Estimates of air–sea feedbacks on sea surface temperature anomalies in the southern ocean
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Published version
Author(s)
Hausmann, U
Czaja, A
Marshall, J
Type
Journal Article
Abstract
Sea surface temperature (SST) air–sea feedback strengths and associated decay time scales in the Southern Ocean (SO) are estimated from observations and reanalysis datasets of SST, air–sea heat fluxes, and ocean mixed layer depths. The spatial, seasonal, and scale dependence of the air–sea heat flux feedbacks is mapped in circumpolar bands and implications for SST persistence times are explored. It is found that the damping effect of turbulent heat fluxes dominates over that due to radiative heat fluxes. The turbulent heat flux feedback acts to damp SSTs in all bands and spatial scales and in all seasons, at rates varying between 5 and 25 W m−2 K−1, while the radiative heat flux feedback has a more uniform spatial distribution with a magnitude rarely exceeding 5 W m−2 K−1. In particular, the implied net air–sea feedback (turbulent + radiative) on SST south of the polar front, and in the region of seasonal sea ice, is as weak as 5–10 W m−2 K−1 in the summertime on large spatial scales. Air–sea interaction alone thus allows SST signals induced around Antarctica in the summertime to persist for several seasons. The damping effect of mixed layer entrainment on SST anomalies averages to approximately 20 W m−2 K−1 across the ACC bands in the summer-to-winter entraining season and thereby reduces summertime SST persistence to less than half of that predicted by air–sea interaction alone (i.e., 3–6 months).
Date Issued
2015-10-28
Date Acceptance
2015-10-09
Citation
Journal of Climate, 2015, 29 (2), pp.439-454
ISSN
1520-0442
Publisher
American Meteorological Society
Start Page
439
End Page
454
Journal / Book Title
Journal of Climate
Volume
29
Issue
2
Copyright Statement
© 2016 American Meteorological Society
Subjects
Science & Technology
Physical Sciences
Meteorology & Atmospheric Sciences
Geographic location
entity
Southern Ocean
Circulation
Dynamics
Atmosphere-ocean interaction
Atm
Ocean Structure
Phenomena
Sea surface temperature
Variability
Climate variability
HEAT-FLUX FEEDBACK
OZONE HOLE
HEMISPHERE
VARIABILITY
MODELS
REANALYSIS
TRANSPORT
ATLANTIC
0401 Atmospheric Sciences
0405 Oceanography
Publication Status
Published