Meteorological considerations of grapevine damage due to temperature variations: the 2019 late spring frost and summer heat wave events in Burgundy
Authors: Planchon Olivier , Cantat Olivier , Bois Benjamin , Beauvais François , Gavrilescu Catinca , David Matthieu 
Published: March 2021

&lt;p&gt;&lt;strong&gt;&lt;span&gt;Meteorological considerations of grapevine damage due to temperature variations:&lt;/span&gt; &lt;span&gt;t&lt;/span&gt;&lt;span&gt;he 2019 late spring frost and summer heat wave events &lt;/span&gt;in Burgundy &lt;/strong&gt;&lt;/p&gt;&lt;p&gt;During 2019, &lt;span&gt;the occurrence of two contrasting weather events, a cold snap and a heat wave, caused extensive damage to the vineyards&lt;/span&gt; of Northern Burgundy. &lt;span&gt;The late spring cold snap, that &lt;/span&gt;&lt;span&gt;occurred&lt;/span&gt;&lt;span&gt; from May 5&lt;/span&gt;&lt;sup&gt;&lt;span&gt;th&lt;/span&gt;&lt;/sup&gt;&lt;span&gt; to 7&lt;/span&gt;&lt;sup&gt;&lt;span&gt;th&lt;/span&gt;&lt;/sup&gt;&lt;span&gt;, generated frost like conditions across the northern and north-western areas of the C&amp;#244;te-d'Or department.&lt;/span&gt; The weather stations of the Northern Auxois area, where the three observation and study sites are located, recorded minimum temperatures &lt;span&gt;ranging &lt;/span&gt;between -1 and -2&amp;#176;C. &lt;span&gt;On the 24&lt;/span&gt;&lt;sup&gt;&lt;span&gt;th&lt;/span&gt;&lt;/sup&gt;&lt;span&gt; and the 25&lt;/span&gt;&lt;sup&gt;&lt;span&gt;th&lt;/span&gt;&lt;/sup&gt;&lt;span&gt; of July vineyards were exposed, yet again, to an extreme temperature variation.&lt;/span&gt; &lt;span&gt;A brief but unusually intense heat wave increased daily maximum temperatures up to 42&amp;#176;C in the department&amp;#8217;s far north. Landforms such as plateaus were less exposed to the increase in temperatures due the limiting effect of higher elevations. This led to temperatures not exceeding 40&amp;#176;C above 300 m, elevation at which the vineyard sites of this study are located.&lt;/span&gt;&lt;/p&gt;&lt;p&gt;Weather conditions that caused the early May frost event were related to a northern circulation &lt;span&gt;present &lt;/span&gt;over Western Europe &lt;span&gt;that persisted &lt;/span&gt;from &lt;span&gt;the 28&lt;/span&gt;&lt;sup&gt;&lt;span&gt;th&lt;/span&gt;&lt;/sup&gt;&lt;span&gt; of April &lt;/span&gt;&lt;span&gt;to&lt;/span&gt;&lt;span&gt; the 6&lt;/span&gt;&lt;sup&gt;&lt;span&gt;th&lt;/span&gt;&lt;/sup&gt;&lt;span&gt; of May&lt;/span&gt;. &lt;span&gt;The strong anticyclonic ridge stretching from Greenland to the Iberian Peninsula directed an air mass of arctic origin towards France.&lt;/span&gt; &lt;span&gt;On July 24&lt;/span&gt;&lt;sup&gt;&lt;span&gt;th&lt;/span&gt;&lt;/sup&gt;&lt;span&gt; and 25&lt;/span&gt;&lt;sup&gt;&lt;span&gt;th&lt;/span&gt;&lt;/sup&gt;&lt;span&gt;, the presence of a surface high pressure system above Scandinavia, associated with a low-pressure center located near the Atlantic Ocean, generated an influx of a very hot air mass from the northern part of the African continent through France and neighbouring countries.&lt;/span&gt;&lt;/p&gt;&lt;p&gt;The local impact of these two weather events was modulated by the topographical features specific to the study area: a limestone plateau strongly dissected by parallel valleys &lt;span&gt;of S.E. / N.W. orientations&lt;/span&gt;. &lt;span&gt;The three observation sites have similar soil characteristics and are located on south facing slopes.&lt;/span&gt; &lt;span&gt;However, damage to vegetation was uneven across sites as well as within each site.&lt;/span&gt; These observations rise up the question of the influence of very fine-scale environmental conditions &lt;span&gt;and the impact they might have on the different vegetative growth stages.&lt;/span&gt; &lt;span&gt;Lastly, the variation in physiological response among grapevines and its effect on their sensitivity to the occurrence of different weather hazards is also to be considered.&lt;/span&gt;&lt;/p&gt;