{"id":25944,"date":"2023-02-20T05:39:21","date_gmt":"2023-02-20T00:09:21","guid":{"rendered":"https:\/\/icsesolutions.com\/?p=25944"},"modified":"2023-02-21T09:37:57","modified_gmt":"2023-02-21T04:07:57","slug":"icse-solutions-for-class-9-geography-atmospheric-pressure-and-winds","status":"publish","type":"post","link":"https:\/\/icsesolutions.com\/icse-solutions-for-class-9-geography-atmospheric-pressure-and-winds\/","title":{"rendered":"ICSE Solutions for Class 9 Geography – Atmospheric Pressure and Winds"},"content":{"rendered":"
ICSE Solutions<\/a>Selina ICSE Solutions<\/a>ML Aggarwal Solutions<\/a><\/p>\n Exercises<\/strong><\/span><\/p>\n I. Short Answer Questions.<\/strong><\/p>\n Question 1.<\/strong><\/span> (a)<\/strong> Pressure Gradient Answer:<\/strong><\/span><\/p>\n (a) Pressure Gradient \u2014<\/strong> It is the rate of change of atmospheric pressure between two points on the earth\u2019s surface. Question 2.<\/strong><\/span> Question 3.<\/strong><\/span> Question 4.<\/strong><\/span> Question 5.<\/strong><\/span> Question 6.<\/strong><\/span> Question 7.<\/strong><\/span> Question 8.<\/strong><\/span> Question 9.<\/strong><\/span> Question 10.<\/strong><\/span> Temperature Cyclones :<\/strong><\/p>\n Question 11.<\/strong><\/span> Question 12.<\/strong><\/span> Question 13.<\/strong><\/span> Question 14.<\/strong><\/span> Question 15.<\/strong><\/span> Question 16.<\/strong><\/span> II. Give reasons for each of the following<\/strong><\/p>\n Question 1.<\/strong><\/span> Question 2.<\/strong><\/span> Question 3.<\/strong><\/span> Question 4.<\/strong><\/span> PQ. Mediterranean lands receive most of the rainfall in winter season.<\/strong> Question 5.<\/strong><\/span> Question 6.<\/strong><\/span> Question 7.<\/strong><\/span> III. Distinguish between the following<\/strong><\/p>\n PQ. Isobars and Isotherms<\/strong> Isotherms :<\/strong><\/p>\n Question 1.<\/strong><\/span> Anticyclones :<\/strong><\/p>\n PQ. Vertical and Horizontal Temperature variation.<\/strong> Horizontal Variation :<\/strong><\/p>\n Question 2.<\/strong><\/span> Periodic winds :<\/strong><\/p>\n Question 3.<\/strong><\/span> Winter Monsoon :<\/strong><\/p>\n IV. Long Answer Questions.<\/strong><\/p>\n Question 1.<\/strong><\/span> Question 2.<\/strong><\/span> Question 3.<\/strong><\/span> Question 4.<\/strong><\/span> Question 5.<\/strong><\/span>
\nDefine the following terms :<\/strong><\/p>\n
\n(b)<\/strong> Winds
\n(c)<\/strong> Coriolis force.
\n(d)<\/strong> Altitude
\n(e)<\/strong> Monsoons.<\/p>\n
\n(b) Winds \u2014<\/strong> Horizontal movements of the air from high pressure to low pressure areas are called winds.
\n(c) Coriolis force \u2014<\/strong> This force is created by the rotation of the earth as the winds in different belts deflect towards right in Northern hemisphere and to the left in Southern hemisphere.
\n(d) Altitude \u2014<\/strong> The pressure also decrease with increasing altitude at the rate of 100 millibars in every 1000 metres of height gained.
\n(e) Monsoons \u2014<\/strong> are the periodic seasonal winds blowing in the regions of South East Asia and Northern Australia. The word monsoon is derived from the Arabic word \u2018Mausim’ meaning \u2018Season\u2019, on account of deeply affecting the seasons of the particular region.<\/p>\n
\nName the four main pressure belts of the earth.
\nAnswer:<\/strong><\/span><\/p>\n\n
\nWhat is Circum-polar Low Pressure Belt ?
\nAnswer:<\/strong><\/span>
\nIt is the belt of low pressure belt between 60\u00b0N – 70\u00b0N and 60\u00b0 S – 70\u00b0 S.<\/p>\n
\nHow does Coriolis Force vary latitudinally ?
\nAnswer:<\/strong><\/span>
\nIn the northern hemisphere the winds deflect towards right and in Southern hemisphere deflect towards left due to the effect of the rotation of the earth, e.g. the trade winds take the Southwest direction in place of southern direction in northern tropical belt and in southern tropical belt these winds take northwest direction in place of northern direction.<\/p>\n
\nName the three chief types of wind.
\nAnswer:<\/strong><\/span>
\nThree chief types of winds are Trade winds, Westerlies, and Polar winds.<\/p>\n
\nWhat are periodic winds ?
