THE ASSESSMENT AND MONITORING OF SPARSELY VEGETATED RANGELANDS USING CALIBRATED LANDSAT DATA
THE ASSESSMENT AND MONITORING OF SPARSELY VEGETATED RANGELANDS USING CALIBRATED LANDSAT DATA
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DOI：
10.1080/01431168808954929
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发表时间：
1988-07-01
影响因子：
3.4
通讯作者：
DAVIS, AW
中科院分区：
文献类型：
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作者：
GRAETZ, RD;PECH, RP;DAVIS, AW
1981 年至 1984 年间，在半干旱灌木牧场内的 58 个永久性 30 公顷站点网络中对植被覆盖度进行了测量。这些植被数据用于校准 Landsat 数据以生成“COVER”图像，这是一个包含所有生物（灌木、草等）和非生物（凋落物）植物材料覆盖百分比的复合变量。补充变量是“裸露”土壤（100 - 覆盖）。回归方程仅包括多光谱扫描仪波段 5 (MSS5)，并用于生成 25000 平方公里测试区域内五种主要牧场类型中每一种 1981 年、1982 年和 1984 年的 COVER 图像。这些 COVER 图像被纳入地理信息系统 (GIS)，用于评估和监测 1981-1984 年期间各个牧场类型和牧区的行为，其中包括 1982-3 年的严重干旱。该地区的陆地卫星数据反映了地面测量数据。干旱条件导致覆盖率水平普遍下降，但下降幅度因牧场类型而异，由牧场的组成和状况决定。同样，各个属性对干旱表现出不同的反应。检测和显示干旱前（1981 年）和干旱后（1984 年）条件之间 COVER 差异的能力说明了牧场类型的不同生态反应。
Measurements of the cover of vegetation were made at a network of 58 permanent 30 ha sites within a semi-arid shrub rangeland from 1981 to 1984. These vegetation data were used to calibrate Landsat data to produce images of ‘COVER’, a composite variable comprising all the percentage cover of living (shrubs, grass, etc.) and non-living (litter) plant material. The complementary variable was ‘BARE’ soil (100 – COVER). The regression equations included only Multispectral Scanner band 5 (MSS5) and were used to generate images of COVER for the years 1981, 1982 and 1984 for each of the five major rangeland types within the 25000 km2test area. These COVER images were incorporated into a Geographical Information System (GIS) and used to assess and monitor the behaviour of individual rangeland types and pastoral properties over the 1981–1984 period which included a severe drought in 1982–3. The Landsatderived data for the region mirrored that measured on the ground. Drought conditions produced a universal decline in COVER levels but the size of the decline was specific to rangeland type being determined by both the composition and condition of the pasture. Similarly, individual properties showed differing responses to the drought. The capacity of detect and display differences in COVER between pre-drought (1981) and post-drought (1984) conditions illustrated the different ecological responses of rangeland types.