Theories, methods and sensors article pdf available in sensors 94. The photos were taken with an automatic 153 exposure looking vertically down at the plots to capture a rectangular area of roughly 50cm 154 by 50cm. Navi is obtained using only two bands on red and near infrared regions of the spectrum. Leaf area index lai estimation in boreal mixedwood forest of ontario. Integrating remote sensing data on evapotranspiration and. Estimation of canopyaverage surfacespecific leaf area using.
The values in the the downloaded raw landsat 8 images are so called digital numbers of the sensor. Example uses of the database for global plant productivity, fractional energy absorption, and remote sensing studies are highlighted. An important vegetation biophysical parameter, the leaf area index lai, is a dimensionless variable and a ratio of leaf area to per unit ground surface area. Calculation of land surface temperature lst from landsat 8. Satellite remote sensing, vegetation index, ndvi, leaf area index, lai. Both parameters are essential for estimating radiation absorption and distribution in the canopy. Lai derived from remote sensing images belongs to apparent lai, since leaves are supposed homogeneous distribution in each pixel. Satellite data radiometric correction and calculations of vegetation indices. The leaf area index lai is an important vegetation parameter, which is used widely in many applications. However, very few studies have considered the effect of clumping index x in the calculation of true lai. Estimating leaf area index from satellite data in deciduous forests of.
Graphic presentation of the proposed approach step 2. Satellite remote sensing for estimating leaf area index, fpar. Leaf area index lai is a measure of foliage density that plays a major role in photosynthesis, groundwatersurface water interactions through. Foliage clumping index leaf area index multiangle remote sensing abstract clumping index ci is a measure of foliage aggregation relative to a random distribution of leaves in space. Description of scale spatial scale in remote sensing refers to pixel spatial resolution r. Vegetation indices vis obtained from remote sensing based canopies are quite simple and effective algorithms for quantitative and qualitative evaluations of vegetation cover, vigor, and growth dynamics, among other applications. Key wordscanopy structure, ecosystem modelling, global ecology, lai, leaf area index, remote sensing. Leaf area index lai is widely used to describe the photosynthetic and transpirational surface of plant canopies. Stomatal conductance, canopy temperature, and leaf area index. Leaf area determination techniques after leaf collection, leaf area can be calculated by means of eitherplanimetric or gravimetric techniques daughtry, 1990. Leaf area index estimation from visible and nearinfrared. In conifers, three definitions for lai have been used.
Retrieving leaf area index from remotely sensed data using. Retrieval and application of leaf area index over china using. Half of the total needle surface area per unit ground surface area. Remote sensing of vegetation liquid water has im portant applications in agriculture and forestry. Mccarty, soil scientist usdaars, hydrology and remote sensing laboratory building 007 room 104 barcwest 10300 baltimore avenue. Applicability of greenred vegetation index for remote. The basic components to record or measure the remotely sensed data. Leaf area index is defined as the projected area of leaves over a unit of land m2 m. Precision agriculture, biomass, crop, narrow band indices abstract. Estimating the crop leaf area index using hyperspectral remote. Leaf area index estimates using remotely sensed data and brdf. Leaf area index lai quantifies the amount of leaf area in a canopy, while clumping index ci characterizes the spatial distribution pattern of leaves in the canopy. A multiyear satelliteindependent method based on withinstand normalized difference vegetation index spatial variability g.
Retrieval and application of leaf area index over china using hj1 data xiaojie zhao a,b, chunxiang cao,c, xiliang ni aand wei chen astate key laboratory of remote sensing science, jointly sponsored by the institute of remote sensing and digital earth of chinese academy of sciences and beijing normal university, beijing, p. How to calculate lai leaf area index using remote sensing. Quality control to estimating leaf area index with remote sensing imagery. Assimilating remote sensing observations of leaf area index. Introduction remote sensing is an effective approach for tracking phenological changes such as leaf greenup and autumn coloring from the regional to the global scale 1. Litterfall measurements patrick schleppi, liisa ukonmaanaho, stefan fleck the litterfall method for leaf area index derivation is a semidirect estimation that has been frequently used in the past for broadleaf stands breda, 2003.
Leaf area index retrieval using gap fractions obtained from high. In fact, timeseries datasets of spectral indices obtained by satellite remote sensing have demonstrated its usefulness in detecting the. Leaf area index lai is a dimensionless quantity that characterizes plant canopies. Remotely sensed information about vegetation often comes in the form of a leaf area index lai m2 m 2 e. Waring department of forest science, oregon state university, corvallis, oregon 97331 usa abstract.
The dynamic leaf area index lai derived from satellite remote sensing was incorporated into the variable infiltration capacity model vic to enable an interannually varying seasonal cycle of vegetation vicveg. The amount of foliage in the plant canopy is one of the basic ecological characteristics commonly quantified by leaf area index lai. The lai products from the advanced very high resolution radiometer avhrr and the moderate resolution imaging spectrora. The normalized difference water index ndwi is a remote sensing derived index estimating the leaf water content at canopy level. In remote sensing the reflectance from the vegetation in different wavelength bands is.
