Aviation 2300 Final Study Guide: Earth Science Terms & Definitions

What are the layers of the atmosphere?

troposphere, stratosphere, mesosphere, thermosphere

Characteristics of the troposphere

-lowest layer.

-below the stratosphere.

- most clouds are found in this layer

- weather changes occur here

- Abrupt change in temp lapse rate

High to low look out below means:

Going from a high pressure to low pressure will cause the plane to think its higher than what it actually is

standard atmosphere

29.92 inches Hg, 15 degrees C at sea level

Standard temperature lapse rate

2 degrees Celsius per 1000 feet

What causes all weather?

uneven heating of the earth's surface

What is the cause for all seasons?

Seasons are caused by the earths tilt (23.5 degrees tilt)

Because of the earths tilt, the northern hemisphere is __________ in summer while the southern hemisphere is _______________ in winter

Warmer, Colder

What are Isobars?

lines of equal pressure

- solid lines that depict sea level pressure

Indicated Altitude

Altitude read directly from the altimeter.

Absolute Altitude

height above the surface

True Altitude

Actual height above mean sea level (MSL)

Pressure Altitude

When altimeter is set to standard (29.92 Hg)

Altimeter Errors

When flying from areas of high pressure to low pressure, you will show higher from the ground than you actually are. High to Low or Hot to Cold, Look out Below.

What does Pressure Gradient Force create?

Creates wind because the atmosphere always want to equalize (flows from high pressure to low pressure)

Does pressure and temperature decrease or increase when we gain Altitude?

Decrease

what is Surface Friction?

Friction from terrain slows the wind down near the surface

Surface friction characteristics

- Flow counterclockwise and into low

- Flow clockwise and out a high

Coriolis Force (Effect)

The earths rotation affects the wind direction. Wind deflects to right in northern and left in southern hemisphere

(No wind = no Coriolis force)

Advection

horizontal movement of air

As temperature increases

density decreases

dry adiabatic lapse rate

The rate at which the temperature of a parcel of dry air decreases as the parcel is lifted in the atmosphere. 3 Degrees Celsius per 1000 ft

The greater the ambient lapse rate the more

unstable the atmosphere

The less ambient lapse rate the more

stable the atmosphere

How can the stability of the atmosphere be determined

The ambient temperature lapse rate

If air accelerate away from the original position, then its said to be

Unstable

If air is displaced then returns to the initial position, then the air is

Stable

Convection

The transfer of heat

Warming the air below creates

instability

Density Altitude

Pressure altitude corrected for non standard temperature or pressure

A stable airmass is more likely to have _________ air than an unstable airmass.

Smoother air and poor visibility

Unstable airmass is more likely to have ______ air than stable

turbulent and good visibility

If Lapse rate > Dry Adiabatic lapse rate

Air parcel is unstable

If lapse rate = Dry lapse rate

Air parcel is neutral

is lapse rate < Dry lapse rate

air parcel is stable

dew point

the temperature at which the water vapor in the air becomes saturated and condensation begins

High dew point means

moist air

Low dew point means

dry air

Types of Fog

Radiation

Advection

Upslope

Steam

Precipitation induced

radiation fog

At night when ground cooler, clear skier, little wind, and small temp/dewpoint spread

- Found in river valleys

advection fog

Forms when warm air moves over a cool surface. Depends on wind to form and clear and does not burn off.

- Found in coastal areas

upslope fog

Moist, stable air being cooled as it moves up sloping terrain. Is often dense

steam fog

condensation of water vapor that results when cool air moves over warm water

Precipitation-induced fog

Warm rain falls through cold air and becomes saturated due to evaporation

Requirements for cloud formation

Water vapor, condensation nuclei, and cooling.

