CHAPTER 17.   OPERATION OF EQUIPMENT

17-1.     Introduction


SECTION 1.   CLOUD HEIGHT MEASUREMENT EQUIPMENT

17-2.     Preparation of Sky Cover Height Tables for Ceiling Lights

17-3.     Ceiling Light

17-4.     Maintaining Ceiling Light

17-5.     Maintaining Clinometer

17-6.     Care and Operation of Ceiling Balloons

Figure 17-1.     10-Gram Balloon Ascension Rates

Figure 17-2.     30-Gram Balloon Ascension Rates


SECTION 2.   PRECIPITATION MEASURING EQUIPMENT

17-7.     Weighing Rain Gauge

17-8.     Changing Weighing Rain Gauge Charts

17-9.     Weighing Rain Gauge - Winter Operation

17-10.   Weighing Rain Gauge - Summer Operation

17-11.   Weighing Rain Gauge - Winding the Clock

17-12.   Maintaining the Weighing Rain Gauge

17-13.   Weighing Rain Gauge - Dashpot

17-14.   Weighing Rain Gauge - Clocks

17-15.   Weighing Rain Gauge - Pens

17-16.   Weighing Rain Gauge - Bucket

17-17.   Weighing Rain Gauge - Evaluation Procedure

Figure 17-3.     Evaluation of Precipitation on Weighing Rain Gauge
                        Chart

17-18.   Weighing Rain Gauge - Annotation of Charts

17-19.   Weighing Rain Gauge - Replacement of Charts

17-20.   Clock Inoperative on Weighing Gauge

17-21.   Zero Adjustment on Weighing Gauge

17-22.   Time Adjustment on Weighing Gauge

17-23.   Emptying the Gauge

17-24.   Ice Accretion Indicators

17-25.   Maintaining the Non-Recording Gauge

17-26.   Maintaining the Tipping Bucket Gauge


 SECTION 3.   VISIBILITY MEASURING EQUIPMENT

17-27.   Transmissometer Operation

17-28.   Transmissometer Background Measurements and Adjustments

17-29.   Transmissometer Daily and Weekly Checks

17-30.   Transmissometer Readout Check

Figure 17-4.     Transmissometer Conversion Tables

17-31.   Transmission Variation

17-32.   Transmissometer Outage

17-33.   Transmissometer Restored to Service


 SECTION 4.   PRESSURE MEASURING EQUIPMENT

17-34.   Obtaining Station Pressure from Mercury Barometers

17-35.   Reading the Mercury Barometer

17-36.   Mercury Barometer - Total Correction

Figure 17-5.     Mercury Barometer Readings Obtained from Various
                        Types of Scales and Verniers

Figure 17-6.     International Table for Mercurial Barometer
                        Temperature Correction

17-37.   Mercury Barometer - Scale Reading

17-38.   Correction of Mercury Barometer Readings

17-39.   Reading Barographs for Station Pressure

17-40.   Barograph Time Check

17-41.   Barograph Clock and Chart Scale

17-42.   Barograms

Figure 17-7.     Barogram

Figure 17-8.     Example of Intersecting Barogram Trace

17-43.   Adjustment of the Barograph Pen for Pressure

17-44.   Barograph Adjustment for Time

17-45.   Selection of Barogram

17-46.   Changing the Barogram

17-47.   Maintenance of Pressure Reduction Computer

Figure 17-9.     Selection of Barograms


SECTION 5.   BAROMETER COMPARISONS

17-48.   General

17-49.   Requirements for Standardizing Instruments

17-50.   Standardizing Procedures

Figure 17-10.   Sample of MF1-13, Barometer Comparison (Front)

Figure 17-11.   Sample of MF1-13, Barometer Comparison (Back)

17-51.   Routine Comparisons

17-52.   Disposition of Form MF1-13


SECTION 6.   PERFORMANCE OF ANEROID INSTRUMENTS

17-53.   General

17-54.   Aneroid Barometer or Altimeter Setting Indicator

17-55.   Excessive Drift

17-56.   Inspection Comparisons

17-57.   Electronic Pressure Transducers


SECTION 7.   TEMPERATURE AND HUMIDITY MEASURING EQUIPMENT

17-58.   Dry-Bulb Thermometer

17-59.   Wet-Bulb Thermometer

17-60.   Wet-Bulb Thermometer - Temperature Above Freezing

17-61.   Wet-Bulb Thermometer - High Temperature and Low Humidity

17-62.   Wet-Bulb Thermometer - Temperatures Below Freezing

17-63.   Wet-Bulb Thermometer - Dry-Bulb Temperature Below 2.8 Degrees Celsius

17-64.   Psychrometric Ventilation

17-65.   Sling Psychrometer Ventilation

17-66.   Obtaining Readings from Sling Psychrometer


SECTION 8.   TEMPERATURE AND HUMIDITY GRAPHING EQUIPMENT

17-67.   Thermograph/Hygrothermograph Time Check Line

17-68.   Changing Thermograph/ Hygrothermograph Charts

17-69.   Annotation of the Thermograph Chart

17-70.   Thermograph/ Hygrothermograph Time Adjustment

17-71.   Thermograph/Hygrothermograph Temperature Adjustment

17-72.   Thermograph/ Hygrothermograph Disposition

17-73.   General Maintenance of Thermograph

17-74.   Maintenance of Thermograph Clock

17-75.   Maintenance of Thermograph Pen


SECTION 9.   HYGROTHERMOMETERS

17-76.   Hygrothermometer (HO-83, ASOS 1088, etc.) - General

17-77.   Hygrothermometer (HO-83) - Operations

17-78.   Hygrothermometer (HO-83) - Instrument Error Indications

17-79.   Hygrothermometer (HO-83) - Quality Control

17-80.   Hygrothermometer (HO-83, ASOS 1088, etc.) - Comparison Checks (NA LAWRS)


 SECTION 10.   MEASURING EQUIPMENT - OTHER

17-81.   Psychrometric Calculator

17-82.   Psychrometric Data

Figure 17-12.   Selection of Psychrometric Calculator on Basis of
                        Standard Atmosphere

17-83.   Using the Calculator

17-84.   Maintenance of Psychrometric Calculator

17-85.   Maintenance of Liquid-in-Glass Thermometers

17-86.   Maintenance of Psychrometers - Weekly Checks

17-87.   Maintenance of Psychrometers - Monthly Checks

17-88.   Instrument Shelter - Illumination

17-89.   Instrument Shelter - Maintenance


SECTION 11.   WIND RETRANSMITTER

17-90.   General

17-91.   Wind Retransmitter - Weekly Check

Figure 17-13.   Wind Speed Comparison Data

17-92.   Wind Retransmitter - Other Checks

17-93. - 17-96. Reserved