Abstract
AbstractThe land–atmosphere interaction for reference and future climate is estimated with a regional climate model ensemble. In reference climate, more than 50% of the models show interaction in southeastern South America during austral spring, summer and autumn. In future climate, the region remains a strong hotspot although somewhat weakened due to the wet response that enhance energy limitation on the evapotranspiration. The region of the Brazilian Highlands and Matto Grosso appears as a new extensive hotspot during austral spring. This is related to a dry response which is probably accentuated by land surface feedbacks.
Highlights
On a monthly to seasonal time scale, soil moisture (SM) has potential to be a low-frequency modulator of climate because of its influence on the partitioning of heat fluxes and its long memory (e.g. Eltahir, 1998)
Has provided the first coordinated ensemble of regional climate models (RCMs) climate change simulations over the South
The ensemble, which covers the period 1961–2100, is designed to span uncertainty of climate change scenarios using several RCMs forced by lateral boundary conditions and sea surface temperature from different global climate model (GCM), for the emission scenario
Summary
On a monthly to seasonal time scale, soil moisture (SM) has potential to be a low-frequency modulator of climate because of its influence on the partitioning of heat fluxes and its long memory (e.g. Eltahir, 1998). Forecasts could be improved by including estimates of SM for the regions and seasons where this variable exerts a control on the atmosphere. For SM to control precipitation (PP), the evapotranspiration (ET) regime has to be limited by SM rather than by radiation. The radiation (or energy)-limited ET regime dominates in wet regions where the moisture stress is low and variability of SM does not affect ET. SM availability is a first-order constraint on ET (e.g. Koster et al, 2004), but in very dry areas, SM does not affect PP because ET variability is too weak to induce PP generation. Regions where SM exerts control on PP tend to appear over transitions zones between dry and wet climates (Koster et al, 2004). A changing climate could alter these regimes due to increasing temperatures and altered PP amounts and temporal distribution
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