Pressure & Wind - Notes | Geography for UPSC 2024 (Pre & Mains) PDF Download

 Page 1


 
 
PRESSURE AND WIND  
CONVERGENCE AND DIVERGENCE OF WINDS  
? Over low pressure area the air will converge and rise.  
? Over high pressure area, the air will subside from above and diverge 
at the surface. 
  
 
 
 
 
CYCLONIC/ ANTICYCLONIC CIRCULATION  
? The wind circulation around the low is called as cyclonic circulation  
? The wind circulation around a high is called anticyclonic circulation 
Page 2


 
 
PRESSURE AND WIND  
CONVERGENCE AND DIVERGENCE OF WINDS  
? Over low pressure area the air will converge and rise.  
? Over high pressure area, the air will subside from above and diverge 
at the surface. 
  
 
 
 
 
CYCLONIC/ ANTICYCLONIC CIRCULATION  
? The wind circulation around the low is called as cyclonic circulation  
? The wind circulation around a high is called anticyclonic circulation 
 
 
CYCLONES ( LOW PRESSURE SYSTEM) 
Cyclones are areas of low pressure. Since air moves from areas of high 
pressure to low pressure, cyclones produce a convergence at the surface. 
This converging air is forced upwards into the atmosphere, creating a 
divergence aloft. As warm, moist air is sucked into the low and forced 
aloft, it produces an unstable atmosphere. This warm, moist air cools, 
condenses and forms storm clouds. That is why the word cyclone is almost 
synonymous with the word storm which denotes a period of heavy rainfall 
over a specific area. 
 
ANTICYCLONE: ( HIGH PRESSURE SYSTEM) 
Anticyclones are areas of high pressure. The sinking air spreads out when 
it reaches the ground, producing a divergence at the surface. Aloft, air 
rushes in to fill the void, creating a convergence aloft. Anticyclones 
produce a stable atmosphere.  
 
 
 
NOTE: 
? A rising pressure indicates fine, settled weather, while a falling 
pressure indicates unstable and cloudy weather. 
 
Page 3


 
 
PRESSURE AND WIND  
CONVERGENCE AND DIVERGENCE OF WINDS  
? Over low pressure area the air will converge and rise.  
? Over high pressure area, the air will subside from above and diverge 
at the surface. 
  
 
 
 
 
CYCLONIC/ ANTICYCLONIC CIRCULATION  
? The wind circulation around the low is called as cyclonic circulation  
? The wind circulation around a high is called anticyclonic circulation 
 
 
CYCLONES ( LOW PRESSURE SYSTEM) 
Cyclones are areas of low pressure. Since air moves from areas of high 
pressure to low pressure, cyclones produce a convergence at the surface. 
This converging air is forced upwards into the atmosphere, creating a 
divergence aloft. As warm, moist air is sucked into the low and forced 
aloft, it produces an unstable atmosphere. This warm, moist air cools, 
condenses and forms storm clouds. That is why the word cyclone is almost 
synonymous with the word storm which denotes a period of heavy rainfall 
over a specific area. 
 
ANTICYCLONE: ( HIGH PRESSURE SYSTEM) 
Anticyclones are areas of high pressure. The sinking air spreads out when 
it reaches the ground, producing a divergence at the surface. Aloft, air 
rushes in to fill the void, creating a convergence aloft. Anticyclones 
produce a stable atmosphere.  
 
 
 
NOTE: 
? A rising pressure indicates fine, settled weather, while a falling 
pressure indicates unstable and cloudy weather.