| 1996—2015年黄河源区植被覆盖度提取和时空变化分析 |
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| 引用本文： | 王俊奇,王广军,梁四海,杜海波,彭红明.1996—2015年黄河源区植被覆盖度提取和时空变化分析[J].冰川冻土,2021,43(2):662-674. |
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| 作者姓名： | 王俊奇 王广军 梁四海 杜海波 彭红明 |
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| 作者单位： | 中国地质大学(北京)土地科学技术学院,北京100083;中国地质大学(北京)水资源与环境学院,北京100083;内蒙古自治区煤田地质局勘测队,内蒙古呼和浩特010010;青海省环境地质勘查局,青海西宁810007 |
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| 基金项目： | 中国科学院战略性先导科技专项(XDA20100103);青海省应用基础研究项目(2017-ZJ-743) |
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| 摘 要： | 研究黄河源区植被覆盖度时空变化对于深入理解青藏高原多年冻土区在气候变化和人类活动双重作用下的植被响应，以及为黄河源区生态环境保护和治理提供决策具有重要的意义。以陆地卫星（Landsat）影像为主要数据源，利用多端元混合像元分解模型（Multiple Endmember Spectral Mixture Analysis，MESMA），完成了1996—2015年黄河源区4.4万km2、7个时相的植被覆盖度提取，并基于转移矩阵和一元线性回归趋势法分析了植被覆盖度变化情况。结果表明：黄河源区东南部植被覆盖度较高，西北部植被覆盖度较低，且植被覆盖度在空间上由东南向西北呈递减趋势。1996—2004年植被覆盖度整体呈下降趋势，2004—2015年植被覆盖度呈增加趋势。1996—2015年植被覆盖度呈增加趋势的区域占57.25%，基本不变的区域占16.02%，植被覆盖度呈下降趋势的区域占26.73%。植被覆盖度下降的主要原因是黄河源头及一些河谷地带、环湖地区受人类影响较大，且东南部海拔较低地区受到过度放牧的影响。尽管黄河源区1996—2015年植被覆盖度总体呈改善趋势，但毒杂草的面积也由1996年的16 060 km2增加到2015年的22 942 km2，20年间增加了6 882 km2，毒杂草面积的增加对黄河源区局部地区畜牧业的发展有不利影响。
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| 关 键 词： | 植被覆盖度 MESMA 黄河源区 时空变化 |
| 收稿时间： | 2020-10-10 |
| 修稿时间： | 2021-01-05 |
Extraction and spatio-temporal analysis of vegetation coverage from 1996 to 2015 in the source region of the Yellow River |
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| WANG Junqi,WANG Guangjun,LIANG Sihai,DU Haibo,PENG Hongming.Extraction and spatio-temporal analysis of vegetation coverage from 1996 to 2015 in the source region of the Yellow River[J].Journal of Glaciology and Geocryology,2021,43(2):662-674. |
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| Authors: | WANG Junqi WANG Guangjun LIANG Sihai DU Haibo PENG Hongming |
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| Institution: | 1.School of Land Science and Technology，China University of Geosciences （Beijing），Beijing 100083，China;2.School of Water Resources and Environment，China University of Geosciences （Beijing），Beijing 100083，China;3.Inner Mongolia Survey Team of Coalfield Geology Bureau，Hohhot 010010，China;4.Qinghai Bureau of Environmental Geology Exploration，Xining 810007，China |
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| Abstract: | Studying the spatial and temporal variation of vegetation coverage in the source region of the Yellow River is of great significance to understand the response of vegetation growth in permafrost area of Qinghai-Tibet Plateau under the dual effects of climate change and human activities， and to provide theoretical basis for the protection and control of the ecological environment in the source region of the Yellow River. Using Landsat as the main data source， this paper uses Multiple Endmember Spectral Mixture Analysis （MESMA） to complete the extraction of vegetative cover of 7 phases of 44 000 km2 from 1996 to 2015 in the source region of the Yellow River respectively， and analyses the change of vegetative cover from 1996 to 2015 based on transfer matrix and unvariable linear regression. The research results show： The vegetation coverage is higher in the southeast and lower in the northwest， and decreases from southeast to northwest in space. Desertification is serious in the north. This is consistent with the hydrothermal conditions in the source region of the Yellow River. From 1996 to 2004， bare land as a whole increased by 10.24%， and the unconverted area accounted for as high as 77.22%. Low coverage type， medium coverage type and medium coverage type remain basically unchanged on the whole， and the conversion is mainly to lower vegetation coverage type. The high coverage type overall decreased by 12.75%. Therefore， the vegetation coverage showed a general trend of falling. However， from 2004 to 2015， the bare land decreased by 12.91% as a whole， which was mainly converted to low coverage type. Low coverage type， low-medium coverage type and medium coverage type remained basically unchanged， and all of them were mainly converted to higher coverage type， while the high coverage type increased by 16.18% as a whole. Based on the above analysis， the overall vegetation coverage of the source region of the Yellow River showed an increasing trend. This also shows that the state in 2005， 2014 implementation of the “Three-River Source Region ecological protection and construction of the first and second phase of the project” has been effective. From 1996 to 2015， 57.25% of the vegetation coverage areas showed an increasing trend. The increased area is mainly distributed in the central and eastern part， the area around the Ngoring Lake and some areas in the north. About 16.02% of the vegetation coverage areas were basically unchanged. Areas that remain largely unchanged are concentrated in the northern and eastern desert regions， and 26.73% of the vegetation coverage areas showed a decreasing trend. The reduced area is mainly distributed in the west of the source region of the Yellow River， the north of Gyaring Lake， the northeast and southeast of the source region. The main reasons for the decrease of vegetation coverage are that the headwaters of the Yellow River and some river valleys and areas around the lake are greatly affected by human beings， and that the lower altitude of the southeastern region is greatly affected by overgrazing， as well as the disappearance of pastures in the north of Gyaring Lake. Although the vegetation coverage of the source region of the Yellow River showed an overall trend of improvement from 1996 to 2015， the area of poisonous weeds also increased from 16 060 km2 in 1996 to 22 942 km2 in 2015， which increased by 6 882 km2 in 20 years. The poisonous weeds in the source region of the Yellow River were mainly Edelweiss and Oxytropis. Edelweiss was mainly distributed in the south side of the study area. Oxytropis was mainly distributed in the north side， and the distribution area of Ajania khartensis was relatively dispersed. The increase of the area of poisonous weeds had a negative impact on the development of livestock husbandry in the source region of the Yellow River. |
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| Keywords: | vegetation coverage MESMA source region of the Yellow River spatio-temporal variation |
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