THE FRENCH SPACE PROGRAMME FOR EARTH OBSERVATION : 
SPACE MISSIONS FOR BIOSPHERE STUDIES 
Th. PHULPIN and M. CHEVREL* 
Centre National d'Etudes Spatiales 
Programme Directorate/Earth Observation 
18 avenue E. Belin 
31055 TOULOUSE Cedex 
FRANCE 
* 2 place Maurice Quentin 
75001 PARIS cedex 02 
ABSTRACT: 
The French Programme for Earth observation aims at providing remote sensing data for reserach or 
applications in the domains of atmosphere, ocean or land. It is conducted in the framework of bilateral 
cooperations or within the European Space Agency optional programme. Its main axis is to set up or maintain 
series of instruments to offer a continuity in the data for a long tune. The SPOT programme, with SPOT2 and 3 
presently operational, will be purshued with SPOT-4 launched in 1997 wich will exhibit several improved 
capabilities for vegetation studies (HRVTR with an additional channel at 1.6 pm). In particular the wide field of 
view VEGETATION instrument will permit a daily global observation at 1km resolution, in channels similar to 
HRVIR. The SPOT-5 satellite presently under study will have a higher spatial resolution and an adavanced 
stereoscopic capability. 
Experimental systems are also planned in a near future or still under study. POLDER onboard ADEOS 
japenese satellite will permit studies of polarized bidirectional signatures of terrestrial targets. In addition, 
IRSUTE, a high spatial resolution multichannel thermal infrared radiometer to be embarked onboard a small 
satellite will be studied in 1994. . All these systems are presented with a description of the specified 
performances and the main products expected. 
1 - INTRODUCTION 
In the domain of vegetation monitoring the main scientific objectives belong to the following categories : 
- land use mapping : 
• for surface estimates in agriculture, but also for land cover change monitoring, local environment 
monitoring (fires.etc.),etc. 
• for derivation of maps of model parameters (i.e Phulpin et al, 1988) 
- estimation of quantitative products. They are : 
• the Net Primary Production (NPP), giving access to crop yields, pastures or timbers productions.etc. 
• descriptors of vegetation functioning for a better understanding of the connexions between vegetation and 
climate, 
• the fluxes of matter (water, carbon, nitrogen, etc.) and energy (Rn, LE, H,etc.) between ground , vegetation 
and atmosphere. This could find applications in meteorology (refining the water cycle description in 
mesoscale to global scale models), in hydrology or agriculture (water management). 
These products may be accessible directly or through the determination of physical variables whose values can 
be more or less validated by means of ground truth. They are for instance : total biomass, vegetation height, 
average leaf area index, fractional cover, APAR, Surface Temperature, surface Humidity, roughness,etc. These 
physical variables are inputs of models predicting crop production (i.e Maas, 1988), or of ecophysiologic 
models (i.e Running et al, 1989 ), these being fed with other kinds of data (meteorological network data, 
information on water management, on agricultural process, DEM, etc.) which are essential to optimize the use 
of satellite data. 
Two categories of users can be distinguished : 
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