Estimation of hourly land surface heat fluxes over the Tibetan Plateau by the combined use of geostationary and polar-orbiting satellites

Abstract

Abstract. Estimation of land surface heat fluxes is important for energy and water cycle studies, especially on the Tibetan Plateau (TP), where the topography is unique and the land–atmosphere interactions are strong. The land surface heating conditions also directly influence the movement of atmospheric circulation. However, high-temporal-resolution information on the plateau-scale land surface heat fluxes has been lacking for a long time, which significantly limits the understanding of diurnal variations in land–atmosphere interactions. Based on geostationary and polar-orbiting satellite data, the surface energy balance system (SEBS) was used in this paper to derive hourly land surface heat fluxes at a spatial resolution of 10 km. Six stations scattered throughout the TP and equipped for flux tower measurements were used to perform a cross-validation. The results showed good agreement between the derived fluxes and in situ measurements through 3738 validation samples. The root-mean-square errors (RMSEs) for net radiation flux, sensible heat flux, latent heat flux and soil heat flux were 76.63, 60.29, 71.03 and 37.5 W m−2, respectively; the derived results were also found to be superior to the Global Land Data Assimilation System (GLDAS) flux products (with RMSEs for the surface energy balance components of 114.32, 67.77, 75.6 and 40.05 W m−2, respectively). The diurnal and seasonal cycles of the land surface energy balance components were clearly identified, and their spatial distribution was found to be consistent with the heterogeneous land surface conditions and the general hydrometeorological conditions of the TP.

Estimation of Land Surface Heat Fluxes Based on Landsat 7 ETM+ Data and Field Measurements over the Northern Tibetan Plateau

“…In previous studies, estimates of 100-1000 km scale land surface heat fluxes distributions have been given much more attention than land-atmosphere interactions at 10-100 km regional scales. AVHRR, MODIS, and FY-2C/SVISSR have been widely used in the estimation of land surface heat fluxes on the Tibetan Plateau [10,14,16,18]. Land-atmospheric flux data derived from 10-100 m spatial resolution satellite products such as Landsat 7 ETM+ are essential and more suitable for estimating turbulent heat fluxes over regions at 10-100 km scales.…”

“…Pioneering works have been done by some researchers on the observation and estimation of land surface heat fluxes on the Tibetan Plateau by satellite remote sensing [10][11][12][13][14][15][16][17][18]. Ma et al [10] used NOAA-14 AVHRR data and field measurements to derive the spatial distributions of land surface net radiation flux and soil heat flux in the GAME-Tibet (Global Energy and Water Cycle Experiment (GEWEX) Asian Monsoon Experiment on the Tibetan Plateau) region of the Tibetan Plateau.…”

“…In previous studies, the most commonly used satellite data for estimates of land surface heat fluxes over the Tibetan Plateau were images with spatial resolutions of 1-10 km [10,12,14,16,18]. Estimations of land surface heat fluxes based on satellite data with 10-100 m spatial resolutions have been applied to the Mt.…”

Evapotranspiration Estimation Using Surface Energy Balance System Model: A Case Study in the Nagqu River Basin

“…Third, the SEBS model itself has assumptions and limitations. For example, the model is based on the Monin-Obukhov similarity theory, which produces larger error under stable atmospheric stratification [17,18,30].…”

“…They have other advantages, such as low cost, continuous monitoring, and clear physical mechanisms involved. The physically-based surface energy balance models have been widely used to estimate AET with the aid of remote sensing techniques [14,15,17,18].…”