Rosenqvist, A. 
  
Airborne SAR campaigns and the Shuttle Imaging Radar missions (SIR-C) have shown the potential of polarimetric 
SAR applications for enhanced thematic sensitivity and vegetation structure. With the forthcoming launch of ENVISAT, 
Radarsat-2 and ALOS (all polarimetric), efforts should be made to develop and enhance polarimetric techniques and to 
align them with the requirements posed by the Kyoto Protocol, and other international global change issues. 
Multi-frequency SAR applications is also an area which largely has been overlooked, despite the fact that ERS-] 
(C-band), Radarsat-1 (C-band) and JERS-1 (L-band) have co-existed for several years. As with the polarimetric issue 
above, airborne SAR campaigns and the Shuttle Imaging Radar missions (SIR-C) have shown the potential of multi-band 
SAR, but the issue should be explored further. 
Spaceborne P-band applications 
Ionospheric interference with the radar signal at low frequencies generally prevent the operation of such sensors from 
space. P-band (~ 70 cm wavelength) is the lowest frequency possible to operate from an orbital platform, in which the 
ionospheric effects can be corrected for by the use of a fully polarimetric system and dawn/dusk acquisitions. Although a 
spaceborne P-band system is yet to be launched, airborne P-band SAR data have a proven sensitivity to above ground 
biomass up to some 200 t/ha, which is a significant improvement compared to today's operational C-band and L-band 
systems. It is recommended that research be dedicated to investigating the use of polarimetric P-band for biomass 
estimations and characterization of vegetation structures in a variety of forest ecosystems, initially by the use of available 
airborne platforms. It is also recommended that the necessity of a spaceborne P-band platform in the context of terrestrial 
carbon assessment be investigated not only in a scientific perspective, but also at political and administrative levels. 
Low frequency SAR 
Low-frequency (VHF and UHF band) radar holds a great potential for biomass determination on a local to regional 
scale. While low-frequency radar data have been demonstrated to be free of saturation characteristics up to as much as 400 
t/ha (Imhoff 2000, Ulander et al. 1998), there are several research questions still to addressed. The first concerns the lack of 
applications data. Further tests of low frequency radar systems should be made to fully explore their capabilities for 
biomass retrieval and for potential for soil penetration. Experiments need to be carried out where the number of test sites 
are expanded to include forests that are fully representative of the worlds forests. The possibility of combining VHF and 
UHF band data with LIDAR and/or optical data should also be explored. 
Field measurements and networking 
Establishment of adequate, global scale, data bases of ground truth data is considered essential for the success of using 
remotely sensed data in support of the Kyoto Protocol. Allometric models linking biophysical parameters and forest 
biomass should also be developed. The distribution, geolocation accuracy, revision frequency, biophysical parameters to be 
measured, etc., should be standardized and managed as a part of an international effort (e.g. IGOS, CEOS GOFC). 
4 CONCLUSIONS 
Although political in its nature, the global impact of the Kyoto Protocol on technical and scientific issues of relevance 
for the remote sensing community is considerable and unprecedented. Issues related to the protocol, in particular to 
afforestation, reforestation and deforestation (ARD) activities, will affect the work of the scientific community for years to 
come. Consequently, it is recommended that a considerable part of international remote sensing research activities be 
focused and aligned to fulfil the specific information needs posed by the Kyoto Protocol, and in a broader context, the needs 
relating to full carbon accounting and an improved understanding of the terrestrial carbon budget. Research topics of 
specific relevance, not only related to directly remote sensing but also to the need for adequate in situ information, have 
been identified above. 
Credibility and international acceptance of any methodology proposed as a result of research into the terrestrial carbon 
budget are paramount. As such. the roles of the IPCC and international science programmes and entities, such as 
IGBP, IHDP, WCRP, IUFRO and IIASA, in providing scientific guidance to the Kyoto Protocol, and to encourage 
dialogue, are duly recognized. Dialogue with other national and international entities, such as the World Bank, GEF and 
national development agencies will also be essential for capacity building and technology transfer. 
The ISPRS, being an international organization without national bias, can play a significant role in this context. It is 
therefore proposed that the ISPRS, in particular Commission VII (Resource and Environmental Monitoring), for its next 
mandate period, 2000-2004, forms a dedicated Kyoto Task Force with the aim of promoting and stimulating remote sensing 
research and development aligned with the topics identified above. It is here acknowledged that harmonizing international 
efforts is essential. Therefore the activities recommended by this group should be performed in the context of the 
terrestrial carbon initiative of the IGOS partnership, and co-ordinated closely with the CEOS GOFC Pilot Project, which is 
considered to be of particular importance and relevance in this context. 
  
1284 International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B7. Amsterdam 2000.