NIFE Weather ELOs
Study online at https://quizlet.com/_e3jbty
1. Describe the characteristics of the troposphere: Layer adjacent to earths
surface, 55k ft over equator to 28k over poles.
avg height is 36k, higher in summer.
temp decreases as altitude increases, and nearly all weather occurs here.
winds range from light at surface to 200 kts near the top
2. Define atmospheric pressure: the pressure exerted by the weight of the atmos-
phere over a column of air.
3. what is the standard unit of pressure measurement and atmospheric pres-
sure at sea level: Pressure measurement is measured in inches of mercury (In-Hg)
and millibars.
standard measurements are 29.92 in-hg and 1013.25 mb
4. explain a pressure gradient: rate of pressure change perpendicular to the
isobars. stronger when isobars are closer together.
5. Standard Lapse Rate: 2 °c/1,000ft
3.6 F/1000ft
rate at which temperature decreases with altitude.
6. what is a standard atmosphere: 29.92 hg or 1013.2mb
15 C or 59 F
1"hg/ 1000ft. or 34 mb/1000ft.
2 C / 1000ft or 3.ft
LSOS 661.7 knots or 340.4 m/s
7. What is the difference in sea level pressure and station pressure: Station
pressure is the atmospheric pressure measured directly at an airfield or other
weather station.
sea level pressure is the pressure that would be measured if the eisting weather
station were at MSL.
Sea level pressure can always be calculated from station pressure by adding or
subtracting the standard lapse rate.
8. define an air mass: Body of air that's humidity and temperature are almost
uniform throughout.
warm air masses bring stable conditions, and cold air masses are usually unstable.
, NIFE Weather ELOs
Study online at https://quizlet.com/_e3jbty
cold air masses come from north and move cold air over warm surfaces, and warm
air masses come from south and are warmer over the surface.
9. Describe saturation: Saturation is when the air contains the maximum amount
of water vapor it can hold for that temperature.
10. Define dew point temperature and dew point depression: Dew point is the
temperature in which saturation occurs.
Difference between the temperature and dew point is called the dew point depres-
sion
A higher dewpoint=more clouds
smaller depression=likely clouds, fog, moisture. (around 4 deg F, 2 deg C)
can also occur from air cooling to dew point temp
11. explain why atmospheric circulation occurs: Occurs from large temperature
difference between tropics and polar region, and complicated further by the uneven
heating of land and water by the sun.
12. Define relative humidity: Amount of moisture in air compared to the saturation
level in percent.
13. Indicated Altitude: Altitude read directly from the altimeter. must have updated
reference in kollsman window to be useful. Will then display MSL.
14. Calibrated altitude: Indicated altitude corrected for instrument error
15. Mean Sea Level (MSL): True altitude, or the average height above standard sea
level where the atmospheric pressure is measured in order to calibrate altitude.
airfields, hazards, and terrain elevations are all stated in MSL.
16. Above Ground Level (AGL): Height above the ground over which you're flying
17. Pressure Altitude: The height above the standard datum plane.
actual elevation from standard pressure plane of 29.92 in-hg.
18. Density Altitude: The pressure altitude corrected for nonstandard temperature.
, NIFE Weather ELOs
Study online at https://quizlet.com/_e3jbty
19. Pressure changes effects on aircraft altimeters: As an aircraft flies from high
to low pressure: "look out below" as your airplane will be lower than your indicated
altitude.
As an aircraft flies from low to high: "plenty of sky" as your aircraft will be higher than
indicated altitude.
A change in pressure of .10 In-Hg will change the altimeter setting 100 feet.
20. How does temperature deviations from standard lapse rate effect aircraft
altimeters: for every 11 deg C that the temp varies from standard, the altimeter will
have a 4 percent error.
If temp is LOWER than standard: Aircraft will be higher than indicated.
If temp is HIGHER than standard: aircraft will be lower than indicated.
21. Define Temperature inversion: A temperature inversion is when the tempera-
ture rises with altitude instead of falls.
22. Explain and identify gradient winds with respect to isobars around pres-
sure systems in northern hemisphere: Air circulates parallel (or close to parallel)
to isobars, and CLOCKwise around high pressure and COUNTERCLOCKwise
around low pressure.
23. Identify surface wind direction with respect to gradient winds in a pres-
sure system in the Northern Hemisphere: Pressure gradient force (high to low
pressure force) causes air to flow perpendicular to isobars, however when coriolis
force is added, this diverts the air to the right with respect to its inital direction of
motion.
Thus the combination of these forces produces the CW motion around high and
CCW motion around low
Found Above 2000 Ft.
24. Surface winds: Blow at a 45 degree angle relative to parallel flow CW around
high and CCW around low
25. describe the jet stream: Strong, narrow band of high speed wind in upper
troposphere.
