Mechanism of Weather in the Summer Season
Surface Pressure and Winds
- As the summer sets in and the sun shifts northwards, the wind circulation over the subcontinent undergoes a complete reversal at both, the lower as well as the upper levels.
- By the middle of July, the low-pressure belt nearer the surface [termed as Inter Tropical Convergence Zone (ITCZ)] shifts northwards, roughly parallel to the Himalayas between 20° N and 25° N.
- By this time, the westerly jet stream withdraws from the Indian region.
Jet Streams and Upper Air Circulation
Easterly Jet Streams flows over the southern part of the Peninsula in June and has a maximum speed of 90 km per hour. In August, it is confined to 15 degrees north latitude, and in September up to 22 degrees north Latitude.
- The easterlies normally do not extend to the north of 30 North degrees latitude in the upper atmosphere.
Easterly Jet Streams and Tropical Cyclones
The easterly jet stream steers the tropical depressions into India. These depressions play a significant role in the distribution of monsoon rainfall over the Indian subcontinent.
- The tracks of these depressions are the areas of highest rainfall in India.
- The frequency at which these depressions visit India, their direction, and intensity, all go a long way in determining the rainfall pattern during the southwest monsoon period.
Conclusion
- Weather is caused mainly by the changes in air pressure, temperature, and moisture from one location to another.
- The significant temperature difference between polar and tropical air causes large-scale atmospheric circulation cells and the jet streams.
- In India, during the winter, the northern region near the Himalayas experiences high pressure. As a result, winds from this area move south, where the pressure is lower.
- The northern section of the country has lower pressure in the summer.
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Mechanism of Weather in the Winter and Summer Season
Mechanism of Weather in the Winter and Summer Season: There are variations in weather conditions during different seasons. These changes occur due to weather temperature, pressure, wind direction, velocity, humidity, precipitation, etc.
In this article, we will focus on the weather mechanism during the winter and summer seasons.
Mechanism of Weather in the Winter and Summer Season