Hydrologic-Land Surface Modelling of a Complex System under Precipitation Uncertainty: A Case Study of the Saskatchewan River Basin, Canada

Vegetation and atmosphere are linked through the perpetual exchange of water, carbon and energy. An accurate representation of the processes involved in these exchanges is crucial in forecasting Earth system states. Although vegetation has become an undisputed key component in land-surface modelling (LSMs), the current generation of models differ in terms of how key processes are formulated. Plant processes react to environmental changes on multiple time scales. Here we differentiate a fast (minutes) and a slower (acclimated &#8211; weeks to months) response. Some current LSMs include plant acclimation, even though they require additional parameters to represent this response, but the majority of them represent only the fast response and assume that this also applies at longer time scales. Ignoring acclimation in this way could be the cause of inconsistent future projections. Our proposition is to include plant acclimation in a LSM schema, without having to include new plant-functional-type-dependent parameters. This is possible by using an alternative model development strategy based on eco-evolutionary theory, which explicitly predicts the acclimation of photosynthetic capacities and stomatal behaviour to environmental variations. So far, this theory has been tested only at weekly to monthly timescales. Here we develop and test an approach to apply an existing optimality-based model of gross primary production (GPP), the P model, at the sub-daily timestep necessary for use in an LSM, making an explicit differentiation between the fast and slow responses of photosynthesis and stomatal conductance. We test model performance in reproducing the diurnal cycle of GPP as recorded by flux tower measurements across different biomes, including boreal and tropical forests. The extended model requires only a few meteorological inputs, and a satellite-derived product for leaf area index or green vegetation cover. It is able to manage both timescales of acclimation without PFT-dependent photosynthetic parameters and has shown to operate with very good performance at all sites so far investigated. The model structure avoids the need to store past climate and vegetation states. These findings therefore suggest a simple way to include both instantaneous and acclimated responses within a LSM framework, and to do so in a robust way that does not require the specification of multiple parameters for different plant functional types.

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ECLand: an ECMWF land surface modelling platform

10.5194/egusphere-egu21-16240 ◽

2021 ◽

Author(s):

Gianpaolo Balsamo ◽

Souhail Boussetta

Keyword(s):

Land Surface ◽

Urban Areas ◽

Land Surface Model ◽

Open Water ◽

Surface Fluxes ◽

Surface Model ◽

New Developments ◽

Surface Modelling ◽

Land Surface Modelling ◽

New Research

The ECMWF operational land surface model, based on the Carbon-Hydrology Tiled ECMWF Scheme for Surface Exchanges over Land (CHTESSEL) is the baseline for global weather, climate and environmental applications at ECMWF. In order to expedite its progress and benefit from international collaboration, an ECLand platform has been designed to host advanced and modular schemes. ECLand is paving the way toward a land model that could support a wider range of modelling applications, facilitating global kilometer scales testing as envisaged in the Copernicus and Destination Earth programmes. This presentation&#160;introduces the CHTESSEL and its recent new developments that aims at hosting new research applications.These new improvements touch upon different components of the model: (i) vegetation, (ii) snow, (iii) soil hydrology, (iv) open water/lakes (v) rivers and (vi) urban areas. The developments are evaluated separately with either offline simulations or coupled experiments, depending on their level of operational readiness, illustrating the benchmarking criteria for assessing process fidelity with regards to land surface fluxes and reservoirs involved in water-energy-carbon exchange, and within the Earth system prediction framework, as foreseen to enter upcoming ECMWF operational cycles.Reference: Souhail Boussetta, Gianpaolo Balsamo*, Anna Agust&#236;-Panareda, Gabriele Arduini, Anton Beljaars, Emanuel Dutra, Glenn Carver, Margarita Choulga, Ioan Hadade, Cinzia Mazzetti, Joaqu&#236;n Mun&#245;z-Sabater, Joe McNorton, Christel Prudhomme, Patricia De Rosnay, Irina Sandu, Nils Wedi, Dai Yamazaki, Ervin Zsoter, 2021: ECLand: an ECMWF land surface modelling platform, MDPI Atmosphere, (in prep).

