物候信息在大范围作物长势遥感监测中的应用

大范围的农作物长势监测可以为农业政策的制订和粮食贸易提供决策依据,也是农作物产量估测的必要前提。遥感估算的作物生物量是评价作物长势的主要群体特征指标,在大范围上开展作物长势监测时,不同区域的作物因为所处的物候阶段不同而导致生物量存在差异,这种差异与因作物长势状况差别而产生的差异混合在一起,增加了长势监测结果的不确定性。以中国河南、山东两省为研究区,以MODIS 250 m NDVI产品数据为主要数据源,结合改进的CASA模型实现了区域内冬小麦生物量的估算,结合冬小麦生长过程特征进行了典型物候期的监测。在此基础上,分析了扬花期前后物候差异对冬小麦生物量估算的影响,研究其特定物候阶段的变化规律,从而实现了生物量的物候归一化,初步探索了如何消除大区域物候差异对作物长势监测与评估的影响。

Integrating Crop Phenophase Information in Large-area Crop Condition Evaluation with Remote Sensing

Meng Jihua,Du Xin,Zhang Miao,You Xingzhi,Wu Bingfang
(Institute of Remote Sensing and Digital Earth,Chinese Academy of Sciences,Beijing 100094,China)
Large-area crop condition information is not only helpful in producing proper agricultural policy and making sound decision in grain trade,but also a premise for crop production prediction.Crop bio-physical parameters(biomass)derived from remote sensing are the major indicators for crop group condition evaluation.When these parameters are used in large-area crop condition evaluation,the parameter difference due to phenophase difference and that difference due to crop condition are mixed,which is hard to distinguish.This will induce much uncertainty in the large\|area crop condition monitoring with these bio\|physical parameters.Taking Shandong and Henan provinces as study area,this study estimated winter wheat biomass and phenophase with 250 m MODIS data.Then the relationship between phenophase and biomass at certain phonological stage for winter wheat was studied.This relationship was used to normalize the winter wheat biomass to same phonological stage.The elimination of uncertainty due to phenophase difference in crop condition monitoring was explored.