Trade winds, Jet Streams and Monsoons

            China is located at 32.9043° N, 110.4677° E, whose general latitude ranges between roughly 20° N - 50° N. The large land mass is thus affected by different wind circulation paths. Trade winds are winds that blow east to west, while winds that flow from west to east are known as jet streams. Jet streams fast-moving high-altitude narrow air currents in the atmosphere. Tropical easterly winds affected by the subtropical jet stream move from east to west toward the ITCZ while westerly winds move to the east toward the subpolar jet stream. China is mainly influenced by the high, subtropical jet stream. Northern jet streams are caused by a combination of the planet’s rotation as well as atmospheric heating, where boundaries of meandering air masses hold differences in temperature. Jet streams move moisture in Earth’s atmosphere and are partially responsible for changes in our weather. 

The photo on the left depicts Earth's trade winds and the corresponding jet streams. Notice direction of the winds as well as the latitudes of the jet streams. The photo on the right depicts the flow of Earth's jet streams, which travel west to east. Right:http://ww2010.atmos.uiuc.edu/guides/mtr/hurr/gifs/mvmt1.gif

Left: http://whyfiles.org/wp-content/uploads/2010/10/jet_stream_globe.jpg

As hot air rises, due to the sun warming the Earth’s surface, water vapor also rises into the sky near the equator. As the Northern hemisphere warms in spring and summer, the winds change due to a differences in pressure, in part caused by warm and cold fronts. Monsoon winds, for example, blow in opposite directions during different times of the year and are accompanied by corresponding changes in perception. Monsoons in China occur in this way. Instead of the winds blowing towards Africa via the tropical easterlies, the wind blows across the Indian Ocean all the way to Japan. China’s summer monsoon includes warm winds from the tropics and picks up large amounts of water due to evaporation as it crosses the India Ocean. As the warm, moist winds lift and travel over the Himalayas and the Tibetan Plateau, it condenses into rain or snow.

This diagram depicts China's summer monsoon winds. Winds pick up large amounts of water from the Indian Ocean and travel towards Japan, changing direction in the fall when the temperatures begin to drop.

Image: http://www.shrimpnews.com/Graphics/ShrimpPictures/Monsoon.JPEG

Info source: http://www.yourchildlearns.com/china-monsoon.html