1976—2021年纳木错和色林错湖泊面积变化及驱动因素分析

Analysis of Lake Area Changes and Driving Factors in Nam Co and Selin Co from 1976 to 2021

湖泊在水循环和水平衡中发挥着重要作用,对气候变化极其敏感。分析青藏高原湖泊面积变化及驱动因素,对揭示高原气候变化具有重要意义。文章通过解译1976—2021年Landsat系列遥感影像,获取纳木错和色林错湖泊水体面积,利用数理统计方法分析湖泊水体面积及气温、降水的变化特征,并探讨了气温和降水量对湖泊面积变化的影响。结果表明:1.纳木错和色林错湖泊面积总体均呈显著增长趋势(P<0.01),增幅分别为2.90%和36.30%,分别于2001年和2002年发生突变,其中,纳木错湖泊面积变化波动较小(CV=1.64%),色林错湖泊面积波动幅度较大(CV=12.65%)。2.纳木错和色林错流域多年平均降水量和气温均呈现显著增加趋势。3.纳木错湖泊面积变化与气温和降水量呈显著正相关,受降水与气温的共同影响;色林错湖泊面积变化与气温呈显著正相关,与降水量无显著相关性,气温增加引起的冰雪加速融化是色林错急剧扩张的主要原因。相关结果为高寒地区湖泊演变机制的研究及生态环境保护措施的制定提供理论依据。

Lakes play an important role in the water cycle and balance,and are extremely sensitive to cli-mate change.The analysis of lake area change and its driving factors in the Qinghai-Xizang Plateau is of great significance to reveal the plateau climate change.The areas of Nam Co and Selin Co lakes were ob-tained based on the Landsat remote sensing images from 1976 to 2021.Mathematical statistics were used to analyze the change characteristics of lake areas,temperature and precipitation,and the influence of tem-perature and precipitation on the change of lake areas was discussed.The results showed that:(1)The lake areas of Nam Co and Selin Co showed significant growth trend(P<0.01),with an increase rate of 2.90%and 36.30%,respectively.Abrupt change of the lake areas occurred in 2001 and 2002,respectively.The variation coefficient of the lake areas of Nam Co was smaller(CV=1.64%)than that of Selin Co(CV=12.65%).(2)The annual average precipitation and temperature in Nam Co and Selin Co watershed in-creased significantly.(3)The change of lake areas in Nam Co was positively correlated with temperature and precipitation,and was affected by both.The lake area of Selinco has a significant positive correlation with air temperature,and no significant correlation with precipitation.The accelerated melting of ice and snow caused by increasing temperature is the main reason for the rapid expansion of Selin Co.These results could provide the theoretical basis for the study of lake evolution mechanism and the formulation of the pro-tection of ecological environment in alpine region.