中国产区苹果越冬冻害的风险评估

越冬期冻害是影响苹果种植分布和质量形成的主要气象灾害之一。论文利用1961-2014年2 084个气象站点资料和冻害调查数据,基于二分类Logistic回归分别建立了越冬期初冬冻害和极端低温冻害发生的概率预测模型,并按照风险极低、低、中度、高、极高等5个等级进行了空间划分。结果表明：建立的初冬冻害和极端低温冻害风险概率预测模型均通过了Hosmer-Losmer检验,独立样本的预测准确率分别达到了83.6%和91.4%。中国产区苹果的越冬冻害主要以初冬冻害为主,覆盖了除黄河故道和云南产区外的大部分果区,而极端低温冻害主要分布在纬度或海拔较高的环渤海湾北部产区、黄土高原西北部和北疆。两种冻害的高风险区域面积基本相当,中度以上风险面积较大的省份依次为甘肃、辽宁、河北和山西,但苹果种植面积最大的陕西和山东遭遇两种冻害特别是极端低温冻害的风险概率总体较低。

The Risk Assessment of Winter Injury in Main Apple-producing Regions of China

Winter injury is one of the main meteorological disasters that affect apple’s growing distribution and quality. Existing research mainly studies the injuries caused by extremely low temperatures during deep dormancy of apples, mostly using the mean temperature of the coldest month, the frequency of extreme minimum temperatures as indicators to assess the risk and divide the boundaries of apple’s distribution. However, cold resistance of fruit trees is different during different dormant phases, and is closely related with the cold-resistance exercises in fall. The probabilistic forecasting models of early winter injury and extreme winter cold injury are established with the binary Logistic regression, on basis of the data of 2 084 meteorological stations and the winter injuries happened during 1981-2010. The space is divided into five risk’s degrees as very low, low, moderate, high and very high. The classification standard of the probability of winter injury was referred from the classification criteria in the IPCC report. The results show that: the probabilistic forecasting models of early winter injury and extreme winter cold injury passed the Hosmer-Losmer test, and the prediction accuracies of independent samples reached 83.6% and 91.4% respectively. Early winter injury depends mainly on time of the first frost day and the time interval between the first frost day and the first day that the lowest temperature is lower than -15 ℃. The extreme winter cold injury is affected by the average temperature of the coldest month and the cold accumulated temperature when the daily minimum temperature is lower than -20 ℃. The freezing injury caused by short-term extreme low temperature is of small occurrence probability and limited influence scope. The extreme low-temperature injury in winter is mainly caused by continuous intimidation of strong and low temperature. Early winter injury is the main freezing injury in apple-producing regions of China, which happens in most apple-producing regions except the ancient Yellow River region and Yunnan producing region. But extreme winter cold injuries mainly happen in high latitude or high altitude regions, including the northern Bohai Gulf, the northwest of the Loess Plateau and Northern Xinjiang. High risk areas of early winter injury and extreme winter cold injury are almost equal. Gansu is the province that has the largest area of risks with moderate degree and above, followed by Liaoning, Hebei and Shanxi. On the other hand, there are low risks of winter injury, especially for extreme winter cold injury, in Shaanxi and Shandong where there are the largest planting areas of apple.