| 谷佳贺,薛华柱,董国涛,程结海.归一化水体指数用于河南省干旱监测适用性分析[J].干旱地区农业研究,2020,38(6):209~217 |
| 归一化水体指数用于河南省干旱监测适用性分析 |
| Applicability analysis of NDWI for drought monitoring in Henan Province |
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| DOI：10.7606/j.issn.1000-7601.2020.06.28 |
| 中文关键词: 归一化水体指数 土壤水分 干旱监测 信息熵 |
| 英文关键词:normalized difference water index (NDWI) soil moisture drought monitoring information entropy |
| 基金项目:国家自然科学基金项目(51779099)；省部级项目“黄河中游水土流失区林草植被发展趋势及对来水来沙和环境的影响”专项研究（CYRF2018002）；河南省科技攻关项目（172102110268） |
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| 中文摘要: |
| 利用30 m分辨率的归一化植被指数（NDVI）图像信息熵对河南省气象站周边地表异质性进行分析，选取观测站周围地表较为均匀的站点实测土壤水分数据，通过计算归一化水体指数（NDWI）与实测土壤水分之间的相关系数，分析比较NDWI用于干旱监测的适用性。研究表明：信息熵方法可有效地对土壤水分观测数据进行筛选；在时间序列上，各站点实测值与NDWI具有负相关关系，在增强型植被指数EVI>0.4时相关性更高，说明在植被覆盖高的区域NDWI对土壤水分的反演更为敏感；空间上，根据地形将河南省分为北部、中部、南部和西部4个区域并选取第121、201、313天的土壤水分数据来分析与NDWI之间的相关性，在地形较为平坦的中北部地区NDWI与土壤水分之间负相关性最稳定且相关系数较高。根据NDWI空间分布可知，2014年河南省大部分地区均遭受了干旱，且干旱地区大部分位于平原，特别是北方地区受灾严重。总体来说，NDWI用于平原地区对作物进行干旱监测精度较高，并可预测干旱发展趋势及程度。 |
| 英文摘要: |
| This paper analyzed the heterogeneity of places near weather stations by means of the entropy of 30 m NDVI images in Henan Province. Homogenous land cover sites were selected to calculate the correlation index between NDWI and measured soil moisture data, thus to demonstrate the applicability of NDWI in drought monitor\|ing.The results show that information entropy method can effectively screen soil moisture observation data; In time series, the measured soil moisture has a negative correlation with NDWI, and the correlation is higher when EVI>0.4. This demonstrates that high vegetation cover zones are more sensitive to the retrieval of soil moisture; According to the topography, Henan Province is divided into four regions of northern, central, southern and western regions. Day 121, day 201 and day 313 are selected to analyze the correlation between soil moisture and NDWI. The negative correlation between NDWI and soil moisture was the most stable and the correlation coefficient was high in the north\|central region where the terrain was relatively flat; According to the spatial distribution of NDWI, most areas of Henan Province suffered from drought in 2014 and most of the arid areas were located in the plain, especially in the north. In general, NDWI can be used to monitor crop drought in plain area and estimate drought trends and level. |
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