Evidence of systematic biases in ocean surface heat fluxes simulated by AGCMs Page: 4 of 9
This article is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided to Digital Library by the UNT Libraries Government Documents Department.
The following text was automatically extracted from the image on this page using optical character recognition software:
Prepared for the Proceedings of the WCRP Ocean Surface Flux Workshop
(ECMWF, 31 Oct - 3 Nov, 1995)
Evidence of systematic biases in ocean surface heat
fluxes simulated by AGCMs
1Peter. J. Gleckler and 2David A. Randall
'Program for Climate Model Diagnosis and Intercomparison
Lawrence Livermore National Laboratory
P. O. Box 808, L-264 Livermore, CA 94551
2Department of Atmospheric Sciences
Colorado State University
Fort Collins, CO
The Atmospheric Model Intercomparison Project (AMIP, Gates 1992) has provid-
ed a unique opportunity to evaluate atmospheric general circulation model (AGCM)
simulations made with realistic boundary forcing. Here we report on some results
from AMIP Subproject No. 5, making use of a suite of observationally-based estimates
of ocean surface heat fluxes to evaluate the seasonal cycle of surface heating as sim-
ulated by AGCMs.
To emphasize the points to be made here, we make use of the AGCM simulations
collectively (as opposed to focusing on an individual simulation). The observational
products will be examined in a manner which illustrates the discrepancies between
them. The model results from the 28 AGCMs used here (described by Phillips, 1994)
are all ten year averages. 30 modeling groups have participated in AMIP, but two of
them did not save the surface fluxes.
Here we focus on the dominant heating and cooling terms of the ocean surface
energy balance: the surface net shortwave radiation, SW (heating), and the latent
heat flux, LH (cooling). The objectives of this study are similar to those of Randall
and Gleckler (1995), but our approach is different. Randall and Gleckler utilized the
uncertainty analysis of Gleckler and Weare (1995). Here we evaluate the model sim-
ulations with respect to a range of observational estimates rather than relying on the
uncertainty estimates that were based on a single product. We will find that the con-
clusions drawn from the two studies are fully consistent, namely that despite the very
large unknowns in the observed surface fluxes, they do suggest systematic biases in
fluxes simulated by AGCMs.
2. OBSERVATIONAL PRODUCTS
Three classes of observationally-based estimates will be used here. The first may
be described as 'surface-based' climatologies. To construct these atlases, researchers
have made use of data products (most notably COADS) that consist of measurements
which are routinely made by the voluntary observational fleet of merchant vessels.
The quantities which are measured or estimated are not fluxes (which are inherently
difficult to measure), but rather fields which are more relevant to surface weather
such as surface air temperature, wind speed, etc. Parameterizations have been devel-
oped which enable estimation of surface fluxes with the commonly observed quanti-
Here’s what’s next.
This article can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Article.
Gleckler, P.J. & Randall, D.A. Evidence of systematic biases in ocean surface heat fluxes simulated by AGCMs, article, January 1, 1995; California. (https://digital.library.unt.edu/ark:/67531/metadc667829/m1/4/: accessed April 19, 2019), University of North Texas Libraries, Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.