An empirical parameterization of subsurface entrainment temperature for improved SST anomaly simulations in an intermediate ocean model

Rong Hua Zhang, Richard Kleeman, Stephen E. Zebiak, Noel Keenlyside, Stephane Raynaud

Research output: Contribution to journalArticle

Abstract

An empirical model for the temperature of subsurface water entrained into the ocean mixed layer (Te) is presented and evaluated to improve sea surface temperature anomaly (SSTA) simulations in an intermediate ocean model (IOM) of the tropical Pacific. An inverse modeling approach is adopted to estimate Te from an SSTA equation using observed SST and simulated upper-ocean currents. A relationship between Te and sea surface height (SSH) anomalies is then obtained by utilizing a singular value decomposition (SVD) of their covariance. This empirical scheme is able to better parameterize Te anomalies than other local schemes and quite realistically depicts interannual variability of Te, including a nonlocal phase lag relation of Te variations relative to SSH anomalies over the central equatorial Pacific. An improved Te parameterization naturally leads to better depiction of the subsurface effect on SST variability by the mean upwelling of subsurface temperature anomalies. As a result, SSTA simulations are significantly improved in the equatorial Pacific; a comparison with other schemes indicates that systematic errors of the simulated SSTAs are significantly small-apparently due to the optimized empirical Te parameterization. Cross validation and comparisons with other model simulations are made to illustrate the robustness and effectiveness of the scheme. In particular it is demonstrated that the empirical Te model constructed from one historical period can be successfully used to improve SSTA simulations in another.

Original languageEnglish (US)
Pages (from-to)350-371
Number of pages22
JournalJournal of Climate
Volume18
Issue number2
DOIs
StatePublished - Jan 15 2005

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entrainment
parameterization
temperature anomaly
sea surface temperature
anomaly
ocean
simulation
sea surface height
temperature
upper ocean
mixed layer
upwelling
decomposition
modeling
water
comparison

ASJC Scopus subject areas

  • Atmospheric Science

Cite this

An empirical parameterization of subsurface entrainment temperature for improved SST anomaly simulations in an intermediate ocean model. / Zhang, Rong Hua; Kleeman, Richard; Zebiak, Stephen E.; Keenlyside, Noel; Raynaud, Stephane.

In: Journal of Climate, Vol. 18, No. 2, 15.01.2005, p. 350-371.

Research output: Contribution to journalArticle

Zhang, Rong Hua ; Kleeman, Richard ; Zebiak, Stephen E. ; Keenlyside, Noel ; Raynaud, Stephane. / An empirical parameterization of subsurface entrainment temperature for improved SST anomaly simulations in an intermediate ocean model. In: Journal of Climate. 2005 ; Vol. 18, No. 2. pp. 350-371.
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