What does the easterly wave do?
What does the easterly wave do?
A tropical wave (also called easterly wave, tropical easterly wave, and African easterly wave), in and around the Atlantic Ocean, is a type of atmospheric trough, an elongated area of relatively low air pressure, oriented north to south, which moves from east to west across the tropics, causing areas of cloudiness and …
Where do easterly waves develop?
Easterly waves originate in and adjacent to the eastern part of tropical oceans and move westward at speeds ranging from 10 to 20 knots. Their nature and structure have been examined in detail, especially in the Atlantic Ocean and the Caribbean.
Where do tropical cyclones acquire most of their energy?
Tropical cyclones typically form over large bodies of relatively warm water. They derive their energy through the evaporation of water from the ocean surface, which ultimately condenses into clouds and rain when moist air rises and cools to saturation.
What causes easterly wave?
Also called an easterly wave, African easterly wave, invest, or tropical disturbance, a tropical wave is generally a slow-moving disturbance that’s embedded in the easterly trade winds. To put that more simply, it’s a weak trough of low pressure that develops from an unorganized cluster of thunderstorms.
What role do African easterly waves play in the formation of tropical cyclones?
These waves, which propagate westward, are important because they are linked with convective rainfall, the variability of which can have devastating societal impacts in Africa. They are also noted for being precursors to tropical cyclones in the tropical Atlantic and east Pacific Ocean basins.
What is an easterly current?
C. Easterly Surface Currents: As western boundary currents reach latitudes of the prevailing westerly winds, they become easterly currents. The best known examples are the continuation of the Gulf Stream as it moves toward Europe and the North Pacific Current.
How often do easterly waves occur?
Easterly waves last from a couple of days to several weeks and new waves are developing at intervals of 3 to 4 days. Generally more slowly than the current in which it is embedded a typical easterly wave travels at speeds between 10 to 15 knots resulting in a wavelength of about 2,000 to 2,500 km.
Where do cyclones derive their energy?
Structurally, a tropical cyclone is a large, rotating system of clouds, wind, and thunderstorms. Its primary energy source is the release of the heat of condensation from water vapor condensing at high altitudes, the heat being ultimately derived from the sun.
What causes tropical cyclones?
Tropical cyclones are low pressure systems that form over warm tropical waters. They typically form when the sea-surface temperature is above 26.5°C. Tropical cyclones can continue for many days, even weeks, and may follow quite erratic paths. A cyclone will dissipate once it moves over land or over cooler oceans.
How are easterly waves associated with hurricanes?
Easterly Waves are not associated with particularly high dew points, but can be associated with enough water vapor so that clusters of thunderstorms can form in association with them. Also, Easterly Waves are associated with only weak to moderately intense surface lows.
How do African easterly waves form?
The mid-level African easterly jet develops because heating of the West African land mass during this time of year creates a surface temperature and moisture gradient between the Gulf of Guinea and the Sahara Desert. The atmosphere responds by generating vertical wind shear to maintain thermal wind balance.
What is easterly wave or trade winds?
Tropical cyclones often develop along easterly waves. These waves, or oscillations, in the trade winds move from east to west across the tropics. Satellite imagery provides the best view of an easterly wave. As low-level winds enter the trough of the wave, they converge, causing convection.
What direction is an easterly wind?
Winds are also described with the direction they blow. Easterly winds blow from the east, while westerly winds blow from the west.
How do tropical cyclones develop?
Several conditions are needed for a tropical cyclone to form: High sea temperatures of at least 27°C. Converging winds near the ocean surface forcing air to rise and form storm clouds. Winds that do not vary greatly with height – known as low wind shear.
Where do tropical cyclones occur?
Tropical cyclones are referred to by different names depending on where they originate in the world. Hurricanes occur in the Atlantic Ocean and the eastern north Pacific Ocean. Typhoons occur in the western Pacific Ocean. Tropical cyclones occur in the south Pacific Ocean and Indian Ocean.
Where do most tropical cyclones occur?
The Pacific Ocean
The Pacific Ocean generates the greatest number of tropical storms and cyclones. The most powerful storms, sometimes called super typhoons, occur in the western Pacific. The Indian Ocean is second in the total number of storms, and the Atlantic Ocean ranks third.
What are the tropical easterlies?
[′träp·ə·kəl ′ēs·tər·lēz] (meteorology) The trade winds when shallow and exhibiting a strong vertical shear; at about 500 feet (152 meters) the easterlies give way to the upper westerlies, which are sufficiently strong and deep to govern the course of cloudiness and weather.
Where are the easterlies?
They are dry and cold prevailing winds that blow specifically from the east, hence the term easterlies. They occur around high-pressure zones within the North and South Poles.
How does a tropical wave become a hurricane?
As a storm grows, it changes. It starts as a tropical disturbance. Then, with cyclonic circulation and faster wind speeds, it becomes a tropical depression. If the wind keeps getting faster, it becomes a tropical storm and then a hurricane if winds are more than 74 miles per hour (mph).