PART IV: DATA COLLECTION AND ANALYSIS 

 Data Acquisition System/Digital Data Collection 



33. The primary data acquisition system was a Data General Corporation 

 (Westboro, Mass.) NOVA-4 minicomputer located in the FRF laboratory building. 

 The backup system consisted of a WICAT Systems Incorporated, Orem, Utah, 



150 WS minicomputer. Signals from the air temperature and atmospheric pres- 

 sure sensors, the anemometer, and wage gages were routinely sampled four times 

 per second for 20 min every 6 hr beginning at or about 0100, 0700, 1300, and 

 1900 hr Eastern Standard Time (EST); these hours correspond to the time that 

 the NWS creates daily synoptic weather maps. During storms, hourly data re- 

 cordings were made. Prior to collection, each gage signal was first amplified 

 and biased to ensure a 0- to 5-V range. 



34. Data were recorded on nine-track magnetic tapes having the follow- 

 ing format: first, two header records of information were written, which in- 

 clude (a) the sensor identification number; and (b) the date, time, calibra- 

 tion, and signal bias factors, followed by 13 records of data for each 20-min 

 recording interval. Each data record contained 384 data values in a binary 

 format, such that each value represented the computer units corresponding to 

 the instantaneous voltage output of the sensor. The above sequence of 



15 records per file was repeated for each sensor and recording interval until 

 the data tape was filled, a total of 600 to 700 files per tape. 



Meteorological Data 



Collection 



35. Maximum and minimum temperatures. High and low temperature values 

 were read daily directly from the instruments and represent the extreme tem- 

 perature values since the last reading. 



36. Microbarograph and rain gage. Each instrument used for monitoring 

 the meteorological conditions at the FRF was read and inspected daily. For 

 the microbarograph and rain gage with analog chart recording capabilities, 

 (a) the pen was zeroed (where applicable) ; (b) the chart time was checked and 

 corrected, if necessary; (c) a daily reading was marked on the chart for 



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