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

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 hydrologic components 5 changes in the Alpine area and northern Italy, on the basis of regional future climate (FC) conditions produced by the Regional Climate Model version 3 (RegCM3) via the IPCC A2 and B2 scenarios. In FCs, the evapotranspiration generally increases, especially over the plain areas, and consequently the surface soil moisture decreases during summer, falling below the wilting point threshold for one more month compared to present climate. In the high-mountain areas, due to the earlier snow melting, the land surface becomes snowless for an additional month. The annual mean number of dry (wet) days increase remarkably 10 (slightly) in FCs; thus increasing the risk of severe droughts, and slightly increasing the risk of floods coincidently. Our results have serious implications on human life, including agricultural production, water sustainability and general infrastructures, and can be used to plan the managements of water resources, floods, irrigation, forestry, hydropower, and many other relevant activities.