A comprehensive set of benchmark tests for a land surface model of simultaneous fluxes of water and carbon at both the global and seasonal scale

Abstract

Evaluating the models we use in prediction is important as it allows usto identify uncertainties in prediction as well as guiding the prioritiesfor model development. This paper describes a set of benchmark tests that isdesigned to quantify the performance of the land surface model that is usedin the UK Hadley Centre General Circulation Model (JULES: Joint UK Land Environment Simulator). The tests are designed to assess the ability of themodel to reproduce the observed fluxes of water and carbon at the global andregional spatial scale, and on a seasonal basis. Five datasets are used totest the model: water and carbon dioxide fluxes from ten FLUXNET sitescovering the major global biomes, atmospheric carbon dioxide concentrationsat four representative stations from the global network, river flow fromseven catchments, the seasonal mean NDVI over the seven catchments and thepotential land cover of the globe (after the estimated anthropogenic changeshave been removed). The model is run in various configurations and resultsare compared with the data. A few examples are chosen to demonstrate the importance of using combineduse of observations of carbon and water fluxes in essential in order tounderstand the causes of model errors. The benchmarking approach is suitablefor application to other global models. © 2011 Author(s).