Water consumption estimation and evapotranspiration inversion based on remote sensing technology

The water consumption quantity and spatial characteristics of green land within the 5th Ring Road of Beijing city was studied based on high resolution remote sensing imagine, long time series meteorology data, and water consumption research results for different green land vegetation types. These procedures included pre-processing remote sensing imagines, distinguishing green land with stratified classification method, estimating irrigation water quantity for green land in different dry scenes accounting for different meteorological conditions and vegetation types, and inversing daily evapotranspiration. The green land area within the 5th Ring Road was 197.3 km2, accounting for 29.7% of total urban area. The annual green land water consumption was 161 Mm3, and the net irrigation water values in different dry scenarios were 109, 75, 59, 35Mm3 for the hydrological years of 95%, 75%, 50% and 25% respectively. Regional daily ET was inversed through Landsat Data and SEBAL model，and daily ET values of different land covers in summer were 11.1mm for urban lakes, 5.7mm for dense vegetation area, 4.0 mm for sparse vegetation area. Total daily water consumption was 1.266 Mm3, and the daily ET values were 0.103, 0.142, 0.204 and 0.817 Mm3 for these regions within 2nd Ring Road, between 2nd and 3rd Ring Road, between 3rd and 4th Ring Road, between 4th and 5th Ring Road, respectively. These results provide total water consumption and spatial distribution information for designing irrigation system of urban green land.