摘要
气候暖干化发展趋势使干旱半干旱地区生态环境受到荒漠化发展的胁迫,植被覆盖度能有效地表达研究区植被分布状况及荒漠化程度。利用遥感技术手段监测区域植被覆盖和荒漠化发展趋势是非常有效的途径。为了给黄土高原地区生态环境建设和荒漠化治理提供科技信息,利用1986—2006年的GIMMS AVHRR NDVI数据,采用像元二分法估算植被覆盖度;借鉴水蚀风蚀研究成果确定植被覆盖度和荒漠化关系并进行分级,对黄土高原地区荒漠化程度及时空变化进行分析。结果表明：1）黄土高原约64%的地区为植被覆盖度为10%~50%的中度和重度荒漠化区;约1/3的地区为植被覆盖度在50%以上的轻度和非荒漠化区;约3%的地区为植被覆盖度〈10%的强烈荒漠化区。2）1986—2006年间,黄土高原地区整体上荒漠化程度表现为降低趋势,期间,中度和重度荒漠化面积显著减少,非荒漠化面积明显增加,而强烈荒漠化面积扩大。荒漠化程度的时间变化具有10年尺度特征。3）中度和重度荒漠化的区域具有转化频繁和连片性特征,轻度和非荒漠化区域空间转化零散破碎,强烈荒漠化扩大区域主要在宁夏甘肃的沿黄两岸。
Under global warming,desertification has brought threats to the ecological environment of arid and semi-arid regions like the Loess Plateau. It is helpful to understand the spatial-temporal trend of desertification for ecological environment projects and desertification management in these regions. The vegetation cover and its spatial distribution can reflect the degree of desertification effectively. It is anefficient way using the remote sensing techniques to observe the trend of vegetation cover and subsequently the development of desertification. The data of GIMMS AVHRR NDVI from 1986 to 2006 on the Loess Plateau were used,and the vegetation cover index was then calculated based on the principle of the dimidiate pixel model. The correlation between degree of desertification and vegetation cover was determined based on researches of wind and water erosion in the study area. The results showed that about 64% of the plateau presented moderate and severe degrees of desertification with 10%- 50%vegetation cover. A third of total plateau belonged to the slight and non-desertification degrees with vegetation cover greater than 50%,and only 3% areas were subjected to extreme desertification with vegetation cover less than 10%. From 1986 to 2006,desertification generally showed a decreasing trend on the Loess Plateau. The areas with moderate and severe degrees of desertification decreased significantly,while the areas without desertification had an apparent increase. However,the area with extreme degree of desertification expanded. The degree of desertification showed a changing rule with a decadal interval. The moderately and severely desertified areas shifted reciprocally and frequently. The areas transferred between slight and non-desertification degrees were sparsely scattered. The extremely desertified areas appeared mainly along the Yellow River of Ningxia and Gansu provinces.
出处
《中国水土保持科学》
CSCD
北大核心
2015年第3期24-31,共8页
Science of Soil and Water Conservation
基金
中国科学院知识创新项目"晋陕蒙能源基地受损生态系统恢复重建关键技术与示范"(KZCX2-XB3-13)
中国科学院重点部署项目"近百年黄土高原侵蚀环境与水沙变化"(KZZD-EW-04-03-03)
国家自然科学基金"典型中尺度流域水沙行为对土地利用/覆被变化响应规律"(41440012)
国家自然科学基金重点项目"气候变化背景下黄土高原土地利用影响径流的空间尺度效应"(41230852)和"典型流域水沙动态过程及对退耕还林(草)响应机理"(41101265)
关键词
荒漠化
时空分布特征
植被覆盖度
黄土高原
desertification
temporal and spatial distribution
vegetation cover index
Loess Plateau
