Wind chime Japanese glass wind bells known as "fūrin" () have been produced since the Edo period, and those at Mizusawa Station are one of the 100 Soundscapes of Japan. Wind chimes are thought to be good luck in parts of Asia and are used in Feng Shui. Wind chimes started to become modernized around 1100 B.C. after the Chinese began to cast bells. A bell without a clapper, called a "yong-zhong", was crafted by skilled metal artisans and primarily used in religious ceremonies. Afterwards, the Chinese created the "feng-ling", which is similar to today's modern wind bell. Feng-lings were hung from
Wind gradient which differences can be as little as 5% in unstable air. In kitesurfing, the wind gradient is even more important, because the power kite is flown on 20-30m lines, and the kitesurfer can use the kite to jump off the water, bringing the kite to even greater heights above the sea surface. Wind gradient can have a pronounced effect upon sound propagation in the lower atmosphere. This effect is important in understanding sound propagation from distant sources, such as foghorns, thunder, sonic booms, gunshots or other phenomena like mistpouffers. It is also important in studying noise pollution, for example from