Geographical information systems and remote sensing methods in the estimation of potential dew volume and its utilization in the United Arab Emirates

In a fast growing region of Middle East and with rapid depletion of fossil groundwater, possibilities for dew utilization as a limited renewable water resource play an important role in the water management of the United Arab Emirates. Despite projected changes in air temperature and rainfall, geographical and topographical features of the UAE show some potential for dew harvesting, mostly at the altitudes higher than 1000 m and some isolated oasis areas. With the help of geographical information system (GIS), remote sensing, and numerical and theoretical methods, approximate volumes of dew were estimated. Meteorological data was inputted together with theoretical and numerical calculations into grids by using pixelization processes. Methods such as zonal statistics, kriging, semi-kriging, and interpolation were implemented through GIS software. Another method used in this research is supervised classification and normalized difference vegetation index (NDVI) which is being determined by means of software IDRISI terra set. After finishing all the proposed methods applied in this research, four belts of potential dew use were presented. The Arabian Desert in the territory of the United Arab Emirates has no potential for dew utilization. The zone close to the oases has very low possibility of dew use. The hilly-mountainous area between 500 and 800 m.a.s.l. has medium possibility for dew use. There is a high possibility for dew use on mountain Al Hajar, occupying the area higher than 800 m; 1.3% of the whole country’s territory has excellent potential for dew use. In this part of the country, theoretically, it is possible to use dew for farming and partial watering. Experimental study together with GIS, remote sensing, and numerical analysis may extend knowledge about dew properties. Although this research includes theoretical calculations of dew utilization and has some limitations, it still presents a new insight into climate cycles in this part of the Arabian Peninsula and a way to understand them better.