1. EGU General Assembly 20111 C. Cassardo 1, M. Galli 1, N. Vela 1 and S. K. Park 2,3 1 Department of General Physics, University of Torino, Italy 2 Department of Environmental Science and Engineering, Ewha Womans University, Seoul, Korea 3 Severe Storm Research Center & Center for Climate/Environment Change Prediction Research, Ewha Womans University, Seoul, Korea Heat and cold spells over the Alpine region in the future climate Ewha Womans University 이 화 여 자 대 학 교

2. 2EGU General Assembly 2011 Outline ::  The aim of the project  The experiment setup  The models used ◦ The Regional Climate Model ◦ The Land Surface scheme  A rapid sketch of the main results ◦ The change of the hydrologic balance in summer ◦ The anticipation of the snow melting season  The analyses carried out ◦ The cold spells ◦ The hot spells ◦ The arid days ◦ The wet days  Conclusions

3. 3EGU General Assembly 2011 Introduction ::  The global aim of the project ◦ To understand the effects of climate change on the Soil- Atmosphere Interface (energy and hydrological budgets) ◦ Highlight on mesoscale: Alps, Po Valley ◦ Occurrence of dry and wet periods ◦ Correct partitioning of energy balance components ◦ Better description of surface layer evolution:  Convective phenomena  Cloud formation  Precipitation

4. 4EGU General Assembly 2011 The method: a simulation chain  General Climate Model simulation ◦ HadAM3H/HadRM3H global climate model (Hadley Centre)  Grid: 1.25° (latitude) x 1.875° (longitude) [high resolution version]  Details from Jones et al. (2001)  Regional Climate Model simulation ◦ Model: RegCM3 (also used in PRUDENCE)  Grid size: 20 km  Details from Giorgi et al. (2003) [Climate Dynamics]

5. 5EGU General Assembly 2011 The data extraction  Data extraction ◦ Domain: rectangle 6°E-15°E and 43°N-47°N ◦ 720 grid points including Alps and the Po river basin (grid size: 20 km) ◦ All 3-hours RegCM3 outputs (but precipitation) were interpolated every hour using cubic splines, while precipitation was simply redistributed assuming a constant rate ◦ 10 soil layers were considered, with thicknesses progressively doubling from surface 5 cm to deepest 25 m (boundary relaxation zone)  Run of the land surface scheme UTOPIA for each grid point

6. 6EGU General Assembly 2011 The simulation domain

7. 7EGU General Assembly 2011 The land surface scheme UTOPIA University of TOrino model of land Process Interaction with Atmosphere  1-D, multilayer, diagnostic model of energy, momentum and water exchanges between soil and atmosphere  Describes the surface processes in terms of physical fluxes and hydrological state of soil  Represents the interactions of soil and vegetation with the atmosphere (big-leaf)  Driven by commonly measured meteorological parameters or by atmospheric models

8. 8EGU General Assembly 2011 The UTOPIA run  Data needed: ◦ surface air temperature, humidity, pressure, wind, precipitation, short- and long-wave radiation  For each grid point: ◦ Soil type assigned using ECOCLIMAP (Masson et al., 2003) ◦ Vegetation type imposed equal to short grass  Run of UTOPIA  Extraction of the following variables: ◦ Soil temperature, soil moisture, sensible and latent heat flux, surface runoff, bottom drainage, evapotranspiration

9. 9EGU General Assembly 2011 The periods simulated  Present climate (1960 - 1990) ◦ useful for comparisons  Future climate (2070 - 2100) ◦ A2 and B2 scenarios

10. 10EGU General Assembly 2011 The analysis of the data  The analysis was carried out considering the soil temperature and the soil moisture ◦Soil temperature exhibits less noise than air temperature (at any level in the surface layer) ◦Soil moisture depends more specifically on hydrological budget than relative or specific humidity  Definitions: ◦Cold days: when T 1 <0°C ◦Warm days: when T 1 >30°C ◦Dry days: when Q I <0 ◦Wet days: when Q I >0.8 T 1 :soil temperature in the uppest 10 cm q 1 :soil moisture in the uppest 10 cm q FC :field capacity q WI :wilting point

11. 11EGU General Assembly 2011 The number of hot days The number of hot days increases in the plain by 30 in B2 and by 40 in A2 with respect to control, and few hot days appear in lower elevations

12. 12EGU General Assembly 2011 The number of cold days The number of cold days is null in the plains in A2 and B2, and reduces by 40 to 80 days in the mountains

13. 13EGU General Assembly 2011 The number of dry days The number of dry days increases by about 20-30 in B2 and by about 30- 40 in A2 mainly in the plains and hills

14. 14EGU General Assembly 2011 The number of wet days The number of wet days increases slightly by about 5- 10 days in some areas in proximity of the mountains, while in few other areas there is a light decrease

15. 15EGU General Assembly 2011 The wet and dry days interannual variability (soil moisture)  No changes for the wet days interannual variability  Decrease of the interannual variability of dry days in Italy and over the Alps, increase in Switzerland

16. 16EGU General Assembly 2011 The warm and cold days interannual variability (soil temperature)  Increase of the interannual variability for warm days  Decrease of the interannual variability for cold days

17. 17EGU General Assembly 2011 Conclusions ::  Aim: to evidence the climate change consequences on Alpine area  Analysis performed on soil temperature/moisture  need to use a model simulation chain: GCM  RCM  LSM  Selected periods: A2, B2 scenarios (2071-2100) vs present climate (1961-1990)  Number of dry days increases, with less variability  future climate is drier  Number of wet days increases sligthly, but variability does not  frequency of floods may increase  Number of hot days increases, as well as their variability  Number of cold days decreases, as well as their variability (but less)

18. 18EGU General Assembly 2011 Acknowledgments  This research is partly supported by the Ministry of Environment, Korea, under the National Comprehensive Measures against Climate Change Program (No. 1700-1737-322-210-13)  N. Vela 3-month stay in Seoul has been supported by the Korean Ministry of Environment  Input data (RegCM3) have been provided by the Earth System Physics Section of the ICTP, Italy  The collaboration between C. Cassardo and S.K. Park has been partly supported by the government of Italy and Korea, respectively, for visiting each institution