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干旱区地理 ›› 2022, Vol. 45 ›› Issue (6): 1847-1859.doi: 10.12118/j.issn.1000-6060.2022.119

• 地球信息科学 • 上一篇    下一篇

基于Sentinel-2时间序列数据及物候特征的棉花种植区提取

美合日阿依·莫一丁1(),买买提·沙吾提1,2,3(),李金朝1   

  1. 1.新疆大学地理与遥感科学学院,新疆 乌鲁木齐 830046
    2.新疆绿洲生态重点实验室,新疆 乌鲁木齐 840046
    3.智慧城市与环境建模自治区普通高校重点实验室,新疆 乌鲁木齐 840046
  • 收稿日期:2022-03-23 修回日期:2022-05-16 出版日期:2022-11-25 发布日期:2023-02-01
  • 通讯作者: 买买提·沙吾提(1976-),男,博士,副教授,主要从事多源遥感信息提取及农业遥感等方面的研究. E-mail: korxat@xju.edu.cn
  • 作者简介:美合日阿依·莫一丁(1997-),女,硕士研究生,主要从事卫星遥感和植被监测等方面的研究. E-mail: mihray_m@163.com
  • 基金资助:
    新疆自然科学计划(自然科学基金)联合基金项目(2021D01C055)

Extraction of cotton planting area based on Sentinel-2 time series data and phenological characteristics

Mihray MOYIDIN1(),Mamat SAWUT1,2,3(),LI Jinzhao1   

  1. 1. College of Geography and Remote Sensing Science, Xinjiang University, Urumqi 830046, Xinjiang, China
    2. Xinjiang Key Laboratory of Oasis Ecology, Xinjiang University, Urumqi 830046, Xinjiang, China
    3. Key Laboratory of Smart City and Environment Modelling of Higher Education Institute, Xinjiang University, Urumqi 830046, Xinjiang, China
  • Received:2022-03-23 Revised:2022-05-16 Online:2022-11-25 Published:2023-02-01
  • Contact: SAWUT Mamat

摘要:

棉花是中国重要的经济作物,在新疆大面积种植。及时、准确获取棉花种植面积,对农业政策制定与农业经济发展有重要意义。以渭干河—库车河三角洲绿洲棉花为主要研究对象,利用2018—2020年(1景/1月)36景哨兵2号(Sentinel-2)数据,构建归一化植被指数(Normalize difference vegetation index,NDVI)和红边归一化植被指数(Red edge normalize difference vegetation index,RENDVI783)时序数据;采用Savitzky-Golay(S-G)滤波法对时序数据进行平滑、重构并提取11个物候特征;利用袋外误差法对11个物候特征进行特征优选;在此基础上利用重构后的时序数据(NDVI Fit)、(RENDVI783 Fit)、物候特征(RENDVI783 Ph)、物候特征优选组合构建6种不同的特征数据集,利用随机森林分类(RFC)方法分别进行分类和提取,并采用最大似然分类方法和支持向量机分类方法对分类效果进行验证。结果表明:(1) NDVI和RENDVI783时序数据变化趋势较为一致,棉花在5月(苗期)到8月初(开花盛期)有明显的上升趋势,在8月末至9月(花铃期)达到峰值。相比NDVI,红边波段构成的RENDVI783时序曲线峰值从0.7提高到0.9,棉花区分效果更佳。(2) 11个物候特征中拟合函数最大值、生长季长度、生长季振幅、生长季结束、生长季大积分和生长季小积分对分类的贡献性最大,重要性得分分别为1.43、1.40、1.23、1.16、1.02和1.01。(3) RFC方法对特征数据集(RENDVI783 Fit+物候特征优选组合)分类精度最佳。总体精度和Kappa系数分别为92.20%和0.92。(4) 研究区内棉花分类精度达到了91.02%,种植面积约为3424 km2,占研究区总面积的24.67%。

关键词: NDVI时间序列, RENDVI时间序列, 物候特征, 袋外误差, 随机森林分类

Abstract:

Cotton is an important economic crop in China and is cultivated on a large scale in Xinjiang. The timely and accurate acquisition of cotton planting areas is significant to agricultural policy formulation and economic development. This study takes the Ugan River-Kuqa River delta oasis cotton as the main research object and uses the Sentinel-2 data of 36 scenes from 2018 to 2020 (1 scene/month) to construct a normalized vegetation index (NDVI) and red-edge normalized vegetation index (RENDVI) time-series data; The Savitzky-Golay filtering method is used to smooth and reconstruct the time-series data, and 11 phenological features are extracted. The out-of-bag method is used to optimize the 11 phenological features. Time-series data NDVI Fit and RENDVI783 Fit, phenological feature RENDVI783 Ph, and phenological feature optimization were combined to construct six different feature datasets, which were classified and extracted by random forest classification (RFC). The maximum likelihood and support vector machine were used to verify the classification effect. The results are as follows: (1) The changing trends of NDVI and RENDVI783 time-series data are relatively consistent. Cotton has an obvious upward trend from May (seedling stage) to early August (blooming stage) and reaches a peak from the end of August to September (flowering and boll stage). Compared with NDVI, the peak value of the RENDVI783 time-series curve composed of the red-edge band is increased from 0.7 to 0.9, and the cotton discrimination effect is better. (2) Among the 11 phenological features, the maximum value of the fitting function, the length of the growing season, the amplitude of the growing season, the end of the growing season, the large integral of the growing season, and the small integral of the growing season contributed the most to the classification effect, with importance scores of 1.43, 1.40, 1.23, 1.16, 1.02, and 1.01, respectively. (3) The RFC method has the best classification accuracy for the feature dataset (RENDVI783 Fit + phenological feature optimal combination). The overall accuracy and Kappa coefficient are 92.20% and 0.92, respectively. (4) The cotton classification accuracy in the study area reached 91.02%, and the planting area was approximately 3424 km2, accounting for 24.67% of the total area of the study area.

Key words: NDVI time-series, RENDVI time-series, phenological characteristics, out-of-bag error method, random forest classification