Application of RS and GIS Technique to Estimate Regional Water-saving Potentiality

It was difficult to acquired regional ET (Evapotranspiration) from dot ET calculated by meteorological station data. As a result, regional water-saving potentiality calculated by traditional method mainly involved the water-saving quantity of water withdrawal with high water use efficiency. Therefore, measuring ET by RS (Remote sensing) technique could break the limitation of transform from dot ET to regional ET. At the same time, it could measure spatial difference of ET and enlarge measuring scope to region with weather data shortage. Based on GIS and RS technique, the relationship among RS ET, RS crop product and water productivity was analyzed. Meanwhile, the magnitude between water requirement and economical ET of main crop was comparatively analyzed. On this basis, the key crop ET quota was brought forward. The winter wheat ET quota and the summer maize ET quota were 346mm, 313mm respectively. Moreover, the rationality of key crop ET quota was validated. By applying key crop ET quota as evaluation criterions, water-saving quantity from water consumption under ET quota management and contribution of reduction integrated ET for Daxing were calculated. The results showed that water-saving potentiality of summer maize was the maximum. Water-saving quantity under ET quota management for summer maize was 11.7675 x 10(6)m(3). The contribution of reduction integrated ET for Daxing for summer maize under ET quota management was 11.27mm. This research provides a beneficial exploration on quantitative evaluation of regional water-saving potentiality form water consumption.