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| 鄱阳湖洪泛区碟形湖数量、空间分布及其影响因素探析 |
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牛汇林1, 王明星2, 施以兵3, 吴桂平1
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1.中国科学院南京地理与湖泊研究所;2.江苏省地质局第六地质大队;3.江苏省地质测绘院
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| 摘要: |
| 碟形湖是鄱阳湖湿地中植被生物量最大、物种多样性最为丰富的区域，承载了全湖80%以上的越冬候鸟，在维护湿地生态系统完整性和物种多样性方面起到至关重要的作用。全面掌握鄱阳湖洪泛区碟形湖的规模及分布特征，对于区域水资源优化配置及湿地生态系统健康保障具有重要意义。本研究以Google Earth Engine云平台为基础，通过融合多时相Sentinel-2A/B卫星影像，充分挖掘多源辅助资料信息，利用地理空间大数据技术，构建了鄱阳湖洪泛区碟形湖精细化空间编目数据库，系统阐明了洪泛区碟形湖真实的数量、大小及其空间分布格局，进而探讨了其分布特征的成因以及当前碟形湖所面临的重大问题。研究结果表明：1）鄱阳湖洪泛区共有0.01km2以上的碟形湖319个，总面积为557.68km2，约占全湖平均面积的28.88%。其中，0.01~1km2的碟形湖分布最为广泛，约占总量的70.85%，随着斑块面积分级的增加，碟形湖数量以幂函数的方式逐渐递减；2）区域分布上，赣抚河口三角洲碟形湖总面积的贡献最大，达到242.82 km2（43.54%），其次是赣修河口及饶河河口三角洲，分别为149.67 km2（26.84 %）和138.62 km2（24.86 %），南部通江水体区由于地处主航道范围，碟形湖面积仅占4.76%；3）洪泛区碟形湖总体呈现“一主、两次、多中心”的团簇状空间聚集模式，且空间密度演化表现为以高密度为核心向外围呈环带状扩散的趋势，“西南密、东北疏”的异质性特征显著；4）随着湖盆高程的升高，碟形湖数量和面积呈现出“先增长后骤降”的变化趋势，且集中分布在水力条件较适宜12~14m高程带上，具有明显的高程选择性；5）在季节性洪泛脉冲为主导的水情条件作用下，鄱阳湖洪泛区碟形湖的规模及分布是区域地形地貌、水文过程、人类活动等多重因素共同驱动的结果。本研究可为鄱阳湖湿地水文过程变化及其生态环境效应等研究提供高质量的数据支持，有望提升当前鄱阳湖枯水期水资源调配及干旱预警的科学性。 |
| 关键词: 鄱阳湖湿地 碟形湖 空间分布 多时相遥感 哨兵2号 GEE云平台 |
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| 基金项目:江西省水利科学院开放研究基金项目（2023SKSH08）; 国家自然科学基金项目（42471435） |
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| Numbers, spatial distribution and characteristics of saucer-shaped lakes in Lake Poyang wetland and influencing factors |
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Niu Huilin,Wang Mingxing,Shi Yibing,Wu Guiping
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Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences
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| Abstract: |
| Saucer-shaped lakes within the Poyang Lake wetlands are regions with the largest vegetation biomass and the richest species diversity, supporting over 80% of the overwintering migratory birds of the entire wetland. These sub-lakes play a crucial role in maintaining the integrity of the wetland ecosystem and preserving species diversity. A comprehensive understanding of the distribution characteristics of the saucer-shaped lakes in the Poyang Lake floodplain is of great significance for the optimal allocation of regional water resources and the health of the wetland ecosystem. Supported by Google Earth Engine cloud platform, this study constructs a refined spatial catalog database of saucer-shaped lakes in Poyang Lake floodplain by integrating high-resolution, multi-temporal Sentinel-2A/B satellite imagery and multi-source auxiliary data to employ geospatial big data techniques. Based on this database, the study first systematically elucidates the true number, size, and spatial distribution patterns of these sub-lakes, and then explores the causes of the spatial distribution patterns and the major challenges faced by the saucer-shaped lakes in Poyang Lake wetlands. The results show that the Poyang Lake floodplain contains 319 saucer-shaped lakes larger than 0.01 km2, with a total area of 557.68 km2, accounting for approximately 28.88% of the annual average area of Poyang Lake area. Among them, lakes ranging from 0.01 to 1 km2 are the most widely distributed, constituting about 70.85% of the total saucer-shaped lakes. As the area of graded patches increases, the number of saucer-shaped lakes gradually decreases following a power function pattern. Regionally, the Gan-Fu estuarine delta contributes the most to the total area of saucer-shaped lakes, with 242.82 km2 (43.54%), followed by the Xiushui and Raohe River deltas, with 149.67 km2 (26.84%) and 138.62 km2 (24.86%) respectively. The southern lake-type water body zone (Zone II) has the smallest share of saucer-shaped lakes, accounting for only 4.76%, due to its location within the main navigation channel. Overall, the saucer-shaped lakes in the floodplain exhibit a "one main core, two secondary cores, and multi-centers" clustered spatial aggregation pattern, with spatial density evolving from high-density cores spreading outward in concentric zones. The spatial heterogeneity characteristics is marked by a "densely packed southwest, sparsely packed northeast" distribution. As the elevation of the lake-bottom increases, the number and area of saucer-shaped lakes show a trend of initial growth followed by a sharp decline, with a significant distribution dominance in the 12～14 meter elevation range. Under the influence of seasonal flood pulses, the scale and distribution of saucer-shaped lakes in the Poyang Lake floodplain are the result of the combined effects of regional topography, hydrological processes, and human activities. This study provides high-quality data support for research on hydrological process changes and their ecological impacts in Poyang Lake wetlands, and is expected to enhance the scientific basis for water resource management and drought early warning during the dry season in Poyang Lake. |
| Key words: Poyang Lake wetland saucer-shaped lake spatial distribution multi-temporal remote sensing Sentinel-2 GEE Cloud Platform |
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