نتایج جستجو برای: canopy angle

تعداد نتایج: 144935  

Journal: :Plant physiology 2015
Alexandra J Burgess Renata Retkute Michael P Pound John Foulkes Simon P Preston Oliver E Jensen Tony P Pridmore Erik H Murchie

Photoinhibition reduces photosynthetic productivity; however, it is difficult to quantify accurately in complex canopies partly because of a lack of high-resolution structural data on plant canopy architecture, which determines complex fluctuations of light in space and time. Here, we evaluate the effects of photoinhibition on long-term carbon gain (over 1 d) in three different wheat (Triticum ...

2003
Nathan Slegers Mark Costello

Controllable parafoil and payload aircraft are controlled with downward deflection of left and right parafoil brakes. Lateral control is obtained by differential deflection while longitudinal control is created by collective deflection of the left and right side parafoil brakes. The work reported considers an alternative method to control parafoil and payload air vehicles by tilting the parafoi...

2017
Naser Bader AlKhalifah

Since the 1950’s, the average maize grain yield, on a per unit area basis, has risen exponentially and without a pause. Associated with this increase have been changes in shoot morphology which permit more light penetration into the canopy. Changes in plant traits including plant height, leaf number, individual leaf area, vertical leaf angle, tassel size and weight, and leaf area density distri...

2006
Ray Leuning Dale Hughes Paul Daniel Nicholas C. Coops Glenn Newnham

The paper describes the design and operation of a multi-angle spectrometer (MAS) for automatic measurement of near-field spectral reflectances of plant canopies at hourly intervals. A novel feature of the instrument is a rotating periscope connected to a spectrometer via a fiber optic cable. Canopy reflectances are calculated for multiple view azimuths, at a single zenith angle from measurement...

Journal: :Int. J. Applied Earth Observation and Geoinformation 2011
Mariano García F. Mark Danson David Riaño Emilio Chuvieco F. Alberto Ramirez Vishal Bandugula

This paper evaluates the potential of a terrestrial laser scanner (TLS) to characterize forest canopy fuel characteristics at plot level. Several canopy properties, namely canopy height, canopy cover, canopy base height and fuel strata gapwere estimated. Different approaches were tested to avoid the effect of canopy shadowing on canopy height estimation caused by deployment of the TLS below the...

1996
P. GONG D. X. WANG S. LIANG

An o-nadir canopy re¯ ectance model, the Liang and Strahler algorithm for the Coupled Atmosphere and Canopy (CAC) model, was used to simulate multi-angle re¯ ectances based on various combinations of canopy bio-physical parameters. Biophysical parameters such as leaf angle distribution (LAD) and leaf area index (LAI) were input to the CAC model along with re¯ ectances of leaf and soil and aeros...

2013
Qinying Yang Wenjiang Huang Jinling Zhao Liang Dong Linsheng Huang Dongyan Zhang Liangyun Liu Guijun Yang Xiaoyu Song

This study presents a method for quantitatively estimating leaf area index (LAI) in winter wheat by exploring bi-directional reflectance distribution function (BRDF) data. In BRDF data, near-infrared reflectance (NIR) which is sensitive to crown component, canopy cover and crown shape, is affected by illuminated crown component, while red reflectance is sensitive to canopy gaps and controlled b...

Journal: :Remote Sensing 2017
Xiaochen Zou Matti Mottus

Leaf inclination angle distribution is an important canopy structure characteristic which directly impacts the fraction of the intercepted solar radiation. Together with the leaf area index (LAI) it determines the structure and fractional cover of a homogeneous crop canopy. Unfortunately, this key canopy parameter has usually been ignored when applying common multispectral vegetation indices to...

Journal: :Tree physiology 1997
D W Gilmore R S Seymour

Data collected from four distinct canopy positions from each of 39 Abies balsamea (L.) Miller trees were used to construct models to describe the cumulative leaf area distribution within the crown and to predict the needle mass of individual branches, the average branch angle, branch diameter, branch length, and crown radius per whorl, and the average number of living branches per whorl. We tes...

Journal: :Journal of plant physiology 2016
Anatoly A Gitelson Yi Peng Andrés Viña Timothy Arkebauer James S Schepers

One of the main factors affecting vegetation productivity is absorbed light, which is largely governed by chlorophyll. In this paper, we introduce the concept of chlorophyll efficiency, representing the amount of gross primary production per unit of canopy chlorophyll content (Chl) and incident PAR. We analyzed chlorophyll efficiency in two contrasting crops (soybean and maize). Given that they...

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