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Exact G-functions for various leaf normal distribution functions applied to analytical two-stream radiative transport in turbid vegetation media

Otto, Sebastian and Trautmann, Thomas (2008) Exact G-functions for various leaf normal distribution functions applied to analytical two-stream radiative transport in turbid vegetation media. In: Abstracts Booklet. International Radiation Symposium (IRS) 2008, 2008-08-03 - 2008-08-08, Foz do Iguaçu (Brazil).

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Abstract

In the radiative transfer theory for turbid vegetation media one defines leaf normal distribution (LND) functions to describe the orientation of the model leaves’ normal vectors. For simulation purposes, standard LNDs are frequently assumed, e.g. based on measurements, which have to fulfil a normalisation condition. Unfortunately, the literature reveals various discrepancies with respect to the proper definition of normalised LNDs. So-called G-functions are derived from the LNDs, and thus they are an important part of the radiative transfer equation for turbid vegetation media. Up to now, analytical G-functions have been derived for the most simple LND cases, only. We will revisit the normalisation problem and present an extended set of analytical expressions of G-functions for the most commonly used LNDs, which are then compared to approximations in literature. Moreover, these considerations allow us to extend the two-stream theory in a stringent analytical manner to various LND scenarios ranging from purely horizontal to purely vertical model leaves. Finally, we applied these very fast radiative transfer schemes to simulate canopy reflectances and transmittances as a function of the ratio of direct and diffuse light impinging on the vegetation medium at its upper boundary.

Document Type:Conference or Workshop Item (Poster)
Title:Exact G-functions for various leaf normal distribution functions applied to analytical two-stream radiative transport in turbid vegetation media
Authors:
AuthorsInstitution or Email of Authors
Otto, SebastianUNSPECIFIED
Trautmann, ThomasUNSPECIFIED
Date:August 2008
Journal or Publication Title:Abstracts Booklet
Refereed publication:No
In ISI Web of Science:No
Status:Published
Keywords:G-function, two-stream radiative transfer
Event Title:International Radiation Symposium (IRS) 2008
Event Location:Foz do Iguaçu (Brazil)
Event Type:international Conference
Event Dates:2008-08-03 - 2008-08-08
Organizer:International Radiation Commission (IRC), part of the International Association of Meteorology and Atmospheric Sciences (IAMAS)
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Transport
HGF - Program Themes:Transport System
DLR - Research area:Transport
DLR - Program:V VS - Verkehrssystem
DLR - Research theme (Project):V - Mittel- und langfristige Entwicklung der Personenverkehrsnachfrage (old)
Location: Oberpfaffenhofen
Institutes and Institutions:Remote Sensing Technology Institute > Atmospheric Processors
Deposited By: Sebastian Otto
Deposited On:19 Jan 2009
Last Modified:12 Dec 2013 20:36

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