Temperature variability between 1951 and 2014 in Germany and associated evolution of apple bloom onset

• Published in: Climatologie
• Main Authors: Weil, Sarah‐sophie, Camberlin, Pierre, Ullmann, Albin
• Other Authors: Biogéosciences UMR 6282 (BGS), Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2018
• Subjects: breakpoint; phenology; Germany; climate change; apple bloom; phénologie; Allemagne; changement climatique; floraison des pommiers; point de rupture; [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology; [SDV.SA.AGRO]Life Sciences [q-bio]/Agricultural sciences/Agronomy; North Atlantic; North Atlantic oscillation
• Online Access: https://hal.science/hal-02456937; https://doi.org/10.4267/climatologie.1314

21 pages International audience Apple tree bloom onset in Germany has advanced by 2 days/decade in 1951-2014 and by 3 days/decade in 1988-2014, behaving similarly in respect to its evolution since 1951 and its sensitivity to temperature to other species’ phenological spring phases. The evolution however was not linear; by conducting a split moving-window dissimilarity analysis (SMWDA) we were able to detect the “break-period” 1987-1989 which coincides with a breakpoint that has been identified in the phases of the North Atlantic Oscillation (NAO). We observed distinct spatial patterns with apple bloom advancing from southwest to northeast and, most interestingly, a longitudinal gradient in the trend of apple bloom onset revealed by a probabilistic principal components analysis (PPCA). In the period of 1951-2014, plants located in the east displayed a much stronger trend (‑16.53 days on average) than those in the western part of the country (‑6.74 days on average). This pattern seems to be linked to patterns in temperature which is highly correlated to apple bloom onset (best one predictor model: mean temperature March to May, R² = 0.82, ‑6 days/°C): the coldest regions exhibit the strongest warming trends and the greatest advances in apple bloom onset. Les dates de floraison des pommiers en Allemagne ont en moyenne avancé de 2 jours/décade de 1951 à 2014 et de 3 jours/décade de 1988 à 2014, en accord avec l’évolution des phases phénologiques d’autres espèces. Cependant, cette évolution n’a pas été linéaire : en réalisant une analyse de dissimilarité d’une fenêtre glissante fractionnée (SMWDA), nous avons détecté une période de rupture entre 1987 et 1989 qui coïncide avec un point de rupture qui a été identifié dans les phases de l’oscillation nord-atlantique (ONA). Nous avons également pu constater une structuration spatiale : la floraison des pommiers progresse du sud-ouest du pays au nord-est en termes de variabilité interannuelle des dates de floraison, il existe, superposé à un mode principal commun ...