Publication Date:
2022-05-25
Description:
Author Posting. © The Author(s), 2016. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Climate Dynamics 48 (2017): 1297–1307, doi:10.1007/s00382-016-3142-3.
Description:
The turbulent air-sea heat
flux feedback (α, in W m-2 K-1) is a major
contributor to setting the damping timescale of sea surface temperature (SST)
anomalies. In this study we compare the spatial distribution and magnitude of
α in the North Atlantic and the Southern Ocean, as estimated from the ERA-Interim reanalysis dataset. The comparison is rationalized in terms of an upper
bound on the heat
flux feedback, associated with \fast" atmospheric export of
temperature and moisture anomalies away from the marine boundary layer, and a
lower bound associated with "slow" export. It is found that regions of cold surface
waters (≤10°C) are best described as approaching the slow export limit. This
conclusion is not only valid at the synoptic scale resolved by the reanalysis data,
but also on basin scales. In particular, it applies to the heat
flux feedback acting
as circumpolar SST anomaly scales are approached in the Southern Ocean, with
feedbacks of ≤10 W m-2 K-1. In contrast, the magnitude of the heat
flux feed-back is close to that expected from the fast export limit over the Gulf Stream and
its recirculation with values on the order of ≈40 W m-2 K-1. Further analysis
suggests that this high value reflects a compensation between a moderate thermo-dynamic adjustment of the boundary layer, which tends to weaken the heat flux
feedback, and an enhancement of the surface winds over warm SST anomalies,
which tend to enhance the feedback.
Description:
Ute Hausmann and John Marshall acknowledge support by the FESD
program of NSF.
Description:
2017-05-04
Keywords:
Sea surface temperature
;
Air-sea interaction
;
Feedback
;
Variability
;
Southern Ocean
;
North Atlantic
Repository Name:
Woods Hole Open Access Server
Type:
Preprint
Permalink