\nAnswer:<\/strong><\/span>
\nPeriodic winds blow at regular intervals or in regular cycles. They are winds that result from localised differences in pressure and temperature. For example, land and sea breezes and the seasonal winds.<\/p>\n
\nWhat are local winds ? Name any two local winds.
\nAnswer:<\/strong><\/span>
\nThe local winds blow in certain places and these are warm and cold according to the area from which they blow, e.g. Foehn winds blow descending on the slopes of the Alps and makes the temperature ideal for grapes due to its warm effect. In the same way Chinook winds blowing and coming down from the Rockies mountains in North America helps to increase the temperature and are beneficial to keep grasslands ice free and warms the ranches, so good for animal rearing.<\/p>\n
\nName two types of variable winds ? Why are they so called ?
\nAnswer:<\/strong><\/span>
\nVariable winds change their direction and force from place to place due to changing the pressure system. These blow for a short time or for a few days. These are cyclones and anticyclones. These are the circular winds with low pressure and high pressure in the centre respectively.<\/p>\n
\nWhy are cyclones frequent in summer in the tropical region ?
\nAnswer:<\/strong><\/span>
\nIn summer in the tropical region due to die shifting of Doldrums, the low pressure region is strongly originate between 8\u00b0 and 20\u00b0 N and S. They mainly originate in China sea and surrounding area. In Bangla Desh, these are known as \u2018KalBaisakhi\u2019 rneaning \u2018Time of Death\u2019 and cause heavy calamities and destruction. These are known as \u2018hurricanes\u2019 in North America, \u2018Typhoons\u2019 in China,\u2018willywillies\u2019 in Australia.<\/p>\n
\nMention any two differences between Tropical Cyclones and Temperature Cyclones.
\nAnswer:<\/strong><\/span>
\nTropical Cyclones :<\/strong><\/p>\n\n
\n
\nHow are cyclones named differently in different parts of the world ?
\nAnswer:<\/strong><\/span>
\nThe name of the cyclones is different in different parts of the world on the basis of the local languages e.g. hurricanes in America, typhoons in China and Japan, meaning the destructive horrible cyclonic winds.<\/p>\n
\nWhat are two chief characteristics of anticyclones ?
\nAnswer:<\/strong><\/span>
\nTwo chief characteristics are that these provide clear weather and the winds blowing from the centre towards outside in clockwise direction.<\/p>\n
\nWhy are the summer monsoons known as South-West Monsoons in the Indian subcontinent ?
\nAnswer:<\/strong><\/span>
\nDue to the low pressure created in the Northern Indian subcontinent and high pressure centre located in the Indian ocean, the Monsoons start to blow from the ocean to the Indian landmass taking a direction from southwest to northeast in summer seasons.<\/p>\n
\nName the two types of instruments used for measuring pressure. State one point of difference between them.
\nAnswer:<\/strong><\/span>
\nTwo types of barometers are used for measuring pressure, e.g. Fortin\u2019s Barometer and Aneroid Barometer. The main difference is that Fortin\u2019s Barometer is filled with mercury, while Aneroid Barometer is without any liquid. Fortin\u2019s Barometer consists of a long narrow tube filled with mercury, while Aneroid is in the round shape like a watch.<\/p>\n
\nBriefly state the variations in the vertical distribution of pressure.
\nAnswer:<\/strong><\/span>
\nMany factors like slope of land, presence of winds and the temperature affect the pressure of air vertically. The rate of decrease is 100 millibars per 1000 metres of height gained. There is a thin air cover at high altitudes, so the percentage and amount of oxygen is also less.<\/p>\n
\nWhy are the months of January and July used to describe the world distribution of pressure ?
\nAnswer:<\/strong><\/span>
\nDue to the lowest and highest temperatures recorded in January and July respectively the pressure areas are also affected, so it is preferred to display the distribution of pressure distinctly in January and July.<\/p>\n
\nThe Westerlies in the Southern Hemisphere blow with greater force than those in the Northern Hemisphere.
\nAnswer:<\/strong><\/span>
\nIn the Southern Hemisphere there is open ocean for free movement along the belt of Westerlies. These blow with roaring sound and great speed along 40\u00b0S. and are known as \u2018Roaring Forties\u2019.<\/p>\n
\nThere is a seasonal shifting in pressure belts.
\nAnswer:<\/strong><\/span>
\nDue to the earth\u2019s changing aspect with respect to the sun, the pressure belts shift northwards by 5\u00b0 in summer and southwards in winter resulting in particular seasonal changes, e,g. The cold waves blow in India in winter due to the sub\u00actropical belt shifting along 30\u00b0N touching the Himalayas. On the other hand in summer the trade winds become powerful in India and push the monsoon winds from east to west in Northern Plain of India.<\/p>\n
\nAs we go higher, the atmospheric pressure decreases.
