Here we are going to discuss “Humidity and Precipitation”. It is a part of environmental studies of the General Awareness section of many competitive exams. Kindly bookmark this article for future reference.
Humidity
- Humidity is the measure of how wet the air is, i.e. amount of water present in the air.
- More the amount of water in the air, the higher will be humidity, less water Low humidity
- Humidity is measured using Hygrometer.
Humidity can be expressed in various forms, like Absolute Humidity, Relative Humidity, and Specific Humidity.
- Absolute Humidity = Mass of water vapor per volume (or mass) of moist air.
- Relative Humidity (%) = (water vapor present in air/maximum possible water which air can hold) × 100
- Specific Humidity = Mass(Volume) of water vapor present per unit Mass(Volume) of air.
- We usually talk about relative humidity as it is a more practical measure of atmospheric moisture.
- Air containing moisture to its full capacity at a given temperature is said to be Saturated.
- Humidity near an ocean or coastal region can be high due to its proximity to water bodies.
- With Height (altitude) the capacity of air to hold water decreases.
- Temperature and humidity share an inverse relationship.
| Temperature | Humidity |
| Increase | Decrease |
| Decrease | Increase |
- Humidity changes with time in a day, It’s high in the morning, then keep decreasing till noon, and then increases again.
- Humidity is affected by Temperature, water body, and air movement.
Precipitation :
- Precipitation means the amount of water that falls from the clouds on the ground.
- Condensation plays a key role in the formation of water droplets from water vapor.
- The process by which water vapor changes into liquid water is called Condensation.
- Due to continuous condensation, the cloud particles become large enough and it becomes difficult for them to hold any further water can be in various forms like Rain, Hail, Snow, sleet etc. Rainfall is most common among them.
- Precipitation is affected by Humidity, wind speed, etc.
- Rainfall is measured by using a Rain Gauge.
Precipitation can be of various types-
- Convectional
- Orographic
- Frontal
Convectional :
When the temperature is high, air becomes warm and hence light so it rises upwards. As it rises it expands and loses heat and condensation take place which results in cloud formation, then heavy rainfall takes place for short duration.
Such rainfall is common in the equatorial region and in the northern hemisphere in the summer season.
Orographic :
Oro means related to mountains. In orographic types of precipitation, rainfall takes place as air mass with good amount of water vapor hit a mountain. After hitting air ascended and rises, air expands, temperature fall, and condensation takes place.
Such type of rainfall cause rain on the windward side only, the Leeward side remains rainless and dry.
Windward side – That side of the mountain in which air directly hits and receives rainfall.
Leeward side- The side opposite to the windward side which remains as a rain-shadow area.
Orographic precipitation is also called Relief rain.
Frontal :
The type of rainfall in which warm or tropical air comes in contact with cold or polar air. The warm air (Front) rises above the cold air (front). Warm air gets cooled and cloud formation takes place.