CHAPTER 9 



SPECIALIZED METEOROLOGICAL 

 EQUIPMENT AND THEIR USES 



Specialized meteorological equipment range 

 from equipment utilized in observing atmospheric 

 conditions aloft to the various computer systems 

 that generate numerical products in support of 

 the operating forces. 



The objective of this chapter is to acquaint 

 the Aerographer's Mate with the function, basic 

 operation, care, and applicable safety precautions 

 of specialized meteorological equipment. 



UPPER AIR/WIND EQUIPMENT 



Upper air/wind equipment may be divided into 

 six general categories: radiosonde transmitters, 

 test and calibration, balloon inflation, balloon 

 launch, tracking, and assoicated hand calculators, 

 computers, and plotting boards. 



RADIOSONDE TRANSMITTER 



The radiosonde transmitter is a balloon- 

 borne, battery-powered instrument used together 

 with ground- receiving equipment to obtain a ver- 

 tical profile of the atmosphere in terms of 

 pressure, temperature, and relative humidity. 

 The basic radiosonde transmitter contains an 

 aneroid baroswitch for measuring pressure, a 

 white-coated thermistor for temperature, and a 

 carbon hygristor for relative humidity. Two basic 

 types of radiosondes are the 1680- and 403-MHz. 

 Ashore, upper-air stations use the 1680-MHz, 

 while ships use the 403-MHz. Radiosonde Ob- 

 servations, FMH No. 3, contains additional in- 

 formation on these instruments. 



TEST AND CALIBRATION 



EQUIPMENT 



In order to ensure a high percentage of suc- 

 cessful radiosonde and rawinsonde flights, a 

 thorough preflight check of the radiosonde and 

 associated battery pack must be performed and 



ground equipment must be maintained at a high 

 level of performance. Usually electronics tech- 

 nicians service ground equipment. 



Signal Generators 



Signal generators are used to calibrate radio- 

 sonde recorders. A signal generator supplies 

 the audio input frequencies which are necessary 

 for accurate computation of frequencies. A signal 

 generator of the type used with meteorological 

 equipment simulates the audiofrequencies the 

 radiosondes would send. 



Detailed calibration procedures may be found 

 in the applicable instrument handbook. 



Humidity Chamber ML-428/UM 



Humidity Chamber ML-428/UM is provided 

 to secure a stable environment of tempera- 

 ture and relative humidity for conditioning 

 403-MHz radiosondes prior to release. 



The humidity chamber is equipped with an 

 automatic switching device. This switching device 

 consists of a synchronous timer unit which 

 automatically connects the three elements of the 

 radiosonde in a predetermined sequence. This, 

 in turn, allows the operator to obtain data 

 essential to the preflight check of 403-MHz 

 radiosondes. 



Refer to the instructions that accompany this 

 equipment for detailed operating and maintenance 

 procedures. 



Radiosonde Baseline Check Sets 

 AN/GMM-1( ), AN/GMM-3, and 

 AN/UMM-1 



Baseline check sets are calibration chambers 

 designed for use with radiosondes used by the 

 Naval Weather Service. 



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