典型喀斯特高原湖泊气候变化特征分析——以贵州草海为例

威宁草海是贵州省内最大的天然淡水湖泊,是喀斯特高原湖泊的典型代表。本研究基于威宁县1951—2016年逐月气温和降水资料,采用累积距平法、Mann—Kendall非参数检验、Sen’s斜率估计及Morlet小波分析等方法分析了草海地区气候变化特征。结果表明：1951—2016年草海地区气候向气温显著上升、降水明显下降的暖干化趋势发展;气温上升率为0.14℃/10 a,不同季节增温速率表现为秋季>冬季>夏季>春季,年降水量下降倾向率为21.46 mm/10 a,不同季节降水量下降速率表现为秋季>夏季>春季>冬季;从年代际变化来看,草海地区气温在20世纪50到70年代呈下降趋势,之后持续升高,不同季节表现为夏冬季开始变暖的时间要比春秋季开始变暖的时间早;年均气温在2002—2003年间发生突变,不同季节突变年份不一致,年降水量和不同季节降水量突变大多发生在1983年左右;Morlet小波分析表明,草海地区气温存在29、14、6年的尺度变化周期,年降水量存在30、20、9、4年的尺度变化周期。研究结果可为草海湿地生态环境保护和可持续发展提供科学依据,同时也为喀斯特高原湖泊区制定应对全球变暖策略提供数据支撑。

Characteristics of Climate Change in Typical Karst Plateau Lake: A Case Study of Caohai in Guizhou

Caohai is the largest natural freshwater lake in Guizhou Province as a typical representative of the lakes in the Karst Plateau. In this study, monthly temperature and precipitation data from 1951 to 2016 of Weining were collected and accumulated anomalies analysis, Mann-Kendall test, Sen’s slope estimation method and wavelet analysis were used to reveal the characteristics of the regional climate change. The results showed that the climate of Caohai has developed into a warmer and drier trend from 1951 to 2016, the annual mean temperature increased significantly at the rate of 0.14℃/10 a, the increase rate in different seasons followed the order of autumn > winter > summer > spring, the annual precipitation declined obviously at the rate of 21.46 mm/10 a, the order in different seasons was autumn > summer > spring > winter. The temperature of Caohai showed a downward trend in the 1950s to 1970s and then continued to rise from the point of decadal variability, the beginning of warming in summer and winter was earlier than the beginning of warming in spring and autumn. The abrupt change of annual mean temperature occurred in 2002 to 2003, which were inconsistent in different seasons, and the abrupt change of annual and seasonal precipitation occurred around 1983. The Morlet wavelet analysis showed that the annual average temperature of Caohai had three evident characteristic time scales, with 29, 14 and 6 years, while four evident characteristic time scales in precipitation with 30, 20, 9 and 4 years. These results could provide a scientific basis for ecological and environmental protection and sustainable development of Caohai, and also provide data support for formulating strategies addressing global warming for the lake region on the Karst Plateau.