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Rosenqvist, A. 
Multi-spectral Sensors. 
SAR data can be used to map the three CH, sources referred 
temporal monitoring of irrigated rice, as regular acquisitions can 
C-band (Le Toan et al 1997) and L-band (Rosenqvist 1999) SAR 
possible to perform this in an operational way, using current sen 
the near future (ALOS PALSAR, ENVISAT ASAR, Radarsat-2). 
LIDAR. 
The feasibility of using LIDAR to address this issue is not currently known. 
to above. SAR data is particularly suitable for multi- 
be performed irrespectable of the cloud conditions. Both 
have been used to map rice growth, and it is now deemed 
sors (ERS-2 and Radarsat-1) as well as sensors planned in 
2.2 In-Situ Data 
For all applications evaluated in section 3.1 above, up-to-date, quantifiable, in situ data is needed for reliable use of the 
remote sensing data and for thematic validation. A thematic product derived from remote sensing data, be it a land cover 
classification, carbon stock estimate or a "simple" ARD c 
hange map, has no value or credibility unless its accuracy can be 
reliably assessed and quantified. Although collection of field data generally is a painstaking, time consuming and expensive 
endeavour, the relevance of in situ data cannot be overly emphasized. 
In any operational monitoring effort using remote sensing technology performed in support to the Kyoto Protocol, 
systematic collection of in situ data should be performed as an integral part of the undertaking. 
3 RECOMMENDED FUTURE ACTIONS 
From the discussion in the previous section, it is clear that while remote sensing technology is the only technology 
which can provide global scale data acquisition schemes and comparable data sets, it can not yet be considered operational 
in more than a handful applications, relevant to the Kyoto Protocol. To a certain point, this may be due to a lack of 
knowledge of the specific thematic requirements posed by the treaty - which are still to be defined. Nevertheless, the outer 
boundaries that comprise the measurement requirements are to a large extent known already. Furthermore, it is important to 
acknowledge that research should not be limited to attempts that only fulfil the requirements of the Kyoto Protocol, it 
should also address the larger context of global change and reduce uncertainties in the terrestrial carbon budget. The Kyoto 
Protocol, in this sense, should constitute a minimum requirement. 
The following areas of research were identified by the Workshop participants: 
Optical and SAR data fusion 
While both optical and microwave technologies have their specific advantages and disadvantages, fusion of the two 
technologies holds a great potential for enhanced thematic mapping and biomass estimation,. Both technologies have co- 
existed for almost a decade but surprisingly little work has attempted to take advantage of the potential of fusion. 
VCL and synergy with other sensors 
The Vegetation Canopy LIDAR (VCL) holds a specific potential for concrete contributions to the Kyoto Protocol, in 
particular to estimations of above-ground biomass. VCL will be able to collect samples which to a large extent resembles in 
situ data, characterizing canopy structure and canopy height. A first research topic should be focused on developing 
adequate allometric models for a variety of ecosystems (forest types), from which above-ground biomass can be derived. 
À second research topic related to the VCL is synergy with other, spatially extensive, sensors. As VCL will only 
provide data in a sampled manner, extrapolation between VCL sample points should be attempted in synergy with optical or 
SAR data, or a combination of both. JERS-1 SAR (GRFM/GBFM) mosaics at high resolution (100 m) covering the tropical 
and boreal belts for instance provide a potential for fusion, as do regional coverages of Landsat or SPOT data. 
Interferometric, polarimetric and/or multi-frequency SAR applications jn 
SAR interferometry has recently indicated a potential for enhanced biomass sensitivity, even for short wave C-band, 
Which with traditional intensity techniques saturate at very low biomass levels. Interferometric C-band techniques also show 
enhanced capabilities in distinguishing forested and non-forested areas. Interferometric applications should be explored 
further, and if possible, also with other frequencies. 
  
International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B7. Amsterdam 2000. 1283