Satellite-only latent heat flux estimation

摘要

Here we present a new method for recovering global latent heat flux (XE) using satellite sounding in conjunction with visible and infra-red geophysical products, from the AIRS (Atmospheric Infrared Sounder) and MODIS (Moderate Resolution Imaging Spectroradiometer) platforms at 1°×1° spatial domain. This method focuses on specifying the day-night net radiation, which is then used in a dynamic surface energy balance framework with day-night land surface temperature to directly retrieve net available energy. The evaporative fraction was estimated from the water vapour and temperature profile information in a Bowen ratio framework. Evaluation of available energy and latent heat flux against 30 terrestrial flux tower sites revealed a pooled root mean square deviation (RMSD) of 98, 72 and 79 Wm~(-2) for net radiation, net available energy, and latent heat flux between satellite and tower, respectively. The results show particular promise of this approach for latent heat flux retrieval under warm, moist conditions, but weaknesses under arid or semi- arid conditions subject to high radiative loads.