Data/hora: 09/06/2024 06:02:38

Provedor de dados: | 5
País: | France
Título: | Surging of global surface temperature due to decadal legacy of ocean heat uptake
Autores: | Sinha, Bablu; Sévellec, Florian; Robson, Jon; Nurser, George.
Data: | 2020-09
Ano: | 2020
Resumo: | Global surface warming since 1850 consisted of a series of slowdowns (hiatus) followed by surges. Knowledge of a mechanism to explain how this occurs would aid development and testing of interannual to decadal climate forecasts. In this paper a global climate model is forced to adopt an ocean state corresponding to a hiatus (with negative Interdecadal Pacific Oscillation, IPO, and other surface features typical of a hiatus) by artificially increasing the background diffusivity for a decade before restoring it to its normal value and allowing the model to evolve freely. This causes the model to develop a decadal surge which overshoots equilibrium (resulting in a positive IPO state) leaving behind a modified, warmer climate for decades. Water mass transformation diagnostics indicate that the heat budget of the tropical Pacific is a balance between large opposite signed terms: surface heating/cooling due to air-sea heat flux is balanced by vertical mixing and ocean heat transport divergence. During the artificial hiatus, excess heat becomes trapped just above the thermocline and there is a weak vertical thermal gradient (due to the high artificial background mixing). When the hiatus is terminated, by returning the background diffusivity to normal, the thermal gradient strengthens to pre-hiatus values so that the mixing (diffusivity x thermal gradient) remains roughly constant. However, since the base layer just above the thermocline remains anomalously warm this implies a warming of the entire water column above the trapped heat which results in a surge followed by a prolonged period of elevated surface temperatures.
Tipo: | Text
Idioma: | Inglês

Identificador:

https://archimer.ifremer.fr/doc/00624/73629/73066.pdf

DOI:10.1175/JCLI-D-19-0874.1

https://archimer.ifremer.fr/doc/00624/73629/

Editor: | American Meteorological Society
Formato: | application/pdf
Fonte: | Journal Of Climate (0894-8755) (American Meteorological Society), 2020-09 , Vol. 33 , N. 18 , P. 8025-8045

Fonte:

info:eu-repo/semantics/openAccess

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