Distribution of Temperature - Notes | Geography for UPSC 2024 (Pre & Mains) PDF Download

 Page 1


 
DISTRIBUTION OF TEMPERATURE  
? Vertical distribution  
? Horizontal distribution  
VERTICAL DISTRIBUTION OF TEMPERATURE  
? Drops with increasing altitude at the rate of 6.5 celsius per thousand 
metre. This is known as normal lapse rate . 
WHY? 
? The lowest layer of the air contains more water vapour and dust 
particles and hence it absorbs larger amount of heat radiated from 
Earth's surface then upper layers . 
? As vs send higher in the atmosphere the amount of  heat gets lost to 
subsequent layer lying below . 
 
HORIZONTAL DISTRIBUTION OF TEMPERATURE  
ISOTHERMS: 
A line on a map connecting points having the same temperature at a 
given time or on average over a given period. 
NOTE: 
 They are reduced to sea level to negate the effects of altitude when 
drawing isotherms of a place  
Page 2


 
DISTRIBUTION OF TEMPERATURE  
? Vertical distribution  
? Horizontal distribution  
VERTICAL DISTRIBUTION OF TEMPERATURE  
? Drops with increasing altitude at the rate of 6.5 celsius per thousand 
metre. This is known as normal lapse rate . 
WHY? 
? The lowest layer of the air contains more water vapour and dust 
particles and hence it absorbs larger amount of heat radiated from 
Earth's surface then upper layers . 
? As vs send higher in the atmosphere the amount of  heat gets lost to 
subsequent layer lying below . 
 
HORIZONTAL DISTRIBUTION OF TEMPERATURE  
ISOTHERMS: 
A line on a map connecting points having the same temperature at a 
given time or on average over a given period. 
NOTE: 
 They are reduced to sea level to negate the effects of altitude when 
drawing isotherms of a place  
 
  
CHARACTERISTICS OF ISOTHERMS  
- Isotherms run along the latitudes, but they are not parallel to the 
latitudes. 
- Generally there and straight but bent at the junction of continents 
and oceans . They take sudden bends at land-water edges because of 
land-water contact. 
- Closely spaced  isotherms indicate Rapid rate of change of temperature 
and vice versa.  
- Irregular in the Northern hemisphere because of large extent of 
continents, but there are more regular in the southern hemisphere 
due to over dominance of oceans  
 
DISTRIBUTION OF ISOTHERMS IN WINTERS 
 
Page 3


 
DISTRIBUTION OF TEMPERATURE  
? Vertical distribution  
? Horizontal distribution  
VERTICAL DISTRIBUTION OF TEMPERATURE  
? Drops with increasing altitude at the rate of 6.5 celsius per thousand 
metre. This is known as normal lapse rate . 
WHY? 
? The lowest layer of the air contains more water vapour and dust 
particles and hence it absorbs larger amount of heat radiated from 
Earth's surface then upper layers . 
? As vs send higher in the atmosphere the amount of  heat gets lost to 
subsequent layer lying below . 
 
HORIZONTAL DISTRIBUTION OF TEMPERATURE  
ISOTHERMS: 
A line on a map connecting points having the same temperature at a 
given time or on average over a given period. 
NOTE: 
 They are reduced to sea level to negate the effects of altitude when 
drawing isotherms of a place  
 
  
CHARACTERISTICS OF ISOTHERMS  
- Isotherms run along the latitudes, but they are not parallel to the 
latitudes. 
- Generally there and straight but bent at the junction of continents 
and oceans . They take sudden bends at land-water edges because of 
land-water contact. 
- Closely spaced  isotherms indicate Rapid rate of change of temperature 
and vice versa.  
- Irregular in the Northern hemisphere because of large extent of 
continents, but there are more regular in the southern hemisphere 
due to over dominance of oceans  
 
DISTRIBUTION OF ISOTHERMS IN WINTERS 
 
 
 
 
? In continents= bent equatorwards  
? In oceans= bend pole words  
WHY? 
? the continentality effect in the continents 
? moderating effect of the ocean 
OR 
In the northern hemisphere, landmasses are cooler than the oceans. As 
the air is warmer over the oceans than over landmasses in the 
northern hemisphere, the isotherms bend towards the north (poles) 
when they cross the oceans and to the south (equator) over the 
continents. 
In the southern hemisphere, the effect of the oceans is well 
pronounced (due to few landmasses). Here, the isotherms are more or 
Page 4


 
DISTRIBUTION OF TEMPERATURE  
? Vertical distribution  
? Horizontal distribution  
VERTICAL DISTRIBUTION OF TEMPERATURE  
? Drops with increasing altitude at the rate of 6.5 celsius per thousand 
metre. This is known as normal lapse rate . 
WHY? 
? The lowest layer of the air contains more water vapour and dust 
particles and hence it absorbs larger amount of heat radiated from 
Earth's surface then upper layers . 
? As vs send higher in the atmosphere the amount of  heat gets lost to 
subsequent layer lying below . 
 
