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キーワード:
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要旨:
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 CO2 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.
