Disturbance analyses of forests and grasslands with MODIS and Landsat in New Zealand
Disturbance analyses of forests and grasslands with MODIS and Landsat in New Zealand
复制标题
DOI：
10.1016/j.jag.2015.10.009
复制
发表时间：
2016-03
期刊：
影响因子：
--
通讯作者：
K. Beurs;B. Owsley;J. P. Julian
中科院分区：
文献类型：
--
作者：
K. Beurs;B. Owsley;J. P. Julian
在这项研究中，我们提出，评估和验证的方法来监测森林和草地干扰。我们适用于新西兰北岛的Landsat和MODIS图像的方法，并验证高分辨率OrbView和Ikonos图像的基础上的结果。我们发现，两个研究的土地覆盖类型的干扰指数的总体准确性为98%。kappa值为0.770，表明与偶然发生的情况相比，一致性好77%。我们发现，草原地区的准确性与森林地区的准确性之间存在差异，草原地区优于森林地区（Kappa值为0.855 vs. 0.656）。我们分裂的验证结果的土壤类型，并评估不同土壤类型的放牧压力的影响。干扰指数表现一致的所有可用的土壤orders.We发现森林干扰约36.2%的外来森林，导致在研究期间的森林的年清除率为2.6%。最后，我们提出了一个近距离的研究，以评估放牧的变化，在一个密集使用的集水区。我们证明，12月/1月的干扰率从2000年的约6%增加到2012年的约16%。
In this study we present, evaluate and validate an approach to monitor forest and grassland disturbance. We apply the approach to both Landsat and MODIS imagery for the North Island of New Zealand and validate the results based on high resolution OrbView and Ikonos imagery. We found an overall accuracy of the disturbance index of 98% for the two studied land cover types. The kappa value was 0.770 indicating a 77% better agreement than what would have occurred by chance. We found that there is a difference between the accuracy received for grassland areas compared to the accuracy received for forest areas, with the grassland areas outperforming the forest areas (Kappa of 0.855 vs. 0.656). We split the validation results by soil type and also evaluate the effect of different soil types with respect to grazing pressures. The disturbance index behaved consistently for all available soil orders.We found forest disturbance for approximately 36.2% of the exotic forests, resulting in an annual clearing rate of 2.6% of the forest over the study period. Lastly we present a close-up study to evaluate the changes in grazing in one intensely used catchment. We demonstrate that the December/January disturbance rates have increased from about 6% in 2000 to about 16% in 2012.