title: MLAOS: a multi-point linear array of optical sensors for coniferous foliage clumping index measurement.
abstract: The canopy foliage clumping effect is primarily caused by the non-random distribution of canopy foliage. Currently, measurements of clumping index (CI) by handheld instruments is typically time- and labor-intensive. We propose a low-cost and low-power automatic measurement system called Multi-point Linear Array of Optical Sensors (MLAOS), which consists of three above-canopy and nine below-canopy optical sensors that capture plant transmittance at different times of the day. Data communication between the MLAOS node is facilitated by using a ZigBee network, and the data are transmitted from the field MLAOS to a remote data server using the Internet. The choice of the electronic element and design of the MLAOS software is aimed at reducing costs and power consumption. A power consumption test showed that, when a 4000 mAH Li-ion battery is used, a maximum of 8-10 months of work can be achieved. A field experiment on a coniferous forest revealed that the CI of MLAOS may reveal a clumping effect that occurs within the canopy. In further work, measurement of the multi-scale clumping effect can be achieved by utilizing a greater number of MLAOS devices to capture the heterogeneity of the plant canopy.
authors.affiliation: State Key Laboratory of Remote Sensing Science, Beijing Key Laboratory for Remote Sensing of Environment and Digital Cities, School of Geography, Beijing Normal University, Beijing 100875, China. qyh@bnu.edu.cn.
authors.forename: Yonghua
authors.initials: Y
authors.lastname: Qu
authors.affiliation: State Key Laboratory of Remote Sensing Science, Beijing Key Laboratory for Remote Sensing of Environment and Digital Cities, School of Geography, Beijing Normal University, Beijing 100875, China. fulizhe0312@163.com.
authors.forename: Lizhe
authors.initials: L
authors.lastname: Fu
authors.affiliation: State Key Laboratory of Remote Sensing Science, Beijing Key Laboratory for Remote Sensing of Environment and Digital Cities, School of Geography, Beijing Normal University, Beijing 100875, China. hwc9028@163.com.
authors.forename: Wenchao
authors.initials: W
authors.lastname: Han
authors.affiliation: State Key Laboratory of Remote Sensing Science, Beijing Key Laboratory for Remote Sensing of Environment and Digital Cities, School of Geography, Beijing Normal University, Beijing 100875, China. zhuyeqing0307@foxmail.com.
authors.forename: Yeqing
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: State Key Laboratory of Remote Sensing Science, Beijing Key Laboratory for Remote Sensing of Environment and Digital Cities, School of Geography, Beijing Normal University, Beijing 100875, China. wangjd@bnu.edu.cn.
authors.forename: Jindi
authors.initials: J
authors.lastname: Wang
mesh_terms: D000383:Agriculture / Q000295:instrumentation*; D004784:Environmental Monitoring / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D065928:Forests; D055096:Optical Devices; D010783:Photometry / Q000295:instrumentation*; D064028:Tracheophyta / Q000254:growth & development*; D014159:Transducers