Final answer:
Monsoons form in China due to the seasonal reversal of winds, bringing in moist air in the summer and dry air in the winter. They change during the summer and winter months, with the summer monsoons providing water for agriculture and the winter monsoons bringing moisture to Sri Lanka and southeastern India. Monsoons in China create well-defined summer rainy seasons in the southern portion of the Yangtze River.
Step-by-step explanation:
The monsoons form in China due to the seasonal reversal of winds that brings in moist air in the summer and dry air in the winter across southern and eastern Asia. In the summer months, the continent heats up, creating a vacuum that pulls in warm, moist air from the Bay of Bengal and the Indian Ocean. This moist air is then precipitated as rain over land. In the winter, cold, dry air from the north replaces the monsoon winds, resulting in a dry season in South Asia.
During the summer months, the monsoon rains are a major source of support for South Asia's large population. The rains bring fresh water to grow food, replenishing rivers and streams. However, they can also lead to flooding, particularly in coastal areas along the Bay of Bengal. In the winter, the monsoon winds that come down from the north can pick up moisture from the Bay of Bengal before depositing it on the shores of Sri Lanka and southeastern India, resulting in a rainy winter monsoon in these regions.
In China, the central portion known as China Proper has a subtropical climate, which includes the southern portion of the Yangtze River. Monsoons play a role in creating well-defined summer rainy seasons in this region.