太阳高度角变化对小麦叶面积指数观测的影响  

Effect of Solar Altitude Angle Variation on the Observation of Wheat Leaf Area Index

作　　者：王龑[1] 田庆久[1] 黄彦[1] 魏宏伟[1] 

机构地区：[1]南京大学国际地球系统科学研究所,江苏南京210023

出　　处：《遥感信息》2013年第6期44-47,共4页Remote Sensing Information

基　　金：高分应用技术中心实验验证先期攻关(30-Y20A01-9003-12/13);全球变化研究国家重大科学研究计划项目课题(2010CB951503)

摘　　要：利用LAI-2000植物冠层分析仪,通过固定点拔节期小麦LAI观测实验,连续测量了晴天条件下定点小麦在24个不同太阳高度角下的LAI数据,并采取控制变量的方法,即利用相同的LAI-2000观测天顶角进行LAI值计算,进而对不同太阳高度角下LAI-2000测得的定点小麦LAI进行了定性分析。研究结果表明,同天内观测的小麦LAI随着太阳高度角的减小而呈明显增大趋势,两者具有很高相关性,负相关系数(R2)达0.859。若利用LAI-2000在晴天观测植被LAI时,可以通过对LAI值进行修正和归一化处理,解决LAI-2000只能在晴天日出前和日落后观测的局限性,进一步拓展LAI-2000晴天时从早晨一直到傍晚观测的适用性和有效性。The LAI-2000plant canopy analyzer was used in the fixed plot observation experiment of wheat.The LAI values of wheat were measured continuously under 24different solar altitude angles on a sunny day.And in the experiment,the method of controlling variables was taken,namely the LAI values of wheat under different solar altitude angles were calculated by using the same zenith angle,and then a qualitative analysis of the wheat LAI values measured with LAI-2000under different solar altitude angles at that fixed plot was made.The results of the research shows that the wheat LAI values measured significantly increases with the solar altitude angle decreasing,and the negative correlation coefficient(R2)between LAI and solar altitude angle is up to 85.9%.Moreover,the time of operation with LAI-2000on sunny days can be extended beyond the diffuse illumination conditions near sunrise and sunset since the influence of the direct sunlight on the LAI measurements can be mostly removed by correcting and normalizing the LAI values,which further expands the applicability and effectiveness of observation from morning to evening with LAI-2000.

关 键 词：LAI-2000 小麦 LAI 太阳高度角 

分 类 号：TP79[自动化与计算机技术—检测技术与自动化装置]