Geography Quiz: Climatology |28 Jan, 2021

The earth’s surface receives most of its energy in short wavelengths.

The energy received by the earth is known as incoming solar radiation which in short is termed as insolation.

As the earth is a geoid resembling a sphere, the sun’s rays fall obliquely at the top of the atmosphere and the earth intercepts a very small portion of the sun’s energy.

On an average the earth receives 1.94 calories per sq. cm per minute at the top of its atmosphere.

Source: NCERT Fundamentals of Physical Geography

The solar output received at the top of the atmosphere varies slightly in a year due to the variations in the distance between the earth and the sun.

During its revolution around the sun, the earth is farthest from the sun (152 million km) on 4th July.

This position of the earth is called aphelion. On 3rd January, the earth is the nearest to the sun (147 million km). This position is called perihelion.

Therefore, the annual insolation received by the earth on 3rd January is slightly more than the amount received on 4th July.

However, the effect of this variation in the solar output is masked by other factors like the distribution of land and sea and the atmospheric circulation.

Source: NCERT Fundamentals of Physical Geography

The amount and the intensity of insolation vary during a day, in a season and in a year. The factors that cause these variations in insolation are:

the rotation of earth on its axis;

the angle of inclination of the sun’s rays;

the length of the day;

the transparency of the atmosphere;

the configuration of land in terms of its aspect.

Source: NCERT Fundamentals of Physical Geography

All clouds are made up of basically the same thing: water droplets or ice crystals that float in the sky.

But all clouds look a little bit different from one another, and sometimes these differences can help us predict a change in the weather.

Cirrus clouds are delicate, feathery clouds that are made mostly of ice crystals. Their wispy shape comes from wind currents which twist and spread the ice crystals into strands.

Altocumulus clouds have several patchy white or gray layers, and seem to be made up of many small rows of fluffy ripples. They are lower than cirrus clouds, but still quite high. They are made of liquid water, but they don’t often produce rain.

Cumulus clouds look like fluffy, white cotton balls in the sky. They are beautiful in sunsets, and their varying sizes and shapes can make them fun to observe!

Stratocumulus clouds are patchy gray or white clouds that often have a dark honeycomb-like appearance.

Source: NCERT XI Fundamentals of Physical geography and G C Leong

Temperature inversion is a reversal of the normal behavior of temperature in the troposphere, in which a layer of cool air at the surface is overlain by a layer of warmer air. (Under normal conditions, temperature usually decreases with height).
Ideal Conditions for Temperature Inversion:
•Long nights, so that the outgoing radiation is greater than the incoming radiation.
•Clear skies, which allow unobstructed escape of radiation.
•Calm and stable air, so that there is no vertical mixing at lower levels.
Source: NCERT XI Fundamentals of Physical geography

Savanna Climate is a type of climate has alternate wet and dry seasons similar to monsoon climate but has considerably less annual rainfall.
•Also, there is no distinct rainy season like in monsoon climate.
•It is confined within the tropics and is best developed in Sudan, hence its name the Sudan Climate.
Source: G C Leong

An isohyet is also known as isohyetal line, and it is a line on a map which connects points that have the same amounts of precipitation in a given period or for a particular storm. The method used in estimating average rainfall across a particular area is known as an isohyetal method.
•Isotherm: a line on a map connecting points having the same temperature at a given time or on average over a given period.
•Isobar: A line drawn on a weather map connecting points of equal pressure is called an isobar. The isobars are generated from mean sea level pressure reports and the pressure values are given in millibars.
Source: G C Leong

Nimbus clouds are black or dark gray. They form at middle levels or very near to the surface of the earth. These are extremely dense and opaque to the rays of the sun.
Sometimes, the clouds are so low that they seem to touch the ground. Nimbus clouds are shapeless masses of thick vapour.
Source: NCERT XI Fundamentals of Physical geography

The Roaring Forties take shape as warm air near the equator rises and moves toward the poles.
•Warm air moving pole-ward (on both sides of the equator) is the result of nature trying to reduce the temperature difference between the equator and at the poles created by uneven heating from the sun.
•This process sets up global circulation cells, which are mainly responsible for global-scale wind patterns.
•The air descends back to Earth’s surface at about 30 degrees’ latitude north and south of the equator. This is known as the high-pressure subtropical ridge, also known as the horse latitudes.
•Here, as the temperature gradient decreases, air is deflected toward the poles by the Earth’s rotation, causing strong westerly and prevailing winds at approximately 40 degrees. These winds are the Roaring Forties.
•The Roaring Forties in the Northern Hemisphere don’t pack the same punch that they do in the Southern Hemisphere.
•This is because the large land masses of North America, Europe, and Asia obstructing the airstream, whereas, in the southern hemisphere, there is less land to break the wind in South America, Australia, and New Zealand.
•While the Roaring Forties may be fierce, 10 degrees south are even stronger gale-force winds called the Furious Fifties.
•And 10 degrees south of the Furious Fifties lay the Screaming Sixties! We can thank the intrepid sailors of yore for these wildly descriptive terms.
Source: G C Leong

The tundra climate (ET) is so called after the types of vegetation, like low growing mosses, lichens and flowering plants.
•This is the region of permafrost where the sub soil is permanently frozen.
•The short growing season and water logging support only low growing plants.
•During summer, the tundra regions have very long duration of day light.
Source: NCERT XI Fundamentals of Physical geography