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| 近40年长江源区湖泊群水色时空演变及其驱动机制 |
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陈齐1, 李志晶1, 金中武1, 张国帅1, 王奕森1, 杨绪海1, 韩俊峰1, 刘玉娇1, 周银军1, 肖俊2
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1.长江科学院河流研究所;2.长江设计集团有限公司
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| 摘要: |
| 受青藏高原气候暖湿化影响，长江源区河湖水系演变剧烈，FUI（Forel-Ule Index）指数可通过量化水色变化以表征水体生态环境状态。摸清该地区湖泊水色时空变化特征及其驱动因子，对于判断未来气候变化背景下长江源区湖泊水环境变化趋势具有重要意义。本研究基于Landsat和MODIS遥感影像，获取了近40年长江源区264个湖泊FUI指数，分析了气象水文条件变化下湖泊水色演变趋势及影响因素。研究表明，1984-2023年长江源区大量荒地和草地转化为水体，湖泊数量增加了1.96倍，流域平均输沙模数增加了1.65倍，区域内湖泊水色指数持续变蓝（FUI指数平均降低了2个级别），其中小型湖泊（<5km2）占比88.55%，其水色分布主要因流域侵蚀作用增强导致大量浅水热融湖盆裸露而呈现黄色（FUI>10）；大型湖泊（>100km2）因水位增加导致湖泊水色持续蓝化（FUI<6）。本研究深化了对近40年长江源区湖泊群生态环境变化特征的认识，可为研判气候变化背景下流域水生态环境演变趋势提供科学参考。 |
| 关键词: 气候变化 长江源区 湖泊 FUI水色指数 地物类型 |
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| 基金项目:国家重点研发计划专题“长江黄河源区大数据和知识挖掘技术开发”（2022YFC3201703-05）；长江勘测规划设计研究有限公司开放创新基金（CX2021K06）；国家自然科学基金重点项目（U2240226&52239007）；中央级科研院所基本科研业务费项目（CKSF2024324） |
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| Spatialtemporal evolution and driving mechanisms of lakes water color in the source region of the Yangtze River basin over the past 40 years |
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CHEN Qi,LI Zhi-jing,JIN Zhong-wu,Zhang Guo-shuai,Wang Yi-sen,YANG Xu-hai,HAN Jun-feng,Liu Yu-jiao,ZHOU Yin-jun,XiaoJun
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Changjiang River Scientific Research Institute
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| Abstract: |
| Under the influence of climate warming and increased humidity on the Qinghai-Tibet Plateau, the river and lake systems in the source region of the Yangtze River have undergone significant changes. The Forel-Ule Index (FUI) can quantifyies water color changes to characterize the ecological status of water bodies. Understanding the spatiotemporal variations in lake water color and its driving factors behind these changes in this region is crucial for predicting future trends in the aquatic environment under changing climatic conditions. This study utilized Landsat and MODIS remote sensing images to obtain FUI indices for 264 lakes in the Yangtze River source region over the past 40 years. The analysis focused on the evolution of lake water color under varying meteorological and hydrological conditions and the factors influencing these changes. The results indicate that from 1984 to 2023, a significant portion of barren land and grassland transformed into water bodies, leading to a 1.96-fold increase in the number of lakes and 1.65-fold increase in the average sediment transport modulus. The average FUI of lake water color decreased by two levels, with small lakes (<5 km2) comprising 88.55% of the total. These small lakes primarily exhibited yellowish hues (FUI > 10) due to the increased erosion of the basin, which has exposed a large number of shallow hot-melt lake basins. In contrast, large lakes (>100 km2) showed a sustained trend towards blue hues (FUI < 6) as a result of rising water levels. This study deepens the understanding of ecological and environmental changes in the lake systems of the Yangtze River source region over the past 40 years and provides valuable insights for assessing the future evolution of the watershed"s aquatic environment under climate change. |
| Key words: Climate change Yangtze River source region lakes FUI water color index LUCC |
