is the correct surface-layer interpretation of z0. Thus,
Andreas, E.L (1987) A theory for the scalar roughness
we see that--as in the surface layer--finding the geo-
and the scalar transfer coefficients over snow and sea
ice. Boundary-Layer Meteorology, 38: 159184.
strophic drag coefficient at neutral stability is tantamount
to finding the effective roughness length, and vice
Andreas, E.L (1988) Estimating averaging times for point
versa.
and path-averaged measurements of turbulence spectra.
Journal of Applied Meteorology, 27: 295304.
Andreas, E.L (1995a) Air-ice drag coefficients in the
SUMMARY
Several good problems in the atmospheric boundary
western Weddell Sea: 2. A model based on form drag
and drifting snow. Journal of Geophysical Research, 100:
layer over sea ice still exist. I have highlighted a few of
these. One is to investigate turbulent exchange and the
48334843.
turbulence statistics in the atmospheric surface layer in
Andreas, E.L (1995b) A physically based model of the
stable conditions. A related study is to narrow the uncer-
form drag associated with sastrugi. USA Cold Regions
tainty in the nondimensional gradient functions, φm and
Research and Engineering Laboratory, CRREL Report
φh, for stable conditions (see Fig. 5). Efforts here would
95-16.
benefit not only polar scientists but boundary-layer
Andreas, E.L and K.J. Claffey (1995) Air-ice drag coef-
meteorologists everywhere. The stable boundary layer
ficients in the western Weddell Sea: 1. Values deduced
from profile measurements. Journal of Geophysical Re-
is seldom in quasi-steady-state at lower latitudes; con-
search, 100: 48214831.
sequently, obtaining robust statistics in stable stratifica-
tion is more difficult here than it is in the polar regions.
Andreas, E.L and B. Murphy (1986) Bulk transfer coef-
Another good problem is to devise a new parameter-
ficients for heat and momentum over leads and polyn-
ization for CDN10 in terms of some measurable surface
yas. Journal of Physical Oceanography, 16: 18751883.
properties that--preferably--can be sensed remotely.
Andreas, E.L, W.B. Tucker III and S.F. Ackley (1984)
The relation from Banke et al. (1980) (eq 111) is quite
Atmospheric boundary-layer modification, drag coeffi-
suggestive but evidently impractical in light of my re-
cient and surface heat flux in the Antarctic marginal ice
cent work on how drifting snow can rapidly alter CDN10.
zone. Journal of Geophysical Research, 89: 649661.
A related issue is obtaining good measurements of
Andreas, E.L, K.J. Claffey and A.P. Makshtas (1993a)
CHN10 and CEN10 over sea ice. These are conspicuous
Low-level jets and inversions on Ice Station Weddell 1.
Antarctic Journal of the United States, 28(5): 274276.
by their absence from the literature. The primary reason
for the scanty number of observations is that the forcing
Andreas, E.L, M.A. Lange, S.F. Ackley and P. Wadhams
terms Ts Θr and Qs Qr necessary to compute CHNr
(1993b) Roughness of Weddell Sea ice and estimates of
and CENr are small over sea ice and notoriously diffi-
the air-ice drag coefficient. Journal of Geophysical Re-
search, 98: 12,43912,452.
cult to measure. It may, thus, be time to revise our typical
measurement practices or to rethink the entire method of
Andreas, E.L, K.J. Claffey and A.P. Makshtas (1995)
parameterizing sensible and latent heat fluxes over sea ice
Low-level atmospheric jets over the western Weddell Sea.
In Preprint Volume, Fourth Conference on Polar Meteor-
in terms of bulk transfer coefficients.
ology and Oceanography, Dallas, Texas, 1520 Janu-
Because the geostrophic drag coefficient is related
monotonically to the effective roughness length z0ef , it
ary 1995. American Meteorological Society, Boston,
should be possible to bootstrap information about geo-
p. 252257.
strophic drag from the many observations of z0 and
Anonymous (1992) U.S. and Russian scientists complete
CDN10 over sea ice. The key step is inferring z0ef from
historic Weddell Sea investigation. Antarctic Journal of
z0. Several have thought about this problem, but, to my
the United States, 27(4): 811.
knowledge, only Arya (1975) has attempted to include
Arya, S.P.S. (1973) Contribution of form drag on pres-
sure ridges to the air stress on Arctic ice. Journal of Geo-
the unique topographic features of sea ice in the trans-
physical Research, 78: 70927099.
formation. In light of the recent flurry of papers on area
averaging (e.g., Mason 1988; Claussen 1990, 1991;
Arya, S.P.S. (1975) A drag partition theory for determin-
Vihma and Savijrvi 1991; Blyth et al. 1993; Moore et
ing the large-scale roughness parameter and wind stress
on the Arctic pack ice. Journal of Geophysical Research,
al. 1993), this problem might be ripe for a productive
revisit.
80: 34473454.
Arya, S.P.S. (1977) Suggested revisions to certain bound-
ary layer parameterization schemes used in atmospheric
LITERATURE CITED
circulation models. Monthly Weather Review, 105: 215
Anderson, R.J. (1987) Wind stress measurements over
227.
Arya, S.P.S. (1988) Introduction to Micrometeorology.
rough ice during the 1984 Marginal Ice Zone Experi-
ment. Journal of Geophysical Research, 92: 69336941.
San Diego: Academic Press.
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