1Department of Civil and Environmental Engineering, Imperial College London, London, UK
2Centre for Water in the Minerals Industry, the University of Queensland, St. Lucia, Australia
3British Geological Survey, Keyworth, UK
Received: 29 Jun 2015 – Discussion started: 07 Aug 2015
Abstract. Land surface models (LSMs) are prospective starting points to develop a global hyper-resolution model of the terrestrial water, energy, and biogeochemical cycles. However, there are some fundamental limitations of LSMs related to how meaningfully hydrological fluxes and stores are represented. A diagnostic approach to model evaluation and improvement is taken here that exploits hydrological expert knowledge to detect LSM inadequacies through consideration of the major behavioural functions of a hydrological system: overall water balance, vertical water redistribution in the unsaturated zone, temporal water redistribution, and spatial water redistribution over the catchment's groundwater and surface-water systems. Three types of information are utilized to improve the model's hydrology: (a) observations, (b) information about expected response from regionalized data, and (c) information from an independent physics-based model. The study considers the JULES (Joint UK Land Environmental Simulator) LSM applied to a deep-groundwater chalk catchment in the UK. The diagnosed hydrological limitations and the proposed ways to address them are indicative of the challenges faced while transitioning to a global high resolution model of the water cycle.
Revised: 09 Nov 2015 – Accepted: 27 Nov 2015 – Published: 18 Jan 2016
Le Vine, N., Butler, A., McIntyre, N., and Jackson, C.: Diagnosing hydrological limitations of a land surface model: application of JULES to a deep-groundwater chalk basin, Hydrol. Earth Syst. Sci., 20, 143-159, doi:10.5194/hess-20-143-2016, 2016.