HR: 14:40h
AN: A33B-05    [Abstracts]
TI: The ENSO Signature in Land Surface Photosynthetic Activity
AU: * Knorr, W
AF: Max-Planck Institute for Biogeochemistry, Hans-Kn\"{o}ll-Str. 10, Jena, 07745 Germany
AU: Gobron, N
AF: Institute for Environment and Sustainability (IES) EC Joint Research Centre (JRC), TP 440 Via E. Fermi, 21020, Ispra Italy
AU: Schnur, R
AF: Max-Planck-Institute for Meteorology , Bundesstr. 53, Hamburg, 20146 Germany
AU: Scholze, M
AF: Department of Earth Sciences University of Bristol, Wills Memorial Building, Bristol, BS8 1SS United Kingdom
AU: Pinty, B
AF: Institute for Environment and Sustainability (IES) EC Joint Research Centre (JRC), TP 440 Via E. Fermi, 21020, Ispra Italy
AB: Seasonal climate prediction in the tropics is still based almost entirely on observation and forecasting of the slowly varying ocean state. By comparison, the land surface state has received rather little attention, even though it has response times of weeks to months and can exert similar magnitudes of atmospheric forcing as the oceans. Here, we present 6 years of a global homogeneous satellite FAPAR product describing the fraction of photosynthetically active radiation absorbed by vegetation. Time series are analysed pixel by pixel at 0.5 by 0.5 degree resolution for significant lagged correlations with Nino-3 SST anomalies. We find essentially the same patterns as with gridded monthly climate observations derived from station data, albeit with far more detail. Further, there appears to be a response time of FAPAR against precipitation of 3-5 months. A biosphere model driven with the same climate data reveals a similar response time for biosphere-atmosphere net CO$_2$ fluxes. Such a response time carries the potential of improving seasonal climate predictions. We conclude that global FAPAR observations from satellites represent a source of information that could be used to study ENSO teleconnections on land, and to improve forecasts through assimilation into coupled biosphere-atmosphere models.
DE: 4215 Climate and interannual variability (3309)
DE: 4522 El Ni¤o
DE: 1620 Climate dynamics (3309)
DE: 1640 Remote sensing
DE: 0315 Biosphere/atmosphere interactions
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting