1990—2016年若尔盖高原荒漠化时空变化分析  

Spatial-temporal Evolution Characteristics of Land Desertification in the Zoige Plateau in 1990—2016

作　　者：游宇驰 李志威[1,2] 黄草 曾杭 

机构地区：[1]长沙理工大学水利工程学院,湖南长沙410114 [2]青海大学三江源生态与高原农牧业国家重点实验室,青海西宁810016 [3]水沙科学与水灾害防治湖南省重点实验室,湖南长沙410114 [4]水利部黄河泥沙重点实验室,河南郑州450003

出　　处：《生态环境学报》2017年第10期1671-1680,共10页Ecology and Environmental Sciences

基　　金：国家自然科学基金项目(91547112);省部共建三江源生态和高原农牧业国家重点实验室开放研究项目(2017-KF-01);青海省科技厅项目(2016-ZJ-Y01);黄河水利科学研究院院所长基金项目(HKY-JBYW-2016-03)

摘　　要：近几十年若尔盖高原的荒漠化呈明显增长趋势,威胁着当地草原生态环境。为获取并定量分析若尔盖高原荒漠化的最新动态及趋势,探讨不同区域的荒漠化变化机制,利用ENVI和ArcGIS对多时相Landsat遥感数据(1990—2016年)进行处理。通过计算NDVI和Albedo,建立荒漠化指数(DDI)模型,开展若尔盖高原荒漠化等级划分以及时空分布特征的定量评估及分析。研究表明,1990—2016年荒漠化面积以2.17 km^2·a^(-1)速率呈增加趋势,1990—2004年主要以轻度和重度荒漠化的面积增加为主,其增幅分别为1.27 km^2·a^(-1)和1.36 km^2·a^(-1);2004—2011年荒漠化整体呈逆转趋势,7年间荒漠化总面积减少33.44%,其中轻度荒漠化减少速率最快,为2 km^2·a^(-1);2011—2016年荒漠化又趋于严重,总面积增加幅度达58.43%,仍以轻度和重度荒漠化为主,增长幅度分别为2.59 km^2·a^(-1)和4.04 km^2·a^(-1)。荒漠化的空间分布及扩张范围为:采日玛乡北部的成片泥炭沼泽的边缘处、河流附近的河漫滩与江心洲、阿西乡西南方向泥炭沼泽范围、若尔盖县西北方向沿泥炭沼泽边缘、阿西乡南部及西南方向相距12.8~18.0 km区域。荒漠化因治沙措施的作用发生短期逆转,但总体上仍呈扩张趋势,其内因是河流地貌过程及其地表以下分布疏松易破碎的堆积物和粒径细的湖相沉积物,外因是气候变化和沟渠排水引起湿地萎缩退化,以及高强度的人类活动(如过度放牧)对地表植被的破坏。In recent decades, the desertification of the Zoige Plateau showed a significant growth trend, which is threatening the grassland ecological environment. Using ENVI and ArcGIS processing the Landsat （1990-2016） is to quantify the trend of desertification in Zoige Plateau, as well as desertification causes in different regions. Based on indexes of NDVI and Albedo, the classification of desertification grade was built to obtain the temporal and spatial distribution of desertification and desertification gradation. Results showed that the area of desertification increased at the rate of 2.17 km2·a-1 in 1990-2016. From 1990 to 2004, the main change was the area of mild and severe desertification and the change rate was 1.27 km2·a-1 and 1.36 km2·a-1, respectively. From 2006 to 2011, the changing trend of desertification was reversal, and the total area of desertification decreased by 33.44% in 7 years, with slight desertification decreasing at the fastest rate of 2 km2·a-1. The total area of desertification increased by 58.43% in the period of 2011-2016, with mild and severe desertification increasing by 2.59 km2·a-1 and 4.04 km2·a-1. The spatial distribution and expansion of desertification was as follows： the edge of the peat swamp around the northern part of Cairima township, the river floodplain and mid-channel bars along the river, the peat swamp on southwest of A’xi township, along the edge of the peat swamp in northwest of Zoige County, about 12.8~18 km away from the southern and southwestern direction of A’xi township. Due to desertification controlling measures, desertification occurred changeover in the short term, while it still showed rising tendency overall. The internal causes of desertification expansion in the region are that there are the loose and fragile deposits and fine lake sediments below the ground surface. External causes is wetland shrinkage and degradation caused by climate change and excavated ditch drainage, as well as intensive human activity （e.g.,

关 键 词：若尔盖高原 荒漠化 荒漠化差值指数 湿地萎缩 人类活动 

分 类 号：P931.3[天文地球—自然地理学] X144[环境科学与工程—环境科学]