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Title: Towards the remote sensing of foliar biochemical content
Author: Smith, Geoffrey Malcolm
Awarding Body: University College of Swansea
Current Institution: Swansea University
Date of Award: 1995
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This study was divided into two main sections; an examination the performance of the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) and attempts to use the imaging spectrometer to estimate foliar biochemical contents over an area of forest. To examine instrument performance the SNR required to estimate foliar biochemical contents from reflectance data was estimated by using laboratory reflectance spectra of vegetation and random noise. A number of methods were used to estimate the SNR of the AVIRIS based on estimates of noise from the instrument and the data. It was concluded that while in 1992 the AVIRIS had barely sufficient SNR to estimate foliar biochemical contents this was no longer a problem. The AVIRIS collected imagery of a forested study site in north central Florida in March and September 1990 and July 1992. These data were used in two attempts to estimate foliar biochemical content. The first attempt used wavebands in the reflectance data which were known to be related to foliar nitrogen, lignin and cellulose contents. This analysis identified the large noise component within the 1990 AVIRIS data and also problems with the repeatability of the AVIRIS when collecting images of the same area only a few minutes apart. It did, however, indicate that some information related to foliar nitrogen contents was being recorded by the AVIRIS. The second attempt used wavebands in the reflectance data that were selected on the basis of a statistical comparison with the foliar chlorophyll, nitrogen, lignin and cellulose contents. Prediction equations were developed which indicated strong relationships between reflectance and foliar biochemical content at the study plots but the extrapolation of the relationships across the study site was less certain. Temporal averaging of the reflectance data was required to increase the SNR before the elevated foliar biochemical contents of the study plots could be identified. From the study it was concluded that while it was possible to estimate foliar biochemical contents of vegetation canopies with reflectance data, in future instruments were required with larger SNRs and simple study sites were required where the interaction of radiation with vegetation canopies could be completely understood.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available