Wetland inundation dynamics in a model of land surface climate: Evaluation in the Niger inland delta region

Dadson, Simon; Ashpole, Ian; Harris, Phil; Davies, Helen; Clark, Douglas B.; Blyth, Eleanor; Taylor, Christopher M.

doi:10.1029/2010jd014474

Cited by 69 publications

(86 citation statements)

References 29 publications

(33 reference statements)

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“…The role of land-atmosphere feedbacks in modifying the climate and in climate impacts is particularly evident in the Niger inland delta, where observed river gauging data show significant evaporative losses from the land and water surface [67]. Adding a subgrid-scale parametrization of overbank inundation to the JULES land surface model enables the salient features of the observed inundation pattern to be reproduced, and reveals that significant evaporative losses from the inundated region account for a doubling in the total land-atmosphere water flux during periods of greatest flooding.…”

Section: (B) Wetland Inundation and Cloud Feedbacksmentioning

confidence: 99%

Water security, global change and land–atmosphere feedbacks

Dadson

Acreman

Harding

2013

Phil. Trans. R. Soc. A.

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Section: (B) Wetland Inundation and Cloud Feedbacksmentioning

confidence: 99%

Water security, global change and land–atmosphere feedbacks

Dadson

Acreman

Harding

2013

Phil. Trans. R. Soc. A.

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“…These changes lead to a cooling of the atmosphere and an alteration of the atmospheric flows resulting in changes in the regional precipitation patterns. Dadson et al (2010) and Taylor (2010) concentrated on the Niger inland delta. The authors related the seasonal inundation in this region with enhanced evaporation and an increase in cloud cover and convection.…”

Section: Wetland Impact On Et and Runoffmentioning

confidence: 99%

Development and evaluation of a global dynamical wetlands extent scheme

Stacke

Hagemann

2012

Hydrol. Earth Syst. Sci.

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Abstract. In this study we present the development of the dynamical wetland extent scheme (DWES) and evaluate its skill to represent the global wetland distribution. The DWES is a simple, global scale hydrological scheme that solves the water balance of wetlands and estimates their extent dynamically. The extent depends on the balance of water flows in the wetlands and the slope distribution within the grid cells. In contrast to most models, the DWES is not directly calibrated against wetland extent observations. Instead, wetland affected river discharge data are used to optimise global parameters of the model. The DWES is not a complete hydrological model by itself but implemented into the Max Planck Institute -Hydrology Model (MPI-HM). However, it can be transferred into other models as well.For present climate, the model evaluation reveals a good agreement for the spatial distribution of simulated wetlands compared to different observations on the global scale. The best results are achieved for the Northern Hemisphere where not only the wetland distribution pattern but also their extent is simulated reasonably well by the DWES. However, the wetland fraction in the tropical parts of South America and Central Africa is strongly overestimated. The simulated extent dynamics correlate well with monthly inundation variations obtained from satellites for most locations. Also, the simulated river discharge is affected by wetlands resulting in a delay and mitigation of peak flows. Compared to simulations without wetlands, we find locally increased evaporation and decreased river flow into the oceans due to the implemented wetland processes.In summary, the evaluation demonstrates the DWES' ability to simulate the distribution of wetlands and their seasonal variations for most regions. Thus, the DWES can provide hydrological boundary conditions for wetland related studies.In future applications, the DWES may be implemented into an Earth system model to study feedbacks between wetlands and climate.

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“…By default, JULES does not account for lateral transfer of energy and water between grid boxes, but the model has successfully been coupled to flow routing schemes to simulate river runoff (e.g. Dadson et al, 2010).…”

Section: Jules Model Descriptionmentioning

confidence: 99%

Simulation of permafrost and seasonal thaw depth in the JULES land surface scheme

2011

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Abstract. Land surface models (LSMs) need to be able to simulate realistically the dynamics of permafrost and frozen ground. In this paper we evaluate the performance of the LSM JULES (Joint UK Land Environment Simulator), the stand-alone version of the land surface scheme used in Hadley Centre climate models, in simulating the largescale distribution of surface permafrost. In particular we look at how well the model is able to simulate the seasonal thaw depth or active layer thickness (ALT). We performed a number of experiments driven by observation-based climate datasets. Visually there is a very good agreement between areas with permafrost in JULES and known permafrost distribution in the Northern Hemisphere, and the model captures 97 % of the area where the spatial coverage of the permafrost is at least 50 %. However, the model overestimates the total extent as it also simulates permafrost where it occurs sporadically or only in isolated patches. Consistent with this we find a cold bias in the simulated soil temperatures, especially in winter. However, when compared with observations on end-of-season thaw depth from around the Arctic, the ALT in JULES is generally too deep. Additional runs at three sites in Alaska demonstrate how uncertainties in the precipitation input affect the simulation of soil temperatures by affecting the thickness of the snowpack and therefore the thermal insulation in winter. In addition, changes in soil moisture content influence the thermodynamics of soil layers close to freezing. We also present results from three experiments in which the standard model setup was modified to improve physical realism of the simulations in permafrost regions. Extending the soil column to a depth of 60 m and adjusting the soil parameters for organic content had relatively little effect on the Correspondence to: R. Dankers (rutger.dankers@metoffice.gov.uk) simulation of permafrost and ALT. A higher vertical resolution improves the simulation of ALT, although a considerable bias still remains. Future model development in JULES should focus on a dynamic coupling of soil organic carbon content and soil thermal and hydraulic properties, as well as allowing for sub-grid variability in soil types.

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Wetland inundation dynamics in a model of land surface climate: Evaluation in the Niger inland delta region

Cited by 69 publications

References 29 publications

Water security, global change and land–atmosphere feedbacks

Water security, global change and land–atmosphere feedbacks

Development and evaluation of a global dynamical wetlands extent scheme

Simulation of permafrost and seasonal thaw depth in the JULES land surface scheme

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