Stein Beldring

Multi-criteria validation of a precipitation–runoff model

Abstract The multi-criteria calibration procedure MOCOM-UA was used to evaluate the validity of a physically based precipitation–runoff model by forcing the model to simulate several observed system responses simultaneously. The model is based on kinematic wave approximations to saturated subsurface flow and saturation overland flow at the hillslope scale in a landcape with a shallow layer of permeable deposits overlying a relatively impermeable bedrock. The following results were found; (i) the MOCOM-UA method was capable of exploiting information about the physical system contained in the measurement data time series; (ii) the multi-criteria calibration procedure provided estimates of the uncertainty associated with model predictions and parameters; (iii) multi-criteria calibration constraining the behavior of the precipitation–runoff model to observed runoff and groundwater levels reduced the uncertainty of model predictions; (iv) the multi-criteria method reduced the uncertainty of the estimates of model parameters; (v) the precipitation–runoff model was able to reproduce several observed system responses simultaneously during both calibration and validation periods; and (vi) the groundwater table depths exerted a major control on the hydrological response of the investigated catchment.

Kinematic wave approximations to hillslope hydrological processes in tills.

This work has been carried out within the framework of NOPEX - a NOrthern hemisphere climate Processes land surface EXperiment. Its purpose is to describe the spatial variability of groundwater lev ...

Climate Change Effects on Spatiotemporal Patterns of Hydroclimatological Summer Droughts in Norway

AbstractThis study examines the impact of climate change on droughts in Norway. A spatially distributed (1 × 1 km2) version of the Hydrologiska Byrans Vattenbalansavdelning (HBV) precipitation-runoff model was used to provide hydrological data for the analyses. Downscaled daily temperature and precipitation derived from two atmosphere–ocean general circulation models with two future emission scenarios were applied as input to the HBV model. The differences in hydroclimatological drought characteristics in the summer season between the periods 1961–90 and 2071–2100 were studied. The threshold level method was adopted to select drought events for both present and future climates. Changes in both the duration and spatial extent of precipitation, soil moisture, runoff, and groundwater droughts were identified. Despite small changes in future meteorological drought characteristics, substantial increases in hydrological drought duration and drought affected areas are expected, especially in the southern and nor...

Water Resources Under Climate Change in Himalayan Basins

Climate change has significant implications for glaciers and water resources in the Himalayan region. There is an urgent need to improve our current knowledge and methods in quantifying changes in water resources in this region. This study uses an integrated approach that couples a hydrological model and a glacier retreat model to assess the future water resources for two Himalayan basins. They are the Chamkhar Chhu basin in Bhutan (Eastern Himalayas) and the Beas basin in India (Western Himalayas). The future climate is simulated by two Regional Climate Models (RCMs) for south Asia under three Representative Concentration Pathways (Rcp2.6, Rcp4.5 and Rcp8.5). The six climate projections for the period 2010–2100 indicate significant warming effects; however, projected changes in precipitation are not consistent. Discrepancies in precipitation are noteworthy between the RCMs and greenhouse gases emissions scenarios. The glaciers in the Chamkhar Chhu basin are predicted to disappear or reduce to a small size before the 2050s, whereas the glaciers in the Beas basin are expected to lose mass before the 2060s, and afterwards to gain mass under Rcp2.6 and Rcp4.5, or to melt at a high rate under Rcp8.5. The available water resources per capita of two basins are projected to decrease in the period 2010–2050. The decreasing water resources are jointly induced by climate change and population growth. The latter is responsible for roughly 40 % of the water declines. Both basins are facing water shortages at present and the water shortages will intensify in the future.

Stability of model performance and parameter values on two catchments facing changes in climatic conditions

Abstract Hydrological models are often used for studying the hydrological effects of climate change; however, the stability of model performance and parameter values under changing climate conditions has seldom been evaluated and compared. In this study, three widely-used rainfall–runoff models, namely the SimHYD model, the HBV model and the Xin’anjiang model, are evaluated on two catchments subject to changing climate conditions. Evaluation is carried out with respect to the stability in their performance and parameter values in different calibration periods. The results show that (a) stability of model performance and parameter values depends on model structure as well as the climate of catchments, and the models with higher performance scores are more stable in changing conditions; (b) all the tested models perform better on a humid catchment than on an arid catchment; (c) parameter values are also more stable on a humid catchment than on an arid catchment; and (d) the differences in stability among models are somewhat larger in terms of model efficiency than in model parameter values.