TY - JOUR
T1 - The transient response of southern ocean circulation to geothermal heating in a global climate model
AU - Downes, Stephanie M.
AU - Hogg, Andrew Mcc
AU - Griffies, Stephen M.
AU - Samuels, Bonita L.
N1 - Publisher Copyright:
© 2016 American Meteorological Society.
PY - 2016
Y1 - 2016
N2 - Model and observational studies have concluded that geothermal heating significantly alters the global overturning circulation and the properties of the widely distributed Antarctic BottomWater. Here two distinct geothermal heat flux datasets are tested under different experimental designs in a fully coupled model that mimics the control run of a typical Coupled Model Intercomparison Project (CMIP) climate model. The regional analysis herein reveals that bottom temperature and transport changes, due to the inclusion of geothermal heating, are propagated throughout the water column, most prominently in the Southern Ocean, with the background density structure and major circulation pathways acting as drivers of these changes. While geothermal heating enhances Southern Ocean abyssal overturning circulation by 20%-50%, upwelling of warmer deepwaters and cooling of upper oceanwaters within theAntarcticCircumpolarCurrent (ACC) region decrease its transport by 3-5 Sv (1 Sv = 106m3 s-1). The transient responses in regional bottom temperature increases exceed 0.1°C. The large-scale features that are shown to transport anomalies far fromtheir geothermal source all exist in the Southern Ocean. Such features include steeply sloping isopycnals, weak abyssal stratification, voluminous southward flowing deep waters and exported bottom waters, the ACC, and the polar gyres. Recently the SouthernOcean has been identified as a prime region for deep oceanwarming; geothermal heating should be included in climate models to ensure accurate representation of these abyssal temperature changes.
AB - Model and observational studies have concluded that geothermal heating significantly alters the global overturning circulation and the properties of the widely distributed Antarctic BottomWater. Here two distinct geothermal heat flux datasets are tested under different experimental designs in a fully coupled model that mimics the control run of a typical Coupled Model Intercomparison Project (CMIP) climate model. The regional analysis herein reveals that bottom temperature and transport changes, due to the inclusion of geothermal heating, are propagated throughout the water column, most prominently in the Southern Ocean, with the background density structure and major circulation pathways acting as drivers of these changes. While geothermal heating enhances Southern Ocean abyssal overturning circulation by 20%-50%, upwelling of warmer deepwaters and cooling of upper oceanwaters within theAntarcticCircumpolarCurrent (ACC) region decrease its transport by 3-5 Sv (1 Sv = 106m3 s-1). The transient responses in regional bottom temperature increases exceed 0.1°C. The large-scale features that are shown to transport anomalies far fromtheir geothermal source all exist in the Southern Ocean. Such features include steeply sloping isopycnals, weak abyssal stratification, voluminous southward flowing deep waters and exported bottom waters, the ACC, and the polar gyres. Recently the SouthernOcean has been identified as a prime region for deep oceanwarming; geothermal heating should be included in climate models to ensure accurate representation of these abyssal temperature changes.
UR - http://www.scopus.com/inward/record.url?scp=84983504638&partnerID=8YFLogxK
U2 - 10.1175/JCLI-D-15-0458.1
DO - 10.1175/JCLI-D-15-0458.1
M3 - Article
SN - 0894-8755
VL - 29
SP - 5689
EP - 5708
JO - Journal of Climate
JF - Journal of Climate
IS - 16
ER -