Cloud Families

High clouds, middle clouds, low clouds, & vertical development

Types of clouds

Cumulus, Stratus, Nimbus

Cumulus

heaped clouds associated with instability at that level

Stratus

Flat louds associated with stability at that level

Nimbus

Dark clouds associated with rain

What does alto mean?

middle

Lenticular altocumulus clouds cause

Turbulence and wind shear

What is a ceiling

Is the lowest broken, overcast, or VV reported

global circulation

Patterns that refer to the general large scale wind pattern that covers the entire world

Hadley Cell

- Equator to 30 degrees

- Air rises at equator then sinks at 30 degrees

- Easterly winds (northeast in northern and southeast in southern)

Ferrel Cell

- 30 to 60 degrees

- Westerly winds that travel towards poles

- strong north/south temperature gradient

Polar Cell

- 60 degrees to the poles

- Air rises at 60 and sinks at poles

- Winds turn eastward

Where are jet streams located?

embedded in waves near the tropopause(24,000ft near poles and 50,000ft near equator)

What are Jet streams

Thousands of miles long, hundreds of miles wide and few miles thick that can range from 60-240 knots

Jets stream and tropopause

- Breaks in tropopause where jets stream are located

- tropopause rises as it heads south from the north poles

- when facing east, abrupt break and much higher

Airmasses are classified by

Temperature and moisture characteristics

Cold fronts

Cold air underrunning warm air, cumuliform clouds along the boundary, Showery precipitation, turbulence, thunderstorms are common

Warm Fronts

Warm air overriding cold air, stratiform clouds, steady precipitation, little turbulence

What forms Infront of cold front

Produce cumulonimbus and towering cumulus clouds

What forms Infront of warm fronts

stratiform clouds(stable) and precipitation

Requirements for a thunderstorm

Moisture, instability, lifting mechanism

Thunderstorm stages

cumulus, mature, dissipating

Cumulus stage

Primarily updrafts

Mature stage

Updrafts and downdrafts, rain at surface

Dissipating stage

Primarily downdrafts, rain shaft cuts off all fuel to storm, anvil top indicates this stage is near

Where can pilots find hail

storms can spit hail 20nm

is a anvil safe?

No, avoid flying beneath the anvil top and avoid overhands

Turbulence

Lifting associated with thunderstorms that can form severe turbulence well outside the storm

Frequency of lighting indicates

severity of a storm

Squall lines

a line of high winds or thunderstorms that form in front of cold fronts

What weather phenomenon is always associated with storms

lighting

Embedded Thunderstorms

obscured by massive cloud layers, cannot be seen.

If a pilot goes into a storm, what should they do

Maintain a straight level altitude on a heading that will take you through the storm area in minimum time

Severe storm characteristics

Hail that spit out 20nm, tornadoes

Land breezes occur

at night, off shore flow

Sea breezes occur

during the day, on shore flow

Lee waves

stable airstream flows over a ridge can create strong vertical speeds

Mountain waves

caused by air that moves upward near mountain ranges and form lenticular clouds

Microburst

a sudden, powerful, localized air current, especially a downdraft.

Low-Level Wind Shear (LLWS)

Wind shear below 2,000 feet AGL along the final approach path or along the takeoff and initial climb out path. Can rapidly change performance of a aircraft and disrupts normal flight altitude

Categories of turbulence

Clear air, Mountain wave, In/near storm, low level

4 intensities of turbulence

- Light: slight change

- Moderate: change with normally control

- Severe: large abrupt change

- Extreme: impossible to control

low level turbulence

turbulence below 15,000 feet MSL

Wake Turbulence

Generated by aircraft in flight, found below the aircraft. Quartering tailwind

Thunderstorm and near turbulence

Associated with thunderstorms that can be hazardous to all aircraft. Can range 20nm away from storm and under anvil

clear air turbulence

Turbulence encountered by aircraft flying through cloudless skies. Thermals, wind shear, and jet streams can each be a factor in producing CAT. upper troposphere/lower stratosphere

Structural Icing

Icing that forms on the external structure of an aircraft.

Induction Icing

The formation of ice on aircraft air induction ports and air filters. carb ice that causes loss of power

Intensities of icing

Trace, light, moderate, severe

Clear Icing

1. between 0 and -10 degrees Celsius - cumulus

2. Large water droplets freeze slowly

3. heavy, hard, brittle

Rime Icing

1. between temperatures -15 and -20 degrees Celsius - stratus

2. small water droplets freezes instantly, opaque (milky white) and brittle

Mixed Icing

1. Combo of Clear and Rime

2. Between Temp -10 to -15 degrees Celsius

3. caused by snow/ice particles trapped in clear ice

In what conditions would icing accumulate faster

The greater the amount and size of the droplets, the greater the icing potential

The greater the amount and size of the droplets, the greater the icing potential

that the air above is warmer

When landing during icing conditions you should

fly approach with more power