Evaluation of Ensemble Climate Model development methods based on CMIP5 to investigate the potential of water harvesting from air humidity

Recognizing the effects of climate change in different sectors, as well as the integration of GCM models and the development of Ensemble Climate Models (ECM) are vital. In this study, the efficacy of the climate models from the CMIP5 in simulating atmospheric variables impacting the potential for water harvesting was assessed. These variables encompass mean air temperature, wind speed, relative humidity, and the feasible quantity of water harvested from air moisture. Also, assessing the efficiency of the optimization algorithm (Genetic Algorithm) in the development of an ensemble climate model was another goal of this research. It is noteworthy that the present investigation employed data from 16 synoptic stations situated in the northern and northwestern regions of Iran during the statistical period of 1991-2005. Results indicated that the performance of individual climate models in simulating variations in wind speed and relative air humidity is deemed poorly. Conversely, GA has yielded a reduction in both error magnitude and biases in climatic outputs in estimating wind speed and relative air humidity. Furthermore, the evaluation of the efficacy of climate models in estimating the water harvesting potential from air humidity indicates the acceptable performance of ECM in simulating changes in the amount of extractable water from air humidity. In general, the results showed that Manjil and Bandar-Anzali stations are the most suitable areas for the implementation of water harvesting projects from air humidity. Conversely, Arak and Hamedan stations exhibit the least potential for water harvesting. Based on the results, the average water that can be extracted from air humidity in the summer season for Manjil and Bandar-Anzali stations is estimated to be 1.56 and 1.78 (l/day.m2). Also, the seasonal changes of water harvesting potential from air humidity showed that the potential of extracting water in summer is more than the other seasons. This accentuates the urgency of water resource management and agricultural planning, prompting the implementation of substantial measures to use this water source. The potential applications of using this source encompass agricultural sectors, green space irrigation, and potentially catering to a portion of drinking water demands, contingent upon quantity and quality parameters.