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Weather Instruments

Gaynor Borade
Our atmosphere is unique not only because it sustains millions of life forms, but also because it fluctuates as our needs change, to accommodate adaptations. Weather conditions can be measured in a number of ways.
The Earth's surface weather conditions are observed via automated machines. These weather instruments are also referred to as AWOS or ASOS. There are a number of airports around the world that maintain sites that are manned to support the machines at weather stations. These sites calculate temperature, dew point, visibility and winds.
The thermometer is used to measure temperature. It reveals maximum or minimum readings for the National Weather Service. The results are then aired or televised all over the world, and affect the working of various related industry individual undertakings.
Air pressure is measured with the help of a barometer, while a rain gauge measures precipitation. There are two types of barometers; the Mercury and Aneroid barometer.
The Mercury Barometer comprises a glass tube inserted in mercury. As the external air exerts pressure on the mercury, the action forces a certain amount of the mercury to enter the tube. The level of mercury is always directly proportional to the atmospheric pressure outside.
The psychrometer measurements on the temperature, humidity and dew point is got on dipping the wick in distilled water. In the sling psychrometer, the measurements are taken by whirling the instrument.
The sling psychrometer works on the level of evaporation of water from the wick on the wet bulb thermometer. This leads to cooling and with the help of the Relative Humidity Table, the difference in temperature results in the understanding of the level of relative humidity, in percent.
The sling psychrometer reading can be accessed from a mobile or stable weather station to measure temperature, dew point and the relative humidity, any time of the day. This instrument is a must at any weather station, especially those at higher altitudes.
Most weather stations maintain readings from two major types of rain gauges. One is the tipping bucket and the other is the 'weighing' rain gauge. The rain gauge, as the name suggests rightly, measures rainfall over a predetermined period of time.
It consists of a funnel at the upper end. The aim is to direct the rainwater into the long and narrow cylinder within the larger outer cylinder.
The readings of this weather equipment are very important to calculate the rainfall received and compare it to the previous year's readings. This enables the Weather Bureau to realize effective measures and timely steps to prevent a further drop or get geared for an over-douse!
Weather instruments also include the anemometer that measures the speed of wind and the wind wane that indicates wind direction. Together they are especially useful to the world of civil aviation.
Humidity levels can be measure with the help of a hygrometer. This tool measures relative humidity or the moisture in the surrounding air. This is achieved by measuring the change in the length of an organic fiber due to absorption of moisture.
The radiosonde or rawinsonde is another important maneuverer. It is basically a complete kit or set up of the different instruments attached to a weather balloon. On release, the kit radios the air observations at different altitudes, back to earth!
A barograph provides a consistent report on the air pressure. A Nephoscope is used for measuring and calculating speed and direction of cloud motion.
The grids in the Grid Nephoscope are referential, while the vertical pointer in the Mirror Nephoscope enables observation of the image of a cloud at the center of the disk, keeping in line with the pointer.
The readings obtained from the different weather instruments maintained at the weather stations all over the world also work towards a synchronized approach to deal with the timely identification of a deterioration of the atmospheric envelop we so depend on.