Space-time variability of spring minimum temperatures in the Champagne vineyard (NE France)

Spring frost damage in Champagne vineyard (NE France) is a major issue among growers. When this natural hazard is due to a cold air mass advection, frost protection methods are generally inefficient because low temperatures occur over the entire region. In contrast, this is not the case when freezing occurs in radiative conditions (clear sky and calm wind), when marked temperatures differentiation can be observed due to a complex interplay between wind, topography, land cover, etc. To better understand the spatial and temporal distribution of nocturnal minimum temperatures during radiative conditions, we applied the numerical model MesoNH and confronted its results to observed data (network of weather stations). In this paper, a particular night in March 2003 is examined, a period during which frost was particularly intense. We find that the model reproduces quite well the direction of wind flow, but it tends to overestimate the minimum temperatures for the coldest sites. Moreover, it gives a clear illustration of the interaction between calm regional wind and local breeze, and its influence on spatial temperature distribution.