2013年12月低温事件对昆明市主要小春农作物生长的影响

Influence of Low Temperature Event on Main Winter Crops in Kunming City Having Occurred in December 2013

为深入认识气候变暖背景下农业低温灾害的特点,从气象分析与农业灾情调查相结合的角度分析了2013年12月中旬昆明地区的严重低温灾害事件。结果表明,此次低温天气过程低温强度大、持续时间较长、影响范围广,是伴随降水、雪灾、强辐射降温、霜冻和冰冻多因素综合影响的"湿冷型"低温灾害,它和1999年12月发生的"干冷型"严重低温霜冻是最近39 a来危害昆明市农业最大的2次冬春季极端低温事件;这意味着气候变暖背景下云南低纬高原地区极端低温事件的频率和危害加大。分析显示了不同发育期的蚕豆遭受的3个冷冻害等级与低温强度的对应关系,低温霜冻对花期蚕豆危害大(主要造成空秕荚率大增和株籽粒数大减)并导致减产,对分蘖后期至拔节初期小麦危害相对较小;作物遭受的冷冻害程度与降温程度和低温持续时间呈正相关关系;高湿度、积雪、和较长时间的冰冻可加重低温天气对农作物的危害。

In order to understand the characteristics of the agrlcultural low-tomperature disasters under the background of climate wanning, a serious low-temperature disaster event having occurred in Kunming district in December 2013 was deep investigated by the combination of meteorological analysis and agricultural disaster survey. The results showed that, this weather process resulted in a low-temperaturo disaster of ‘ wet-cold type＇ which had a very strong low-temperature with a long duration and a extensive scope of influence, accompanied together by some weather phenomenon such as rainfall, snowfall, radiation cooling, frost and freezing. This low-temperature disaster and the other one of ‘dry-cold type＇ having occurred in December 1999 were the two extreme low-temperature events in winter and spring which had the furthest damage to the agriculture in Kunming City since 1975. This meant that the frequency and damages of extreme low-temperature events in- creased in Yuunan province under the background of climate warming. This investigation showed a corresponding relationship between the three grades of freezing injury for vicia faba and the low-temperature intensities. The low temperature and frost event did great harm to vicia faba during its flowering phase and finally resulted in big reduction of its output with a higher proportion of empty-unfilled pod and a biggish decrease of pea number for each plant. But it was relatively less harmful to wheat during the tillering phase and early days of elongation stage. And the detriment degrees of freezing injury for a variety of crops were positively correlated with the low-temperature extent and its du- ration. In this low-temperature ease, snow, high humidity and freeze with long time aggravated the agricultural low-temperature disaster.