Emerging remote sensing platforms and techniques can complement existing groundbased measurement of lai. Relationships of ndvi, biomass, and leaf area index lai for. Leaf area index lai is widely used to describe the photosynthetic and transpirational surface of plant canopies. Integrating remote sensing data on evapotranspiration and. It is derived from the hyperspectral naoc index, which was initially developed for the chl mapping. Pdf leaf area index estimates using remotely sensed data and. Retrieving leaf area index from remotely sensed data using. 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. Leaf area index lai is a measure of foliage density that plays a major role in photosynthesis, groundwatersurface water interactions through.
Leaf area index lai is a dimensionless quantity that characterizes plant canopies. Leaf area index is defined as the projected area of leaves over a unit of land m2 m. As a fundamental plant parameter leaf area index lai leaf area ground surface. Satellite remote sensing, vegetation index, ndvi, leaf area index, lai. Great effort has been dedicated to the mapping of leaf area and biomass using remotely sensed data. In conifers, three definitions for lai have been used. Leaf area index estimation from visible and nearinfrared. Satellite remote sensing for estimating leaf area index, fpar. Example uses of the database for global plant productivity, fractional energy absorption, and remote sensing studies are highlighted. Leaf area index retrieval using hyperion eo1 databased vegetation indices in himalayan forest system cite 2 recommendations. Estimating leaf area index from satellite data in deciduous forests of. Terrestrial laser scanning tls is a promising tool for estimating leaf area index lai. 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.
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. The normalized difference water index ndwi is a remote sensing derived index estimating the leaf water content at canopy level. Satellite data radiometric correction and calculations of vegetation indices. Description of scale spatial scale in remote sensing refers to pixel spatial resolution r. For these reasons, remote sensing of lai is the subject of numerous works. 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.
Navi is obtained using only two bands on red and near infrared regions of the spectrum. Estimation of canopyaverage surfacespecific leaf area using. Both parameters are essential for estimating radiation absorption and distribution in the canopy. 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. Theories, methods and sensors article pdf available in sensors 94. Recently, methods of remotely sensing canopy biochem istry have been developed using hyperspectral scanners to. Leaf area index estimates using remotely sensed data and brdf. The lai products from the advanced very high resolution radiometer avhrr and the moderate resolution imaging spectrora. Retrieval and application of leaf area index over china using. Relationship between leaf area index lai estimated by. For our analysis and calculation of the lst we need band 10 and band 11 only. 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.
Half of the total needle surface area per unit ground surface area. Remotely sensed information about vegetation often comes in the form of a leaf area index lai m2 m 2 e. Information about weather is used to force crop simulations directly. Mccarty, soil scientist usdaars, hydrology and remote sensing laboratory building 007 room 104 barcwest 10300 baltimore avenue.
However, very few studies have considered the effect of clumping index x in the calculation of true lai. Lai derived from remote sensing images belongs to apparent lai, since leaves are supposed homogeneous distribution in each pixel. 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. In remote sensing the reflectance from the vegetation in different wavelength bands is. Significant progress has been made in mapping lai in the past few decades. Leaf area determination techniques after leaf collection, leaf area can be calculated by means of eitherplanimetric or gravimetric techniques daughtry, 1990. The ci can help with estimating fractions of sunlit and shaded leaves for a given leaf area index lai value. The amount of foliage in the plant canopy is one of the basic ecological characteristics commonly quantified by leaf area index lai. In fact, timeseries datasets of spectral indices obtained by satellite remote sensing have demonstrated its usefulness in detecting the. 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.
Quality control to estimating leaf area index with remote sensing imagery. Assimilating remote sensing observations of leaf area index. Key wordscanopy structure, ecosystem modelling, global ecology, lai, leaf area index, remote sensing. Waring department of forest science, oregon state university, corvallis, oregon 97331 usa abstract.
Estimating the crop leaf area index using hyperspectral remote. 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. Applicability of greenred vegetation index for remote. 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. Graphic presentation of the proposed approach step 2. How to calculate lai leaf area index using remote sensing.
Remotely sensed images including landsat, spot, naip orthoimagery, and lidar and relevant processing tools can be used to predict plant stomatal conductance g. The basic components to record or measure the remotely sensed data. 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. How to calculate lai leaf area index in remote sensing. Precision agriculture, biomass, crop, narrow band indices abstract. 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. For determining the relationship between naoc and navi we used 257 spectra obtained with the probachris sensor during the. 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. To estimate leaf area index lai, intercepted radiation, and other related. A scale transform method for leaf area index retrieved from. Remote sensing of vegetation liquid water has im portant applications in agriculture and forestry. Pdf retrieving leaf area index lai using remote sensing. Optical remote sensing of forest leaf area index and biomass. 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 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. Algorithm development for remote sensing of chlorophyll. Leaf area index, lai, is an important biophysical parameter in ecological modeling. Vegetation index to estimate chlorophyll content from. Retrieving leaf area index lai using remote sensing. The indirect estimation of leaf area index lai in large spatial scales is crucial for several environmental and agricultural applications. 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. In this article, a normalized difference water index ndwi that uses two nearir channels centered approximately at 0. Leaf area index lai is a key parameter of atmospherevegetation exchanges. Leaf area index retrieval using gap fractions obtained from high. Calculation of land surface temperature lst from landsat 8. Stomatal conductance, canopy temperature, and leaf area index estimation using remote sensing and obia techniques s. A pdf version of this document can be downloaded from. The leaf area index lai is an important vegetation parameter, which is used widely in many applications.
The values in the the downloaded raw landsat 8 images are so called digital numbers of the sensor. These indices have been widely implemented within rs applications using different airborne and satellite platforms with recent advances using unmanned aerial. Stomatal conductance, canopy temperature, and leaf area index. Calculation by combining multispectral data and insitu measurements use different methods than ones based on highres lidar data or hyperspectral images. 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. 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. 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. Ndwi a normalized difference water index for remote sensing. A multiyear satelliteindependent method based on withinstand normalized difference vegetation index spatial variability g. Leaf area index lai estimation in boreal mixedwood forest of ontario. This ratio can be related to gasvegetation exchange processes such as photosynthesis 1, evaporation and transpiration 24, rainfall interception 5, and carbon flux 68. Investigating laser pulse penetration through a conifer canopy by integrating airborne and terrestrial lidar. Lai directly quantifies canopy structure, and can be used to predict primary productivity and crop growth. 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.
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