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以福建省长汀县为研究对象,利用1995年、2005年的遥感图像,运用RS和GIS技术分析了用动态变化过程以及土地利用各类型之间的相互转化情况。在此基础上,求得研究区土地利用的转移矩阵,据此分析了长汀县1995年-2005年间土地利用动态变化的空间过程。同时运用马尔可夫模型对2015和2025年的土地利用动态变化及演变趋势预测进行了分析,得出长汀县内土地利用变化情况。 相似文献
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以因冰雪灾害造成森林资源损失较为严重的福建省长汀县为例,选取受灾乔木林为研究对象,结合实地踏查和典型抽样统计数据,评估森林乔木层C贮量损失并分析其主要影响因素．分析结果表明：冰雪灾害造成长汀县乔木林地受损面积达40178．87hm^2,占灾前面积的19．1％;损失蓄积95．69×10^4m^3,占灾前蓄积的38．6％,折合成森林乔木层C贮量损失34．55×10^4t,占灾前C贮量的41．4％,受损最为严重的四都、红山、古城等6个乡（镇、场）都靠近武夷山脉南麓;同一区域相同的立地条件下,针叶树种比阔叶树种受灾严重,松组和杉组C贮量相对损失比均超过阔叶树组的3倍,其中松组C贮量损失23．02×10^4t,占总C贮量损失的66．6％,占灾前松组C贮量的65．0％;中龄林C贮量损失12．84×10^4t,占灾前中龄林C贮量的56．6％,相对损失比最大,近成过熟林次之,幼龄林最小;海拔越高,C贮量损失比例越大,海拔450m以上区域C贮量损失达30．15×10^4t,占总C贮量损失的87．3％;迎风坡面和山脊西北侧的乔木林受灾相对严重,朝西、西北、北3个方向的C贮量损失20．11×1064t,占总C贮量损失的58．2％;位于中上部坡位的乔木林受灾相对严重,且坡位越高,C贮量损失越大． 相似文献
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Hyper-spectral data is widely used to determine soil properties. However, few studies have explored the soil spectral characteristics as response to soil erosion. This study analysed the spectral response of different eroded soils in subtropical China, and then identify the spectral characteristics and soil properties that better discriminate softs with different erosion degrees. Two methods were compared： direct identification by inherent spectral characteristics and indirect identification by predictions of critical soft properties. Results showed that the spectral curves for different degrees of erosion were similar in morphology, while overall reflectance and characteristics of specific absorption peaks were different. When the first method is applied, some differences among different eroded groups were found by integration of associated indicators. However, the index of such indicators showed apparent mixing and crossover among different groups, which reduced the accuracy of identification. For the second method, the correlation between critical soil properties, such as soil organic matter （SOM）, iron and aluminium oxides and reflectance spectra, was analysed. The correlation coefficients for the moderate eroded group were primarily between -0.3 to -0.5, which were worse than the other twogroups. However, the maximum value of R2 was obtained as 0.86 and 0.94 for the non-apparent eroded and the severe group. Furthermore, these two groups also showed some differences in the spectral response of iron complex state （Fep）, Aluminium amorphous state （Alo） and the modelling results for soil organic matter （SOM）. The study proved that it is feasible to identify different degrees of soil erosion by hyperspectral data, and that indirect identification by modelling critical soil properties and reflectance spectra is much better than direct identification. These results indicate that hyper-spectral data may represent a promising tool in monitoring and modelling soil erosion. 相似文献
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传统的像元信息分解法在计算端元丰度时端元组合是固定不变的,而在土地利用复杂地区,固定端元组合并不符合实际情况。文章针对研究区用地类型特点,预先设定数种端元组合,通过最小二乘法选择误差最小的端元组合进行端元丰度反演,进而计算出植被覆盖度;并以实测的地表反射率作为端元反射率,避免了大气差异造成的多时相误差,有利于进行动态监测;预先进行水陆分离,仅对陆地像元进行计算,可以避免水体像元的干扰并提高模型效率。辅以同期成像的高分影像对模型精度进行验证,相关系数达到0.98。将模型应用于长汀县近18 年4 个时相的Landsat 卫星数据,认为近年来长汀县植被覆盖度总体呈现变好的趋势,尤其是汀江沿岸;而城市化、火烧坡、大型工程建设是长汀县植被覆盖度局部变差的主要原因。 相似文献
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极点排序和除趋势对应分析(DCA)排序法是不同时期具有代表性的群落排序方法。通过以长汀县水土流失区调查数据为例进行分析发现,两种排序结果比较一致,但也存在差异。极点排序第一轴的排序效果不如DCA排序,但第二轴排序效果优于DCA排序。极点排序最终结果是两轴共同作用的结果,而DCA排序则是以第一轴结果为主。就排序轴的生态意义而言,极点排序要比DCA排序更直观。 相似文献
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长汀县的水土流失治理经过多年努力取得了较大的成效,但缺乏有效的信息系统的支持。该文将GIS技术应用到长汀县的水土流失治理,实现了水土流失治理现状展示、水土流失治理辅助决策和动态监测,对促进长汀县的水土流失治理起到了良好作用。 相似文献
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为揭示南方红壤丘陵区水土流失地质成因规律和模式,促进水土流失精准治理,选择福建长汀县开展地质背景与水土流失关系研究。结果表明:岩性对水土流失侵蚀速度、侵蚀剧烈程度、水土流失发育阶段等具有控制作用;地形坡度和部位、节理裂隙对水土流失程度具有重要影响;区内不同岩性不同地形部位风化壳-土壤分布具明显的规律性。建议长汀县进一步依据地质背景优化水土流失治理布局,优选水保植物和种植方式,优化茶果园等坡地农业开发项目。 相似文献