Katabatic winds at Hells Gate

Measurements performed at Hells Gate in the austral summers 1993-1994,
1994-1995, 1995-1996, 1996-1997, 1997-1998, 2001-2002 with three three-axial
fast response Sonic Anemometers GILL RESEARCH, one three-axial fast response
Sonic Anemometer KAJIO DENKI, one three-axial Sonic Anemometer METEK, three
slow response impact Anemometers SITEP, three fast response Kripton Lamp
Igrometers CAMPBELL KH20, three fast response Thermometers and Igrometers
SITEP, one global Solarimeter Sitep, three Ice Thermometers, two Barometers
SETRA, a Barometer SITEP, two Microbarometers SETRA (signal filtered before
acquisition with low-pass Bessel 50 sec filter - during austral summers
2001-2002).

The scanning time interval is of about 1/20 sec for the three-axial Sonic
Anemometers; 1/10 sec for the Kripton Lamp Igrometers CAMPBELL KH20; 1/4sec for
the SITEP Anemometers; 60sec for slow response instruments (Thermometers,
Igrometers, Solarimeter and Barometers); 1/10 sec for the Microbarometer SETRA
without low-pass Bessel 50 sec filter and 10 sec with low-pass Bessel 50 sec
filter.

Turbulent fluxes of mechanical momentum, sensible and latent heat into the
first 10 meters, were evaluated by means of the eddy correlation methodology.
Data was taken under clear and cloudy sky conditions at three levels,
respectively at 5, 7.5 and 10 meters (sonic anemometer); 2 meters (barometer &
Microbarometer). Legal maximum value for each components of the wind speed is
30.00 m/s (resolution 0.01 m/s) and for sound speed is 290-370 m/s (Gill-Solent
sonic anemometer); 800-1100 hPa for Barometer); about +/- 70 Pa for
Microbarometer. Legal maximum value for U and V components of the wind speed is
30.00 m/s (resolution 0.005 m/s) and 10.00 m/s for W. Temperature is 40 degrees
C (resolution 0.025 degrees C) (Kaijo Denki sonic anemometer). Legal maximum
value for horizontal wind speed is 60 m/s for SITEP Anemometers. Slow sensors:
air humidity from 0 to 100% , air temperature from - 30 degrees C to + 70
degrees C (resolution +/- 0.3 degrees C), ice temperature from - 50 degrees C
to +50 degrees C, global radiation from 0 to 1500 w/m2, atmospheric pressure
from 800 to 1100 mbar. Missing data are indicated with a -100.00 for the Sonic
Anemometers GILL RESEARCH.