Trade winds originate more from the direction of the poles (northeast in the Northern Hemisphere, southeast in the Southern Hemisphere) during the cold season, and are stronger in the winter than the summer. … The cold phase of the AO leads to weaker trade winds.
What causes strong trade winds?
Trade winds are caused by the strong warming and evaporation within the atmosphere around the equator. (1) Around the equator, the warm air rises rapidly, carrying a lot of moisture. … (4) There, it changes direction and flows back towards the equator, to restart the circulation process.
What effect do trade winds have on weather?
Intense solar heat in the doldrums warms and moistens the trade winds, thrusting air upwards into the atmosphere like a hot air balloon. As the air rises, it cools, causing persistent bands of showers and storms in the tropics and rainforests.
What is the strength of trade winds?
Its average speed is about 5 to 6 metres per second (11 to 13 miles per hour) but can increase to speeds of 13 metres per second (30 miles per hour) or more. The trade winds were named by the crews of sailing ships that depended on the winds during westward ocean crossings.
What are the main features of trade winds?
The main characteristics of the Trade winds are:
- The Trade winds blow in the tropics between the sub tropical high pressure belt to the equatorial low pressure belt between 30°N and 30°S.
- Trade winds are warm winds and hence they pick up moisture and bring heavy rainfall on the eastern sides of the tropical islands.
What causes the trade winds to weaken?
The easterly trade winds are driven by a surface pressure pattern of higher pressure in the eastern Pacific and lower pressure in the west. When this pressure gradient weakens, so do the trade winds. The weakened trade winds allow warmer water from the western Pacific to surge eastward, so the sea level flattens out.
Why is it called trade winds?
Named from Old English Trade = path, because of their regular course, these winds are the tropical easterlies, northeast Trades in the Northern Hemisphere and southeast Trades in the Southern Hemisphere.
Are westerlies trade winds?
The remaining air (air that does not descend at 30 degrees North or South latitude) continues toward the poles and is known as the westerly winds, or westerlies. The trade winds are so named because ships have historically taken advantage of them to aid their journies between Europe and the Americas (Bowditch, 1995).
Are westerlies warm or cold?
The winter westerlies, often from the southwest, bring in warm tropical air; in summer, by contrast, they veer to the northwest and bring in cooler Arctic or subarctic air. In Mediterranean Europe the rain-bearing westerlies chiefly affect the western areas, but only in winter.