Climate change over the high-mountain versus plain areas: Effects on the land surface hydrologic budget in the Alpine area and northern Italy

Claudio Cassardo,Marco Galli,Seon Ki Park,Sungmin O

doi:10.5194/hess-22-3331-2018

Abstract

Abstract. Climate change may intensify during the second half of the current century. Changes in temperature and precipitation can exert a significant impact on the regional hydrologic cycle. Because the land surface serves as the hub of interactions among the variables constituting the energy and water cycles, evaluating the land surface processes is essential to detail the future climate. In this study, we employ a trusted soil–vegetation–atmosphere transfer scheme, called the University of Torino model of land Processes Interaction with Atmosphere (UTOPIA), in offline simulations to quantify the changes in hydrologic components in the Alpine area and northern Italy, between the period of 1961–1990 and 2071–2100. The regional climate projections are obtained by the Regional Climate Model version 3 (RegCM3) via two emission scenarios – A2 and B2 from the Intergovernmental Panel on Climate Change Special Report on Emissions Scenarios. The hydroclimate projections, especially from A2, indicate that evapotranspiration generally increases, especially over the plain areas, and consequently the surface soil moisture decreases during summer, falling below the wilting point threshold for an extra month. In the high-mountain areas, due to the earlier snowmelt, the land surface becomes snowless for an additional month. The annual mean number of dry (wet) days increases remarkably (slightly), thus increasing the risk of severe droughts, and slightly increasing the risk of floods coincidently. Our results have serious implications for human life, including agricultural production, water sustainability, and general infrastructures, over the Alpine and adjacent plain areas and can be used to plan the managements of water resources, floods, irrigation, forestry, hydropower, and many other relevant activities.

Highlights

IntroductionRecent reports from the Intergovernment Panel on Climate Change (IPCC), based on the coupled atmosphere–ocean general circulation models (GCMs), on the condition of increasing concentration of greenhouse gases (IPCC, 2007, 2013) indicate that climate change by the end of this century (e.g., increase in the mean temperature and change in the precipitation amount) is expected to occur irregularly in space and time but to mostly affect some specific and critical regions (Beniston, 2006), including the vicinity of the Mediterranean – well known as one of the world’s climatic hotspots (Giorgi, 2006; Diffenbaugh and Giorgi, 2012; Gobiet et al, 2014; Vautard et al, 2014; Coppola et al, 2016; Paeth et al, 2017)
We investigated the characteristic changes in hydrologic budget components and soil moisture, over the Alpine areas and northern Italy, under the projected conditions of the future climate (FC; 2071–2100), compared to the reference climate (RC)
The meteorological input data in FCs are provided by the Regional Climate Model version 3, based on the A2 and B2 scenarios from the Intergovernment Panel on Climate Change Special Report on Emissions Scenarios

Summary

Introduction

Recent reports from the Intergovernment Panel on Climate Change (IPCC), based on the coupled atmosphere–ocean general circulation models (GCMs), on the condition of increasing concentration of greenhouse gases (IPCC, 2007, 2013) indicate that climate change by the end of this century (e.g., increase in the mean temperature and change in the precipitation amount) is expected to occur irregularly in space and time but to mostly affect some specific and critical regions (Beniston, 2006), including the vicinity of the Mediterranean – well known as one of the world’s climatic hotspots (Giorgi, 2006; Diffenbaugh and Giorgi, 2012; Gobiet et al, 2014; Vautard et al, 2014; Coppola et al, 2016; Paeth et al, 2017) Within this region, the Alpine and adjacent areas are expected to undergo a relatively larger temper-. To evaluate the local net effect of changing climate on water resources, the hydrologic budget must be detailed (Bocchiola et al, 2013)

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