\nAnswer:<\/strong><\/span>
\nAs the air become thinner with increasing height, so, the air pressure also decreased. The rate of decrease is 100 millibars per 1000 metres of height gained. So mountain hikers take oxygen cylinder with them to compensate the air inhaled.<\/p>\n
\nThe winds are directed to the right of their flow in the Northern Hemisphere.
\nAnswer:<\/strong><\/span>
\nDue to the rotation of the earth from west to east, the winds are deflected to the right e.g. the trade winds blowing from north, to south take north easterly direction.<\/p>\n
\nAnswer:<\/strong><\/span>
\nMediterranean lands come along the belt of Westerlies along 30\u00b0S in place of 40\u00b0N in winter. So, the Mediterranean countries along 30\u00b0N get ample rainfall. Similarly in the Southern Hemisphere the Westerlies blow along 30\u00b0S, in winter, so, the southern Mediterranean countries get winter rainfall.<\/p>\n
\nTemperature and pressure are inversely related to one another.
\nAnswer:<\/strong><\/span>
\nWhen the temperature increases and the air start to rise upwards. creating a low pressure area, but when the temperature decreases, the air start to sink downwards creating a high pressure area on land surface. So, the temperature and pressure are inversely related to one another.<\/p>\n
\nHumid air is lighter than dry air.
\nAnswer:<\/strong><\/span>
\nIn tropical region the air is greatly humid due to excess of evaporation creating a low pressure conditions, while the cold regions with less humidity are high pressure areas. So, the humid air is lighter than dry air.<\/p>\n
\nDoldrums is a low pressure belt.
\nAnswer:<\/strong><\/span>
\nDoldrums is a low pressure belt along the equator from 5\u00b0N to 5\u00b0S. In this belt due to high amount of evaporation, the atmosphere is very calm and quiet due to no circulation of winds and continuous rising air mass creating a hollow like condition in this belt. Inspite of air pushed towards the equator, it is immediately deflected to right and left, creating a vacuum like condition resulting in a belt of calm named as \u2018Doldrums\u2019<\/p>\n
\nAnswer:<\/strong><\/span>
\nIsobars :<\/strong><\/p>\n\n
\n
\nCyclones and Anticyclones.
\nAnswer:<\/strong><\/span>
\nCyclones :<\/strong><\/p>\n\n
\n
\nAnswer:<\/strong><\/span>
\nVertical Variation :<\/strong><\/p>\n\n
\n
\nPermanent and Periodic Winds.
\nAnswer:<\/strong><\/span>
\nPermanent winds :<\/strong><\/p>\n\n
\n
\nSummer and Winter Monsoons.
\nAnswer:<\/strong><\/span>
\nSummer Monsoon :<\/strong><\/p>\n\n
\n
\nWhat is meant by the term \u2018Atmospheric Pressure\u2019 ? Explain briefly the factors that affect Atmospheric Pressure.
\nAnswer:<\/strong><\/span>
\nAtmospheric Pressure refers to the force per unit area exerted against a surface by the weight of the air above that surface. Pressure is expressed in millibars (mb) and measured with a mercury barometer. The average atmospheric pressure at sea level is 1013.25 mb or 760 mm (the) height of the column of mercury in a barometer at sea level). Atmospheric Pressure decreases with height.
\nFactors affecting Atmospheric Pressure are as below :<\/strong><\/p>\n\n
\nExplain the swinging of the pressure belts.
\nAnswer:<\/strong><\/span>
\nIn summer the pressure belts are pushed northwards and in winter southwards.
\n
\nThis shifting takes place upto 5\u00b0 distance. In summer, it results in remarkable change in weather and climate, e.g. summer monsoon with thunderstorms, lightening and rainfall etc. while, in winter, the Mediterranean climatic regions get rainfall due to Westerlies coming from sea towards land.<\/p>\n
\nBriefly explain the three chief types of winds.
\nAnswer:<\/strong><\/span>
\nThe three chief types of winds are Trade winds, Westerlies and polar winds.
\nTrade winds :<\/strong> blow along the tropical belt from sub-tropical High to equatorial low pressure belts. The name trade is given due to the past time, when trade ships were sailed according to the direction of these winds.
\nWesterlies :<\/strong> are the winds blowing from western direction. These are south-westerly in northern and north-westerly in the southern hemispheres.
\nThe Polar :<\/strong> winds are icy cool winds blowing from poles towards Circum polar low pressure belts, which are also known as Blizzards.<\/p>\n
\nDescribe some of the important types of local winds.
\nAnswer:<\/strong><\/span>
\nChinook in North America blowing eastwards from the Rockies slopes make the climate of Central Plains ideal for animal rearing and agriculture.
\nFoehn :<\/strong> winds descending down from the Alps makes the agriculture successful in PO basin and
\nMistral :<\/strong> from the Alps along France towards the Mediterranean sea brings the temperature suddenly down instead of bright sunshine.<\/p>\n
\nExplain the weather conditions associated with tropical and temperate cyclones.
\n