Open AccessCan Oceanic Freshwater Flux Amplify Global Warming?
Author(s) -
Liping Zhang,
Lixin Wu
Publication year - 2012
Publication title -
journal of climate
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.315
H-Index - 287
eISSN - 1520-0442
pISSN - 0894-8755
DOI - 10.1175/jcli-d-11-00172.1
Subject(s) - environmental science , global warming , climatology , climate model , precipitation , advection , sea surface temperature , water cycle , atmospheric sciences , subtropics , latitude , flux (metallurgy) , middle latitudes , climate change , oceanography , geology , meteorology , geography , ecology , physics , materials science , geodesy , biology , metallurgy , thermodynamics
The roles of freshwater flux (defined as evaporation minus precipitation) changes in global warming are studied using simulations of a climate model in which the freshwater flux changes are suppressed in the presence of a doubling of CO 2 concentration. The model simulations demonstrate that the warm climate leads to an acceleration of the global water cycle, which causes freshening in the high latitudes and salinification in the subtropics and midlatitudes. It is found that the freshwater flux changes tend to amplify rather than suppress global warming. Over the global scale, this amplification is largely associated with high-latitude freshening in a warm climate, which leads to a shoaling of the mixed layer depth, a weakening of the vertical mixing, and thus a trapping of CO 2 -induced warming in the surface ocean. The latitudinal distribution of SST changes due to the effects of freshwater flux changes in a warm climate is complicated, involving anomalous advection induced by both salinity and wind stress changes. In addition, atmospheric feedbacks associated with global warming also amplify the SST warming.