Atmosphere composition
78% nitrogen
21% oxygen
1% other gases
4 layers of the atmosphere
Troposphere
Stratosphere
Mesosphere
Thermosphere
What are the layers of the atmosphere defined by?
-average lapse rates
-chemical composition
-movement
-density
Where does most weather occur?
The troposphere
What separates the troposphere from the stratosphere?
The tropopause at 36,000ft
Standard temp
15C/59F
Standard temp lapse rates
2C/1000ft/3.5F/1000ft
Standard pressure
1013.25 HPA/29.92”Hg
Pressure lapse rate
1”Hg/1000ft
Relative humidity
Water vapor in the air/water vapor capacity
Cloud base calculation
((OAT-dewpoint)/4.4F or 2.5C)*1000
Types of fog
Advection
Radiation
Ice
Upslope
Steam
Advection fog
Warm air moving over a cold surface, common in coastal areas where warm ocean air moves over the cold ground
Radiation fog
Formed by the ground cooling rapidly and cooling the air with it, common on clear nights with no wind in low areas
Ice fog
Similar to radiation fog, but with temps below -25
Upslope fog
Moist, stable air is pushed up a mountain, cooling and forming fog that can last for days
Steam fog
Cold dry air moved over warm water, and evaporating water is cooled into fog
High pressure systems
-clockwise
-down and out
-stable
-poor visibility
-less severe weather
Low pressure system
-counter clockwise
-in and up
-unstable
-good visibility
-more severe weather
What do you need to look out for if you fly from a high pressure area to a low pressure area?
Your altimeter will read higher than your true altitude, so you will be flying lower than you think you are
Warm front
-slow moving 10-25mph
-high humidity
-stable air
-widespread layered stratiform cloudiness
-poor visibility
Cold front
-faster 25-30 mph
-storms
-unstable
-good visibility
Cold front occlusion
-Cold front is colder than the airmass it is replacing
-mix of warm and cold front
Warm front occlusion
-air in front of the front is colder than the cold front
-more severe weather
