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Geography ANSWERS AFTER THE QUESTIONS

1.         State three causes of desertification.                                                                                    

2.         a)i) Differentiate the term aridity and  desertification                                                           

                ii) Differentiate between weather and climate                                                      

              b) State two causes of temperature inversion                                                                     

            c) Explain the occurrence of a land breeze                                                               

3.         a) Give three characteristics of the inter- tropical convergence zone                                 

            b) (i) State three natural causes of climate change                                                   

                ii) Explain four consequences of climate change on the physical environment      

            c) Give four reasons why some areas within the equatorial belt do not experience true

              equatorial climate                                                                                                             

4.         (a) Describe the climatic conditions experienced in the Kenya highlands                           

            (b) Explain four effects of folding to human activities                                                    

5.         (a) Distinguish between weather and climate                                                                 

            (b) State six characteristics of equatorial climate                                                             

 6.        (a) Explain how the following factors influence climate:

               (i) Ocean currents                                                                                                          

               (ii) Altitude 

7.         (a) State three conditions necessary for the formation of dew                                        

            (b) State two climatic reasons why the government should evict settlers from the Mau

                  forest complex in the Rift valley of Kenya                                                                

8.         (a) (i) What is a fog?                                                                                                              

                (ii) State any two conditions necessary for the formation of fog.                                     

            (b) Name any two isothermic layers of the atmosphere.                                                       

9.         (a) What is an air mass?                                                                                                         

(b) Give two climatic characteristics of the Inter-Tropical Convergence Zone (ITCZ)       

10.        (a) Describe two characteristics of a mountain climate                                                        

             (b) (i) State two human causes of climate change                                                                

                  (ii) Explain three consequences of climate change                                                        

            (c) Four classes intend to visit a weather station near your school to study the instruments

                 for measuring weather element:-

               (i) Describe how you would use a rain gauge to measure rainfall                                      

                (ii) Name two instruments you would find inside a Stevenson screen                 

11.       a) What do you understand by:

               i) Micro- climate                                                                                                     

              ii) Green house effect                                                                                                          

            b) Name two weather recording instruments that are placed in a Stevenson’s screen          

12.       (a) What is an air mass?                                                                                                         

(b) What two conditions favour formation of air mass?                                                       

13.       (a) What is the Inter-tropical convergence Zone?                                                                 

            (b) Account for any four characteristics of tropical rainforests.                                           

14.       (a) What is an air mass?                                                                                                         

15        (a) (i) What is global warming?                                                                                             

              (ii) Give any four causes of climate change.                                                                                          

              (iii) Name four Green house gases                                                                                      

          (b)(i) Explain five effects of climate change                                                                           

   (ii) Identify with evidence two climatic aspects that could have influenced the distribution

     of  vegetation                                                                                                               

16.       (a Differentiate between:

                (i) Aridity and desertification                                                                                       

            (b) Give three reasons why the recording of weather data at a weather station may be inaccurate  

            (c) State two qualities that makes Stevenson screen suitable for its work                              

            b) i) Briefly explain the green house effect and the global warming                        

               ii) Explain three effects of climatic change on the physical environment             

            c)   Explain how the following factors influence climate

                        i) Altitude                                                                                                                  

                        ii) Continentality                                                                                                        

                        iii) Ocean currents    

GEOGRAPHY ANSWERS FOR TOPICAL QUESTIONS ON WEATHER AND CLIMATE   

WEATHER AND CLIMATE

1.         -population pressure leading to clearing of forest                                                                     

  • climatic changes/global warming/destruction of ozone layer
  • accidental fires
  • poor methods of farming /overgrazing

2.           a i) Aridity refers  to a  state  of  dryness or deficiency of rainfall  in an area  while      

                     desertification refers  to the encroachment  of desert  like  conditions  into

                    productive  or arable  land  √√        

                   ii)  Weather atmospheric condition of a place over a short period of time                  

           Climate- Average weather condition of a given place over a long period

               b)- Moist warm air meets dry cold air mass                                                             

                   – Mountain slopes adjacent to a valley cause anabatic and katabatic winds

             c)    – Sea heats faster than the land during the day                                                 

– Air over the sea rises creating low pressure over the sea

– Cooler air over the land blows towards the sea

                        – Cool air from the land is called land breeze

3.               a)        – Zone of low pressure                                                                                            

– High temperature

– High convectional rainfall

– Trade winds converge here

                        – Moves with movement of the sun       

              (b)i) -Variation of solar output                                                                                     

       – Volcanic eruption

– Variations in the earth’s orbital characteristics

– Variation in atmospheric carbon dioxide          

             iii) –  Increase in temperature causing rise in sea level due to melting ice                       

– Changes in wind speed causing erosion

– Changes in seasons leading to severe drought

– Increase in precipitation causing flooding of large areas       

    c)      – Relief features such as high mountains influence temperature and rainfall pattern  

