☁️Cloud Stability & Instability

resisted, work

In stable air parcels, vertical motion is [term]. To produce motion, you have to do [term].

enhanced, cloud development

In unstable air parcels, vertical motion is [term], promoting rapid [term development].

warm over cold

Atmospheric stability is characterized by [term] air layer sitting [term] a [term] air layer.

cold over warm, warm rises, convection

Atmospheric instability is characterized by a [term] air layer sitting [term] a [term] air layer, because the [term] air [terms] through [term]

lapse rate, weather balloon, parcel theory, parcel, near surface, lifts, compares, surrounding air temperature.

There are two approaches to assessing atmospheric stability — examining the [term term], or temperature change with height, to identify areas of relatively high or low stability. This is typically done by sending up a [term term]. Then there’s [term term], a hypothetical scenario where one starts with a [term] of air [term] the [term], then [terms] it and [terms] it with [surrounding air term].

rise, more dense, higher pressure

Warm air tends to [rise/fall]. It is [more dense/less dense] and has a [higher/lower pressure].

fall, less dense, lower pressure

Cold air tends to [rise/fall]. It is [more dense/less dense] and has a [higher/lower pressure].

decrease, expands, cools

As air rises, density and temperature [term]. In other words, air [terms] and [terms] as it rises.

increase, compresses, warms

As air sinks, density and temperature [term]. In other words, air [terms] and [terms] as it sinks.

Adiabatic process

A process where an air parcel’s temperature changes due to pressure changes (expansion, compression), and no heat is added or removed from the parcel in processes like convection, conduction, or radiation.

Diabatic process

A process where heat is added to the parcel from the parcel’s environment. Includes other processes like convection, conduction, and radiation, as well as latent heat.

Lapse rate

The rate of temperature change with height.

Ckm^-1

Write the units of lapse rate.

Dry Adiabatic Lapse Rate

DALR is an abbreviation for…

Dry Adiabatic Lapse Rate, unsaturated, constant, 9.8Ckm^-1

The [Term Term Term Term], or DALR, applies to [term] or “dry” parcels, which cool at a [term] rate of [### units].

Moist Adiabatic Lapse Rate, saturated, 6Ckm^-1, slower rate than DALR, latent heat, warmer, instability

The [Term Term Term Term], or MALR, applies to [term] parcels, which cool at [###units] — a [slower/faster rate than DALR] — because of [term term] released from condensation that offsets the cooling from expansion. Because latent heat in MALR leads to [warmer/colder] parcels than DALR, it encourages more [stability/instability].

temperature, higher, lower

Saturation vapor pressure depends non-linearly on [term]. A higher temperature corresponds to a [higher/lower] saturation vapor pressure, while a lower temperature corresponds to a [higher/lower] saturation vapor pressure.

a little, a lot, large

Very warm, saturated air cools [a lot/a little] because [a lot/a little] latent heat is released from the [small/large] change in saturation vapor pressure as air rises and cools.

almost the same rate, adiabatic lapse rate, a little, small

Very cold, saturated air cools at [a very different rate / almost the same rate] as the [term term term], because [a lot/a little] latent heat is released from the [large/small] change in saturation vapor pressure with temperature.

temperature of a parcel

Tpar

temperature of the environment

Tenv

impossible

If you don’t know the temperature of the environment around the parcel (Tenv), it is [still possible/impossible] to assess stability and instability.

Parcel theory, compare parcel temperature and environment temperature

In [term term], to determine whether a parcel rises/sinks in the atmosphere, one should [compare term term and term term].

warmer than the environment, rise

Tpar > Tenv

Is the parcel [warmer/cooler than the environment]? Or are [the parcel and the environment the same temperature]?

Will the parcel [rise] or [fall]? Or will it [stay where it is]?

cooler than the environment, fall

Tenv > Tpar

Is the parcel [warmer/cooler than the environment]? Or are [the parcel and the environment the same temperature]?

Will the parcel [rise] or [fall]? Or will it [stay where it is]?

the parcel and the environment the same temperature, stay where it is

Tenv = Tpar

Is the parcel [warmer/cooler than the environment]? Or are [the parcel and the environment the same temperature]?

Will the parcel [rise] or [fall]? Or will it [stay where it is]?

Pyrocumulus

This type of cloud forms when fire heats the air and creates a warmer, less dense thermal relative to its surroundings. The warm, less dense air rises rapidly, but still cools as it rises and expands (adiabatic cooling), eventually reaching Td and forming a [term] cloud.

environmental lapse rate

ELR stands for…

DALR > MALR > ELR

Write the absolute stability condition (use abbreviations)

temperature of a saturated parcel

Tspar stands for the…

temperature of an unsaturated parcel

Tupar stands for the…

Height of the air parcel

In the lapse rate equation, what does Z stand for?

-^T/^Z = (T2-T1) / (Z2 - Z1)

Write the lapse rate equation.

Tenv larger than Tspar, Tupar

In the absolute stability condition, [Tttt] is always [term than] [Tttt] and [Tttt].

always absolutely stable, cold, warm

Inversions are [always term term], with [term] air near the surface and [term] air above it.

