Sodar data in some Antarctic coastal bases between 1986 and 1995

The Antarctic continent plays an important role in the climate determination as
well as in the global atmospheric circulation. The low level circulation, one
of the main features of the Antarctic climate, is mainly characterized by
gravity driven air masses that flow from the interior of the continent toward
the coast following the orographic falling line. These currents are usually
referred to as inversion winds on the Antarctic Plateau, and katabatic winds on
the coastal escarpment. The katabatic winds concentrate in a limited number of
coastal section called confluence zones where extremely strong winds can be
observed. In these zones a considerable mass and sensible heat exchange between
Antarctica and northern latitude takes place.

Measurement performed in these locations can be assumed representative of wider
portion of the ice sheet. Surface measurements are not sufficient to
characterize the complexity of the circulation in these places. Flows are often
originated by different processes (barrier winds, katabatic winds-breeze, large
scale circulation, may interact with each other and in some cases appear
superimposed on each other) .

The monostatic Doppler sodar allowed to highlight some features of that
complexity by providing with the vertical structure of the wind field and with
the picture of the thermal stratification evolution.

During the 1986- 1995 period the sodar in Antarctica worked several times, in
several sites and in different configurations. Below, the general
characteristics of the experiment are listed (place, date, instrument):

A-Terra Nova Bay, 1986-1987, one axis sodar
B-Terra Nova Bay, 1987-1988, three axis sodar
C-Nansen Ice Sheet, 26/12/1988-4/2/1989, three axis sodar
D-Dumont d'Urville, 18/12/1992-20/1/1995, three axis sodar
E-Nansen Ice Sheet, 25/11/1994-7/1/1995, three axis cross-beam
F-Reeves Nevee, 25/11/1994-6/1/1995, three axis cross-beam

Based on the instrument configuration the Doppler sodar can provide facsimile
record of the echo return (fax), vertical profile of the averaged horizontal
wind (wd) and vertical velocity (vv).

Below are listed the parameters characteristic of the measurement
(Site: Parameters, time rept./aver., vertical res., range):
A- TNB: fax, vv; 6s, 30 m, 800 m
B- TNB: WD, fax, vv; 6s/10 min., 30 m, 800 m
C- NIS: WD, fax, vv; 6s/10 min., 27 m,800 m
D- DDU: WD, fax, vv; 6s/10 min., 27 m, 800 m
E- NIS: WD, fax, vv; 6s/10 min., 27 m, 800 m
F- RNE: WD, fax, vv; 3s/10 min., 14 m, 400 m