Pdf retrieving leaf area index lai using remote sensing. Optical remote sensing of forest leaf area index and biomass. Emerging remote sensing platforms and techniques can complement existing groundbased measurement of lai. As a fundamental plant parameter leaf area index lai leaf area ground surface.
The ci can help with estimating fractions of sunlit and shaded leaves for a given leaf area index lai value. The indirect estimation of leaf area index lai in large spatial scales is crucial for several environmental and agricultural applications. Remotely sensed images including landsat, spot, naip orthoimagery, and lidar and relevant processing tools can be used to predict plant stomatal conductance g. Relationships of ndvi, biomass, and leaf area index lai for. How to calculate lai leaf area index in remote sensing.
Leaf area index, lai, is an important biophysical parameter in ecological modeling. Measurement of leaf relative water content by infrared. Leaf area index is an indicator of the density of vegetation, and is relatively easy to measure. Remote sensing of leaf area index lai and a spatiotemporally parameterized model for mixed grasslands li shen zhaoqin li xulin guo department of geography and planning university of saskatchewan saskatoon, sk s7n5c8, canada abstract leaf area index lai is an important biophysical variable used to reflect the vegetation condition in ecosystems. The planimetric approach is based on the principle of the correlation between the individual leaf area and the number of area units covered by that leaf in a horizontal plane. A scale transform method for leaf area index retrieved from. Significant progress has been made in mapping lai in the past few decades. Great effort has been dedicated to the mapping of leaf area and biomass using remotely sensed data. Leaf area index retrieval using hyperion eo1 databased vegetation indices in himalayan forest system cite 2 recommendations. In a recent article, bausch 1993 described the derivation of crop water use coefficients from visible and nearinfrared reflectance data, as well as various radiometric vegetation indices such as the normalized difference vegetation index ndvi. A pdf version of this document can be downloaded from. Pdf leaf area index estimates using remotely sensed data and. The most popular and widely accepted definition of the true leaf area index tlai is defined as one half of total leaf area per unit surface.
For determining the relationship between naoc and navi we used 257 spectra obtained with the probachris sensor during the. In this article, a normalized difference water index ndwi that uses two nearir channels centered approximately at 0. Recently, methods of remotely sensing canopy biochem istry have been developed using hyperspectral scanners to. Information about weather is used to force crop simulations directly.
It is defined as the onesided green leaf area per unit ground surface area lai leaf area ground area, m2 m2 in broadleaf canopies. Leaf area index lai is a key parameter of atmospherevegetation exchanges. Algorithm development for remote sensing of chlorophyll. For these reasons, remote sensing of lai is the subject of numerous works. Lai directly quantifies canopy structure, and can be used to predict primary productivity and crop growth. For our analysis and calculation of the lst we need band 10 and band 11 only. Terrestrial laser scanning tls is a promising tool for estimating leaf area index lai. To estimate leaf area index lai, intercepted radiation, and other related. Leaf index calculation masuzi april 2, 2020 uncategorized 0 leaf area index of cuber leaf area index lidar360 user guide leaf area index and biomass estimation the calculation of leaf area index lai. Stomatal conductance, canopy temperature, and leaf area index estimation using remote sensing and obia techniques s. Lai can be simply defined as the amount of leaf surface area per unit ground area, and has broad applications in ecophysiology, water balance modeling, and characterization of vegetationatmosphere interactions.
Calculation by combining multispectral data and insitu measurements use different methods than ones based on highres lidar data or hyperspectral images. These indices have been widely implemented within rs applications using different airborne and satellite platforms with recent advances using unmanned aerial. Leaf area index lai, the area of leaves per unit ground area, is an important variable for quantifying the cycling of water, carbon and nutrients through ecosystems demarty et al. It is derived from the hyperspectral naoc index, which was initially developed for the chl mapping. This ratio can be related to gasvegetation exchange processes such as photosynthesis 1, evaporation and transpiration 24, rainfall interception 5, and carbon flux 68. Relationship between leaf area index lai estimated by. Vegetation index to estimate chlorophyll content from. Leaf area index lai is the ratio of upper leaf surface area to ground area for broadleaf canopies, or projected conifer needle surface area to ground area for coniferous plants for a given unit area. Mar 24, 2020 leaf area index formula remote sensing masuzi march 24, 2020 uncategorized 0 leaf area index and biomass estimation overy leaf area index estimation definition leaf area index is defined what is leaf area index quora. Ndwi a normalized difference water index for remote sensing. Retrieving leaf area index lai using remote sensing. Investigating laser pulse penetration through a conifer canopy by integrating airborne and terrestrial lidar.
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