Articles | Volume 11, issue 24
Biogeosciences, 11, 7369–7382, 2014
Biogeosciences, 11, 7369–7382, 2014

Research article 22 Dec 2014

Research article | 22 Dec 2014

Components of near-surface energy balance derived from satellite soundings – Part 2: Noontime latent heat flux

K. Mallick1, A. Jarvis2, G. Wohlfahrt3,8, G. Kiely4, T. Hirano5, A. Miyata6, S. Yamamoto7, and L. Hoffmann1 K. Mallick et al.
  • 1Environmental Research and Innovation (ERIN), Luxembourg Institute of Science and Technology (LIST), L4422, Belvaux, Luxembourg
  • 2Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
  • 3Institute of Ecology, University of Innsbruck, 6020 Innsbruck, Austria
  • 4Hydrology Micrometeorology and Climate Investigation Centre, Department of Civil and Environmental Engineering, University College Cork, Cork, Ireland
  • 5Division of Environmental Resources, Research Faculty of Agriculture, Hokkaido University, Hokkaido, Japan
  • 6National Institute for Agro-Environmental Sciences, Tsukuba, Japan
  • 7Graduate School of Environmental Science, Okayama University Tsushimanaka 3-1-1, Okayama 700-8530, Japan
  • 8European Academy of Bolzano, 39100, Bolzano, Italy

Abstract. This paper introduces a relatively simple method for recovering global fields of latent heat flux. The method focuses on specifying Bowen ratio estimates through exploiting air temperature and vapour pressure measurements obtained from infrared soundings of the AIRS (Atmospheric Infrared Sounder) sensor onboard NASA's Aqua platform. Through combining these Bowen ratio retrievals with satellite surface net available energy data, we have specified estimates of global noontime surface latent heat flux at the 1°×1° scale. These estimates were provisionally evaluated against data from 30 terrestrial tower flux sites covering a broad spectrum of biomes. Taking monthly average 13:30 data for 2003, this revealed promising agreement between the satellite and tower measurements of latent heat flux, with a pooled root-mean-square deviation of 79 W m−2, and no significant bias. However, this success partly arose as a product of the underspecification of the AIRS Bowen ratio compensating for the underspecification of the AIRS net available energy, suggesting further refinement of the approach is required. The error analysis suggested that the landscape level variability in enhanced vegetation index (EVI) and land surface temperature contributed significantly to the statistical metric of the predicted latent heat fluxes.

Short summary
We have successfully used NASA-AIRS temperature-humidity profiles and associated radiances within a Bowen ratio framework to produce the first ever global sounder latent and sensible heat fluxes (SoLH and SoSH). These SoLH and SoSH estimates do not require any land surface parameterisations of the aerodynamic and stomatal conductances and hence are ideally suited to interrogate or improve the surface paramaterisations embedded in the land components of Earth system models.
Final-revised paper