气候变化对不同产区苹果安全越冬的可能影响

为科学评估气候变化对中国产区苹果安全越冬的影响,结合现有成果提出了分别表征果树初冬低温伤害风险、冬季持续性低温伤害风险、冬季极端低温危害风险和脱驯化期的低温伤害风险4个农业气象指标,利用1961—2015年中国苹果主产区的气象资料,分黄土高原、环渤海湾、黄河故道、西南高地和新疆5个产区,评估了气候变化对苹果安全越冬的可能影响。结果表明：苹果产区越冬期升温明显,霜冻日数和极端低温事件发生频次显著减少。初冬首次低温与初霜日间隔缩短导致渤海湾北部产区、黄河故道及北疆苹果的初冬低温伤害风险增加。越冬期持续性低温伤害风险和极端低温危害风险总体降低,特别是中高纬度表现明显,而黄土高原和新疆产区的极端低温事件发生的不确定性较大。同时黄土高原、辽宁、川西和北疆等产区苹果脱驯化期的低温伤害风险有所增加。总体上,苹果深度休眠期的冬季极端低温和持续性低温冻害风险有所降低,而初冬和脱驯化期低温冻害风险显著增加。

Possible Impacts of Climate Change on the Risk of Apple Overwintering in China

Safe overwintering is an important index to assess the possible impact of climate change on apple planting boundary and variety selection. Based on existing research, four agro-climatic indices were proposed to evaluate the effect of climate change on apple safe overwintering in China. The four agro-climatic indices, respectively, indicate the risk of damage to apple by early winter frost, the risk of the intensity and duration of low freezing temperature, the risk of damage by extreme low temperature, and the risk of damage to developing flower buds by late spring frost. We studied the variation trends and abrupt change characteristics of the four agro-climatic indices across main apple-producing regions of China, including the Loess Plateau, Bohai Bay, Old Course of the Yellow River, Southwest Highlands and Xinjiang, by using statistical methods and the ArcGIS analysis tools based on meteorological observational data from 1961 to 2015. The results showed that temperature significantly increased during the apple overwintering period in main apple-producing regions of China, while the number of annual accumulative frost days and the frequency of extreme low temperature events significantly decreased. The risk of damage to apple by early winter frost was increased due to the shortened interval between first frost and first low temperature in northern Bohai Bay, Old Course of the Yellow River and northern Xinjiang. The risk of the intensity and duration of low freezing temperature during the apple overwintering period decreased, so did the risk of damage by extreme low temperature, especially in high latitude regions. But the frequency of extreme low temperature events was uncertain in the Loess Plateau and Xinjiang producing regions. In addition, the risk of damage to developing apple flower buds by late spring frost increased in the Loess Plateau, Liaoning, western Sichuan and Xinjiang producing regions. To sum up, the risk of the intensity and duration of low freezing temperature and the risk of damage by extreme low temperature decreased, but the risk of damage to apple by early winter frost and the risk of damage to developing flower buds by late spring frost increased.