| 摘要: |
| 【目的】以像元为基本单元，研究青海省归一化植被指数（NDVI）的时空变化特征，以揭示NDVI对气候变化的响应规律，分析青海省未来植被变化趋势，为青海省生态建设提供参考。【方法】以青海省2000-2015年的MODIS13Q1/NDVI为数据源，将反映趋势变化的Theil-Sen Median方法与检验趋势显著性的Mann-Kendall方法结合使用，研究青海省NDVI的变化趋势，并采用Hurst指数方法判断变化趋势的可持续性。【结果】1)青海省NDVI的空间分布整体呈从西北向东南逐渐增加的趋势。2)16年间NDVI整体呈增长趋势，增速为每10年1.5%，旱地及草原与稀树灌木草原增速最快，分别为每10年2.7%和2.3%。3)16年间青海省植被覆盖改善区域(60.51%)明显大于退化区域(17.87%)，其中植被覆盖明显改善区占全省面积的21.26%，轻微改善占39.25%，轻微退化占15.75%，严重退化占2.12%，基本不变的占21.62%。4)青海省植被覆盖未来改善的区域占整个区域面积的62.23%，其中持续性改善占38.01%，由退化转为改善的占24.22%；植被未来有退化趋势的区域占18.30%，其中持续性退化占7.74%，由改善变为退化趋势的占10.56%；稳定不变的区域为8.43%；植被未来变化趋势不确定区域占11.04%。【结论】青海省植被覆盖变化受气候和人类活动的共同影响，大部分地区植被未来呈改善趋势。 |
| 关键词: 青海省 归一化植被指数（NDVI） 时空变化 Sen+Mann-Kendall Hurst指数 |
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| 基金项目:青海省科技厅项目“青海东部农作物侯期与种植制度的遥感提取研究”（2013-Z-936Q）;青海省地理空间信息技术与重点实验室2017年度开放课题(QDXS-2017-03) |
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| Spatial-temporal variations of vegetation coverage in Qinghai from 2000 to 2015 |
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DAI Zijun,ZHAO Xia,LI Guanwen,et al
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| Abstract: |
| 【Objective】This paper studied the spatial variation characteristics of NDVI in Qinghai base on pixel unit,analyzed the response of vegetation NDVI to climate change and predicted the future trend of vegetation change to provide reference for ecological construction in Qinghai.【Method】MODIS13Q1/NDVI data of Qinghai from 2000 to 2015 were used to analyze NDVI trends through the Theil-Sen Median trend analysis with the Mann-Kendall test,and the Hurst index was used to evaluate the sustainability of NDVI trend.【Result】1) The vegetation NDVI in Qinghai increased from northwest to southeast.2) NDVI showed an overall increasing trend in recent 16 years,with a growth rate of 1.5%/10 a.Dryland/grassland and savannah grassland experienced the highest growth rates of 2.7%/10 a and 2.3%/10 a.3) In the 16 years,the improvement area of vegetation cover in Qinghai was significantly larger than the degraded area (17.87%).Vegetation coverage area with significant improvement was 21.26%,that with slight improvement was 39.25%,that with slightly degradation was 15.75%,that with severe degradation was 2.12%,and that remained unchanged was 21.62%.4) In the future,the vegetation covered area in Qinghai accounted for 62.23% of the total area,of which 38.01% was continuously improved area and 24.22% was improved from degradation to improvement.The area with degradation trend was 18.30%,of which 7.74% was persistent degradation and 10.56% was from improvement to degradation.The stable area was 8.43% and the uncertain area was 11.04%.【Conclusion】The NDVI in Qinghai was affected by both climate and human activities,and most areas showed improving trend. |
| Key words: Qinghai normalized difference vegetation index (NDVI) temporal-spatial variation Sen+Mann-Kendall Hurst index |
