Coupled runoff simulations as validation tools for atmospheric models at the regional scale

Abstract

SUMMARYHigh-resolution atmospheric forecasting systems are characterized by an increasing complexity which renders validation and interpretation of the model results more and more demanding. This is especially evident in complex terrain. In such areas, the limited density of meteorological observing stations does not allow an accurate evaluation of high-resolution weather forecasts. Accordingly, advanced tools for the validation of atmospheric models are necessary and of great interest to forecasters. In this paper we address this issue, and present the possibilities and advantages offered by coupling atmospheric and hydrological models. A distributed hydrological model has been used to estimate the forecast quality of two different weather prediction models at different resolutions for the mesoscale Ticino-Verzasca-Maggia watershed, a high catchment located in the southern European Alps draining from the north into the Lago Maggiore. For this area, several hydrological forecast-driven model experiments have been carried out as one-way nested simulations using hourly time steps and 0:5 £ 0:5 km grid resolution. The availability of meteorological forecast sequences allowed continuous atmospheric-hydrological simulations covering non-overlapping periods of 3.5 years and 2.5 months. The model results have been analysed using multiple comparisons including rainfall and runoff measurements, as well as observation-driven model results of river runoff and water balances at the catchment-scale. It is shown that the hydrological model is suf ciently sensitive to provide substantial information for the validation of atmospheric models.

On interpreting hydrological change from regional climate models

“…It includes a soil-vegetation-atmosphere-transfer scheme (SVAT), a soil-water model, a groundwater model, and a runoff generation and routing scheme (Jasper and Kaufmann 2003;Jasper et al 2004). The WASIM simulations in this study cover 20 subcatchments of the Rhine River down to Cologne for a total area of 145,000 km 2 .…”

SILVAQUA - Auswirkungen forstlicher Bewirtschaftungsmaßnahmen auf den Zustand von Gewässern in bewaldeten Einzugsgebieten am Beispiel der Oker im Nordharz

“…(GURTZ et al 2003, KRAUSE u. BRONSTERT 2005. Auf unterschiedlichen räumlichen Skalen (< 1 bis > 1.000 km 2 ) werden dabei die Prozesse des Wasserhaushaltes regional differenziert abgebildet (FIEBIGER et al 2008, JASPER u. KAUFMANN 2003. Die Übertragbarkeit auf Einzugsgebiete unterschiedlicher Größe und Gebietsausstattung ist somit gewährleistet .…”

The hydro-meteorological chain in Piemonte region, North Western Italy - analysis of the HYDROPTIMET test cases

“…Uncertainty sources are found either in the meteorological input as well as in the hydrological conceptualisation and parameters. From a theoretical point of view a probabilistic approach should be considered (Krzysztofowicz, 1999) event though it often produce big difficulties in warning dissemination (Parker and Fordham, 1996). In this work a deterministic hydrometeorological chain is adopted because the aim is to understand the role and the weight of the different uncertainty sources in an operational frame, rather than to propose a new or a better approach.…”

“…In this work a deterministic hydrometeorological chain is adopted because the aim is to understand the role and the weight of the different uncertainty sources in an operational frame, rather than to propose a new or a better approach. In fact the hydrological simulation and the alert system are here used for validation purposes (Jasper and Kaufmann, 2003) allowing an objective comparison between results obtained using different configuration of the chain. In particular different Lokal Modell set up are used and compared with the 'perfect meteorological forecast' results.…”