Subject: Physical Geography

The tectonic plate movements and crustal deformation over millions of years have given rise to magnificent mountain ranges across the globe, significantly influencing local and regional weather patterns through various orographic effects.

Major Mountain Ranges and Their Alignment

• North-South Alignment:

  • The American Cordilleras (Rocky Mountains and Andes) run along the western margins of North and South America.
  • The Ural Mountains separate Europe from Asia.
  • The Western Ghats along India's western coast.

• East-West Alignment:

  • The Alpine-Himalayan system stretches from the Alps through the Caucasus to the Himalayas.
  • The Atlas Mountains in North Africa.
  • The Great Dividing Range in Australia.

Impact on Local Weather Conditions

• Temperature Variations:

  • Mountains create distinct vertical temperature zones.
  • Temperature decreases at approximately 0.6°C per 100m elevation due to decreasing air pressure.
  • Example: The Himalayas create a stark temperature contrast between the Tibetan Plateau and the Indian subcontinent.

• Precipitation Patterns:

  • Orographic Effect on windward slopes:
    • The Andes show peak rainfall at 1.3 km elevation due to easterly winds.
    • The Western Ghats receive heavy monsoon rainfall on their western slopes.
  • Rain Shadow Effect on leeward sides:
    • Creation of arid regions like Death Valley (east of Sierra Nevada).
    • Formation of the Atacama Desert (east of Andes).
    • Development of the Gobi Desert (north of Himalayas).

The world's mountain ranges, from the oldest Barberton Mountains (3.5 billion years) to the relatively younger Himalayas, continue to play a crucial role in shaping Earth's climate systems, biodiversity patterns, and human settlements through their profound impact on local weather conditions.