Presence of high mountains and orography

The main reason for the variation in rainfall received by different regions of India during the monsoon season is the presence of high mountains and orography. The topography of a region plays a significant role in influencing the distribution and intensity of rainfall during the monsoon.

The Influence of Mountains
Mountains act as barriers to the flow of moist air masses, causing them to rise and cool. As the air rises, it cools and condenses, leading to the formation of clouds and precipitation. Therefore, regions located in the windward side of the mountains receive higher rainfall compared to the leeward side.

Orographic Precipitation
Orographic precipitation refers to the rainfall that occurs due to the lifting of moist air over mountains. When the moisture-laden monsoon winds encounter a mountain range, they are forced to ascend. As the air rises, it cools and condenses, resulting in rainfall. This phenomenon is known as orographic rainfall.

Effect on Rainfall Distribution
The presence of the Western Ghats along the west coast of India and the Himalayan mountain range in the north significantly influence the distribution of rainfall during the monsoon season.

Western Ghats
The Western Ghats act as a barrier to the southwest monsoon winds, causing them to rise and bring heavy rainfall to the windward side, which includes the coastal regions of Kerala, Karnataka, and Maharashtra. These regions receive abundant rainfall during the monsoon season.

Himalayas
The Himalayan mountain range plays a crucial role in determining the rainfall patterns in northern India. The monsoon winds, after crossing the Western Ghats, move towards the north and encounter the Himalayas. As the winds ascend the slopes of the Himalayas, they cool and condense, resulting in heavy rainfall in the foothills and the northern plains of India. However, the rain shadow effect occurs on the leeward side of the Himalayas, leading to a decrease in rainfall in regions such as Ladakh and parts of Rajasthan.

Conclusion
In conclusion, the presence of high mountains and orography greatly influences the variation in rainfall received by different regions of India during the monsoon season. The mountains act as barriers and cause the moist air to rise, leading to orographic precipitation. The Western Ghats and the Himalayas play a significant role in determining the distribution and intensity of rainfall, resulting in varying rainfall patterns across different regions of India.

The main reason for the variation in rainfall received by different regions of India during the monsoon season is the presence of high mountains and orography. When moist air is forced to ascend the slopes of mountain ranges or the edge of plateaus, it cools down, gets saturated, and leads to heavy rainfall on windward slopes. This creates variations in rainfall patterns across the country.