small volume of air |
parcel of air |
IF A PARCEL OF AIR EXPANDS AND COOLS, OR COMPRESSES AND WARMS, WITH NO INTERCHANGE OF HEAT WITH ITS SURROUNDINGS. as long as the air remains unsaturated (relative humidity is less than 100), the rate remains constant at 10 C per 1000 m |
adiabatic process |
as long as the air remains unsaturated (relative humidity is less than 100), the rate remains constant at 10 C per 1000 m |
dry adiabatic rate |
is the rising air cools to dew point, it reaches 100 percent humidity. cloud forms and latent heat is released. 6C per 1000m. |
moist adiabatic rate |
rate at which the air temperature will be changing around us if we were to climb up in the atmosphere |
environmental lapse rate |
when the rising air is colder and heavier than the air around it- when the environmental lapse rate is less than moist adiabatic rate (6C) |
absolutely stable atmosphere |
inversions that form as air slowly sinks over a large area |
subsidence inversion |
if the environmental lapse rate is exactly equal to the dry adiabatic rate, rising or sinking unsaturated air will cool or warm at the same rate as the air around it |
neutral stability |
when rising air is warmer and less dense; environmental lapse rate is greater than the dry adiabatic rate |
absolutely unstable atmosphere |
when rising air is unsaturated, the atmosphere is stable because the parcel is colder than its surroundings; saturated air rising is saturated, the atmosphere is unstable because the parcel is warmer than its surroundings; occurs when environmental lapse rate is between the moist and dry rate |
conditionally unstable, potential |
the elevation where the could first forms |
condensation level |
lifting a stable layer |
convective instability |
mixing of cooling air into a rising cloud, increases the rate at which the rising cloud cool |
entrainent |
forced lifting along a topographic layer |
orographic uplift |
warmer air, leeward side of mountain, less precipitation |
rain shadow |
… |
rotor clouds |
the addition/ subtraction of heat form air without external heating/ cooling |
What is the adiabatic process? |
Dry adiabatic rate is roughly 10 C/km while the moist adiabatic rate is usually slower (around 6 C/Km) as condensation in the rising air adds latent heat |
Why are moist and dry adiabatic rates of cooling different? |
The environmental lapse rate is the actual decrease of temperature with altitude. This is often meaured by instrumented balloon. The dry adiabatic lapse rate is the rate at which air temperature would drop with altitude due to expansion. |
Explain the difference between environmental lapse rate and dry adiabatic rate |
Any process that creates a steeper lapse rate will cause the air to become less stable. This could be warming near the surface or cooling aloft or both. |
List and explain several processes by which a stable atmosphere can be made unstable. |
Lake effect storms form when cold, stable air passes over a warm, moist surface. The heat added from below causes the lapse rate to increase (become less stable) while the mositure added from below becomes the source of the eventual precipitation. |
How does atmospheric stability influence the formation of lake effect snowstorms? |
Cumulonimbus clouds can grow to such a height that they encounter the bottom of the stratosphere, which is extremely stable with rising temperatures with altitude (inversion). The rising cumulonimbus cannot enter the stratosphere and hence spread out |
Why do cumulonimbus clouds (thunderstorms) often have flat tops? |
46 F |
Suppose the surface air temperature is 66°F. If the base of a cumulus congestus cloud directly above you is 2000 feet, what would be the approximate temperature at an altitude of 5000 feet above you inside the cloud? |
convection |
The vertical motion of air caused by sun heating the ground is called: |
air motions caused by subsidence |
Which of the following is not a way of producing clouds? |
decreases at a slower rate than the parcel temperature |
In a rising thermal, the dew-point temperature |
cumulonimbus |
Which cloud type below would most likely form in an unstable atmosphere? |
thick, strong |
If you observe large raindrops hitting the ground, you could probably say that the cloud overhead was ____ and had ____ updrafts. |
stratus |
Which cloud would most likely produce drizzle? |
mix the air in the layer, life the entire air layer, cool the upper part of the layer |
Which condition below could make a layer of air more unstable? |
stable, unstable |
A conditionally unstable atmosphere is ____ with respect to unsaturated air and ____ with respect to saturated air. |
unstable |
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 |
an inversion |
Which of the following conditions would be described as the most stable? |
stratus |
Which cloud type would most likely form in absolutely stable air? |
cool the surface and warm the air aloft |
Which set of conditions, working together, will make the atmosphere the most stable? |
stable |
Most thunderstorms do not extend very far into the stratosphere because the air in the stratosphere is |
the fact that latent heat is released by a rising parcel of saturated air |
The difference between the moist and dry adiabatic rates is due to |
temperature changes in a rising or descending parcel of unsaturated air |
The dry adiabatic rate is the rate at which |
moist adiabatic lapse rate |
The rate at which the temperature changes inside a rising (or descending) parcel of saturated air is called the |
environmental lapse rate |
The rate at which the actual air temperature changes with increasing height above the surface is referred to as the |
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 |
15 C |
If the environmental lapse rate is 5°C per 1000 m and the temperature at the earth’s surface is 25°C, then the air temperature at 2000 m above the ground is |
always cools due to expansion |
The temperature of a rising air parcel |
2500 |
What would be the height of the base of a cumulus cloud when the surface air temperature is 45°C and the dew point is 25°C? |
air temperature 90°F, dew point temperature 60°F |
Which of the following sets of conditions would produce a cumulus cloud with the lowest base? |
conditional instability |
If unsaturated stable air is lifted to a level where it becomes saturated and unstable, this type of instability is called: |
clouds forming on the windward slope of a mountain |
An example of orographic clouds would be: |
absolutely unstable |
When the environmental lapse rate decreases more rapidly with height than the dry adiabatic rate, the atmosphere is |
greater, less |
In a conditionally unstable atmosphere, the environmental lapse rate will be ____ than the moist adiabatic rate and ____ than the dry adiabatic rate. |
11°C per 1000 m |
Which of the following environmental lapse rates would represent the most unstable atmosphere in a layer of unsaturated air? |
latent heat is released by rising saturated air |
The reason that rising saturated air cools at a lesser rate than rising unsaturated air is |
warm the surface and cool the air aloft |
What two sets of conditions, working together, will make the atmosphere the most unstable? |
10°C colder than at the surface |
If a parcel of unsaturated air with a temperature of 30°C rises from the surface to an altitude of 1000 m, the unsaturated parcel temperature at this altitude would be about: |
Chapter 5- Clouds and Stability
Share This
Unfinished tasks keep piling up?
Let us complete them for you. Quickly and professionally.
Check Price