洞庭湖生态经济区热量资源变化特征

基于洞庭湖生态经济区25个地面气象观测站1961-2013年的逐日平均气温、最高气温和最低气温观测资料，组合成100项热量特征指标，利用统计方法系统性分析该区域的热量资源变化特征，并采用贡献率探讨了最高、最低气温在年平均气温变化中的作用。结果表明：洞庭湖生态经济区不同气温要素的空间分布形态不同，日平均气温≥0℃、≥5℃、≥10℃、≥15℃、≥20℃的积温空间分布形态一致，均呈西低东高分布；稳定通过0℃、5℃、10℃、15℃、20℃的初、终日期在区域内相对集中。年平均气温、年平均最高气温、年平均最低气温均呈显著或极显著上升趋势，但存在升温的不均匀性，气候变暖以最低气温升高为主要特征，最高气温在春季起到升温加速作用，导致洞庭湖区春季气温上升速率较其他季节大。气候变暖带动日平均气温≥0℃、≥5℃、≥10℃、≥15℃、≥20℃的积温呈极显著上升趋势，但升温的不均匀性直接关联到稳定通过一定界限日平均温度初、终日期的变化及积温突变时间的变化，5℃、15℃初日呈显著提前趋势，≥0℃、≥5℃、≥10℃积温增加突变时间与最低气温相近，≥15℃、≥20℃积温增加突变时间与最高气温相近。

Variations of Heat Resources in Dongting Lake Region

Based on the 1961-2013 daily maximum/mean/minimum temperature at 25 meteorological observation stations across Dongting Lake ecological economic zone, the change characteristics for heat resources were systematically analyzed by using the relevant statistical methods. Moreover, the impacts of maximum/minimum temperature on the variations of mean temperature were also analyzed by caculating the contribution ratio. Results show that different temperature elements show different spatial distribution patterns. The spatial distribution of steady temperature above 0/5/10/15/20℃ accumulated temperature are consistent, which are high in west and low in east. The largest difference between the beginning and ending dates of steady temperature above 0/5/10/15/20℃ is 10 days at different stations. But most of the difference is within 5 days. Significant increasing or extremely significant increasing trends are identified in the maximum/mean/minimum temperature. But in terms of the warming, there is inhomogeneity in different meteorological elements and seasons. The main feature of climate warming is the increase of minimum temperature. The maximum temperature increasing plays a role in acceleration of warming in spring, which leads to the biggest seasonal temperature rising rate. Extremely significant increasing trends are identified in steady temperature above 0/5/10/15/20℃ accumulated temperature for the climate warming. The variations of beginning and ending dates of steady temperature, abrupt change time are directly affected by inhomogeneous temperature increase. The beginning date of steady above 5/15℃ is earlier than before significantly. The abrupt change time of the steady above 0/5/10℃ accumulated temperature is similar to that of minimum temperature, and the abrupt change time of the steady above 15/20℃ accumulated temperature is similar to that of maximum temperature. Spring cold damage will happen more likely under the background of climate warming.