Global Pressure Belts | Geography for UPSC 2024 (Pre & Mains) PDF Download

 Page 1


 
 
GLOBAL PRESSURE BELTS  
 
 
 
EQUATORIAL LOW PRESSURE BELT   
? 5
0 
N – 5
0
S latitudes.  
? Since the vertical rays of the Sun fall on the Earth, the heat is 
intense and the temperature is high. The air becomes warm and 
expands. 
? This leads to the creation of a low pressure belt in the region. 
? The convection currents also help to spread the heat to the upper 
layers of the atmosphere. 
? Winds in this pressure belt do not blow at a fast pace and hence 
this belt is also known as the Belt of Calms or the Belt of 
Doldrums. 
Page 2


 
 
GLOBAL PRESSURE BELTS  
 
 
 
EQUATORIAL LOW PRESSURE BELT   
? 5
0 
N – 5
0
S latitudes.  
? Since the vertical rays of the Sun fall on the Earth, the heat is 
intense and the temperature is high. The air becomes warm and 
expands. 
? This leads to the creation of a low pressure belt in the region. 
? The convection currents also help to spread the heat to the upper 
layers of the atmosphere. 
? Winds in this pressure belt do not blow at a fast pace and hence 
this belt is also known as the Belt of Calms or the Belt of 
Doldrums. 
 
 
? The position of the belt varies with the apparent movement of 
the Sun. 
? Zone of convergence of trade winds . 
? Vertical winds (convection) carrying moisture form 
cumulonimbus clouds and lead to thunderstorms (convectional 
rainfall). 
? Inspite of high temperatures, cyclones are not formed at the 
equator because of ‘zero’ coriolis force.  
 
 
SUB – TROPICAL HIGH PRESSURE BELT  
 
? Extends between the latitudes of 25
0
-35
0
 in both the hemispheres.  
Page 3


 
 
GLOBAL PRESSURE BELTS  
 
 
 
EQUATORIAL LOW PRESSURE BELT   
? 5
0 
N – 5
0
S latitudes.  
? Since the vertical rays of the Sun fall on the Earth, the heat is 
intense and the temperature is high. The air becomes warm and 
expands. 
? This leads to the creation of a low pressure belt in the region. 
? The convection currents also help to spread the heat to the upper 
layers of the atmosphere. 
? Winds in this pressure belt do not blow at a fast pace and hence 
this belt is also known as the Belt of Calms or the Belt of 
Doldrums. 
 
 
? The position of the belt varies with the apparent movement of 
the Sun. 
? Zone of convergence of trade winds . 
? Vertical winds (convection) carrying moisture form 
cumulonimbus clouds and lead to thunderstorms (convectional 
rainfall). 
? Inspite of high temperatures, cyclones are not formed at the 
equator because of ‘zero’ coriolis force.  
 
 
SUB – TROPICAL HIGH PRESSURE BELT  
 
? Extends between the latitudes of 25
0
-35
0
 in both the hemispheres.  
 
 
? As the air at the equator moves toward the Poles, it begins to cool 
and sink down at about 30° North and South of the Equator.  
? Descent of winds results in the contraction of their volume and 
ultimately causes high pressure.  
? Zone is characterized by anticyclonic conditions . 
? This is one of the reasons for the presence of hot deserts of the 
world . 
? Horse Latitudes.  
 
 
 
 
SUB – POLAR LOW PRESSURE BELT  
Page 4


 
 
GLOBAL PRESSURE BELTS  
 
 
 
EQUATORIAL LOW PRESSURE BELT   
? 5
0 
N – 5
0
S latitudes.  
? Since the vertical rays of the Sun fall on the Earth, the heat is 
intense and the temperature is high. The air becomes warm and 
expands. 
? This leads to the creation of a low pressure belt in the region. 
? The convection currents also help to spread the heat to the upper 
layers of the atmosphere. 
? Winds in this pressure belt do not blow at a fast pace and hence 
this belt is also known as the Belt of Calms or the Belt of 
Doldrums. 
 
 
? The position of the belt varies with the apparent movement of 
the Sun. 
? Zone of convergence of trade winds . 
? Vertical winds (convection) carrying moisture form 
cumulonimbus clouds and lead to thunderstorms (convectional 
rainfall). 
? Inspite of high temperatures, cyclones are not formed at the 
equator because of ‘zero’ coriolis force.  
 
 
SUB – TROPICAL HIGH PRESSURE BELT  
 
? Extends between the latitudes of 25
0
-35
0
 in both the hemispheres.  
 
 
? As the air at the equator moves toward the Poles, it begins to cool 
and sink down at about 30° North and South of the Equator.  
? Descent of winds results in the contraction of their volume and 
ultimately causes high pressure.  
? Zone is characterized by anticyclonic conditions . 
? This is one of the reasons for the presence of hot deserts of the 
world . 
? Horse Latitudes.  
 
 
 
 
SUB – POLAR LOW PRESSURE BELT  
 
 
 
? Located between 60
0
-65
0
 latitudes in both the hemispheres. 
? It is a zone of two winds; the warm Westerly winds meet the cold 
polar Easterlies.  
? As the Westerlies are lighter, they rise over the cold polar winds 
creating a low pressure area. 
? These belts experience stormy weather and cyclonic activity 
especially during the winters. 
? The area of contrast between cold and warm air masses produces 
polar jet streams . 
 
POLAR HIGH PRESSURE BELT  
Page 5


 
 
GLOBAL PRESSURE BELTS  
 
 
 
EQUATORIAL LOW PRESSURE BELT   
? 5
0 
N – 5
0
S latitudes.  
? Since the vertical rays of the Sun fall on the Earth, the heat is 
intense and the temperature is high. The air becomes warm and 
expands. 
? This leads to the creation of a low pressure belt in the region. 
? The convection currents also help to spread the heat to the upper 
layers of the atmosphere. 
? Winds in this pressure belt do not blow at a fast pace and hence 
this belt is also known as the Belt of Calms or the Belt of 
Doldrums. 
 
 
? The position of the belt varies with the apparent movement of 
the Sun. 
? Zone of convergence of trade winds . 
? Vertical winds (convection) carrying moisture form 
cumulonimbus clouds and lead to thunderstorms (convectional 
rainfall). 
? Inspite of high temperatures, cyclones are not formed at the 
equator because of ‘zero’ coriolis force.  
 
 
SUB – TROPICAL HIGH PRESSURE BELT  
 
? Extends between the latitudes of 25
0
-35
0
 in both the hemispheres.  
 
 
? As the air at the equator moves toward the Poles, it begins to cool 
and sink down at about 30° North and South of the Equator.  
? Descent of winds results in the contraction of their volume and 
ultimately causes high pressure.  
? Zone is characterized by anticyclonic conditions . 
? This is one of the reasons for the presence of hot deserts of the 
world . 
? Horse Latitudes.  
 
 
 
 
SUB – POLAR LOW PRESSURE BELT  
 
 
 
? Located between 60
0
-65
0
 latitudes in both the hemispheres. 
? It is a zone of two winds; the warm Westerly winds meet the cold 
polar Easterlies.  
? As the Westerlies are lighter, they rise over the cold polar winds 
creating a low pressure area. 
? These belts experience stormy weather and cyclonic activity 
especially during the winters. 
? The area of contrast between cold and warm air masses produces 
polar jet streams . 
 
POLAR HIGH PRESSURE BELT  
 
 
 
? This belt is located between 85°N to 90°N and 85°S to 90°S. 
? The Polar Regions experience cold climatic conditions as the rays of 
the Sun are extremely slanting. 
? The cold air sinks down giving rise to high pressure areas.