Ning Zeng, Katrina Hales, and J. David Neelin
J. Climate, 15, 3474-3487, 2002.
Paper (PDF 433KB).
© Copyright 2002 by the American Meteorological Society.
Abstract. Although the global vegetation distribution is largely controlled by large-scale climate pattern, the observed vegetation-rainfall relationship is also influenced by vegetation feedback and climate variability. Using a simplified coupled atmosphere-vegetation model, this work focuses on the effects of these on the gradient of desert-forest transition. A positive feedback from interactive vegetation leads to a wetter and greener state everywhere compared to a state without vegetation. As a result, the gradient in vegetation and rainfall is enhanced at places with moderate rainfall. Climate variability is found to reduce vegetation and rainfall in moderate to high rainfall regions, while enhancing them in low rainfall regions, thus smoothing out the desert to savanna gradient. This latter effect is due to the nonlinear vegetation response to precipitation. The analyses explain results from a three-dimensional climate model. The results suggest that in a varying environment, vegetation plays an active role in determining the observed vegetation-rainfall distributions.
Citation. Zeng, N., K. Hales, and J. D. Neelin, 2002: Nonlinear dynamics in a coupled vegetation-climate system and implications for desert-forest gradient. J. Climate, 15, 3474-3487.
Acknowledgments.
This research was supported by NSF Grants ATM-0196210,
ATM-0082529, and NOAA Grant NA86GP0314.
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