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During June, July and August 2003, an exceptional heat wave affected western and central Europe. In Piedmont, a region located in northwestern Italy at the foot of the Alps, many stations recorded the highest mean summer temperatures since the beginning of their instrumental record. Some consequences of this extraordinary hot summer in Piedmont and in many European countries include severe drought conditions, with strong effects on agriculture and electric production, an acceleration of glacier ablation, and an increase in the frequency of forest fires. This heat wave has been analyzed by running a Soil-Vegetation Atmosphere Transfer scheme for 5 years (1999-2003): the LSPM (Land Surface Process Model). The attention was focused on energy and hydrologic budget components by performing two simulations in climatically different sub-areas of Piedmont. The increment in the observed solar radiation during summer 2003 produced an increment in the net radiation, which in turn generated an increase of sensible (more) and latent (less) heat flux, and soil-vegetation heat flux. The latter caused a consistent warming of soil and vegetation surfaces, which acted partially as a negative feedback increasing the longwave radiation emitted by the terrestrial surface. Latent heat flux showed a small increment in summer 2003, because the evapotranspiration was limited by the soil moisture unavailability, particularly during July and August, due to the scarcity of precipitations during the previous spring. The drought conditions, acting as a positive feedback, caused the effects of the heat wave to be more severe, favored its persistence and enhanced the further reduction of soil moisture. The comparison among the results of the two simulations allowed to highlight the role of two phenomena that concurred to exacerbate the heat wave: the enhancement of the drought conditions and the increment of the adiabatic compression connected with the anticyclonic conditions. A rough estimate allowed us to quantify in about 2 C the contribution of the former.

来源平台：ASIA-PACIFIC JOURNAL OF ATMOSPHERIC SCIENCES