The influence of climate feedbacks on regional hydrological changes
under global warming
Abstract
The influence of climate feedbacks on regional hydrological changes
under warming is poorly understood. Here, a moist energy balance model
(MEBM) with a Hadley Cell parameterization is used to isolate the
influence of climate feedbacks on changes in zonal-mean
precipitation-minus-evaporation (P-E) under greenhouse-gas forcing. It
is shown that cloud feedbacks act to narrow bands of tropical P-E and
increase P-E in the deep tropics. The surface-albedo feedback shifts the
location of maximum tropical P-E and increases P-E in the polar regions.
The intermodel spread in the P-E changes associated with feedbacks
arises mainly from cloud feedbacks, with the lapse-rate and
surface-albedo feedbacks playing important roles in the polar regions.
The P-E change associated with cloud feedback locking in the MEBM is
similar to that of a climate model with inactive cloud feedbacks. This
work highlights the unique role that climate feedbacks play in causing
deviations from the “wet-gets-wetter, dry-gets-drier” paradigm.