Accounting for global mean warming and scaling uncertainties in climate change impact studies: application to a regulated lakes system

Abdelkader Mezghani, André Musy, Bettina Schaefli
2007
Journal paper

Abstract

A probabilistic assessment of climate change and related impacts should consider a large range of potential future climate scenarios. State-of-the-art climate models, especially coupled atmosphere-ocean general circulation models and Regional Climate Models (RCMs) can however not be used to simulate such a large number of scenarios. This paper presents a methodology to obtain future climate scenarios through a simple scaling methodology: The projections of several key meteorological variables obtained from a few regional climate model runs are scaled based on different global-mean warming projections drawn in a probability distribution of future global-mean warming. The resulting climate change scenarios are used to drive a hydrological and a water management model to analyse the potential climate change impacts on a water resources system. This methodology enables a joint quantification of the climate change impact uncertainty induced by the global-mean warming scenarios and the regional climate response. It is applied to a case study in Switzerland, a water resources system formed by three interconnected lakes located in the Jura Mountains. The system behaviour is simulated for a control period (1961 - 1990) and a future period (2070-2099). The potential climate change impacts are assessed through a set of impact indices related to different fields of interest (hydrology, agriculture and ecology). The obtained results show that future climate conditions have a significant influence on the system performance and that the uncertainty induced by the inter-RCM variability contributes to a large part to the total impact prediction uncertainty.

Official source

https://infoscience.epfl.ch/record/55849?ln=en

About this result

This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.

Related concepts

Related publications

Abdelkader Mezghani, André Musy, Bettina Schaefli
2007
Journal paper

Abstract

Official source

https://infoscience.epfl.ch/record/55849?ln=en

About this result

Related concepts (20)

Related concepts

Related publications (15)

Related publications

, ,

The present study analyzes the uncertainty induced by the use of different state-of-the-art climate models on the prediction of climate change impacts on the runoff regimes of 11 mountainous catchments in the Swiss Alps having current glaciation rates between 0 and 50 %. The analyzed climate change scenarios are the result of 19 Regional Climate Model (RCM) runs obtained for the period 2070 – 2099 based on two different green house gas emission scenarios (the A2 and B2 scenarios defined by the Intergovernmental Panel on Climate Change) and on three different coupled Atmosphere-Ocean General Circulation Models (AOGCMs) called HadCM3, ECHAM4/OPYC3 and ARPEGE/OPA. The hydrological response of the studied catchments to the climate scenarios is simulated through a conceptual reservoir-based precipitation-runoff transformation model called GSM-SOCONT. For the glacierized catchments, the glacier surface corresponding to these future scenarios is updated through a conceptual glacier surface evolution model. The obtained results show that all climate change scenarios induce in all catchments an earlier start of the snowmelt period leading to a shift of the hydrological regimes and of the maximum monthly discharges. The mean annual runoff undergoes in most cases a significant decrease. For the glacierized catchments, the simulated regime modifications are mainly due to the increase of the mean temperature and corresponding impacts on the snow accumulation and melting processes. The hydrological regime of the catchments located at lower altitudes is more strongly affected by the changes of the seasonal precipitation. For a given emission scenario, the simulated regime modifications of all catchments are highly variable for the different RCM runs. This variability is induced by the driving AOGCM but also to a large part by the inter-RCM variability. The differences between the different RCM runs is so important that the predicted climate change impacts for the two emission scenarios A2 and B2 are overlapping.

2006

This PhD thesis presents the development of a methodological framework to analyse potential climate change impacts on a high mountainous water resources system and to quantify the associated modelling uncertainties. The main objective is to show whether state-of-the-art hydrological modelling techniques driven by currently available climate change scenarios enable a prediction of the long-term evolution of the analysed system. The case study is a highly glacierized catchment feeding a hydropower plant located in the Swiss Alps. The climate change impact analysis is based on a classical simulation approach: The system behaviour is modelled for an observed control period (1961 to 1990) and for a future period (2070 to 2099) characterised by a modified (predicted) climate. The climate change impact on the studied system is assessed through the comparison of some key characteristics of the system for the two periods (e.g. the mean annual discharge or the hydropower production). The system simulation is completed through a set of four models, a water management model, a hydrological discharge model, a glacier surface evolution model and a model for the production of local scale meteorological time series (precipitation and temperature) based on global and regional climate model outputs. The local scale models have been specifically developed for the purposes of this thesis. For each of them, an appropriate statistical method for the quantification of the inherent modelling uncertainties has been developed. A special emphasis is given to the modelling uncertainties induced by the conceptual hydrological model. A method has been developed to quantify the statistical and the multi-objective modelling uncertainty in a multi-model framework including several equivalent model structures. This method has been specially designed for the quantification of the prediction uncertainty in climate change impact studies but it is transposable to other hydrological modelling contexts. The overall prediction uncertainty and the contribution of each source of modelling uncertainty is quantified through Monte Carlo simulations of the system behaviour combining successively the different sources of modelling uncertainty. It is shown that the uncertainties induced by the prediction of the climate evolution are much higher than the ones induced by the local scale models of the system behaviour. The uncertainty related to the use of different regional climate models is however nearly as important as the one due to the choice of the underlying global climate model and the green house gas emission scenario. Using a fixed hydrological model structure, the predicted climate evolution induces a significant reduction of the hydropower production performance due to a considerable hydrological regime modification. The available data, the current discharge modelling techniques and the knowledge about the underlying processes are however not sufficient to chose an objectively best model structure. Considering the multi-model approach (including different hydrological model structures), an unambiguous prediction of the hydrological reaction to the analysed climate change reveals impossible at the given temporal horizon.

EPFL2005

This paper addresses two major challenges in the field of climate change impact analysis on water resources systems: i) incorporation of a large range of potential climate change scenarios and ii) quantification of related modelling uncertainties. The developed methodology of climate change impact modelling is presented and illustrated through an application to a hydropower plant in the Swiss Alps that uses the discharge of a highly glacierized catchment. The potential climate change impacts are analysed in terms of system performance for the control period (1961 – 1990) and for the future period (2070 – 2099) under a range of climate change scenarios. The system performance is simulated through a set of 4 model types including the production of regional climate change scenarios based on global-mean warming scenarios, the corresponding discharge model, the model of glacier surface evolution and the hydropower management model. The modelling uncertainties inherent to each model type are characterised and quantified separately. The overall modelling uncertainty is simulated through Monte Carlo simulations of the system behaviour for the control and the future period. The obtained results for both periods lead to the conclusion that potential climate change has as statistically significant negative impact on the system performance.

2007

, ,

2006

EPFL2005