DOI: 10.5194/hess-21-459-2017
Scopus记录号: 2-s2.0-85010825626
论文题名: Towards a simple representation of chalk hydrology in land surface modelling
作者: Rahman M ; , Rosolem R
刊名: Hydrology and Earth System Sciences
ISSN: 10275606
出版年: 2017
卷: 21, 期: 1 起始页码: 459
结束页码: 471
语种: 英语
Scopus关键词: Calibration
; Catchments
; Fracture
; Groundwater
; Groundwater flow
; Heat flux
; Hydraulic conductivity
; Hydrology
; Parameterization
; Porosity
; Porous materials
; Runoff
; Soil moisture
; Surface measurement
; Water resources
; Chalk unsaturated zone
; Hydrological process
; Land surface modelling
; Management practices
; Resource assessments
; Saturated hydraulic conductivity
; Soil moisture profiles
; Threshold parameters
; Limestone
; chalk
; fracture flow
; hydraulic conductivity
; land surface
; management practice
; numerical model
; porous medium
; preferential flow
; resource assessment
; soil moisture
; subsurface flow
; vadose zone
; water resource
; England
; Kennet River
; United Kingdom
英文摘要: 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. © Author(s) 2017. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/79285
Appears in Collections: 气候变化事实与影响
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作者单位: Department of Civil Engineering, University of Bristol, Bristol, United Kingdom; Cabot Institute, University of Bristol, Bristol, United Kingdom
Recommended Citation:
Rahman M,, Rosolem R. Towards a simple representation of chalk hydrology in land surface modelling[J]. Hydrology and Earth System Sciences,2017-01-01,21(1)