Daily Evapotranspiration Mapping Program for California Using Surface Energy Balance Algorithm.

The year 2012-15 marks another period of continued drought for the state of California. Spatial actual evapotranspiration (ET_a) dataset has emerged as the single most important information not only for managing water but also for developing the legal structure for monitoring and regulating the water of the state. In this work a comprehensive framework for spatially mapping ET_a using publically available data resources comprising of historic satellite imagery, weather data, and surface energy balance algorithms, was developed. Daily ET_a at 250 m resolution was developed using Terra-MODIS satellite data for application in regional scale studies while another dataset at 30 m resolution using Landsat data was developed for field scale applications. A multi-location validation using AmeriFlux and other observed data suggests very good performance of the model. The high valued cropping system, growing urban water market and the demand for ecosystem services, could lead to unsustainable water resource. Hence, this dataset of long term historic and near real term high resolution spatial ET_a for the state of California would be the primary tool for copping the future water scarcity.