  • Presence of large water bodies that modify temperatures of the surrounding lands through breezes
  • Continentality- many regions are in the interior of the continents making them receive low amounts of rains
  • Winds- some areas are influenced by cold onshore winds that lower temperature of the surroundings

4.         (a)     – Temperature varies between 17C to 24C                                                                     

  • Lower slopes have higher temperatures than upper slopes
  • Mean annual range of temperature is between 3C to 5C
  • Rainfall is received throughout the year
  • Rainfall is high 1000 -15000 mm
  • Rainfall is double maxima
  • Rainfall is relief- orographic
  • High rain on the wind ward slopes
  • Rainfall is caused by S.E trade
  • Coolest months are between June and August      

           (b  – Fold mountains receive heavy rainfall/ snow falls give rise to many rivers for

                   HEP, irrigation, water for domestic and industrial use                                  

  • Wind wards sides receive high rainfall which promote agriculture/ forest growth
  • Leeward side have violent wind which destroy crops
  • Folding leads to exposer of some minerals or bring minerals near surface for mining
  • Folding hinders construction of communication
  • Folding acts as barriers during wars
  • Folding offer sceneries which attract tourists hence foreign exchange
  • Folds mountains make visibility poor hence hindering air transport        

5.         a) Weather is the daily condition of atmosphere taken in short period usually 24hrs

                 while climate is  the average weather condition taken for a period of 30 – 35 yrs      

b)  – High rainfall/ no marked dry season/ (1500mm – 2000 mm)                                      

  • High temperatures throughout the year/ (24º– 27º)
  • High humidity throughout the year with relative humidity about 80%
  • Rainfall throughout the year
  • Small temperature range/ 4ºC
  • Double maxima (March – May and Oct – Nov)
  • Major winds are South East and North East
  • Low pressure all the year/ Doidrums/ Equatorial low
  • Rainfall mainly convectional falling in the afternoon accompanied with lightening and thunderstorm
  • Thick cloud cover all the year/ thick cumulonimbus clouds          

6.        (a)   i) – Warm ocean currents raise temperature of the adjustment land/ warm current

                        increase rainfall                                                                                               

   – Cold ocean current lower temperature of the regions/ lower rainfall/ create dryness                                                                                                        

            ii) High areas have low temperatures/ Mt areas receive high rainfall                             

  Mountain sides facing sun are warmer than sides facing away from sun (Aspect)

       b i)-  Rainfall of double maxima                                                                                            

– High temperatures throughout the year about 270°C

– Low temperature range

– Rainfall falls throughout the year

– Rainfall is high average 2000mm

– Low pressure due to over head sun

– Rainfall is mainly convectional

–  High humidity content     

7.         a)    – Air should be calm so that it can remain in contact with the ground long

                      enough to be cooled  below dew point                                             

  – Day time should be warm to speed up evaporation and provide a lot of water in the air

     – There should be cloudless nights    

        b) – To increase precipitation in the area                                                                      

– To regulate in the area

– Forest to help air purification

8.         a) i)  A fog is a mass of water droplets suspended in the lower atmosphere which limits

                   visibility to less  than a kilometer                                                                             

                ii)   – Air must have abundant moisture                                                                                 

                       – The night should be clear/cloudless to facilitate terrestrial radiation

                   – The air should be clam/gentle air currents to help the water droplets in suspension

b)    – Troposphere                                                                                                              

– Stratosphere

– Mesopause

9.         a)     -it is a large volume of air whose temperature and humidity are fairly uniform 

                  and covers an extensive surface area                                                                                

        b)     -it experiences high temperature                                                                                           

   -it is a zone of low pressure and the doldrums

   -the zone migrates to the north and south of the equator with apparent movement of

   the  overhead sun

-it is a zone where the S.E and N.E trade winds converge

-it is associated with convectional rain and thunderstorms     

10.       a) – Temperature  decreases with increase in  altitude.                                               

                     – Rainfall increases with height upto 300m then it starts to decrease

                      – Windward slopes are wetter than leeward slopes.

