Planetary wind is the out gassing of what?
A: Light chemical elements from a planet's atmosphere into space.
Winds are commonly classified by their what?
A: Their spatial scale, their speed, the types of forces that cause them, the regions in which they occur, and their effect.
The strongest observed winds on a planet in the Solar System occur on what two planets?
A: Neptune and
Winds have various aspects, an important one being its velocity (wind speed); another is what?
A: The density of the gas involved and another is its energy content or
Wind is also a great source of transportation for what?
A: Seeds and small birds; with time things can travel thousands of miles in the wind.
In meteorology, winds are often referred to according to their what?
A: Their strength, and the direction from which the wind is blowing.
Short bursts of high-speed wind are termed what?
What are strong winds of intermediate duration (around one minute) termed?
Long-duration winds have various names associated with their what?
A: Average strength, such as breeze, gale, storm, and
Wind occurs on a range of scales, from thunderstorm flows lasting tens of minutes, to local breezes generated by what?
A: Heating of land surfaces and lasting a few hours, to global winds resulting from the difference in absorption of solar energy between the climate zones on Earth.
What are the two main causes of large-scale atmospheric circulation?
A: The differential heating between the equator and the poles, and the rotation of the planet (Coriolis effect).
Within the tropics, thermal low circulations over terrain and high plateaus can drive what?
A: Monsoon circulations.
In coastal areas the sea breeze/land breeze cycle can define what?
A: Local winds; in areas that have variable terrain, mountain and valley breezes can dominate local winds.
In human civilization, the concept of wind has been explored in
mythology, influenced the events of
history, expanded the range of transport and warfare, and provided a what?
A: A power source for mechanical work,
electricity and recreation.
Wind powers the voyages of what?
A: Sailing ships across Earth's
Hot air balloons use the wind to take short trips, and powered flight uses it to what?
A: Increase lift and reduce fuel consumption.
Areas of wind shear caused by various weather phenomena can lead to what?
A: Dangerous situations for
When winds become strong, trees and human-made structures can be what?
A: Damaged or destroyed.
Winds can shape landforms, via a variety of aeolian processes such as the formation of what?
A: Fertile soils, such as loess, and by erosion.
Dust from large deserts can be moved great distances from its source region by what?
A: The prevailing winds.
Winds that are accelerated by rough topography and associated with dust outbreaks have been assigned regional names in various parts of the
world because of what?
A: Their significant effects on those regions.
Wind also affects the spread of what?
When combined with cold temperatures, wind has a negative impact on what?
Wind affects animals'
food stores, as well as their what?
A: Hunting and defensive strategies.
When a difference in atmospheric pressure exists, air moves from the higher to the lower pressure area, resulting in what?
A: Winds of various speeds.
On a rotating planet, air will also be deflected by what?
A: The Coriolis effect, except exactly on the equator.
Globally, the two major driving factors of large-scale wind patterns (the atmospheric circulation) are what?
A: The differential heating between the equator and the poles (difference in absorption of solar energy leading to buoyancy forces) and the rotation of the planet.
Outside the tropics and aloft from frictional effects of the surface, the large-scale winds tend to approach what?
A: Geostrophic balance.
Near the Earth's surface, friction causes the wind to be what?
A: Slower than it would be otherwise.
Surface friction also causes winds to blow more what?
A: Inward into low-pressure areas.
The geostrophic wind component is the result of the balance between what?
A: The Coriolis force and pressure gradient force.
It flows parallel to isobars and approximates the flow above the what?
A: The atmospheric boundary layer in the midlatitudes.
The thermal wind is the difference in the geostrophic wind between what?
A: Two levels in the atmosphere.
It exists only in an atmosphere with what?
A: Horizontal temperature gradients.
Wind direction is usually expressed in terms of the direction from which it what?
For example, a northerly wind blows from where to where?
A: The north to the south.
Weather vanes pivot to indicate what?
A: The direction of the wind.
At airports, windsocks indicate wind direction, and can also be used to estimate what?
A: Wind speed by the angle of hang.
Wind speed is measured by what?
A: Anemometers, most commonly using rotating cups or propellers.
Another type of anemometer uses pitot tubes that take advantage of what?
A: The pressure differential between an inner tube and an outer tube that is exposed to the wind.
Sustained wind speeds are reported globally at what height?
A: At 10 meters (33 ft) high, and are averaged over a 10‑minute time frame.
The United States reports winds over a 1‑minute average for what?
A: Tropical cyclones, and a 2‑minute average within weather observations.
Knowing the wind sampling average is important, as the value of a one-minute sustained wind is typically 14% greater than what?
A: A ten-minute sustained wind.
Geostationary satellite imagery can be used to estimate the winds throughout the atmosphere based upon what?
A: How far clouds move from one image to the next.
Wind engineering describes the study of the effects of the wind on what?
A: The built environment, including buildings, bridges and other man-made objects.
Historically, the Beaufort wind force scale (created by Beaufort) provides an empirical description of wind speed based on observed what?
A: Sea conditions.
Originally it was a 13-level scale, but during the
1940s, the scale was expanded to how many levels?
The Enhanced Fujita Scale (EF Scale) rates the strength of
tornadoes in the United States based on what?
A: The damage they cause.
Wind energy is the kinetic energy of what?
A: The air in motion.
Easterly winds, on average, dominate the flow pattern across what?
A: The poles.
Westerly winds blow across what?
A: The mid-latitudes of the earth, polewards of the subtropical ridge.
Directly under the subtropical ridge are the doldrums, or horse latitudes, where winds are what?
Many of the Earth's deserts lie near the average latitude of the subtropical ridge, where descent reduces what?
A: The relative humidity of the air mass.
The strongest winds are where?
A: In the mid-latitudes where cold polar air meets warm air from the tropics.
The trade winds (also called trades) are the prevailing pattern of easterly surface winds found where?
A: In the tropics towards the Earth's equator.
The trade winds blow predominantly from where?
A: From the northeast in the Northern Hemisphere and from the southeast in the Southern Hemisphere.
The trade winds act as the steering flow for what?
A: Tropical cyclones that form over the world's oceans.
Trade winds also steer African dust westward across the Atlantic Ocean into where?
A: The Caribbean, as well as portions of southeast North America.