叶面积指数间接测量方法
Review of indirect methods for leaf area index measurement
- 2016年20卷第5期 页码:958-978
纸质出版日期: 2016
DOI: 10.11834/jrs.20166238
扫 描 看 全 文
浏览全部资源
扫码关注微信
纸质出版日期: 2016 ,
扫 描 看 全 文
[1]阎广建,胡容海,罗京辉,穆西晗,谢东辉,张吴明.叶面积指数间接测量方法[J].遥感学报,2016,20(05):958-978.
YAN Guangjian, HU Ronghai, LUO Jinghui, et al. Review of indirect methods for leaf area index measurement[J]. Journal of Remote Sensing, 2016,20(5):958-978.
叶面积指数是对地遥感的关键参数。间接测量法快速高效
已广泛应用于叶面积指数的地面测量和遥感验证中
服务于众多行业和领域
表现为论文被引数远远大于发文数。从理论基础、代表算法、测量仪器、影响因素几个方面全面总结了叶面积指数间接测量方法的发展和现状
指出聚集/尺度效应、叶倾角分布、木质组分、地形效应是影响测量精度的关键因素
针对这些影响因素对未来发展方向进行了展望。
Leaf Area Index(LAI) is a key parameter for terrestrial remote sensing. Indirect methods are fast and efficient
and they arewidely used in ground measurement and the remote sensing validation of the LAI. These methods servea large number of industries and fields
as theircitation count is far greater than theirliterature count. This paper comprehensively reviews the development and current status of indirect LAI measurement with regard to theories
algorithms
instruments
and influence factors. The latest progress and future prospects are summarized and discussed onthe basis off our challenges
including clumping/scale effect
leaf angle distribution
woody component
and slope effect. First
the basic concepts and theoretical background are summarized to provide an overview of indirect LAI measurement. The basic concepts include LAI definition
gap probability
leaf angle distribution
leaf projection function
clumping index
needle-to-shoot area ratio
and woody-to-total area ratio. Theoretical derivations begin with the introduction of Beer’s law on indirect LAI measurement
followed by three essential adaptations concerning leaf angle distribution
clumping effect
and woody component. Second
representative methods for quantifying the clumping effect are reviewed
with the clumping effect beingthe most important factor. These methods consist of the finite-length averaging method
the gap-size distribution method
the combination of finite-length averaging and gap-size distribution method
and the path length distribution method. Third
representative instruments for indirect measurement are reviewed. These instruments include LAI-2000
TRAC
line quantum sensors(Accu PAR
Sun Scan
and LAInet)
DEMON
imaging instruments(Hemi View
MVI
and MCI)
and Li DAR. Airborne and spaceborne Li DAR are also reviewed because they also use Beer’s law as the indirect LAI measurement. Finally
four key factors that limit indirect LAI measurement accuracy are discussed. These factors are the clumping/scale effect
leaf angle distribution
woody component
and slope effect. The mixed effects of these factors are also explained.The clumping effect has attracted the most attention in the community
with several related methods having beendeveloped and being widely used in field measurement.The non-randomness inside canopies and the scale effect of measurement is also worth studying further. The theory of leaf angle distribution is well-developed
whereas the spherical distribution assumption(G≡0.5) is often used because of the inconvenience of measurement.The spherical distribution assumption should be used with caution because it is only valid near a zenith angle of 57.3°. The efforts to develop fast and automatic methods for measuring leaf angle distribution show greatpromise. The importance of woody components is widely recognized
but they are always ignored in measurement because commercial instruments are incapable of distinguishing woody components.Near-infrared technology and instruments should be applied to ground measurement to distinguish the LAI from the plant area index. The slope effect has attracted more attention than before. Research shows that it canbe ignored when the slope is less than 30°; otherwise
it could be a moderate source of error. Generally
making a break through in theories is difficult
although the main constraints have been identified and much progress hasbeen made. With a focuson these aspects
developing new instruments and calculation and validation methods
further exploring existing data
and finally improving the accuracy and stability of indirect LAI measurement are endeavors worth pursuing.
叶面积指数间接测量聚集效应尺度效应叶倾角分布木质组分地形效应
leaf area indexindirect measurementclumping effectscale effectleaf angle distributionwoody componentsslope effect
相关作者
相关机构