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中国沙漠 ›› 2021, Vol. 41 ›› Issue (1): 28-36.DOI: 10.7522/j.issn.1000-694X.2020.00094

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基于GEE19872019年民勤绿洲NDVI变化特征及趋势分析

张华(), 安慧敏   

  1. 西北师范大学 地理与环境科学学院,甘肃 兰州 730070
  • 收稿日期:2020-06-26 修回日期:2020-09-03 出版日期:2021-01-29 发布日期:2021-01-29
  • 作者简介:张华(1978—),女,甘肃兰州人,副教授,主要从事生态水文与环境遥感方面的工作。E-mail: zhanghua2402@163.com
  • 基金资助:
    国家自然科学基金项目(41461011);兰州市人才创新创业项目(2019-RC-105)

Analysis of NDVI variation characteristics and trend of Minqin Oasis from 1987 to 2019 based on GEE

Hua Zhang(), Huimin An   

  1. College of Geography and Environment Science,Northwest Normal University,Lanzhou 730070,China
  • Received:2020-06-26 Revised:2020-09-03 Online:2021-01-29 Published:2021-01-29

摘要:

Google Earth Engine(GEE)是目前最先进的地理大数据分析和可视化平台,使遥感监测地表植被突破了数据获取难、本地存储量大、处理效率低的限制。基于GEE云平台计算Landsat系列卫星影像,研究了1987—2019年民勤绿洲NDVI的时空变化,并通过一元线性趋势分析、稳定性分析、Hurst指数对变化趋势进行了分析和预测。结果表明:(1)1987—2019年民勤绿洲NDVI年均值从0.172上升到0.230,多年平均值为0.244,1989—2007、2010—2016年呈上升趋势,1987—1989、2007—2010、2016—2019年呈下降趋势。年内NDVI-0.017—0.333,高值集中在每年4—10月。空间上来看,绿洲外围NDVI明显增大,绿洲向荒漠扩张。(2)1987—2019年民勤绿洲大部分区域NDVI基本不变,坝区、泉山区绿洲外围、湖区南部和青土湖呈增大趋势,坝区中部民勤县城区、湖区北部绿洲边缘呈减小趋势,基本不变、增大、减小区域分别占总面积的81.90%、16.25%和1.85%。(3)1987—2019年民勤绿洲NDVI变化稳定性高的区域主要位于坝区东南部、泉山区东部、湖区北部荒漠区域;波动性高的区域主要位于坝区、泉山区绿洲外围、湖区南部和青土湖。(4)未来民勤绿洲大部分区域NDVI变化趋势保持基本不变,坝区、泉山区绿洲外围、湖区北部和青土湖,NDVI未来有可能增大,坝区中部民勤县城区、湖区北部向荒漠过渡地带,NDVI未来有可能减小,基本不变、未来有可能增大、减小的区域面积分别占71.62%、12.96%、15.42%。

关键词: GEE, NDVI, 变异系数, Hurst指数, 民勤绿洲

Abstract:

Google Earth engine (GEE) is the most advanced platform for analysis and visualization of geographic big data, which makes remote sensing monitoring surface vegetation break through the limitations of data acquisition, local storage and low processing efficiency. Based on GEE cloud platform to calculate the NDVI of Landsat series satellite images, this paper studied the spatial and temporal variation of NDVI in Minqin oasis from 1987 to 2019, analyzed and predicted the variation trend of NDVI in Minqin oasis through unvariable linear trend analysis, stability analysis and Hurst index. The results shows that: (1) From 1987 to 2019, the annual average NDVI value of Minqin Oasis increased from 0.172 to 0.230 at the speed of 4.6%?(10a)-1, and the multi-year average value was 0.244, showing an upward trend in 1989-2007 and 2010-2016, and a downward trend in 1987-1989, 2007-2010 and 2016-2019. During the year, NDVI ranged from -0.017 to 0.333, and the highest value was from April to October every year. In terms of spatial changes, NDVI in the periphery of the oasis has increased obviously, and the oasis has expanded to desert. (2) From 1987 to 2019, most areas of NDVI in Minqin Oasis remained basically unchanged. The periphery of the oasis in dam region and Quanshan region, the south of the lake region and Qingtu Lake showed an increasing trend. The urban area of Minqin County in the middle of the dam region and the edge of the oasis in the north of the lake region showed a decreasing trend. Basically unchanged, increasing and decreasing areas account for 81.90%, 16.25% and 1.85% of the total area respectively. (3) From 1987 to 2019, the areas with high NDVI change stability in Minqin oasis are mainly located in the southeast of the dam region, the east of Quanshan region and the north of the lake region; the regions with high volatility are mainly located in the periphery of the oasis in dam region and Quanshan region, the south of the lake region and Qingtu lake. (4) Hurst index shows that the trend of NDVI change in most areas of Minqin Oasis remains unchanged in the future. In the periphery of the oasis in the dam region and Quanshan region, in the north of the lake region and in Qingtu Lake, NDVI is likely to increase. In the middle of minqin County and the north of the lake region, NDVI is likely to decrease. The areas of NDVI basically unchanged, increased and decreased accounted for 71.62%, 12.96% and 15.42%, respectively.

Key words: GEE, NDVI, coefficient of variation, Hurst index, Minqin Oasis

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