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Land-surface modelling in hydrological perspective

Biogeosciences Discussions ◽

10.5194/bgd-2-1815-2005 ◽

2005 ◽

Vol 2 (6) ◽

pp. 1815-1848 ◽

Cited By ~ 4

Author(s):

J. Overgaard ◽

D. Rosbjerg ◽

M. B. Butts

Keyword(s):

Remote Sensing ◽

Land Surface ◽

Potential Evapotranspiration ◽

Distributed Data ◽

Atmospheric Models ◽

Dynamic Coupling ◽

Surface Modelling ◽

Evaluation Procedures ◽

Surface Models ◽

Land Surface Modelling

Abstract. A comprehensive review of energy-based land-surface modelling, as seen from a hydrological perspective, is provided. We choose to focus on energy-based approaches, because in comparison to the traditional potential evapotranspiration models, these approaches allow for a stronger link to remote sensing and atmospheric modelling. New opportunities for evaluation of distributed land-surface models through application of remote sensing are discussed in detail, and the difficulties inherent in various evaluation procedures are presented. Remote sensing is the only source of distributed data at scales that correspond to hydrological modelling scales. Finally, the dynamic coupling of hydrological and atmospheric models is explored, and the future perspectives of such efforts are discussed.

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Comparing Assimilation of Synthetic Soil Moisture versus C‐band Backscatter for Hyper‐resolution Land Surface Modelling

Water Resources Research ◽

10.1029/2020wr028921 ◽

2021 ◽

Author(s):

Leqiang Sun ◽

Stephane Belair ◽

Marco L. Carrera ◽

Bernard Bilodeau ◽

Mohammed Dabboor

Keyword(s):

Soil Moisture ◽

Land Surface ◽

Surface Modelling ◽

Land Surface Modelling

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Irrigation management under limited water resources : radar retrieved topsoil moisture, disaggregation, crop growth and land surface modelling and data assimilation

10.3990/1.9789036545952 ◽

2018 ◽

Author(s):

Omar Ali Ahmed Mohamed

Keyword(s):

Water Resources ◽

Data Assimilation ◽

Land Surface ◽

Irrigation Management ◽

Crop Growth ◽

Surface Modelling ◽

Land Surface Modelling

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Towards a simple representation of chalk hydrology in land surface modelling

Hydrology and Earth System Sciences ◽

10.5194/hess-21-459-2017 ◽

2017 ◽

Vol 21 (1) ◽

pp. 459-471 ◽

Cited By ~ 9

Author(s):

Mostaquimur Rahman ◽

Rafael Rosolem

Keyword(s):

Land Surface ◽

Unsaturated Zone ◽

Large Scale ◽

Management Practices ◽

Preferential Flow ◽

Water Movement ◽

Model Parameters ◽

Catchment Scale ◽

Surface Modelling ◽

Land Surface Modelling

Abstract. Modelling and monitoring of hydrological processes in the unsaturated zone of chalk, a porous medium with fractures, is important to optimize water resource assessment and management practices in the United Kingdom (UK). However, incorporating the processes governing water movement through a chalk unsaturated zone in a numerical model is complicated mainly due to the fractured nature of chalk that creates high-velocity preferential flow paths in the subsurface. In general, flow through a chalk unsaturated zone is simulated using the dual-porosity concept, which often involves calibration of a relatively large number of model parameters, potentially undermining applications to large regions. In this study, a simplified parameterization, namely the Bulk Conductivity (BC) model, is proposed for simulating hydrology in a chalk unsaturated zone. This new parameterization introduces only two additional parameters (namely the macroporosity factor and the soil wetness threshold parameter for fracture flow activation) and uses the saturated hydraulic conductivity from the chalk matrix. The BC model is implemented in the Joint UK Land Environment Simulator (JULES) and applied to a study area encompassing the Kennet catchment in the southern UK. This parameterization is further calibrated at the point scale using soil moisture profile observations. The performance of the calibrated BC model in JULES is assessed and compared against the performance of both the default JULES parameterization and the uncalibrated version of the BC model implemented in JULES. Finally, the model performance at the catchment scale is evaluated against independent data sets (e.g. runoff and latent heat flux). The results demonstrate that the inclusion of the BC model in JULES improves simulated land surface mass and energy fluxes over the chalk-dominated Kennet catchment. Therefore, the simple approach described in this study may be used to incorporate the flow processes through a chalk unsaturated zone in large-scale land surface modelling applications.

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