Question

What is the process of measuring Air temperature, Wind velocity and Cloud cover?

Answer 1

Hint:
 Air Temperature is usually expressed in degrees Fahrenheit or Celsius. An Atmospheric thermometer measures the air temperature. The speed or velocity of wind can be measured using a tool called an Anemometer. Ceilometers is an instrument which can measure cloud height and cover.

Complete answer:
- Atmospheric Thermometers - An atmospheric thermometer is a kind of device that helps in measuring the temperature of the outdoor and indoor atmosphere. A thermometer has two important elements: (1) a temperature sensor; (2) some means of converting this change into a numerical value. Usually a thermometer consists of a long tube that contains mercury or colored alcohol at the base, although there are also other kinds, such as spring and digital thermometers.

- Anemometer - This instrument calculates wind speed and direction. It is also a common weather station instrument. Types of Velocity anemometers are:
A) Cup anemometers - It consisted of four hemispherical cups mounted on horizontal arms, which were mounted on a vertical shaft.
B) Vane anemometers - It may be described as a windmill or a propeller anemometer.
C) Hot-wire anemometers - Hot wire anemometers use a fine wire electrically heated to some temperature above the ambient. Air flowing past the wire cools the wire.
D) Laser Doppler anemometry - laser Doppler anemometers use a beam of light from a laser that is divided into two beams, with one propagated out of the anemometer.
E) Ultrasonic anemometers - It uses ultrasonic sound waves to measure wind velocity.
F) Acoustic resonance anemometers - Acoustic resonance sensors use ultrasonic or resonating acoustic waves within a small purpose-built cavity in order to perform their measurement.
G) Ping-pong ball anemometers - It is for very basic use. It is constructed from a ping-pong ball attached to a string.

- Ceilometer - This device uses a laser or other light source to determine the height of a cloud ceiling or cloud base. It is commonly used in airports to determine the cloud ceilings. This device works by shining an intense beam of light (often produced by an infrared or ultraviolet transmitter or a laser), modulated at an audio frequency, at overhead clouds. The photocell present in the receiver of the ceilometer detects the reflections of this light from the base of the clouds. Mainly there are two types of ceilometers: the rotating transmitter and the scanning receiver.

Note:
Temperatures in the troposphere drop an average of 6.5 degrees C per kilometer. The anemometer measures the wind velocity in feet per minute, or FPM. Ceilometers on the other hand are also in use to measure the aerosol concentration within the atmosphere.