[ecco-support] [EXTERNAL] ECCO surface boundary conditions: air-sea heat flux terms

[Wang, Ou (US 329B)]

Hello,

In ECCO Version 4, Release 4 (as well as in previous releases 1-3), ERA-Interim long-wave and shortwave fluxes were used as the first guess, and they were subsequently adjusted through optimization.

The sensible and latent heat fluxes were estimated using atmospheric states (e.g., air temperature, specific humidity, etc.) and the ocean state (SST) with the Large and Yeager bulk formula. This provides fluxes more in tune with the model's underlying ocean state than those taken directly from ERA-Interim. As part of this process, we adjusted some atmospheric states through optimization. However, the sensible and latent heat fluxes directly from ERA-Interim could be used, allowing the optimization to adjust them.

Best,
Ou Wang

From: ecco-support <ecco-support-bounces at mit.edu> on behalf of Emily E. Hayden <haydenem at oregonstate.edu>
Date: Friday, September 8, 2023 at 1:30 PM
To: ecco-support at mit.edu <ecco-support at mit.edu>
Subject: [EXTERNAL] [ecco-support] ECCO surface boundary conditions: air-sea heat flux terms
Good afternoon —

I am working with the ECCO dataset to analyze temperature variability and anomalies in the Bering Sea and their relationship to the atmospheric state and I have a few questions about the surface boundary conditions.

In Forget et al. (2015), it says that radiative and turbulent heat fluxes through the free surface are computed using the bulk formula of Large and Yeager (2004) and 6-hourly ERA-Interim fields for the near-surface atmospheric state.

I have a few questions about these surface heat flux terms:


  1.  What upward long wave and shortwave fluxes are used as surface boundary conditions? Are these fields taken directly from ERA-interim, or are they estimated from ocean emissivity and albedo?
  2.  Why are the sensible and latent heat fluxes at the surface estimated from ERA-Interim fields using the Large and Yeager bulk formula? Why are the ERA-Interim fields of latent and sensible heat flux not used directly?

Thank you very much!
--------
Emily E. Hayden
Ph.D. Student | College of Earth, Ocean, and Atmospheric Sciences
National Defense Science and Engineering Graduate Fellow
haydenem at oregonstate.edu






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