文献 | 利用时间序列Sentinel - 1、Sentinel - 2和Landsat影像绘制广西甘蔗种植动态变化图

Sugarcane is a major crop for sugar and ethanol production and its area has increased substantially in tropicaland subtropical regions in recent decades.Updated and accurate sugarcane maps are critical for monitoringsugarcane area and production and assessing its impacts on the society,economy and the environment.To date,no sugarcane mapping tools are available to generate annual maps of sugarcane at thefield scale over largeregions.In this study,we developed a pixel-and phenology-based mapping tool to produce an annual map ofsugarcane at 10-m spatial resolution by analyzing time-series Landsat-7/8,Sentinel-2 and Sentinel-1 images(LC/S2/S1)during August 31,2017-July 1,2019 in Guangxi province,China,which accounts for 65%of sugarcaneproduction of China.First,we generated annual maps of croplands and other land cover types in 2018.Second,we delineated the cropping intensity(single,double and triple cropping in a year)for all cropland pixels in 2018.Third,we identified sugarcanefields in 2018 based on its phenological characteristics.The resultant 2018 su-garcane map has producer,user and overall accuracies of 88%,96%and 96%,respectively.According to theannual sugarcane map in 2018,there was a total of 8940 km2sugarcane in Guangxi,which was~1%higher thanthe estimate from the Guangxi Agricultural Statistics Report.Finally,we identified green-up dates of thosesugarcanefields in 2019,which could be used to support the sugarcane planting and management activities.Ourstudy demonstrates the potential of the pixel-and phenology-based sugarcane mapping tool(both the algorithmsand the LC/S2/S1 time series images) in identifying croplands,cropping intensity and sugarcanefields in thecomplex landscapes with diverse crop types,fragmented cropfields and frequent cloudy weather.The resultantannual maps from this study could be used to assist farms and sugarcane mills for sustainable sugarcane pro-duction and environment.  

甘蔗是生产食糖和乙醇的主要作物，近几十年来其面积在热带和亚热带地区大幅增加。更新和准确的甘蔗种植图对于监测甘蔗种植面积和产量以及评估其对社会、经济和环境的影响至关重要。迄今为止，还没有任何甘蔗制图工具可以在大区域的田间尺度上生成甘蔗的年度图。本研究通过分析广西2017年8月31日至2019年7月1日期间的Landsat - 7 / 8、Sentinel - 2和Sentinel - 1时序影像( LC / S2 / S1 )，开发了基于像元和物候的制图工具，制作了10 m空间分辨率的甘蔗年图，占全国甘蔗产量的65 %。首先，研究生成了2018年的耕地和其他土地覆盖类型的年度图。其次，研究划定了2018年所有耕地像元的种植强度(一年一熟、一年二熟和一年三熟)。研究根据2018年蔗田的物候特征，对2018年蔗田进行了识别，生成的2018年甘蔗图生产者、用户和总体精度分别为88 %、96 %和96 %。根据2018年年度甘蔗分布图，广西共有8940 km2甘蔗，比《广西农业统计报告》中的估计高~ 1 %。最后，研究确定了这些蔗田2019年的返青日期，可用于支持甘蔗种植和管理活动。研究表明，基于像元和物候的甘蔗制图工具(算法和LC / S2 / S1时间序列图像)在识别作物类型多样、作物地块破碎和多云天气频繁的复杂景观中的农田、种植强度和蔗田的潜力。本研究得到的年图可用于帮助农场和甘蔗工厂实现可持续的甘蔗生产和环境。