Assimilation of Earth Observation Variables and In Situ Measurements in a Surface Energy Balance Model: A Case Study of a Desert City Area

Abstract

Satellite based data and ground measurements were assimilated in a surface energy balance (SEB) model to assess urban energy fluxes in Abu Dhabi (UAE) metropolitan area during the winter and the summer seasons. Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data were used to derive land surface variables such as albedo, emissivity, and land cover. Solar radiation parameters (incoming shortwave and longwave radiation) have been derived from the Spinning Enhanced Visible and Infrared Imager (SEVIRI)/METEOSAT and from a ground station located in the study area. Meteorological variables have also been assimilated into the model. The analysis highlighted the particular characteristics of cities located in desert areas. The irrigated vegetation increases the contribution of latent heat flux (QE) component in the SEB of downtown areas compared to the surrounding desert areas. The hazy atmosphere observed during the summer period has also affected the retrieval of incoming shortwave radiation from satellite-based methods. The sensitivity of the model to this variable has been assessed and evaluated with in situ solar radiation measurements.