Jung-Eun Lee, Benjamin R. Lintner, J. David Neelin, Xianan Jiang, Pierre Gentine, C. Kevin Boyce, Joshua B. Fisher, J. Taylor Perron, Terence L. Kubar, Jeonghoon Lee, and John Worden Geophys. Res. Lett., 39, LXXXXX, doi:10.1029/2012GL053417.
Abstract
Tropical rainforests are known to exhibit low intraseasonal
precipitation variability compared with oceanic areas
with similar mean precipitation in observations and models.
In the present study, the potential role of transpiration for
this difference in precipitation variability is investigated
using the National Center for Atmospheric Research
(NCAR) atmospheric general circulation model. Comparing
model results with and without transpiration shows that in
the absence of transpiration, mean precipitation decreases as
may be expected. However the incidence of both higher
daily total column water and more intense precipitation
increases without transpiration; consequently the variability
of precipitation increases substantially. These results can be
understood in terms of the complex interplay of local near-
surface and remote moist dynamical processes with both
local positive (boundary-layer drying) and large-scale negative
(increased large-scale convergence) feedbacks when
transpiration is disabled in the model. It is also shown that
surface turbulent fluxes over tropical rainforests are highly
correlated with incoming solar energy but only weakly correlated
with wind speed, possibly decoupling land precipitation
from large-scale disturbances like Madden-Julian Oscillation.
Citation Reduction of tropical land region precipitation variability via transpiration. Lee, J.-E., B. R. Lintner, J. D. Neelin, X. Jiang, P. Gentine, C. K. Boyce, J. B. Fisher, J. T. Perron, T. L. Kubar, J. Lee, and J. Worden. Geophys. Res. Lett., 39, LXXXXX, doi:10.1029/2012GL053417.