The value of multiple data set calibration versus model complexity for improving the performance of hydrological models in mountain catchments

Abstract

The assessment of snow, glacier, and rainfall runoff contribution to discharge in mountain streams is of major importance for an adequate water resource management. Such contributions can be estimated via hydrological models, provided that the modeling adequately accounts for snow and glacier melt, as well as rainfall runoff. We present a multiple data set calibration approach to estimate runoff composition using hydrological models with three levels of complexity. For this purpose, the code of the conceptual runoff model HBV-light was enhanced to allow calibration and validation of simulations against glacier mass balances, satellite-derived snow cover area and measured discharge. Three levels of complexity of the model were applied to glacierized catchments in Switzerland, ranging from 39 to 103 km 2 . The results indicate that all three observational data sets are reproduced adequately by the model, allowing an accurate estimation of the runoff composition in the three mountain streams. However, calibration against only runoff leads to unrealistic snow and glacier melt rates. Based on these results, we recommend using all three observational data sets in order to constrain model parameters and compute snow, glacier, and rain contributions. Finally, based on the comparison of model performance of different complexities, we postulate that the availability and use of different data sets to calibrate hydrological models might be more important than model complexity to achieve realistic estimations of runoff composition.

Future Water Availability from Hindukush-Karakoram-Himalaya upper Indus Basin under Conflicting Climate Change Scenarios

“…These models further allow spatially explicit distribution of snow pack and existing glacial extent and masses, which are primitive to reduce the typical uncertainties of compensation between the glacier and snowmelt. Further, the hydrological model calibration/validation against the multiple dataset of observed snow cover, glacial mass balances and discharges together improve the overall runoff estimation, and yields realistic snow and glacier melts components [89]. This will be the focus of a follow up study.…”

Glacio-hydrological melt and runoff modelling: a limits of acceptability framework for model selection

“…These data have been archived since 2000 and consist of daily 500 m gridded maps of snow cover extent with values ranging between 0 and 1 which relate to the proportion of the ground that is snow covered. While they do not provide a direct measurement of snow mass balance, they have shown to be a useful data source for evaluating the performance of GHMs (Hanzer et al, 2016;Finger et al, 2015). The quality of the data in high latitude regions such as Iceland are variable due to the need for good light and little or no cloud cover.…”

“…For this purpose, signatures need not be derived just from river discharge data, but should also be taken from other observation sources such as ice melt and snow coverage as these have shown to be useful for evaluating the consistency of GHMs across different aspects of glacio-hydrological systems (Finger et al, 2015;Hanzer et al, 2016;Mayr et al, 2013;Finger et al, 2011). By doing so, this framework could facilitate better predictions of river flow regime changes in glaciated river basins; firstly by helping to diagnose 25 deficiencies in GHM structures that require improvement, and secondly, by objectively selecting the range of acceptable model structures and parameterisations so that prediction uncertainty can be better constrained.…”

Bridging Glaciological and Hydrological Trends in the Pamir Mountains, Central Asia

“…Further, it is well known that glacio-hydrological models benefit from additional calibration data in order to constrain uncertainties of the glacier mass balance [51], especially when precipitation data are scarce (e.g., Mölg et al [52] Areal glacier evolution was estimated based on optical satellite data to receive glacier outlines for all glaciers located within the Gunt River Basin, for the years 1998 and 2011. Landsat Thematic Mapper (TM) images from 1998 and 2011 were used for classification of glacier outlines [23].…”