Study online at https://quizlet.com/_e3jbty
1. Describe the characteristics of the troposphere: Layer adjacent to earths
surface, 55k ft over equator to 28k over poles.
avg height is 36k, higher in summer.
temp decreases as altitude increases, and nearly all weather occurs here.
winds range from light at surface to 200 kts near the top
2. Define atmospheric pressure: the pressure exerted by the weight of the atmos-
phere over a column of air.
3. what is the standard unit of pressure measurement and atmospheric pres-
sure at sea level: Pressure measurement is measured in inches of mercury (In-Hg)
and millibars.
standard measurements are 29.92 in-hg and 1013.25 mb
4. explain a pressure gradient: rate of pressure change perpendicular to the
isobars. stronger when isobars are closer together.
5. Standard Lapse Rate: 2 °c/1,000ft
3.6 F/1000ft
rate at which temperature decreases with altitude.
6. what is a standard atmosphere: 29.92 hg or 1013.2mb
15 C or 59 F
1"hg/ 1000ft. or 34 mb/1000ft.
2 C / 1000ft or 3.ft
LSOS 661.7 knots or 340.4 m/s
7. What is the difference in sea level pressure and station pressure: Station
pressure is the atmospheric pressure measured directly at an airfield or other
weather station.
sea level pressure is the pressure that would be measured if the eisting weather
station were at MSL.
Sea level pressure can always be calculated from station pressure by adding or
subtracting the standard lapse rate.
8. define an air mass: Body of air that's humidity and temperature are almost
uniform throughout.
warm air masses bring stable conditions, and cold air masses are usually unstable.
, NIFE Weather ELOs
Study online at https://quizlet.com/_e3jbty
cold air masses come from north and move cold air over warm surfaces, and warm
air masses come from south and are warmer over the surface.
9. Describe saturation: Saturation is when the air contains the maximum amount
of water vapor it can hold for that temperature.
10. Define dew point temperature and dew point depression: Dew point is the
temperature in which saturation occurs.
Difference between the temperature and dew point is called the dew point depres-
sion
A higher dewpoint=more clouds
smaller depression=likely clouds, fog, moisture. (around 4 deg F, 2 deg C)
can also occur from air cooling to dew point temp
11. explain why atmospheric circulation occurs: Occurs from large temperature
difference between tropics and polar region, and complicated further by the uneven
heating of land and water by the sun.
12. Define relative humidity: Amount of moisture in air compared to the saturation
level in percent.
13. Indicated Altitude: Altitude read directly from the altimeter. must have updated
reference in kollsman window to be useful. Will then display MSL.
14. Calibrated altitude: Indicated altitude corrected for instrument error
15. Mean Sea Level (MSL): True altitude, or the average height above standard sea
level where the atmospheric pressure is measured in order to calibrate altitude.
airfields, hazards, and terrain elevations are all stated in MSL.
16. Above Ground Level (AGL): Height above the ground over which you're flying
17. Pressure Altitude: The height above the standard datum plane.
actual elevation from standard pressure plane of 29.92 in-hg.
18. Density Altitude: The pressure altitude corrected for nonstandard temperature.
, NIFE Weather ELOs
Study online at https://quizlet.com/_e3jbty
19. Pressure changes effects on aircraft altimeters: As an aircraft flies from high
to low pressure: "look out below" as your airplane will be lower than your indicated
altitude.
As an aircraft flies from low to high: "plenty of sky" as your aircraft will be higher than
indicated altitude.
A change in pressure of .10 In-Hg will change the altimeter setting 100 feet.
20. How does temperature deviations from standard lapse rate effect aircraft
altimeters: for every 11 deg C that the temp varies from standard, the altimeter will
have a 4 percent error.
If temp is LOWER than standard: Aircraft will be higher than indicated.
If temp is HIGHER than standard: aircraft will be lower than indicated.
21. Define Temperature inversion: A temperature inversion is when the tempera-
ture rises with altitude instead of falls.
22. Explain and identify gradient winds with respect to isobars around pres-
sure systems in northern hemisphere: Air circulates parallel (or close to parallel)
to isobars, and CLOCKwise around high pressure and COUNTERCLOCKwise
around low pressure.
23. Identify surface wind direction with respect to gradient winds in a pres-
sure system in the Northern Hemisphere: Pressure gradient force (high to low
pressure force) causes air to flow perpendicular to isobars, however when coriolis
force is added, this diverts the air to the right with respect to its inital direction of
motion.
Thus the combination of these forces produces the CW motion around high and
CCW motion around low
Found Above 2000 Ft.
24. Surface winds: Blow at a 45 degree angle relative to parallel flow CW around
high and CCW around low
25. describe the jet stream: Strong, narrow band of high speed wind in upper
troposphere.
