research data . Dataset . 2016

New method of determination of total amount of chlorophyll in the vegetation crown

I. H. Abdurrahmanova;
Russian
  • Published: 01 Jan 2016
  • Publisher: Theoretical and Applied Ecology
Abstract
Commonly the amount of chlorophyll in leaves can be determined taking into account the reflection spectrum, because the red zone of spectrum is strongly absorbed by chlorophyll. But changes in the red zone of reflection spectrum are low if calculated per unit of chlorophyll measurement upon increase of chlorophyll content. The increase of LAI index leads to increase of content of chlorophyll in the vegetation crown independently from changes of the average amount of chlorophyll in leaves. Chlorophyll a and b absorb less radiation in green spectral zone, as well as in and the «red edge» band. The indices «Chl-G» and «Chl-Re» are more sensitive to changes of leaves chlorophyll content because these indices use green and red spectral zones. Triangular vegetation index (TGI), calculated using a triangle with node points (λn , Rn ), (λr , Rr ) и (λg ,Rg ), Rn is a reflectance coefficient in the near infrared band, , λn , λr and λg are accordingly central wavelengths in near infrared, red and green bands, is characterized by a significantly different dependence on chlorophyll content a+b and on leaf area index. The paper studies the possibility of determination of temporal maximum of total amount of chlorophyll in the vegetation crown with the help of triangular vegetation index. The formula for determination of total amount of chlorophyll in the crown in application to time point of juncture of vegetation and reproduction cycles in the vegetation phenology is derived. It is shown that product Chl × LAI has a maximum of the triangular vegetation index TGI. At the same time the maximums of Chl × LAI depending on TGI coincides with the maximum of Chl × LAI in dependence of current time of phenology cycle Tfen . Therefore, the extremum value of total content of chlorophyll in the vegetation crown during the vegetational cycle can be calculated using TGI index. It is shown that it can simplify significantly the measuring procedures and for that purpose it would be enough to measure the TGI index in the temporal sequence of vegetational cycle or normalized difference of measured spectral values in two spectral bands.
Persistent Identifiers
Subjects
free text keywords: vegetation, chlorophyll, spectrum, vegetation index, remote sensing, triangular index
Communities
  • Rural Digital Europe
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