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林业科学 ›› 2015, Vol. 51 ›› Issue (10): 35-42.doi: 10.11707/j.1001-7488.20151005

• 论文与研究报告 • 上一篇    下一篇

基于FVC的新疆植被覆盖度时空变化

邵霜霜1, 师庆东1,2   

  1. 1. 新疆大学资源与环境科学学院 乌鲁木齐 830046;
    2. 新疆大学绿洲生态教育部重点实验室 乌鲁木齐 830046
  • 收稿日期:2014-11-17 修回日期:2014-12-17 出版日期:2015-10-25 发布日期:2015-11-10
  • 通讯作者: 师庆东
  • 基金资助:
    国家自然科学基金项目(31160114);新疆研究生科研创新项目(XJGRI2013025)。

Spatial and Temporal Change of Vegetation Cover in Xinjiang Based on FVC

Shao Shuangshuang1, Shi Qingdong1,2   

  1. 1. College of Resources and Environment Sciences, Xinjiang University Urumqi 830046;
    2. Key Laboratory of Oasis Ecology of Ministry of Education, Xinjiang University Urumqi 830046
  • Received:2014-11-17 Revised:2014-12-17 Online:2015-10-25 Published:2015-11-10

摘要: [目的] 对新疆植被覆盖变化的空间自相关性进行分析,研究植被覆盖的时间变化特征、空间分布特征及变化趋势等,为改善区域生态环境提供参考。[方法] 利用新疆1998—2012年NDVI数据,采用像元二分法获取植被覆盖指数(FVC)数据,在此基础上运用Sen+Mann-Kendall 趋势分析和空间自相关分析方法,研究新疆植被覆盖的变化趋势特征和空间分布的聚集性特点。[结果] 1) 15年间新疆植被覆盖度略有下降趋势,山地和平原均呈下降趋势,山地较平原变化大。2) Sen+Mann-Kendall趋势分析可反映新疆FVC变化趋势的空间分布特点,全疆植被改善区域占25%,退化区域占28%,47%的区域变化不大,其中明显改善区域和严重退化区域所占比例均为10%左右。植被改善区域主要分布在天山北坡一带,退化区域主要分布在山地和平原的交错带,伊犁地区退化程度尤为严重。植被覆盖度极低地区基本不变,退化区域主要分布在植被低覆盖度区域周围。3) 空间自相关分析进一步验证了Sen+Mann-Kendall 趋势分析结果,新疆植被有明显的聚集现象。全局自相关性分析表明,当距离大于3 km后,空间自相关影响不大。局部相关性分析表明,新疆植被覆盖以"高-高聚集"和"低-低聚集"为主。[结论] 植被盖度相对较高的地区植被覆盖越易改善,盖度较低或无覆盖的地区越难改善,而且退化越明显。根据植被盖度的聚集性可以看出,植被覆盖呈现明显的"高-高聚集"和"低-低聚集"格局,这与区域气候、水资源分布及人类活动的影响有着潜在的联系。今后可重点分析植被覆盖变化的影响因素,以了解干旱区植被覆盖变化的驱动机制。由于人类活动在短时期内对植被覆盖变化的影响比较显著,因此在空间上分析人类活动对植被覆盖变化的影响可为改善干旱区植被覆盖提供相应指导。[其他] 本文从植被覆盖的空间聚集性解释了植被覆盖变化特点,一方面是对Sen+Mann-Kendall 趋势分析的验证,另一方面为整体分析植被的变化特征提供了依据。

关键词: 植被覆盖指数(FVC), Sen+Mann-Kendall趋势分析, 空间自相关分析, 空间分布特征, 新疆

Abstract: [Objective] Fractional vegetation cover(FVC)can reflect the status of land use/cover enougth, especially the arid areas where are sensitive to vegetation change degree significantly. Xinjiang belongs to arid areas, because of the influence of human activities and climate change vegetation cover in Xinjiang has changed in recent years.Therefore, it is necessary to monitor and investigate the change of Xinjiang vegetation cover dynamically, which would provide a reference for improving regional ecological environment. [Method] Based on the NDVI data from 1998 to 2012 of Xinjiang and the FVC data obtained by using dichotomy, this paper studied the characteristics of vegetation changing trend and its spatial clustering distribution through Sen + Mann Kendall trend analysis and spatial auto-correlation analysis. [Result] The results show that: 1) The vegetation cover declines slightly among 15 years in Xinjiang. 2) Sen + Mann Kendall analysis reflects the spatial distribution characteristics of FVC changing trend in Xinjiang. Improvement areas of vegetation cover are mainly distributed in the north slope of Tianshan Mountain, and degradation areas are mainly distributed in the ecotone of mountains and plains, degradation degree is particularly severe in Ili region. Meanwhile, the areas with very low vegetation coverage remain unchanged basically, and degradation areas are mainly distributed around the low coverage region. 3) The spatial auto-correlation analysis further verifies the results of Sen + Mann Kendall analysis. Vegetation cover exhibits apparent agglomeration phenomenon in Xinjiang.Partial correlation analysis shows that vegetation coverage is given priority to "high-high concentration" and "low-low concentration".[Conclusion] It can be seen that the relatively high vegetation coverage areas are easier to be improved, while low coverage areas or areas without coverage are more difficult to be improved, and present obvious degradation. According to the clustering characteristics of vegetation coverage, vegetation coverage presents obviously "H - H gathered" and "L-L gathered" pattern. This phenomenon has potential links with the regional climate, water resources distribution and the influence of human activities. In order to understand the driving mechanism of vegetation change in arid areas, we can analyze the affecting factors on the changes of vegetation cover in the future. Due to the influence of human activities on vegetation coverage change in a short period is more significant, the space analysis can provide corresponding guidance for improving vegetation in arid areas. [Other] This paper explains the characteristic of vegetation changes from the perspective of vegetation spatial clustering. On the one hand, it validate the results of Sen + Mann Kendall trend analysis, on the other hand, it would provide a basis for the overall analysis of characteristics of the vegetation changes.

Key words: fractional vegetation cover(FVC), Sen + Mann-Kendall trend analysis, spatial auto-correlation analysis, spatial distribution characteristics, Xinjiang

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