Ning Zeng, Katrina Hales, and J. David Neelin
J. Climate, 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.