Weather Flashcards
The atmosphere is made up of what?
78 % Nitrogen, 21 % Oxygen, and 1% other
How high does the Troposphere extend?
Up to 20,000 feet over the northern and southern poles, 48,000 over the equatorial regions.
In the Troposphere what is the Temperature and pressure decrease rate?
Temp. 2 for every 1,000
Pres. 1 in. per 1,000 feet gained
Where is the tropopause?
Boundary layer above the troposphere.
How high is the stratosphere?
Above the Tropopause up to 160,000 feet.
What is standard level pressure and temp.?
29.92 and 15 degrees C.
What is the conditions for Low Level Wind Shear?
Directional wind changes of 180 degrees and speed changes of 50 knots or more.
What is a micro burst?
Occurs in a space of less than one mile horizontally and within 1,000 feet vertically. Life span of about 15 min. produce down drafts up to 6,000 per minute.
What is the dry adiabatic lapse rate? (unsaturated air)
3 degrees C per 1,000 feet
Moist Adiabatic lapse rate?
1.1 to 2.8 degrees C per 1,000 feet
What are the three states that water can be present in the atmosphere?
Liquid, Solid, Gaseous
What is humidity?
Refers to the amount of water vapor present in the atmosphere at a given time.
What is dew point?
Is the temperature at which the air can hold no more moisture.
What are the 4 methods that air can reach its saturation point?
- when warm air moves over a cold surface, the air temp. drops and reaches saturation.
- Cold air and warm air mix.
- Air cools at night through contact with the cooler ground
- air is lifted or is forced upward in the atmosphere
What is fog?
A cloud that begins within 50 feet of the surface.
Radiation Fog?
Ground cools rapidly and the surrounding air reaches saturation. If thicker than 20 feet is known as ground fog.
Advection Fog
Same as radiation fog, but with a wind up to 15 knots.
Up Slope Fog
When moist, stable air is forced up sloping land features like a mountain range.
Steam fog
Cold dry air, moves over warm water. Low level turbulence and icing are commonly associated with steam fog.