Diego Miralles and Brecht Martens (Ghent University)

Project Overview: The World Climate Research Programmes (WCRP) Global Energy and Water Exchanges (GEWEX) Data and Assessments Panel (GDAP) is currently running the LandFlux initiative, aiming at deriving global land surface heat flux products that can be used together with other GEWEX endorsed satellite products to allow a comprehensive observation-based analysis of the water and energy cycles. These GEWEX efforts are supported by related activities from programs such as the ESA Water Cycle Observation Multi-mission Strategy project (WACMOS-ET) and the NASA Energy and Water cycle Study (NEWS). LandFlux is coordinating two interrelated research efforts that seek to: (i) intercompare long-term gridded surface flux data sets and identify their skill and reliability (i.e. product-benchmarking), and (ii) simulate and intercompare evaporation models to identify algorithms appropriate for developing a global flux product (i.e. model-benchmarking). Intercomparison efforts (LandFlux-EVAL), have resulted in some published product evaluations (Jimenez et al., 2011,  Mueller et al, 2011) and the generation of a multi-year global merged benchmark synthesis product based on the analyses of existing land evaporation datasets (Mueller et al., 2013). This monthly product covers the periods 1989-1995 and 1989-2005, and can be downloaded from the LandFlux-EVAL website. Work is ongoing to produce a similar product at daily resolution and covering 1980-2010.

Running a selection of evaporation models with forcings that seek consistency with other GEWEX products has resulted in a preliminary global latent flux product (see discussions about our preliminary v0 product at  Jimenez et al, 2012 ). Current developments are focusing on a new version v1, with efforts concentrating on model evaluation (Jimenez et al., 2015) and the completion of a 3-hourly 1983-2007 latent flux product (expected release by end of 2016). Work is also ongoing in developing a sensible flux product to complete the description of turbulent fluxes at the surface by research collaborators at Princeton University.

GEWEX LandFlux multi-model product for the years 1985-2003. The algorithms comprising this global (0.5 degree and 3-hourly) product include the PM-Mu, GLEAM and PT-JPL models. Further details on the validation of this new data-set can be found in McCabe et al., 2015.