8910 - Laurie


Location:  
	77 degrees 33 minutes S, 169 degrees 54 minutes E.  8 miles east-southeast of Cape Crozier on the Ross Ice Shelf at an elevation of approximately 20 meters.

Hex id:
	8B3b1

Power:
	36 6-volt PS-6200 gel cell batteries.  Eight 2.5 watt solar panels and a shunt regulator are used for recharging.

Aerovane:
	12-78-09 installed.

Deployed:
	15 December 81 by Stearns and Savage.

Calibration: 
	27 November 81 0400 Z at Mcmurdo lab.

Parameter		Input			Test Set Output		Difference

temperature		 14.4 C			 15.3 C			 + .9 C
pressure		978.7 mb		978.6 mb		 - .1 mb
inst wind speed		 38.9 m/s *		 43.2 m/s		 + 11%
			 19.5 m/s *		 20.9 m/s		 +  7% 
inst wind direction	    0 degrees 		    0 degrees	       	 -----
mean wind speed		 19.5 m/s		 20.9 m/s		 +  7%
mean wind direction	    0 degrees		    0 degrees		 -----
anemometer		  .50 volts (1800 rpm)	  132 bits
			  .25 volts (900 rpm)	   65 bits

	*Wind speed simulated with calibrated instrument

Field Calibration:
	15 December 1981 at time of installation

Parameter		Input			TIP output		Difference

temperature		  -1.7 C		 -2.5 C			 + 0.8 C
pressure		 976.6 mb		983.6 mb		 + 7.0 mb
inst wind speed		 15-20 kt		   16 kt		 --------
inst wind direction	   NNW			  329 deg		 --------
mean wind speed 	 15-20 kt		   16 kt		 --------
mean wind direction	   NNW			  309 deg 		 --------
battery voltage		  6.33 volts		  5.4 volts		 - 0.9 v

Modifications:
	1. RTG regulator diode removed.
	2. Heater circuit and diode removed.
	3. Low output generator anemometer installed.  Voltage appears in frame 7 word 1.
	4. Minimum thermometer installed.
	5. Reflective temperature probe shroud and insulating bushing installed.


Comments:

	1. Power consumption is 135 mA at idle: 1.5 A at transmit.
	2. The ARGOS test set was not taken to the installation site due to helicopter load limits.
	3. Discrepancy in pressure between measured value in field and value delivered by TIP is large.  The December data tape confirms the TIP reading, and the calibration coefficients for the pressure sensor has been checked and are correct.  On the previous day the barometers were used at 8911 and agreed very well with the pressure reading from that AWS.  Also, 2 barometers were used and several readings were taken with each over a period of an hour.  Therefore it appears that the pressure sensor in the AWS has drifted and is now reporting pressures that 7 mb too high.