                    – Atmospheric pressure decreases with increasing altitude.

       – Local winds are common, they blow up slope during the day and down slope

               during night.

     – In temp. regime slopes facing the equator are warmer than those facing the poles

             b) i)-  Increases air pollution from industrial activities.                                                

       – Deforestation /uncontrolled logging.

            ii) – Widespread changes in the natural ecosystem with grasslands and deserts areas

                     expanding as  forested areas shrinks.                                                                             

– Possible rise in temp. may increase evaporation rates leading increased rainfall

 in some areas.

– Increased rainfall will cause flooding of low lying areas.

– Water stored in polar glacier will melt leading to rise in sea levels and flooding of

  coastal  lands.

– In temperate regions, winters are likely to be wetter and summer drier.

– Wetter & warmer conditions may increase pests & diseases thereby affecting humans,  

      crops &   livestock.

– Change in climate is likely to cause extinction of various plants and animal species.

– Possible drought might increase in most parts of the world.

– Cause in change in agricultural activities & massive crop failure leading to food

   shortage.

        c i)  – A rain gauge consists of a funnel, metallic cylindrical container and a collecting jar.  

  • When it rains, water from direct rain drops collects into the jar through the funnel
  • The water collected is then poured into a graduated (in mm) measuring cylinder.
  • The readings taken & recorded.

    c ii) – Thermometers /six thermometers.                                                                                           

– Hygrometer.

11.    a i)  – This is climatic conditions in a restricted area due to small differences of aspect

                  slope, vegetation and human landscapes                                                             

          ii)   It is a condition where the incoming solar radiations pass through the atmosphere

                while the  outgoing terrestrial radiation is blocked by gases/ clouds/ atmosphere

                  making the earth retain the terrestrial radiation/ re-radiation. (This makes earth to

                  be warmer than it would have been)/ it is a condition where the atmosphere

                  balances the incoming and outgoing terrestrial radiation making the earth to

                 retain optimum heat                                                                 

     b)   – A thermometer / maximum and minimum/ six’s thermometer                                              

– A hygrometer/ wet and dry bulb thermometers

12        a) -body  of air/wind  with uniform conditions moving  in a  given  direction             

            b)   -same temperature                                                                                                     

                  -air pressure-move  from H.P  to L.P

                -earth’s movement

13.      (a) Tropical convergence zone is a low pressure belt that lies between the tropics 

                    where the North East  and South East trade winds converge                                      

            b) – The forest is evergreen due to high rainfall and abundant sunshine                            

– The trees grow tall to complete for sunlight

– Trees have broad leaves to encourage water loss through evapo-transpiration  /

   transpire excess water due to high rainfall

– these are mainly hardwoods due to abundant sunshine

– Trees have buttressed roots to support their great heights and large trunks in the

    wet soils.

– Tree roots go deep into the ground for anchorage

– There are many tree species due to the tropical conditions.

– The forest has little underground because the canopies block sunlight from reaching the

   ground

– The forests have numerous lianas/climbers which twine around the tall trees to reach       

    sunlight in the dense forest.

– Trees grow rapidly due to the high temperatures and high rainfall

14.       a) It is large volume of air/ wind with similar/ uniform temperature humidity and covers

                over a large  area and flows over along distance                                                               

         b)           A-  North East polar winds                                                                                                

                       B- South West westerlies/ S. West winds

                       C – North east trade winds

                       D – South East trade winds

15.      a i)  – Global warming is the increase of average temperatures on earth as result of green

                   house  effect/ gases reflecting back to earth part of heat radiation                              

                ii)     –    The orbital position of the earth or effect of the distance of the earth from

                              the sun

  • High amount of carbon dioxide in the air from industries
  • The volcanic emption raise heat/ temperature
  • High amount of solar radiation reaching the earth due to depletion of Ozone layer      

              iii) – Carbon dioxide (CO2)                                                                                                          

   – Chlorofluorocarbons (CFS)

