Changement climatique - Recherche française (avec laboratoires CNRS) - 2010-2015

Time-series of growing season air temperature anomalies in the Parisian region and of Pinot noir grape harvest dates (GHD) in Burgundy (1676-2004) are analyzed in the frequency domain. Variability of both time-series display 3 significant frequency-bands (peaks significant at the 5% level): (1) a low-frequency-band (multi-decadal) with a 25 yr peak period, (2) a 3 to 8 yr band period (inter-annual) with a 3.1 yr peak period, and (3) a 2 to 3 yr band period (quasi-biennial) with a 2.4 yr peak period. Joint sea surface temperature/sea level pressure (SST/SLP) EOF analyses based on data from the 20th century along with spatio-temporal patterns for the above frequency-bands, are presented. SST anomalies were found to display early significant spatial SST patterns in the north Atlantic ocean (air temperature lagging by 6 mo) similar to those obtained from EOF analyses. It is proposed that the robust power spectra for the above frequency-bands are linked with Atlantic climate variability modulating western European climate: (1) the global Multi-Decadal Oscillation (MDO) with its Atlantic Multi-decadal Oscillation (AMO) footprint, (2) the Atlantic Inter-Annual (IA) fluctuations, and (3) the Atlantic Quasi-Biennial (QB) fluctuations. Moreover these specific western European climate signals are perceived as contributors to the timing of GHD in Burgundy. Thus, advance knowledge on the evolution and phasing of the above climate fluctuations become important elements for viticulture and wine industry management, since anthropogenic effects could have modified time-series patterns, particularly since the mid-1980s.