Variations in atmospheric pressure

Variations in atmospheric pressure

The average weight that air exerts on the earth's surface is 1034 mg per cm². The atmospheric pressure is measured using an instrument called Mercury Barometer. It is recorded in units like millibar (Mb) and hectopascal (hPa). The level of mercury at normal atmospheric pressure will be 76 cm. The atmospheric pressure at that point will be 1013.2 Mb or 1013.2 hPa. 

Isobars

Atmospheric pressure is represented in maps using flow lines. This imaginary

lines drawn on maps connecting points of equal atmospheric pressure are called Isobars.

The factors responsible for changes in atmospheric pressure are:

• Temperature

• Altitude of a place

• Humidity

Temperature and atmospheric pressure

In places where more solar energy is received, the air gets heated up.  The heated air loses its density as a result of which it expands and rises up. This result in a lowering of pressure. As the air becomes cooler, it becomes denser. Since dense colder air sinks down an increase in pressure are felt. As temperature increases pressure becomes low and as temperature decreases, the pressure becomes high. 

Atmospheric pressure and altitude 

The atmospheric pressure decreases with altitude. The pressure decreases at the rate of 1 millibar (Mb) per an altitude of 10 meters. As one goes up, there is a decrease in atmospheric pressure due to the rarification of air with altitude. The atmospheric pressure and altitude are inversely proportional. 

Humidity and atmospheric pressure

Humidity refers to the quantity of water present in the atmosphere. Water vapour is lighter than air and hence it ascends. If the quantity of water vapour is more in a unit volume of air, then naturally the atmospheric pressure will be less. Humidity and atmospheric pressure are inversely proportional. 

📌Related Topics
👉 Mountain and valley breeze
👉 Land breeze and Sea breeze
👉 Periodic winds: Monsoon winds
👉 Variable winds
👉 Atmospheric pressure and winds
👉 Weather and Climate
👉 Global pressure belts
👉 Variations in atmospheric pressure
👉 The atmosphere 
👉 Geography - Questions and Answers 

<ഈ ബ്ലോഗിലെ മുഴുവന്‍ പോസ്റ്റുകളും ഒരുമിച്ച് കാണുക>

PSC Solved Question Papers ---> Click here 

PSC TODAY's EXAM RESULTS ---> Click here

PSC EXAM PROGRAMME -> Click here

CURRENT AFFAIRS QUESTIONS -> Click here

PSC Degree Level Questions & Answers - Click here

PSC 10th, +2 Level Questions & Answers - Click here

PSC RANK LISTS / SHORTLISTS -> Click here

PDF BOOKS - Click here

TEACHING APTITUDE TEST (K-TET, C-TET,, etc.) ---> Click here

* SCERT KERALA TEXTBOOKS FOR CLASS II, IV, VI, VIII, IX, X, XII – FREE DOWNLOAD ---> Click here

* NCERT & CBSE TEXTBOOKS FOR ALL CLASSES – FREE DOWNLOAD ---> Click here

* SCERT TEXTBOOKS SOLUTIONS FOR ALL CLASSES ---> Click here

* NCERT & CBSE TEXTBOOKS SOLUTIONS FOR ALL CLASSES ---> Click here