   – Methane

                – Nitrous oxide (N2O)    

           b)(i) –  Change in the ecosystems with grass land and deserts expanding while

                 forests shrink    

  • Rise in the sea level due to thawing of glaciers that leads to flooding of coastal low lands
  • Rise in global temperatures leading to increased rainfall due to increased evaporation
  • Wetter winters and dry summers in temperature regions
  • Shrinking water bodies e.g. lakes, rivers and drying up of streams
  • Reduced animal and plant species due to adaptation difficulties
  • Extinction of some species of flora and fauna
  • Low production of food due to failing soil fertility and absence of rain/ too much of rainfall

in other areas           

(ii) – High rainfall evidenced by many permanent rivers                                                     

               – Cool temperatures from high altitudes e.g. 2000m

16.       a) Aridity is dryness/ insufficient rainfall, while desertification is the expansion/             

                    encroachment of  desert conditions      

             b)     – Use off defective instruments√                                                                            

– Personnel my have inadequate /limited skills√

– Vagaries of nature such as earth tremous√

               c) – painted white to prevent over heating√                                                                

    – raised to a height of 121m to prevent contact with direct radiation from the

         earth’s surface√

             – it has louvers at the side to  allow free air circulation√           

17.      a)-  2-modified tropical climate  of the  highland                                               

     – 3-modified equatorial  climate  of  the  lake basin

           b)   – it receives very low rainfall of less than 250mm annually                                              

  • the  mean annual  temperature are  high above 29ºc
  • large diurnal range  of  temperature
  • day temperature are high
  • humidity  is low
  • sand storms are common occurrence
  • there are occasional floods caused  by sporaduram
  • the region  is under  the  influence of dry north east trade  winds

19.      a i)       X – Mediterranean                                                                                     

                        Y – Equatorial climate

ii)         – Rainfall is low/ below 250mm per year                                                             

  • Rainfall is erratic/ unreliable
  • Occasional flash floods
  • Temperatures are high throughout the year
  • Intense solar radiation
  • Diurnal range of temperature is large/ extreme hot days and cold nights
  • High rates of evaporation
  • Skies are clear/ high terestial radiation
  • Low humidity
  • Strong dusty winds

           b i)-  Green house effect is general increase of the temperatures of the globe due

                    to increase  in the level of CO2 and other green houses gases. This result into

                   a condition where  the  incouncy solar radiation passes through the atmosphere   

                  while the outgoing terrestrial  radiation s blocked by the gases and the clouds

  ii) Increase in temperature                                                                                                          

Effects

  • Rainfall increase
  • Melting of ice caps
  • Rise in sea level
  • High evaporation
  • Abnormal growth of plants

Change in rainfall pattern

Effects

  • Floodings
  • Rise in sea level
  • Drought
  • Soil erosion by water

Change in seasonal patterns

Effects

  • Severe winter/ short summer
  • Drought
  • Shifting of vegetation zones
  • Extinct of some species

Change in winds

            -More frequent & more destructive

            – High waves

            – Flooding

            – Wind erosion/ wind storms

c i)    – Temperature decreases with increasing height above sea level. This is because    

            atmospheric air at low altitude is denser than high above. Heat loss is greater at high  

          altitude than at lower altitude                                                                                                         

  • Rise in altitude cause  fall in temperature and a cooling effect that causes condensation of moisture in the air. This leads to precipitation forming at high altitude
  • Atmospheric pressure is higher at low altitude and lower at high altitude. This is because the weight of the atmospheric air at low altitude is more than at high altitude

ii) In summer, coastlands are relatively cooler than in land areas. This is because the

      winds bring   the cooling effect of the sea to the land, by the time winds reach inland

     they are heated  by warm   land resulting in higher temperature over the interior of

      the land  

In winter the onshore winds bring the warming effect of the sea into the land causing a rise in  temperature. By the time these winds reach the interior of the land, they are cooled by cold land thus enhancing the low temperature

Onshore winds cause a lot of rain in the coastal areas throughout the year. This is because the wind picks up moisture over the sea and drop it on the nearby land. The continental interiors  receive less rain, mainly in summer, because the winds have dropped mot of the moisture in the coastal lands

            iii) Ocean currents                                                                                                              

  • Cold ocean currents bring about the cooling effect in the temperature
  • Also bring a dry effect because the cold air is not able to rise

Warm ocean currents

  • Bring a warm effect (rise in temperature)
  • Heavy rainfall because the warm air is able to rise and condense to form rainfall