In the previous article we have learned about measurement of various Met elements with the help of conventional equipment. In this section we shall learn briefly about the field Met equipment which are also used to measure these Met elements.
Digital Aneroid Barometer (DAB)
The Digital Aneroid Barometer uses a silicon resonant pressure transducer for measurement of pressure and altitude. It should be protected from fall, direct sunlight, strong Electromagnetic radiation and heat sources. The instrument can also communicate, through a serial RS232 connector, with a compatible computer system or printer.
The instrument is switched on by the OFF/ON push button. The instrument “times out” after a period of one minute if no push button selections are made. Press the MODE button for local (QFE), Sea (QFF) and altitude measurement.
If the instrument operation becomes corrupt the display shows as under:
(a) SYSTEM ERROR
(b) ERRORnn- where nn is a decimal number Error numbers are:
04 – Bad data detected by checksum
16 – hardware fault
32 – Pressure outside range
User maintenance on this unit is limited to battery replacement and cleaning the system with a soft cloth.
Precision Aneroid Barometer (PAB)
PAB is an electronic pressure sensor using transducer as a sensor. It is extremely sensitive. It should be protected from fall, direct sunlight, strong EM radiation and heat sources.
Operating procedure of PAB are as follows:
(a) Insert 3 (1.5Volt) pencil cell in the battery chamber.
(b) Switch on the equipment by pressing On/Off button.
(c) Use the ‘MODE’ button for pressure reading.
Always ensure the following.
(a) The equipment is to be protected from violent pressure change, jerk and fall.
(b) When PAB is not in use, batteries are to be removed from equipment.
Laser Range Finder (LRF)
The Laser range finder is an electro optical instrument. This instrument is used to measure the height of low clouds.
The operating procedure is as follows:
(a) Open lens cover from the front side channel and laser transmitter.
(b) Look through the eyepiece and aim the LRF in the direction of the Target.
(c) Press ‘power button’ and wait until the green LED glows. The Power switch must be pressed during the entire measuring procedure.
(d) Press and release the Range Button.
(e) Read the range of the target from the display. The range will be displayed nearest to five meters.
(f) The range will remain displayed for approximately 03 seconds.
(g) If an error occurred during measurement, the display will then show “220.127.116.11.8.”
(h) Release the power switch.
Do’s and Don’ts
(a) Check the battery voltage before putting it in the battery compartment.
(b) Remove the battery when equipment is not in use.
(c) Charge battery regularly once in a month.
(d) Close lens cover and keep the equipment in carrying bag when it is not in use.
(e) Clean the optical surface of equipment with lens paper sheet only.
(f) Handle LRF carefully as it is an optical instrument.
(a) Don’t look towards the laser beam.
(b) Don’t drop/hit LRF on hard surface.
(c) Don’t dispose batteries in a fire. The may explode.
(d) Don’t apply extra pressure on any switches.
(e) Don’t clean lens with rough cloth.
(f) Don’t short the battery terminals.
(g) Don’t fire the beam in close room.
(h) Don’t fire the beam towards human beings.
(j) LRF should not be used during rain.
Pocket Weather Tracker (PWT)
Pocket Weather Tracker (PWT) is a sensor based Met Equipments used for measurement of vital met elements. This system can upload the stored data to any computer for long-term storage and deep analysis.
Pocket weather tracker can be utilized for extracting the following met elements.
(a) Wind direction and speed
(b) Cross, head and tail wind
(c) Dry bulb temperature
(d) Wet bulb temperature
(e) Dew point temperature
(f) Relative Humidity
(g) Wind Chill
(h) Heat Stress
(j) Barometric Pressure
(k) Altitude and density Altitude.
Steps for operating Pocket Weather Tracker:
(a) Insert 2 (A3) batteries in battery chamber.
(b) Switch on the equipment
(c) Press on/off button and select system.
(d) Select Compass calibration.
(e) Hold kestrel upright and rotate 3 times slowly @10 Sec/turn.
(f) Equipment will show calibration successfully completed.
(g) Select Barometric calibration and set the current QFE.
(h) System is ready for observation.
Follow the following procedure for taking observation from PWT.
(a) Remove the impeller cover from the wind censor.
(b) Stand outside by facing windward side, for 3 minutes.
(c) Press up/down button
(d) All elements can be viewed by clicking up/down buttons.
Do’s and Don’t’s.
(a) Clean the equipment with soft dry cloth.
(b) No oil or soap water is to be used .
(c) Make a regular check of battery voltage.
(a) Don’t leave the batteries inside the chamber when equipment is not in use.
(b) Don’t put your finger on the censors.
(c) Don’t’ keep the equipment without stand or Kestrel interface.
(d) Don’t keep the equipment in open sunshine.