Inversions
What conditions favor a temperature inversion?
What are the results of air being forced upward?
Where would you see the first sign of ice buildup?
The first sign of ice buildup is often seen on the leading edges of aircraft surfaces, such as wings and tail surfaces, anything protruding into the relative wind due to the impact of supercooled water droplets.
What causes global circulation?
Differential heating is why we have different weather patterns, jet streams, deserts, and prevailing winds. Global atmospheric circulation is caused by the rotation of the Earth and the amount of heat different parts of the globe receive.
What is the Coriolis effect in simple terms?
Because the Earth rotates on its axis, circulating air is deflected toward the right in the Northern Hemisphere and toward the left in the Southern Hemisphere. This deflection is called the Coriolis effect.
What happens when an inversion occurs?
Temperature Increase with Altitude: Instead of cooling with altitude, the temperature increases, creating a stable layer in the atmosphere.
Suppression of Vertical Movement: The inversion layer acts as a barrier, preventing air from rising and mixing, which can trap pollutants and lead to poor air quality.
Fog Formation: If the surface air is moist, it can cool to its dew point, leading to fog formation beneath the inversion layer.
Stable Conditions: The atmosphere becomes more stable, reducing the likelihood of cloud formation and thunderstorms.
Why don't clouds drift upward into outer space?
Clouds don’t float into outer space because gravity keeps the tiny water droplets or ice crystals in the Earth's atmosphere. Despite their low density, gravity prevents them from escaping into space.
Name 3 kinds of structural icing.
rime, clear, mixed
What is the 3-cell model?
In each hemisphere, air circulates through three cells (Hadley, Ferrel, and Polar) across the troposphere, which extends from the Earth's surface up to 10-15 km (32,808 to 49,213 feet) in altitude.
What is Geostrophic Wind?
Geostrophic wind results from the balance between the pressure gradient force and the Coriolis force, blowing parallel to isobars in the upper atmosphere where friction is minimal.
What does "subsidence" mean in the context of inversions?
In the context of inversions, "subsidence" refers to the downward movement of air from higher altitudes. This descending air can compress and warm as it descends, reinforcing the inversion layer and trapping pollutants near the surface.
What are the 4 cloud families?
Low, middle, high, and clouds with vertical development.
The two ingredients for structural icing?
What are the 3 cells in the global circulation?
Hadley, Ferrel, and Polar
What are isobars?
Isobars are lines on a weather map that connect points of equal atmospheric pressure.
Can a temperature inversion cause fog?
Yes, a temperature inversion can cause fog. Inversions trap cooler air near the surface, and if the air near the ground is moist, it can cool to its dew point, forming fog.
What is the composition of cirrus clouds?
Ice crystals
The first places that a pilot should look for the formation of ice on the aircraft are
leading edges of the airfoils, any objects that protrude into the air flow, such as antennas, OAT probe, etc.
Why is Global Circulation important?
Atmospheric circulation transports heat over the surface of the Earth that affects the water cycle, including the formation of clouds and precipitation events. The movement of air masses brings us our daily weather, and long-term patterns in circulation determine regional climate and ecosystems.
Why the Coriolis effect is zero at the Equator?
As air tries to move from high to low pressure in the atmosphere, the Coriolis force diverts the air so that it nearly aligns parallel to the pressure contours.
What are the effects of temperature inversion?
Poor air quality, reduced vision, turbulence, wind shear, abnormal aircraft performance, and decreased rain cloud formation are among the problems.
Why are clouds white?
Clouds are white because their water droplets or ice crystals scatter all wavelengths of light, combining to create white light.
The three types of icing intensities are
trace, moderate, and severe
Why does air rise at 60 latitude?
Around 60°N and 60°S, warm air from the tropics meets colder polar air. The lighter, warmer air rises as these two air masses collide.
Why does the pressure gradient force point from high to low pressure?
The wind is caused by pressure differences, with the pressure gradient driving the air from high to low pressure. Strong gradients lead to higher wind speeds, while weak gradients result in lighter winds. Air curves around pressure systems due to Coriolis and centrifugal forces, with friction not included here.