AVS 1201 CH 6 Stability and Cloud Development
If a parcel of unsaturated air with a temperature of 30 degrees Celsius rises from the surface to an altitude of 1000 m, the unsaturated parcel temperature at this altitude would be about...
10°C colder than at the surface.
If the environmental lapse rate is 5 degrees Celsius per 1000 m and the temperature at the earth's surface is 25 degrees Celsius, then the air temperature at 2000 m above the ground is...
15°C.
An atmospheric condition that exists when the environmental lapse rate is greater than the dry adiabatic rate. This results in a lifted parcel of air being warmer than the air around it.
Absolutely Stable
When the environmental lapse rate is greater than (getting cold faster than) the dry adiabatic lapse rate the atmosphere is said to be...
Absolutely Unstable
If parcel of air expands and cools, or compresses and warms, with no interchange of heat with surroundings.
Adiabatic Process
A rising parcel of air that does not exchange heat with its surroundings is an example of...
An Adiabatic Process
Winds bringing in colder air(cold advection) Clouds emitting infrared radiation to space(radiational cooling)
Cause of Instability (Cooling of the Air aloft)
Daytime solar heating of the surface An influx of warm air brought in by the wind(warm advection) Air moving over a warm surface
Cause of Instability (Warming of the surface air)
An inversion represents an extremely stable atmosphere because an adiabatic parcel of air that rises into the inversion will be __________ and __________ dense than the surrounding air.
Colder..More
At an elevation of 1000m, the air has cooled to the dew point, the relative humidity is 100%, condensation begins, and a cloud forms.
Condensation Level
If unsaturated stable air is lifted to a level where it becomes saturated and unstable, this type of instability is...
Conditional Instability
The principle method used by the atmosphere to redistribute heat is called...
Convection
Which set of conditions, working together, will make the atmosphere the most stable?
Cool the surface and Warm the air aloft.
Which cloud type below would most likely form in an unstable atmosphere?
Cumulonimbus
In a rising thermal, the dew-point temperature...
Decreases at a slower rate than the parcel temperature
This rate of heat or cooling is about 10 degrees C for every 1000m of change in elevation(5.5 degrees F per 1000ft)and applies only to unsaturated air.
Dry Adiabatic Rate
The vertical development of a convective cloud also depends upon the mixing that takes place around its periphery. The rising, churning cloud mixes cooler air into it.
Entrainment
Because this is the rate at which the air temperature surrounding us will be changing if we to climb upward into the atmosphere.
Environmental Lapse Rate
Subsidence inversions develop with __________ pressure areas because of the __________ air motions associated with them.
High..Sinking
The rate at which the air temperature changes with altitude.
Lapse Rate
Which cloud type would commonly be found downwind of a mountain?
Lenticular Clouds
The rising cooling air reaches its dew point and becomes saturated at 1000m.
Lifting Condensation Level (LCL)
Standing wave clouds (ACSL) are usually a form of...
Low Clouds
Because the heat added to during condensation offsets some of the cooling due to expansion, the air no longer cools at the dry adiabatic rate but at a lesser rate.
Moist Adiabatic Rate
The rate at which the actual air temperature changes with increasing height above the surface is referred to as the...
Moist adiabatic lapse rate
The rate at which the temperature changes inside a rising (or descending) parcel of saturated air is called the...
Moist adiabatic lapse rate
Horizontally moving air obviously cannot go through a large obstacle, such as a mountain, so the air must go over it.
Orographic Uplift
Imaginary small body of air a few meters wide that is used to explain the behavior of air. (Small volume of air)
Parcel of air
A vertical sounding of temperature and dew-point can be measured using a...
Radiosonde
The name commonly used to describe the drier region downwind (leeward) side of a mountain range is...
Rain Shower
The rising part of the swirling air may cool enough to produce a visible cloud
Rotor Cloud
If an air parcel is given a small push upward and it continues to move upward on its own accord, the atmosphere is said to be...
Stable
If an air parcel is given a small push upward and it falls back to its original position, the atmosphere is said to be...
Stable
Most thunderstorms do not extend very far into the stratosphere because the air in the stratosphere is...
Stable
A conditionally unstable atmosphere is __________ with respect to unsaturated air (dry adiabat) and __________ with respect to saturated air (moist adiabat).
Stable..Unstable
Which cloud type would most likely form in stable air?
Stratus
Basically, the following mechanisms are responsible for the development of the majority of clouds we observe:
Surface heating and free convection Uplift along topography Widespread ascent due to convergence of surface air Uplift along weather fronts
The difference between the "moist" and "dry" adiabatic rates is due to...
The fact that latent heat is released by a rising parcel of saturated air
Soaring birds in flight, like hawks and eagles, often indicate the presence of...
Thermals
What two sets of conditions, working together, will make the atmosphere the most unstable?
Warm the surface and Cool the air aloft
