Analysis of hydrological extremes at different hydro-climatic regimes under present and future conditions

I G Pechlivanidis,B Arheimer,P Shi,L Samaniego,C Donnelly,S Huang,V Aich,S Eisner,Y Hundecha

doi:10.1007/s10584-016-1723-0

Abstract

We investigate simulated hydrological extremes (i.e., high and low flows) under the present and future climatic conditions for five river basins worldwide: the Ganges, Lena, Niger, Rhine, and Tagus. Future projections are based on five GCMs and four emission scenarios. We analyse results from the HYPE, mHM, SWIM, VIC and WaterGAP3 hydrological models calibrated and validated to simulate each river. The use of different impact models and future projections allows for an assessment of the uncertainty of future impacts. The analysis of extremes is conducted for four different time horizons: reference (1981–2010), early-century (2006–2035), mid-century (2036–2065) and end-century (2070–2099). In addition, Sen’s non-parametric estimator of slope is used to calculate the magnitude of trend in extremes, whose statistical significance is assessed by the Mann–Kendall test. Overall, the impact of climate change is more severe at the end of the century and particularly in dry regions. High flows are generally sensitive to changes in precipitation, however sensitivity varies between the basins. Finally, results show that conclusions in climate change impact studies can be highly influenced by uncertainty both in the climate and impact models, whilst the sensitivity to climate modelling uncertainty becoming greater than hydrological model uncertainty in the dry regions.

Highlights

The increase in the atmospheric concentrations of greenhouse gases has led to the global climate change phenomenon which is expected to have a strong impact on water resources at local, regional and global scales (IPCC 2013)
An increasing trend in high and low flows is shown for the Lena basin but in the Rhine basin only for the end-century for RCP2.6
Projected changes in the Ganges are largely variable between the driving global climate models (GCMs) models, the direction of change is consistent between the hydrological model (HM) for a given GCM model

Summary

Introduction

The increase in the atmospheric concentrations of greenhouse gases has led to the global climate change phenomenon which is expected to have a strong impact on water resources at local, regional and global scales (IPCC 2013). Projecting climate impacts on hydrological processes is often prone to considerable uncertainties (i.e. from greenhouse gas emission scenarios, climate models and their parameterisation, downscaling techniques, bias correction methods, hydrological models structure and parameters), which are unavoidably propagated through the entire modeling chain and further interact with each other (Minville et al 2008; Refsgaard et al 2010). These uncertainties can propagate in a very complex way (e.g. magnitude of error could vary both in space and time), which could be misinformative for management decisions. An increasing interest has been shown to quantify the contribution from each uncertainty source to the total uncertainty (Preston and Jones 2008; Poulin et al 2011; Teutschbein and Seibert 2012)

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