Changes in global ocean bottom properties and volume transports in CMIP5 models under climate change scenarios

Heuzé, Céline, Heywood, Karen J. ORCID: https://orcid.org/0000-0001-9859-0026, Stevens, David P. ORCID: https://orcid.org/0000-0002-7283-4405 and Ridley, Jeff K. (2015) Changes in global ocean bottom properties and volume transports in CMIP5 models under climate change scenarios. Journal of Climate, 28 (8). 2917–2944. ISSN 0894-8755

Preview

PDF (Accepted_manuscript_version) - Accepted Version Download (11MB) | Preview

Abstract

Changes in bottom temperature, salinity and density in the global ocean by 2100 for CMIP5 climate models are investigated for the climate change scenarios RCP4.5 and RCP8.5. The mean of 24 models shows a decrease in density in all deep basins except the North Atlantic which becomes denser. The individual model responses to climate change forcing are more complex: regarding temperature, the 24 models predict a warming of the bottom layer of the global ocean; in salinity, there is less agreement regarding the sign of the change, especially in the Southern Ocean. The magnitude and equatorward extent of these changes also vary strongly among models. The changes in properties can be linked with changes in the mean transport of key water masses. The Atlantic Meridional Overturning Circulation weakens in most models and is directly linked to changes in bottom density in the North Atlantic. These changes are due to the intrusion of modified Antarctic Bottom Water, made possible by the decrease in North Atlantic Deep Water formation. In the Indian, Pacific and South Atlantic, changes in bottom density are congruent with the weakening in Antarctic Bottom Water transport through these basins. We argue that the greater the 1986-2005 meridional transports, the more changes have propagated equatorwards by 2100. However, strong decreases in density over 100 years of climate change cause a weakening of the transports. The speed at which these property changes reach the deep basins is critical for a correct assessment of the heat storage capacity of the oceans as well as for predictions of future sea level rise.

Item Type:	Article
Uncontrolled Keywords:	sdg 13 - climate action ,/dk/atira/pure/sustainabledevelopmentgoals/climate_action
Faculty \ School:	Faculty of Science > School of Mathematics (former - to 2024) Faculty of Science > School of Environmental Sciences University of East Anglia Research Groups/Centres > Theme - ClimateUEA
UEA Research Groups:	Faculty of Science > Research Groups > Marine and Atmospheric Sciences (former - to 2017) Faculty of Science > Research Groups > Meteorology, Oceanography and Climate Dynamics (former - to 2017) Faculty of Science > Research Groups > Climate, Ocean and Atmospheric Sciences (former - to 2017) Faculty of Science > Research Groups > Centre for Ocean and Atmospheric Sciences Faculty of Science > Research Groups > Fluid and Solid Mechanics (former - to 2024) Faculty of Science > Research Groups > Fluids & Structures Faculty of Science > Research Groups > Numerical Simulation, Statistics & Data Science
Depositing User:	Pure Connector
Date Deposited:	19 Feb 2015 14:16
Last Modified:	07 Nov 2024 12:38
URI:	https://ueaeprints.uea.ac.uk/id/eprint/52356
DOI:	10.1175/JCLI-D-14-00381.1

Downloads

Actions (login required)

View Item