Proceedings of the Symposium on Global and Environmental Monitoring: Proceedings of the Symposium on Global and Environmental Monitoring

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Multivolume work

Persistent identifier:: 856665355

Title:: Proceedings of the Symposium on Global and Environmental Monitoring

Sub title:: techniques and impacts ; September 17 - 21, 1990, Victoria Conference Centre, Victoria, British Columbia, Canada

Year of publication:: 1990

Place of publication:: Victoria, BC

Publisher of the original:: [Verlag nicht ermittelbar]

Identifier (digital):: 856665355

Language:: English

Document type:: Multivolume work

Volume

Persistent identifier:: 856669164

Title:: Proceedings of the Symposium on Global and Environmental Monitoring

Sub title:: techniques and impacts; September 17 - 21, 1990, Victoria Conference Centre, Victoria, British Columbia, Canada

Scope:: XIV, 912 Seiten

Year of publication:: 1990

Place of publication:: Victoria, BC

Publisher of the original:: [Verlag nicht ermittelbar]

Identifier (digital):: 856669164

Illustration:: Illustrationen, Diagramme, Karten

Signature of the source:: ZS 312(28,7,1)

Language:: English

Usage licence:: Attribution 4.0 International (CC BY 4.0)

Editor:: International Society for Photogrammetry and Remote Sensing, Commission of Photographic and Remote Sensing Data

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2016

Document type:: Volume

Collection:: Earth sciences

Chapter

Title:: [WP-4 INTERPRETATION AND MODELLING]

Document type:: Multivolume work

Structure type:: Chapter

Chapter

Title:: A GLOBAL TRIANGLE MODEL FOR CHARACTERIZING VEGETATION IN RELATION TO ITS ECOLOGICAL ENVIRONMENT. Li Jiang

Document type:: Multivolume work

Structure type:: Chapter

A GLOBAL TRIANGLE MODEL FOR CHARACTERIZING VEGETATION IN RELATION TO ITS ECOLOGICAL ENVIRONMENT Li Jiang (Arizona Remote Sensing Center, University of Arizona, Tucson, AZ) Abstract This study is to propose a global triangle model based on the characteristics of data structure observed in the thermal and NDVI spectral spaces of NOAA- AVHRR data. The development of the global triangle model is an attempt to study vegetation in relation to its ecological environment, and to understand the Earth as an integrated system. — A scatter plot was produced with data from channel 2 and 4 of the NOAA- AVHRR scene of January 3, 1989, (Figure 1). Figure 1 is a "global view" of the West Africa in the near and thermal infrared (NIR and TIR) space. The view observed looks like a huge triangle containing a variety of plants, soils, and land surface covers. Similar triangle shape has been observed in five AVHRR data-sets of West Africa acquired on January 3 and 23, February 11 and 22, and march 23, 1989. This same phenomena was observed when scenes were cut in half but still contained the various African landscapes. The triangle was also observed using AVHRR bands 2 and 5 in a similar fashion as observed using bands 2 and 4, since bands 4 and 5 are both thermal channels performing in adjoining spectral ranges of 10.5 - 11.5 pm, and 11.5 - 12.5 pm respectively. Four small sites(ocean, bare soil, dry grassland, and dense vegetation) selected based on visual interpretation of the image and NDVI value were used to make separate scattergraphs as illustrated in Figure 1 and 2. Soils occur at the bottom left corner of the triangle where minimum vegetation and high temperature are usual the case. The vegetation points lay at the top of the triangle where the pixels are characterized by high vegetation and relative low temperature. All water pixels crowd around the bottom right comer of the triangle where temperature and vegetation are both minimal. If the near-infrared band is replaced with a NDVI band, the scattergraph still looks like a triangle, but changes in shape and orientation become apparent. It can be seen from Figure 2, the global triangle is rotated clockwise in the NDVI and band 4 spectral plane. The high vegetation corner is tilted towards lower temperature regions, which is often true because of the cooling effect of green vegetation. The desert corner is lifted a little above the water comer since some vegetation, more or less, is always found in desert areas. The basic relationship and distribution of the triangular structure stay the same, and the thermal and NDVI model looks more reasonable than the triangle observed in the TIR and NIR space. A possible explanation for this improvement is that the NDVI is a better vegetation indicator than the near-infrared band alone. The DN values of deep ocean from the thermal bands were found to be quite constant both spatially and temporally, and may be used as a reference for comparison across time and space for vegetation and terrain analysis. DN values of desert areas vary greatly from day to day and from day to night, (Figure 4 and

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