Volume 1 - The Atmospheric Studies Group at TRC

Winds in the UP.DAT file are given no influence in the boundary layer where the
tracer transport and dispersion takes place.
Over water, the boundary layer structure is characterized by the wind speed, air-sea
temperature difference, relative humidity and vertical temperature gradient listed in
the SEA.DAT file. The overwater mixing height is taken directly from the
SEA.DAT file and treated as an observation. Over land, the boundary layer structure
is characterized by the wind speed and cloud cover listed in the SURF.DAT file,
along with the gridded surface characteristics contained in the geophysical data file
that account for land use variations. The daytime mixing height over land includes
the history of the computed surface fluxes and accounts for the modification of the
temperature structure aloft provided in the UP.DAT file. Note that mixing heights
are modified for advection affects which for on-shore flow typical of these datasets
produces a daytime thermal internal boundary layer (TIBL).
Alternate methods for computing the overwater boundary layer parameters are
selected at each site to explore the sensitivity of model performance to these choices.
The new COARE algorithm option switch (ICOARE) has the following settings:
0: OCD-like original flux model (default)
10: COARE with no wave parameterization (Charnock parameter for the open
ocean, or “deep water” – can be modified for “shallow water”)
11: COARE with wave option 1 (Oost et al., 2002) and default equilibrium wave
properties
-11: COARE with wave option 1 (Oost et al., 2002) and observed wave
properties (provided in revised SEA.DAT input file)
12: COARE with wave option 2 (Taylor and Yelland, 2001) and default
equilibrium wave properties
-12: COARE with wave option 2 (Taylor and Yelland, 2001) and observed wave
properties (provided in revised SEA.DAT input file)
Because observed wave properties are not part of these datasets, options -11 and -12
are not tested. When ICOARE=10, an adjustment to the Charnock constant in the
roughness length can be applied to differentiate between open-ocean (“deep water”)
locations and near-shore (“shallow water”) locations. We test this using both the
original deep water and the proposed shallow water limits to determine if the original
deep-water formulation may be used everywhere. The goal of this endeavor is to
determine if any of these options is able to produce significantly better performance,
thereby guiding the recommendation for configuring this aspect of the COARE
module. Results for each of these options are labeled as 0, 10d, 10s, 11, 12, where
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