speed transmitter and indicator assemblies was (a) 1 percent up to 100 m/sec 

 and (b) 2 percent over 100 m/sec. The wind direction transmitter and indica- 

 tor assemblies were accurate to +5 deg at an airspeed of 0.26 m/sec or greater. 



27. In April, NOAA/National Weather Service (NWS) personnel calibrated 

 the speed cups and verified that the direction was referenced to true north. 

 The speeds were found to be approximately 13 percent (linear) faster than 

 actual, and the instrument was reset. Generally, speeds lower than the manu- 

 facturer's specifications for this anemometer are due to deterioration of 

 bearings; however, speeds found faster than specified usually are due to an 

 accidental shift of the chart recorder calibration. The chart calibration is 

 controlled by a lever which could easily have been bumped when chart paper was 

 changed at the end of the month. It is suggested that the data reported here 

 be scaled lower by 13 percent for January through 23 April. 



28. The wind speed and direction were recorded on a battery-powered 

 Esterline-Angus recorder. Problems with the recorder's clock and tape-advance 

 mechanism and the pen actuator (for indicating direction) were frequently 

 found, and the unit required day-to-day maintenance. Maintenance of the 

 anemometers consisted of troubleshooting the recorders and resetting the in- 

 strument based on the calibration results. 



Microbarograph 



29. This recording instrument, an aneroid sensor used to measure atmos- 

 pheric pressure, responded to pressure changes on the order of 0.169 mb. The 

 microbarograph, manufactured by the Belfort Instrument Company, Baltimore, 



Md. , was located inside the laboratory building, 9 m above NGVD (Figure 2). 



30. The microbarograph was compared to an NWS aneroid barometer daily; 

 infrequent adjustments were made as necessary. The microbarograph required 

 very little maintenance except that required to ink the pen and wind the clock 

 every 3 days when the chart paper was changed. 



Maximum/Minimum thermometers 



31. NWS maximum and minimum thermometers were used to determine the 

 daily extreme air temperatures. The thermometers were housed in an NWS in- 

 strument shelter located 43 m behind the dune (Figure 2). The shelter was de- 

 signed with louvered sides, a double roof, and a slatted bottom for housing 

 instruments requiring protection from direct sunlight. 



32. The actual temperature readings at the time the thermometers were 

 read (i.e., the present temperature) were compared to ensure accuracy of 



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