额尔古纳市森林草原过渡带极端气候指数变化

Changes of extreme climate index in forest-steppe ecotone in Erguna

极端气候事件发生频率伴随着全球气候变暖不断升高,由此引发的气象灾害也随之增加。利用线性倾向估计法、GM(1,1)灾变预测法对1957—2017年额尔古纳市气象资料进行分析,研究中国北方森林草原过渡带极端气候特征。结果表明:1957—2017年年平均气温为-2.43℃,增长速率为0.33℃·10 a-1,最低气温的升高是导致气温升高的主要原因。霜冻日数、冰冻日数、最低气温极大值、最低气温显著下降,而夏天日数、生长季长度、气温日较差、最高气温、最高气温极小值、暖夜日数、暖昼日数显著上升;1957—2017年年均降水量为361.6 mm,其中降水主要集中在夏秋季节,有效降水日数以8.17 d·10 a-1的速率显著下降,降水强度以3 mm·d-1·10 a-1的速率显著上升,连续有雨日数以0.47 d·10 a-1的变化速率显著下降;使用灰色GM(1,1)模型进行灾变预测,表明额尔古纳市下一次旱灾可能在2027—2028年。

Increasing frequency of extreme climate events is accompanied by global warming,leading to increasing meteorological disasters.The linear propensity method and GM(1,1)catastrophic prediction method were used to analyze the meteorological data of Erguna during 1957-2017,with the aim to clarify the extreme climatic characteristics of forest-steppe ecotone in northern China.Mean annual temperature from 1957 to 2017 was-2.43℃,with a growth rate of0.33℃·10 a-1.The elevation of minimum temperature was the main contributor to the rising temperature.The number of frost days and freezing days,minimum temperature and its maximum value all significantly decreased,while the number of summer days,growing season length,temperature difference,maximum temperature,minimum temperature,the number of warm nights and the number of warm days increased significantly.The mean annual precipitation in Erguna in1957-2017 was 361.6 mm,which was mainly concentrated in summer and autumn.The number of effective precipitation days decreased significantly,with a rate of 8.17 d·10 a-1.The precipitation intensity increased significantly with a rate of 3 mm·d-1·10 a-1.The number of consecutive rainy days decreased significantly with a rate of 0.47 d·10 a-1.Grey GM(1,1)model predicted that the next heavy drought event in Erguna might occur during years of 2027-2028.