PHAK 12: Weather Flashcards
How high does the Earth’s atmosphere extend vertically?
Almost 350 miles.
What is the composition of the atmosphere?
- 78% Nitrogen
- 21% Oxygen
- 1% Other gases (mostly Argon)
What are the layers of the atmosphere from Earth to space?
- Troposphere
- Tropopause
- Stratosphere
- Mesosphere
- Thermosphere
- Exosphere
Certain factors combine to set the atmosphere in motion, but a major factor is…
The uneven heating of the Earth’s surface.
What causes higher temperatures in equatorial areas?
Solar heating.
How much would a sealed column of air 350 miles high with a 1 square inch footprint weigh?
14.7 lbs
What is the Coriolis force?
A force caused by Earth’s rotation that deflects moving air and water.
Mercurial Barometer
A barometer that measures atmospheric pressure using a column of mercury.
Aneroid barometer
An instrument that measures the absolute pressure of the atmosphere by balancing the weight of the air above it against the spring action of the aneroid.
The Coriolis force deflects air to the ______ in the Northern Hemisphere.
Right
Standard Sea Level Pressure
- 59°F or 15°C
- 29.92” Hg or 1013.2 mb
What causes Convective Currents?
Plowed ground, rocks, sand, and barren land absorb solar energy quickly and can therefore give off a large amount of heat; whereas, water, trees, and other areas of vegetation tend to more slowly absorb heat and give off heat. The resulting uneven heating of the air creates small areas of local circulation called convective currents.
Effect of Obstructions on Wind
Obstructions on the ground affect the flow of wind and can be an unseen danger. Ground topography and large buildings can break up the flow of the wind and create wind gusts that change rapidly in direction and speed.
Depiction of winds on a surface weather chart.
Calm
Depiction of winds on a surface weather chart.
NW/5 kts
Depiction of winds on a surface weather chart.
SW/20 kts
Depiction of winds on a surface weather chart.
E/35 kts
Depiction of winds on a surface weather chart.
N/50 kts
Depiction of winds on a surface weather chart.
W/105 kts
Wind conditions
Each barb represents a speed of…
10 knots.
Wind conditions
Each half barb represents a speed of…
5 knots.
Wind conditions
Each pennant represents a speed of…
50 knots.
What are the characteristics of stable air?
Calm conditions and smooth airflow.
What type of clouds form in Stable Air?
Stratiform clouds