Remote sensing for resources development and environmental management: Remote sensing for resources development and environmental management

Damen, M. C. J.

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Multivolume work

Persistent identifier:: 856342815

Title:: Remote sensing for resources development and environmental management

Sub title:: proceedings of the 7th international Symposium, Enschede, 25 - 29 August 1986

Year of publication:: 1986

Place of publication:: Rotterdam; Boston

Publisher of the original:: A. A. Balkema

Identifier (digital):: 856342815

Language:: English

Additional Notes:: Volume 1-3 erschienen von 1986-1988

Editor:: Damen, M. C. J.

Document type:: Multivolume work

Volume

Persistent identifier:: 856343064

Title:: Remote sensing for resources development and environmental management

Sub title:: proceedings of the 7th international Symposium, Enschede, 25 - 29 August 1986

Scope:: XV, 547 Seiten

Year of publication:: 1986

Place of publication:: Rotterdam; Boston

Publisher of the original:: A. A. Balkema

Identifier (digital):: 856343064

Illustration:: Illustrationen, Diagramme

Signature of the source:: ZS 312(26,7,1)

Language:: English

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

Editor:: Damen, M. C. J.

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:: 3 Spectral signatures of objects. Chairman: G. Guyot, Liaison: N. J. J. Bunnik

Document type:: Multivolume work

Structure type:: Chapter

Chapter

Title:: Spectral and botanical classification of grasslands: Auxois example. C. M. Girard

Document type:: Multivolume work

Structure type:: Chapter

Symposium on Remote Sensing for Resources Development and Environmental Management / Enschede / August 1986 269 Spectral and botanical classification of grasslands: Auxois example C.M.Girard Institut National Agronomique, Paris-Grignon, France ABSTRACT:The author has performed botanical observations in the field, and in situ reflectance measurements over a French test-site at four different periods during the growing season.Factorial analysis of botanical relevés leads to agroecological units definition which are then spectrally characterized. RESUME: Des observations botaniques et des mesures de réflectance sur le terrain ont été réalisées sur une zone-test française à quatre différentes périodes.L'analyse factorielle des relevés conduit à la définition d'unités agroécologiques qui font ensuite l'objet d'une caractérisation spectrale saisonnière. 1 INTRODUCTION Grasslands have been less studied than crops because of their less direct economical value: they corres pond mainly to a domestic use, and of their greater complexity in terms of species, canopy structure, phenological stages. Till now the main works per formed on grasslands concern: 1. Mapping of grasslands,or rangeland units through aerial photographies or satellite data( Everitt and all 1985, Brown and all 1983...) 2. Evaluation of green biomass or forage produc tion from spectral measurements in the field(Grou- zis and all 1983, Thalen and all 1980, Richardson and all 1983...) or from multispectral photography or MSS data (Curran 1983, Tucker and all 1983 *..) The work presented here has for aim to determine a methodology enabling to classify grasslands on behalf of their botanical composition and their reflectance behaviour in order to better use remote sensina data for their evaluation and monitoring. 2 MATERIAL AND METHODS This research was based on 98 botanical stations of grasslands situated in Auxois(Cote d'Or, France) test-site of 220 sc km centered on the citv of Vitteaux (47° 24'- 4° 33'). The area is characterized bv a temperate climate with a sub-montainous tendancv. Winters are wet and fresh while summers are moist and hot. Geomorphology is characterized by plateaux cut by valleys oriented NNW-SSE. Plateaux correspond to calcareous rocks, while val leys and their flanks correspond to marl covered by more or less deep colluvium deposits. Crops are located on plateaux or on alluvial cones grasslands occupy flanks and bottom of the valleys. Soils vary according to slope but are mainly brown soils. Their characteristics important for grasslands are: depth and water capacity. Soils on top of the flanks are shallow with low water capacity, while soils in the bottom of the valleys are deep with high water capacity and hydromorphic features. Data were collected from mid-April to mid-July du ring 1980, 1981, 1982, 1983 and completed in 1984, 1985, in order to survey the period of maximum vege tation. The stations area vary from 25 to 60 sq m. Botanical data were collected according the phyto- sociological method (Guinochet 1973). Present species abundancy is noted according to Braun-Blanquet's coefficients (Braun-Blanquet 1925), as well as phe nological stages for the more abundant species. Spectral data were collected using an ISCO SR 140 spectroradiometer, mounted on a rigid support at 1.5 m high.This spectroradiometer works in the visible: 380- 750 nm with a 25 nm spectral resolution, and in the near infra-red:750- 1450 nm with a 50 nm spec tral resolution.Its field of view is of approximately 100°. It enables to measure grassland exitance:M. Solar ir- radiance is measured by the same spectroradiometer and we worked on reflectance: R=M/E. Spectral data were collected mainly on clear sunny days during midday hours. They were referenced to a barium sulfate calibration panel approximately each 30 mn. Both botanical and spectral data were handled using principal component analysis.(PCA). 3 RESULTS 3.1 Botanical data Numerical handling of botanical data enabled to rela te grasslands stations to the following phyto sociolo- gical alliances: Xerobromion erecti Br.Bl et Moor 38, Cynosurion cristati Tx. 47, and Agropyro-rumicion crispi North 40, corresponding respectively to: xerophilous natural rangelands, mesophile or mesohyg- rophile grasslands, and wet grasslands. But we continued this analysis keeping only the more abundant species.This is justified by the fact that the agronomical value of grasslands is depen dent on the more abundant species and their area coverage. Abundancy coefficients were converted in per cent coverage (Van der Maarel 1979),and a PCA was perfor med with all relevés at each period (April, May, June, July) for the 26 more abundant species. Relevés cluster in 8 units called agro-ecological units which are characterized by species and their varying coverage through time, they correspond to various soil characteristics : depth, water regime, trophic level, pH... (Figure 1). Table 1 gives a model for analyzing phytosociologi cal relevés according to abundancy of different spe cies through spring. This model is used for grass lands in calcareous Burgundy and may be extended to other temperate areas with slight modifications. It has been validated with three stations situated in a neiahbouring area and which wi 11 serve for testing the spectral behaviour model.

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