The application of remote sensing to pollen based biome and climate reconstructions
by
Simon Brewer
IMEP-CNRS, Centre Universitaire d'Arles, Arles, 13200, France
Coauthors: Basil Davis (IMEP-CNRS)

The reconstruction of Plant Functional Type (PFT) scores and biomes from palaeocological data has become a widely applied technique (eg Biome6000 project). For the European area alone, over 6 different biomisation schemes have been applied for snapshot 6K, 18K and time series reconstructions. Each scheme however can be shown to produce quite different results, irrespective of the influence of the external parameters they are designed to reflect. This does not necessarily mean that one scheme is 'better' than the other, more that different schemes have been designed and validated against different datasets and with different objectives. Validation has involved comparing results from pollen surface samples with Biome model output (potential vegetation), various vegetation maps (both actual and potential), as well as qualitative vegetation descriptions.

This poster shows how high resolution remote sensing data can be used to provide a standardised validation method at a global scale, whilst also at a resolution (1km2) comparable with individual surface samples. Combining information on dominant species, phenology and leaf type, PFT and biome scores can be calculated in a similar way to pollen biomisation. This also provides an intermediate step between pollen data based on actual vegetation and potential vegetation represented by Biome models, which themselves require validation against actual vegetation data.

This method also has a further application in providing a solution to a number of problems in quantitative pollen-climate reconstruction. Using information on both PFT distribution and (for the first time) frequency, it is possible to define the optimum climate space of each PFT at a global scale. Comparison with the climate space sampled within a pollen surface sample dataset can reveal how representative the surface sample data is to the actual PFT climate space. Missing analogues can be located and surface samples collected from these areas. Similarly, missing modern analogues can be found in the modern vegetation by matching fossil pollen samples with their modern PFT equivalent. This allows a proactive targetting strategy for the compilation of surface sample datasets.

Date received: May 15, 2001

Copyright © 2001 by the author(s). The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Conferences Inc. Document # cahi-94.