In our daily life, we are very much familiar with the word weather because it has an impact on human activity. The word climate automatically comes with the weather, they are interrelated. Weather is a set of atmospheric elements in a particular region at a particular time or whole day. The elements of weather can change in a very short time. The state of these elements is dependent on one another. The average atmospheric conditions of a particular geographical location over a long period of time (a minimum of 35-year period or more) is called Climate.
To describe the weather as well as the climate for a particular region some measurement of elements is required, they are;
- Air pressure
- Sunshine (intensity and duration)
- Wind speed and direction
Overview of the elements of weather and Climate
Precipitation includes rainfall, snow, sleet, hail, mist, fog, drizzle, etc. Precipitation is the fall of any type of water form from overhead cloud formations. When water vapor in the air is condensed water droplets are formed. These droplets join together to form large and heavy water droplets.
These heavy water droplets fall into the ground in the form of rain. Precipitation is the result of evaporation and condensation. The amount of rain in a particular place s measured by a metal instrument called a rain gauge. While plotting rainfall maps, places having the same mean annual rainfall are joined by a line called an isohyet.
2. Air pressure
Air pressure is the result of the pressure created by the weight of air in the atmosphere. Particles in the air exert pressure due to gravitational force. The air pressure decrease as altitude increases. On average, for every 900 feet ascent, a 1-inch drop can be seen in mercury level in a barometer. The instrument for measuring atmospheric pressure is a barometer. From the name barometer, atmospheric pressure is also called barometric pressure. In general, pressure dominated by low pressure tends to be moist, while those dominated by high pressure are dry. Scientists use different units to measure atmospheric pressure. Meteorologists in general use metric bar, millibar, or pascals.
Temperature is the measure of the degree of coldness or hotness in a particular place. In scientific terms, temperature is the measure of kinetic energy present in the air, which manifests itself through the experience of hot or cold. It is a very important factor in determining whether because it influences or controls the other elements of weather.
The instrument used in measuring temperature is a thermometer which is a narrow glass tube fills with mercury or alcohol, works on the principle that mercury expands when heated and contracts when cooled. In the diagrammatical representation, the line connecting those places having the same monthly mean temperature is called isotherm. Temperature decrease at the rate of a 1-degree Fahrenheit drop in temperature for 300 feet ascent in altitude.
Humidity is the measure of the dampness of the atmosphere. Actually, it is the measure of water vapor present in the atmosphere at a specific time in a particular geographical location.
The instrument used for measuring relative humidity is called a Hygrometer. There are three types of humidity.
- Absolute humidity: The actual amount of water vapor present in the air which is expressed in grams per cubic meter, is called absolute humidity.
- Relative Humidity: At a specific temperature, the ratio of water vapor present in air having definite volume to the maximum water vapor that the air is able to hold.
- Specific Humidity: It is defined as the mass of actual water vapor present in gram contained in a kilogram of air – represents the actual quantity of water vapor present in a definite air.
When the relative humidity reaches 100 percent, the air is completely saturated. At this point, the air temperature is called dew-point.
Sunshine in a particular region depends on the season and the latitudes and longitudes position of that region. Sunshine has a great influence on other elements of weather. In a meteorological station, sunshine duration is recorded by a Sun-dial. In a graphical representation, the paces having equal sunshine are connected by a line is called isohels.
The equatorial region gets the maximum sunshine, the intensity and duration of sunlight decrease as we go from the equator to the poles.
Tiny droplets of water that are too small to fall as rain or snow are suspended in the air and float like clouds. Clouds are the base of precipitation. On summer days they provide protection from the ray of the sun and in winter they diminish the nocturnal radiation and check the fall of temperature.
On maps places with an equal degree of cloudiness are joined by lines known as isonephs. Cloudiness indicates the temperature rise or fall and the possibility of various forms of precipitation.
7. Wind speed and direction
Simply wind is the air in motion. The horizontal motion of the atmosphere can be termed wind. It can be felt only when in motion. Wind vane or weather cork is primarily used to measure wind direction. The speed of wind is usually measured by an anemometer. The speed of wind depends on the pressure difference created between a high-pressure zone and a low-pressure zone.
There are three types of wind – strong and short winds (gusts), strong intermediate winds (termed squalls), and strong and long-lasting winds (typhoons, hurricanes, storms, gales, or breezes), this classification is based on duration. Gravity is a driving force in controlling the vertical movement of air. Earth’s rotation is the cause of the deflection of objects, including planes, birds, and missiles from a straight line. The wind is no exception and is deflected to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.
Visibility is a measure of the distance at which an object or light can be clearly discerned. The Obstructions to visibility include clouds, fog, smoke, haze, and precipitation. In extremely clean air in Arctic or mountainous areas, the visibility can be up to 70 kilometers (43 mi) to 100 kilometers (62 mi). The international definition of fog is a visibility of less than 1 km (3,300 ft); mist is a visibility of between 1 km (0.62 mi) and 2 km (1.2 mi) and haze from 2 km (1.2 mi) to 5 km (3.1 mi). Visibility sensors like “forward scatter sensor” are the instruments used to measure visibility.
Quiz on the elements of weather and Climate
- A ____________ is an instrument that measures rainfall.
- A. Hygrometer
- B. Anenometer
- C. Rain Guage
- D. Spoon
- The condition of the atmosphere in a certain place at a certain time is known as _________.
- A. Solubility
- B. Weather
- C. Water Cycle
- D. Matter
- The breakdown of rock material in its current location. This is a definition of…
- A. Erosion
- B. Weathering
- C. Transportation
- D. Deposition
- E. Freeze Thaw