Tag: elements of weather and climate :humidity

Cover of clouds in portion of the sky visible from the observation point is known as cloud cover. Weather observer or meteorologists estimates the amount of cloud cover in sky. Cloud cover is an important factor which decides the weather of an area. The amount of cloud cover in the sky is measured in units called oktas or eight for meteorological purposes. Each okta represents one eighth of the sky covered by cloud.

The process of changing of water from the liquid state to the gaseous state is called evaporation. It occurs every day in natural and man-made environments. It occurs most often around the areas which are situated near water bodies. It is the most important process in case of water cycle because the water from water bodies goes into atmosphere through the process of evaporation. The rate of evaporation increases with the increase in the temperature.

The amount of water vapor in the air is known as humidity. It can make hot temperatures even more unbearable than they already are. It affects both weather as well as climate. It also affects global climate change. Both low humidity as well as high humidity is harmful for us. Humidity is of two types:- Absolute humidity and Relative humidity.

Hail is a small ball of ice in the atmosphere, especially at night. It is a result of precipitation. It is produced by intense thunderstorms when snow and rain coexists. As the snowflakes fall, liquid water freezes onto them. It forms ice pellets that continue to grow as more droplets accumulate. When the ball of ice becomes so large and heavy, they fall as hailstones.

Cirrus, cumulus, and stratus are the types of cloud. Cirrus clouds are very thin and white in colour. They are formed of ice crystals and give a feathery appearance. They are the highest clouds. Cumulus clouds are generally dense and with sharp outlines, developing vertically in the form of rising mounds, domes or towers, of which the bulging upper parts often resemble a cauliflower. Stratus clouds resemble fog and made up of almost equal layers. Occasionally, they are broken into patches separated by blue sky by the incoming wind. Stratus clouds are grey in colour. 

The particles of condensed moisture held in suspension close to the surface of the earth are known as mist. They form at lower density as compared to fog. Their visibility is more than 1,000 meters. They are quicker to dissipate. They can rapidly disappear with even slight winds. Mist is what we see when we see our breath on a cold day.

An isohyet is a line on a map connecting points that receive the same amount of rainfall over a given period.

Water in atmosphere is recharged through hydrological cycle. In hydrological cycle, water is evaporated from the surface of the ocean. As moist air is lifted, it cools and clouds are formed by condensation of water vapors. These clouds transfer this water to ground through rains. Groundwater either seeps its way to into the oceans, rivers, and streams, or is released back into the atmosphere through transpiration. This cycle keeps repeating itself to keep balance of water.

A hygrometer is the standard instrument used to measure the moisture content or relative humidity in the air. A hydrometer measures liquid density, and a barometer measures atmospheric pressure.

The Earth continues to absorb solar radiation even after noon. The heat accumulated throughout the day leads to the highest temperatures occurring in the afternoon rather than at the exact moment of the sun's peak intensity at noon.