| 引用本文: | 汤旭光,李恒鹏,聂小飞,李鹏程.应用MODIS数据监测千岛湖流域植被覆盖动态(2001-2013年).湖泊科学,2015,27(3):511-518. DOI:10.18307/2015.0319 |
| TANG Xuguang,LI Hengpeng,NIE Xiaofei,LI Pengcheng.Vegetation dynamical status in the Lake Qiandao drainage basin using time-series MODIS data (2001-2013). J. Lake Sci.2015,27(3):511-518. DOI:10.18307/2015.0319 |
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| 摘要: |
| 流域植被覆盖状况对于水源地生态环境保护具有重要的指示作用.当前的水质目标管理不仅要着眼于湖库水质参数控制,更应该从整个流域的角度维系生态平衡.在此背景下,依托长时间序列MODIS遥感数据对千岛湖流域20012013年植被覆盖状况进行监测,采用最小二乘法趋势分析和Mann-Kendall显著性检验方法分析了千岛湖流域植被的空间分布特征、时间变化特征与长期变化趋势.研究表明该方法能够有效地监测流域植被覆盖的时空动态变化:1) 从空间分布上来看,千岛湖流域植被覆盖状况整体较好,但同时也发现受人为干扰较大的地域如河、湖附近的城镇建设用地、农业用地以及园地,其NDVI值明显低于自然林地;2) 从时间变化特征上看,2001-2013年千岛湖流域植被年际NDVI在0.69~0.73之间波动,且近年来有增长趋势,年内季节性NDVI动态分析表明高时间分辨率的MODIS数据能够用来区分常绿植被与落叶植被的物候特征,以分析不同植被类型对流域氮、磷流失的风险差异;3) 从变化趋势上看,2001-2013年植被覆盖状况改善的区域远大于退化的区域,其中改善区域约占流域面积的55.90%,呈现出一定退化状态的区域约占29.60%(严重退化区域仅占3.97%),而相对稳定不变区域约占14.51%.经与气温与降水等气候因子进行相关性分析表明,植被NDVI与气温呈显著正相关,而降水则不敏感,说明气温是研究区植被生长的主导气候因子.同时发现,人类活动对局部植被变化影响较大.研究结果可为流域水资源与生态环境保护提供空间数据支撑. |
| 关键词: 千岛湖流域 植被动态 时空变化 趋势分析 |
| DOI：10.18307/2015.0319 |
| 分类号: |
| 基金项目:国家自然科学基金项目(41271500,41401221)、中国科学院重点部署项目(KZZD-EW-10-04)和鄱阳湖湿地与流域研究教育部重点实验室(江西师范大学)开放基金项目(PK2013001)联合资助. |
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| Vegetation dynamical status in the Lake Qiandao drainage basin using time-series MODIS data (2001-2013) |
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TANG Xuguang1,2, LI Hengpeng1, NIE Xiaofei1, LI Pengcheng1
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1.Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, P.R.China;2.Key Laboratory of Poyang Lake Wetland and Watershed Research (Jiangxi Normal University), Ministry of Education, Nanchang 330022, P.R.China
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| Abstract: |
| The status of vegetation coverage in the drainage basin is an important indicator to eco-environmental conservation of the drinking water source reservoirs.Current water quality target management should not only focus on monitoring water quality parameters in the lake, but also maintain the ecological balance of the whole drainage basin.With this background, long-term MODIS time series were used to analyze the vegetation dynamical status during 2001-2013 for the Lake Qiandao drainage basin.The NDVI was used as a proxy of vegetation cover, and the least squares regression trend analysis with the Mann-Kendall test were used to analyze the characteristics of distribution, time variations and spatial trends of the vegetations.The study showed that it's an effective way to reflect the spatial-temporal patterns of vegetation coverage for the Lake Qiandao drainage basin.The basic conclusions from the study are as follows:1) From the spatial distribution of the annual mean NDVI in the study area, the vegetation coverage performs well as a whole.However, the NDVI values at the locations disturbed by intensive human activities, such as urban construction land, agricultural land and garden plots sited near the river and lake, are obviously lower than those at natural woodland.2) Based upon the time series of annual mean NDVI in the vegetation area in the basin, the NDVI values fluctuate between 0.69 and 0.73 from 2001 to 2013, and have increased since 2008, indicating seasonal changes of phenological characteristics of evergreen from that of deciduous vegetation.This can be used to analyze the risk of nitrogen and phosphorus loss of different vegetation types.3) From the spatial trends of NDVI, the area where the NDVI values increased is much larger than the area that the NDVI values decreased.The improved vegetation area occupies 55.90% of the basin, while the degenerative vegetation-covered area accounts for 29.60%.The other 14.51% of the total area remained unchanged during the period of 2001-2013.We also found that the changes in vegetation coverage are more positively correlated with temperature in most part of the basin, while precipitation is not obviously sensitive to vegetation change in the water-rich eastern region, which suggested that temperature is the controlling climatic factor.Meanwhile, local vegetation changes are significantly affected by human activities.These results have provided scientific foundations for protecting the water resource and ecological environment of the drainage basin. |
| Key words: Lake Qiandao drainage basin vegetation dynamical status spatial-temporal patterns trend analysis |
