比，灌溉导致农田的 LST 降低幅度更大，空间变异性更大。此外，我们发现，在评估灌溉冷却能力时，年际变化在种植实践中的作用比气候条件的年际差异更为重要。因此，遥感植被产品可以在量化 LST 减少和灌溉需求以实现热改善目标方面发挥重要作用。经验证模型的数值实验还表明，与城市地区相比，灌溉导致农田的 LST 降低幅度更大，空间变异性更大。此外，我们发现，在评估灌溉冷却能力时，年际变化在种植实践中的作用比气候条件的年际差异更为重要。因此，遥感植被产品可以在量化 LST 减少和灌溉需求以实现热改善目标方面发挥重要作用。经验证模型的数值实验还表明，与城市地区相比，灌溉导致农田的 LST 降低幅度更大，空间变异性更大。此外，我们发现，在评估灌溉冷却能力时，年际变化在种植实践中的作用比气候条件的年际差异更为重要。因此，遥感植被产品可以在量化 LST 减少和灌溉需求以实现热改善目标方面发挥重要作用。