{"id":120,"date":"2016-08-01T16:40:44","date_gmt":"2016-08-01T15:40:44","guid":{"rendered":"http:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/?page_id=120"},"modified":"2020-09-24T15:58:38","modified_gmt":"2020-09-24T14:58:38","slug":"4-1-electromagnetic-radiation-and-plants","status":"publish","type":"page","link":"https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/4-electromagnetic-interactions-with-the-earths-surface\/4-1-electromagnetic-radiation-and-plants\/","title":{"rendered":"4.1. Electromagnetic Radiation and Plants"},"content":{"rendered":"<p><strong>Why Plants?<\/strong><\/p>\n<p>Why are we interested in the interaction between EMR and Vegetation? The answer is that it is:<\/p>\n<ul>\n<li>Often the first surface encountered by the energy used for RS<\/li>\n<li>Plants play a vital role in the carbon cycle and thus global warming studies<\/li>\n<li>Plants can are an indirect indicator of geologic conditions and\/or soil genesis\/development<\/li>\n<li>We wish to study plants to know about plant disease, agriculture, forestry and climate change<\/li>\n<\/ul>\n<p>The global distribution of vegetation is shown by this image<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/vegetation.png\" alt=\"vegetation\" width=\"578\" height=\"289\" class=\"alignnone wp-image-631 \" srcset=\"https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/vegetation.png 3000w, https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/vegetation-300x150.png 300w, https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/vegetation-768x384.png 768w, https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/vegetation-1024x512.png 1024w\" sizes=\"auto, (max-width: 578px) 100vw, 578px\" \/><\/p>\n<p>Greens show a covering of vegetation and deserts appear light brown. It is impossible at this scale to identify sub classes of vegetation.<\/p>\n<p><strong>The Effect of Plants on EMR<\/strong><\/p>\n<p>View this presentation, it discusses the effect of plants on the first two of these three types of EMR:<\/p>\n<ol>\n<li>Visible Light<\/li>\n<li>Near Infrared (NIR)<\/li>\n<li>Far Infrared<\/li>\n<\/ol>\n<p><em>N\/B: The slides below will not show on the webpage, but you can save\/keep them on your computer and view them using the Adobe Flash Player 32 you downloaded earlier<\/em><\/p>\n<p><iframe loading=\"lazy\" src=\"http:\/\/www.edshare.soton.ac.uk\/id\/document\/291425\" width=\"640\" height=\"480\"><\/iframe><\/p>\n<hr \/>\n<p><strong>Reflection<\/strong><\/p>\n<p id=\"ta69_8\" class=\"block\">Which of the following features<\/p>\n<ul>\n<li>Leaf Structure<\/li>\n<li>Leaf Age<\/li>\n<li>Water absorption<\/li>\n<li>Chlorophyll absorption<\/li>\n<\/ul>\n<p>are most characteristic in the wavelengths:<\/p>\n<p>Visible, NIR, Far infrared.<\/p>\n<hr \/>\n<p><strong>Measuring Plant Reflectance<\/strong><\/p>\n<p>In this section so far we have examined a number of graphs of reflectance. How are these graphs produced? The answer is a &#8216;spectroradiometer&#8217;. These can be based in multiple locations:<\/p>\n<ul>\n<li>Laboratory: As we&#8217;ve seen so far<\/li>\n<li>Field: To measure reflectance under field conditions, measuring the reflectance at ground level without the effect of the atmosphere on the EMR from ground to instrument<\/li>\n<li>Airborne<\/li>\n<li>Spaceborne<\/li>\n<\/ul>\n<p>Of course the spectra the instrument measures is dependent on the incident radiation so we need to calibrate the measurement by taking a measurement on a white panel with near perfect 100% reflectance at all wavelengths.