Neutral Stability: ELR = DALR, well-mixed layer

(Term Term) occurs when (ELR =DALR). It happens when surface heating and convection create a (term-term layer).

Absolute instability: ELR > DALR > MALR, unsaturated and saturated parcels are always warmer than the environment and will continue to ascend.

The condition for (term term: ) is (ELR > DALR > MALR). In this state, both (unsaturated and saturated parcels are always termer than the environment and will term to term).

ELR > DALR > MALR

Absolute instability condition

ELR = DALR

Neutral Stability Condition

DALR > MALR > ELR

Absolute Stability Condition

DALR > ELR > MALR

Conditional Instability condition

Conditional instability: An unsaturated parcel will be cooler than the environment and sink back to the ground; in other words, it will be stable. On the other hand, a saturated parcel will be warmer than the environment because of latent heat released from condensation; it will continue to ascend. In other words, it will be unstable.

Under (Conditional Instability):

[An TERM parcel will be TERMER than the environment and TERM back to the ground; in other words, it will be TERM].

[On the other hand, a TERM parcel will be TERMER than the environment because of TERM TERM released from condensation; it will TERM to TERM. In other words, it will be TERM.]

atmosphere: stable layers, unstable layers

It’s useful to break the (atmosphere) into (term terms) and (term terms) when identifying stability.

Processes that can destabilize the atmosphere: advection, surface heating/insolation —both occur in low-pressure systems, mixing by convection, wind turbulence

(Processes that can destabilize the atmosphere:)

(term) — wind blows cold air above warm air

(term term/term) —incoming radiation warms the surface layer

(—both occur in low-pressure systems)

(term by), which can be created thermally by (term) or mechanically by (term term)

Mixing= ELR→ Adiabatic lapse rate. Below, go up, cooled; above, go down, warmed.

(Mixing=) a layer drives the (TTT→) towards an (term lapse rate). Parcels (term) (go up) and are (termed). Parcels (term) (go down) and are (termed).

absolutely stable=clouds unlikely

shallow conditionally unstable= clouds likely but vertical development limited

deep conditionally unstable= clouds likely and vertical development significant

(termly term) environment (=clouds unlikely)

(term term termly) environment (=clouds likely), (but term term limited).

(term termly term) environment (=clouds likely), (term term significant).

Clouds develop by convection: surface heats, parcel detaches and rises warmer than the environmental temperature, parcel cools to the dew point at the lifting condensation level. Below and within, rises. Around, falls.

One way (clouds develop) is (by TERM).

The (term terms), and a (Term terms and terms), staying (termer than the environmental TERM). Then, the (term cools to the term term at the term term term). (Environmental term determines term). (term and term) the cumulus clouds, air (Terms). (Term) the cloud, the air (terms).

overshooting top

when a cumulonimbus cloud floofs up and reaches the top of the troposphere (the tropopause) and the violent convection makes it so that a bit of the cloud “puffs up” above the tropopause, this is called an:

Environmental instability controls cloud growth and height

(Environmental TERM controls cloud TERM and TERM).

an air parcel’s dew point and temperature determine its lifting condensation level, which is where air cools enough to condense into a cloud

(an air parcel’s TERM TERM and TERM determine its TERM TERM TERM, which is where air cools enough to condense into a TERM).

vertical parcel motions that create clouds are generated naturally in the atmosphere through:

surface heating and free convection

topography

widespread ascent due to convergence of surface air

uplift along weather fronts

(Vertical parcel motions that create clouds are generated naturally in the atmosphere through:)

(Term term and term term)

(Term)

(Term term due to term of term air)

(Term along term terms)

In topographic lifting, wind forces air up and over elevated terrain like a hill, mountain, or gradual sloping plain. The windward side will be cloudy and rain as air ascends and cools to its dew point. The leeward side will be warmer and drier as air descends and warms. This side is often called the rain shadow.

(in TERM TERM, wind forces air up and over TERM TERM like a hill, mountain, or gradual sloping plain. The windward side will be TERM and TERM as air ascends and cools to its dew point. The leeward side will be TERMER and TERMER as air descends and warms. this side is often called the TERM TERM.)

Clouds can also develop through convergence. If air converges at a given location near the surface, it does not compress, the ground prevents downward motion, and so it rises. This is a common forcing mechanism at the center of a cyclone.

(Clouds can also develop through TERM. If air converges at a given location near the surface, it does not TERM, the TERM prevents downward motion, and so it TERMS. This is a common TERM TERM at the center of a cyclone.)

Clouds can also develop through frontal lifting. In warm fronts, if air is lifted into a stable layer, stratus or nimbostratus clouds can form. In cold fronts, if air is lifted into a conditionally unstable layer, cumulus or cumulonimbus can form.

(Clouds can also develop through TERM TERM. In warm fronts, if air is lifted into a TERM layer, TERM or TERM clouds can form. In cold fronts, if air is lifted into a TERM TERM layer, TERM or TERM can form.)