Q. Briefly mention the alignment of major mountain ranges of the world and explain their impact on local weather conditions, with examples.

Model Answer: 

Major mountain ranges of the world have a significant impact on local weather conditions due to their alignment, altitude, and geographic location. Mountain ranges act as barriers to air masses, affecting the distribution of precipitation, temperature, and wind patterns. This leads to diverse microclimates within a region, influencing agriculture, wildlife, and human settlements. Some notable examples include the Himalayas, the Andes, the Rockies, and the Alps.

1. Himalayas

Alignment: The Himalayas are a vast mountain range in Asia, stretching over 2,500 km from the Indus River in the west to the Brahmaputra River in the east.

Impact on Weather: The Himalayas act as a barrier to the south-westerly monsoon winds, causing heavy rainfall on their southern slopes and creating a rain shadow on their northern side. This leads to the formation of the Thar Desert in India and the high-altitude arid plateau of Tibet. The immense altitude of the range also results in a wide range of temperature and precipitation variations across its slopes, supporting diverse ecosystems from tropical forests to alpine tundra.

2. Andes

Alignment: The Andes is the longest continental mountain range in the world, extending over 7,000 km along the western edge of South America.

Impact on Weather: The Andes play a crucial role in the climate of South America by blocking moist easterly trade winds from the Atlantic Ocean. This results in a sharp contrast between the wet eastern side of the range, where the Amazon rainforest thrives, and the arid western side, which includes the Atacama Desert, one of the driest places on Earth. The high elevations of the Andes also create a variety of microclimates, with temperature and precipitation decreasing with altitude.

3. Rockies

Alignment: The Rocky Mountains stretch over 4,800 km from British Columbia in Canada to New Mexico in the United States.

Impact on Weather: The Rockies influence weather patterns in North America by creating a barrier to the west-to-east movement of air masses. As a result, they cause the orographic lifting of moist air from the Pacific Ocean, leading to heavy precipitation on their western slopes and forming a rain shadow on the eastern side. This results in the semi-arid climate of the Great Basin and the Great Plains. The varied elevation of the Rockies also creates diverse microclimates, from subalpine forests to alpine tundra.

4. Alps

Alignment: The Alps are a prominent mountain range in Europe, spanning approximately 1,200 km across eight countries, including France, Italy, Switzerland, and Austria.

Impact on Weather: The Alps act as a climatic divide in Europe, affecting the distribution of precipitation and temperature. The range intercepts moist air masses from the Atlantic Ocean and Mediterranean Sea, causing heavy rainfall on the southern slopes and creating a rain shadow on the northern side. This leads to the relatively dry climate of the Po Valley in Italy and the Swiss Plateau. The high altitude of the Alps also results in a wide range of microclimates, supporting a diverse range of flora and fauna.

Conclusion

In summary, the alignment of major mountain ranges significantly impacts local weather conditions by acting as barriers to air masses and influencing precipitation, temperature, and wind patterns. This leads to the formation of rain shadows, diverse microclimates, and unique ecosystems. Examples of mountain ranges with notable impacts on weather include the Himalayas, the Andes, the Rockies, and the Alps.