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Humidity
Humidity refers to the amount of water vapor in the air. There are three main types of humidity: absolute, relative, and specific. Absolute humidity is a direct measure of the mass of water in a given volume of air. Relative humidity compares the actual water content of the air to the maximum amount the air can hold at a given temperature. Specific humidity measures the ratio of water vapor to total air mass. Relative humidity is affected by temperature and the amount of water in the air. High humidity can impact climate, plants, animals, human comfort, and more. The most humid areas tend to be near the equator and coastal regions.
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Humidity
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- 2. Humidity A measure ofthe amount of water in the air Water is added to the air by the process of EVAPORATION.
- 3. Humidity Humidity indicates the likelihoodof precipitation, dew, or fog. Humidity is as well as relative humidity measured in % The amount of water that is actually in the air measured in g/mᵌ
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- 5. ABSOLUTE HUMIDITY: Absolutehumidity (expressed as grams of water vapor per cubic meter volume of air) is the mass of water in the air. Types Of Humidity
- 6. • RELATIVE HUMIDITYis the amount of water in the air compared to the amount of water the air could possibly hold. • Humidity values are usually given as Relative Humidity. Examples: if the air is holding half the water it could hold, it’s Relative Humidity is 50%. If the air is holding no water, relative humidity is 0% If it holding a quarter of the water it could hold, 25% Types Of Humidity
- 7. Factors that AffectRelative Humidity •Amount of water: If you increase the amount of water in the air (by adding it due to evaporation), Relative humidity will go up. •Temperature: Since warm air can hold more water than cold air, if you lower the temperature the Relative Humidity will go up, even if you don’t add more water. Types Of Humidity
- 8. • Specific humidityis the ratio of the mass of water vapor to the total mass of the moist air parcel. • Water (mass) mixing ratio is the mass of water vapor compared to mass of dry air Types Of Humidity
- 9. Temperature vs RelativeHumidity
- 10. Temperature vs RelativeHumidity
- 11. If the airis holding ALL the water it can hold it is saturated and the relative humidity is 100% Saturation
- 12. • DEW POINTis the temperature at which condensation will occur. The Dew point is the temperature the air must be in order to be saturated. Dew Point
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- 15. • WARM AIRCAN HOLD MORE WATER VAPOR THAN COLD AIR, so with the same amount of absolute/specific humidity, • cooler air will have a HIGHER relative humidity, and warmer air a LOWER relative humidity. 6/12 *100=50% 6/24*100=25% Facts
- 16. Water capacity ofair at different temperatures
- 17. What temperature canhold more water vapor?
- 18. • Relative Humidityis measured using a PSYCHROMETER. – A psychrometer is made of two thermometers. One is covered with a wet cloth. When air moves over the wet cloth, evaporation occurs and lowers the temperature on that thermometer. If you compare the temperature on the two thermometers you can get the relative humidity. Measuring Humidity
- 19. • In thearea of the vegetation, relative humidity is high whereas in the bare land there is less moisture and relative humidity is also less.Vegetation • The relative humidity increases as the altitude increases. Because as we go higher, there is the decrease in the temperatureAltitude • At the higher elevation than 800m relative humidity is less compared to sea level.Orographic effect • The average maximum diurnal relative humidity occurs in early morning and the minimum diurnal humidity occurs in the early afternoon.Transfer of humidity Factors which affect the humidity
- 20. Humidity affects globalclimate in in two major ways. • First, water vapor in the atmosphere contains "latent" energy. During transpiration or evaporation, this latent heat is removed from surface liquid, cooling the earth's surface. This is the biggest non-radiative cooling effect at the surface. It compensates for roughly 70% of the average net radiative warming at the surface. • Second, water vapor is the most abundant of all greenhouse gases. It absorbs the infrared energy emitted (radiated) upward by the earth's surface.This selective absorption causes the greenhouse effect. Global Climate
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- 23. Spatial distribution • Themost humid cities on earth are generally located closer to the equator, near coastal regions. • Cities in South and Southeast Asia are among the most humid. Kuala Lumpur, Jakarta, and Singapore have very high humidity all year round because of their proximity to water bodies and the equator and often overcast weather. Some places experience extreme humidity during their rainy seasons such as Kolkata, Chennai and Cochin in India, and Lahore in Pakistan. • Sukkur city located on the Indus River in Pakistan has some of the highest and most uncomfortable dew point in the country frequently exceeding 30 °C (86 °F) in the Monsoon season. • Shanghai and Hong Kong in China also have an extreme humid period in their summer months. • In cooler places such as Northern Tasmania, Australia, high humidity is experienced all year due to the ocean between mainland Australia and Tasmania. • The most humid cities on earth are generally located closer to the equator, near coastal regions. • Cities in South and Southeast Asia are among the most humid. Kuala Lumpur, Jakarta, and Singapore have very high humidity all year round because of their proximity to water bodies and the equator and often overcast weather. Some places experience extreme humidity during their rainy seasons such as Kolkata, Chennai and Cochin in India, and Lahore in Pakistan. • Sukkur city located on the Indus River in Pakistan has some of the highest and most uncomfortable dew point in the country frequently exceeding 30 °C (86 °F) in the Monsoon season. • Shanghai and Hong Kong in China also have an extreme humid period in their summer months. • In cooler places such as Northern Tasmania, Australia, high humidity is experienced all year due to the ocean between mainland Australia and Tasmania.
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