TY - JOUR

T1 - Modelling the Chloride Signal at the Plynlimon Catchments, Wales Using a Modified Dynamic TOPMODEL.

AU - Page, Trevor

AU - Beven, Keith J.

AU - Freer, Jim

AU - Neal, Colin

PY - 2007/1/30

Y1 - 2007/1/30

N2 - The application of a modified version of dynamic TOPMODEL for two subcatchments at Plynlimon, Wales is described. Conservative chemical mixing within mobile and immobile stores has been added to the hydrological model in an attempt to simulate observed stream chloride concentrations. The model was not fully able to simulate the observed behaviour, in particular the short- to medium-term dynamics. One of the primary problems highlighted by the study was the representation of dry deposition and cloud-droplet-deposited chloride, which formed a significant part of the long-term chloride mass budget. Equifinality of parameter sets inhibited the ability to determine the effective catchment mixing volumes and coefficients or the most likely partition between occult mass inputs and chloride mass inputs determined by catchment immobile-store antecedent conditions. Some success was achieved, in as much as some aspects of the dynamic behaviour of the signal were satisfactorily simulated, although spectral analysis showed that the model could not fully reproduce the 1/f power spectra of observed stream chloride concentrations with its implications of a wide distribution of residence times for water in the catchment.

AB - The application of a modified version of dynamic TOPMODEL for two subcatchments at Plynlimon, Wales is described. Conservative chemical mixing within mobile and immobile stores has been added to the hydrological model in an attempt to simulate observed stream chloride concentrations. The model was not fully able to simulate the observed behaviour, in particular the short- to medium-term dynamics. One of the primary problems highlighted by the study was the representation of dry deposition and cloud-droplet-deposited chloride, which formed a significant part of the long-term chloride mass budget. Equifinality of parameter sets inhibited the ability to determine the effective catchment mixing volumes and coefficients or the most likely partition between occult mass inputs and chloride mass inputs determined by catchment immobile-store antecedent conditions. Some success was achieved, in as much as some aspects of the dynamic behaviour of the signal were satisfactorily simulated, although spectral analysis showed that the model could not fully reproduce the 1/f power spectra of observed stream chloride concentrations with its implications of a wide distribution of residence times for water in the catchment.

KW - chloride • Plynlimon • dynamic TOPMODEL

U2 - 10.1002/hyp.6186

DO - 10.1002/hyp.6186

M3 - Journal article

VL - 21

SP - 292

EP - 307

JO - Hydrological Processes

JF - Hydrological Processes

SN - 0885-6087

IS - 3

ER -