HORIZONTAL DISTRIBUTION OF TEMPERATURE  
ISOTHERMS: 
A line on a map connecting points having the same temperature at a 
given time or on average over a given period. 
NOTE: 
 They are reduced to sea level to negate the effects of altitude when 
drawing isotherms of a place  
 
  
CHARACTERISTICS OF ISOTHERMS  
- Isotherms run along the latitudes, but they are not parallel to the 
latitudes. 
- Generally there and straight but bent at the junction of continents 
and oceans . They take sudden bends at land-water edges because of 
land-water contact. 
- Closely spaced  isotherms indicate Rapid rate of change of temperature 
and vice versa.  
- Irregular in the Northern hemisphere because of large extent of 
continents, but there are more regular in the southern hemisphere 
due to over dominance of oceans  
 
DISTRIBUTION OF ISOTHERMS IN WINTERS 
 
 
 
 
? In continents= bent equatorwards  
? In oceans= bend pole words  
WHY? 
? the continentality effect in the continents 
? moderating effect of the ocean 
OR 
In the northern hemisphere, landmasses are cooler than the oceans. As 
the air is warmer over the oceans than over landmasses in the 
northern hemisphere, the isotherms bend towards the north (poles) 
when they cross the oceans and to the south (equator) over the 
continents. 
In the southern hemisphere, the effect of the oceans is well 
pronounced (due to few landmasses). Here, the isotherms are more or 
 
less parallel to the latitudes and the variation in temperature is more 
gradual than in the northern hemisphere. 
 
DISTRIBUTION OF ISOTHERMS IN SUMMER 
 
? In continent= bent poleward  
? In ocean= bent equatorward  
 
WHY? 
? the continentality effect in the continents 
? moderating effect of the ocean 
OR 
 
Page 5


 
DISTRIBUTION OF TEMPERATURE  
? Vertical distribution  
? Horizontal distribution  
VERTICAL DISTRIBUTION OF TEMPERATURE  
? Drops with increasing altitude at the rate of 6.5 celsius per thousand 
metre. This is known as normal lapse rate . 
WHY? 
? The lowest layer of the air contains more water vapour and dust 
particles and hence it absorbs larger amount of heat radiated from 
Earth's surface then upper layers . 
? As vs send higher in the atmosphere the amount of  heat gets lost to 
subsequent layer lying below . 
 
HORIZONTAL DISTRIBUTION OF TEMPERATURE  
ISOTHERMS: 
A line on a map connecting points having the same temperature at a 
given time or on average over a given period. 
NOTE: 
 They are reduced to sea level to negate the effects of altitude when 
drawing isotherms of a place  
 
  
CHARACTERISTICS OF ISOTHERMS  
- Isotherms run along the latitudes, but they are not parallel to the 
latitudes. 
- Generally there and straight but bent at the junction of continents 
and oceans . They take sudden bends at land-water edges because of 
land-water contact. 
- Closely spaced  isotherms indicate Rapid rate of change of temperature 
and vice versa.  
- Irregular in the Northern hemisphere because of large extent of 
continents, but there are more regular in the southern hemisphere 
due to over dominance of oceans  
 
DISTRIBUTION OF ISOTHERMS IN WINTERS 
 
 
 
 
? In continents= bent equatorwards  
? In oceans= bend pole words  
WHY? 
? the continentality effect in the continents 
? moderating effect of the ocean 
OR 
In the northern hemisphere, landmasses are cooler than the oceans. As 
the air is warmer over the oceans than over landmasses in the 
northern hemisphere, the isotherms bend towards the north (poles) 
when they cross the oceans and to the south (equator) over the 
continents. 
In the southern hemisphere, the effect of the oceans is well 
pronounced (due to few landmasses). Here, the isotherms are more or 
 
less parallel to the latitudes and the variation in temperature is more 
gradual than in the northern hemisphere. 
 
DISTRIBUTION OF ISOTHERMS IN SUMMER 
 
? In continent= bent poleward  
? In ocean= bent equatorward  
 
WHY? 
? the continentality effect in the continents 
? moderating effect of the ocean 
OR 
 
 
? During summer in the northern hemisphere, isotherms bend towards 
the equator while crossing oceans and towards the poles while 
crossing landmasses. 
? Isotherms are wide spaced over oceans while they are closely spaced over 
landmasses. 
 
HORIZONTAL DISTRIBUTION: 
 
 
TROPICAL ZONE  
? No winter around the equator because of high temperature  
TEMPERATE ZONE  
? Variation of temperature between summers and winters 
FRIGID ZONE  
? Exceptionally low temperatures  
 
ADDITIONAL INFO: 
- Earth receives maximum energy at 12:00 noon but the maximum 
temperature never occurs at 12:00 noon but the transformation of 
solar energy into heat requires time.