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/4.2-300x225.jpg\" class=\"alignnone wp-image-123 size-medium\" height=\"225\" width=\"300\" srcset=\"https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/4.2-300x225.jpg 300w, https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/4.2.jpg 661w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/> <img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/4.3-300x225.jpg\" class=\"alignnone wp-image-124 size-medium\" height=\"225\" width=\"300\" srcset=\"https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/4.3-300x225.jpg 300w, https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/4.3.jpg 685w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/p>\n<p>An example of a Radiometer from Southampton&#8217;s Lab: The FieldSpec 3 VNIR<\/p>\n<hr \/>\n<p><strong>Activity<\/strong><\/p>\n<p>Download the <a href=\"http:\/\/edshare.soton.ac.uk\/id\/document\/321300\" target=\"_blank\" rel=\"noopener noreferrer\">Liberty model<\/a> (<span lang=\"EN-GB\">Leaf Incorporating Biochemistry Exhibiting Reflectance and transmittance Yields). <\/span><\/p>\n<p class=\"O\">a] Unzip and run the model. Change the parameters:<\/p>\n<ol>\n<li>Click Parameters &gt; Click the Input file button (above &#8216;Input File&#8217;) to define the output file. Needs to be changed for each run.<\/li>\n<li>Change Parameters as necessary &gt; OK<\/li>\n<li>Now click simulation to run the model<\/li>\n<\/ol>\n<p class=\"O\">b] Simulation runs to complete leaving everything else constant:<\/p>\n<p><i>Chlorophyll:<br \/>\n<\/i>20, 40, 60, 80&#8230;. and at 20 increments until &#8230;.160, 180 and 200<\/p>\n<p><i>Water Content:<br \/>\n<\/i>100, 120, 140 &#8230;. and at 20 increments until &#8230;.260, 280 and 300<\/p>\n<p class=\"O\">c] Import the files into excel\/matlab and plot the spectral reflectances for these parameters<\/p>\n<p class=\"O\">d] Find a wavelength or wavelength range that is sensitive to chlorophyll and plot a graph between chlorophyll concentration and reflectance<\/p>\n<hr \/>\n<div class=\"FreeTextIdevice\" id=\"id72\">\n<div class=\"iDevice emphasis0\">\n<div id=\"ta72_1\" class=\"block\">\n<p><b>Other Factors Effecting Spectral Reflectance of Vegetation<\/b><\/p>\n<p>It is not just the relflectance of the plants themselves that controls the spectral radiation being emitted from a patch of ground, also having an effect:<\/p>\n<ol>\n<li>The reflectance of the soil beneath the plants<\/li>\n<li>Solar and sensor elevation<\/li>\n<li>Canopy geometry<\/li>\n<li>Phenology<\/li>\n<\/ol>\n<hr \/>\n<p><strong>References<\/strong><\/p>\n<p>Dawson, T.P., Curran, P.J. and Plummer, S.E. (1998), LIBERTY &#8211; Modelling the effects of leaf biochemistry on reflectance spectra, <em>Remote Sensing of Environment<\/em>, 65, 50-60.<\/p>\n<p>Jago, R.M., M. E. J. Cutler and P. J. Curran (1999)<br \/>\nEstimating canopy chlorophyll concentration from field and\u00a0airborne spectra. <em>Remote Sensing of Environment<\/em> 68 p217-224<\/p>\n<p>USTIN, S. L., SMITH, M. O., JACQUEMOUD, S., VERSTRAETE, M. and GOVAERTS, Y., 1999, Geobotany: Vegetation mapping for Earth science. In Remote Sensing for the Earth Science: Manual of Remote Sensing, edited by A. N. Rencz, pp. 189-247 (New York: John Wiley &amp;sons, Inc.)<\/p>\n<hr \/>\n<\/div>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>Why Plants? Why are we interested in the interaction between EMR and Vegetation? The answer is that it is: Often the first surface encountered by the energy used for RS Plants play a vital role in the carbon cycle and thus global warming studies Plants can are an indirect indicator of geologic conditions and\/or soil [&hellip;]<\/p>\n","protected":false},"author":1726,"featured_media":0,"parent":118,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-120","page","type-page","status-publish","hentry"],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-json\/wp\/v2\/pages\/120","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-json\/wp\/v2\/users\/1726"}],"replies":[{"embeddable":true,"href":"https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-json\/wp\/v2\/comments?post=120"}],"version-history":[{"count":18,"href":"https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-json\/wp\/v2\/pages\/120\/revisions"}],"predecessor-version":[{"id":880,"href":"https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-json\/wp\/v2\/pages\/120\/revisions\/880"}],"up":[{"embeddable":true,"href":"https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-json\/wp\/v2\/pages\/118"}],"wp:attachment":[{"href":"https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-json\/wp\/v2\/media?parent=120"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}