气候变暖对长江中下游地区热量资源分布的影响分析

利用1960—2010年长江中下游地区90个气象站日平均气温资料,运用线性倾向估计等方法,对近51 a来≥0 ℃和≥10 ℃积温及其持续天数和起止日期的时空分布特征进行分析,以了解气候变暖对该区热量资源分布的影响。结果表明:近51 a来长江中下游地区气温持续增暖,回归系数达0.21 ℃/10 a,略低于同期中国的增温速率(0.27 ℃/10 a),且与各项热量资源指标有显著的相关性。随着气候变暖,≥0 ℃和≥10 ℃积温及持续天数普遍显著增加,是受起始日期提前和终止日期延后的共同影响,而前者的影响更明显。21世纪00年代起北亚热带和中亚热带在长江中下游地区北移特征显著,明显与20世纪90年代以前的界线拉开了距离;20世纪90年代以后,一年三熟制种植北界和双季稻可种植区北界明显北移,21世纪00年代与19世纪60年代相比,其平均移动幅度超过2个纬距。

Impact of Climate Warming on the Distribution of Thermal Resources in the Lower-middle Reaches of the Changjiang River

Based on the daily average air temperature data from 90 meteorological stations in the lower-middle reaches of the Changjiang River from 1960 to 2010, the temporal and spatial variation characteristics of accumulated temperature steadily above 0 ℃ and 10 ℃, their lasting days, the beginning and ending date over recent 51 years were identified by using linear trend estimation, so as to find out the impact of climate warming on the distribution of thermal resources in the lower-middle reaches of the Changjiang River. The results showed that the air temperature increased continuously in the lower-middle reaches of the Changjiang River, and the regression coefficient of annual average air temperature was 0.21 ℃/10 a, the trend coefficient was 0.63(P<0.001), a slight lower than China during the same period, and it was well correlated with the other thermal resources indexes(P<0.05). The lasting days steadily above 0 ℃ and 10 ℃ increased generally in the lower-middle reaches of the Changjiang River along with climate warming, the accumulated temperature steadily above 0 ℃ and 10 ℃ increased significantly during the same period. The widespread increase of the accumulated temperature steadily above 0 ℃ and 10 ℃ and their lasting days was influenced by the beginning date advancing and the ending date delaying. Furthermore the influence of the beginning date advancing was more obvious than that of the ending date delaying. The north subtropical zone and middle subtropical zone have moved greatly northward in the lower-middle reaches of the Changjiang River since the 2000s, the northern boundary of north subtropical zone has moved out of the lower-middle reaches of the Changjiang River before the 1990s, the northern boundary of middle subtropical zone moved to near 32°N, i. e., 2-3 degrees of latitude northward, compared to the period 1960-1999. The northern limits of the three-cropping systems and the cultivable areas for double harvest rice moved northward obviously after the 1990s, and the mean movement magnitude was bigger than two latitude distance in comparison with the 1960s.