METR 1014 Exam 2 OU

DALR

10°C for every 1 km rise in altitude Before and Including LCL height

MALR

6°C for every 1 km rise in altitude After LCL height since air parcel is now saturated and moist.

Cloud Condensation Nuclei (CCN)

Aerosols that serve as the centers for developing cloud droplets

When water molecules undergoing a phase change ABSORB latent heat from the surrounding air, we can expect that the released energy would ​[?] the surrounding air.

COOL

Cold cloud

Cloud composed of ice crystals or supercooled water droplets or a mixture of both have temperatures below 0 degrees Celsisus

warm clouds

Clouds that have above-freezing temperatures at all levels

Air Temp and saturation mixing ratio

Direct relationship. saturation mixing ratio increases exponentially as air temperature warms.

Terminal velocity equation

Distance= velocity x time

What is sensible heat?

Energy absorbed or emitted by water that results in its temperature change

True or false: Horizontal wind speed is FASTER where isobars and isoheights are spaced FARTHER apart.

FALSE

When water goes from ice to a liquid, is it gaining or losing energy?

Gaining

When water ABSORBS latent heat it gains or loses energy? What phase changes occur?

Gains. Ice to liquid liquid to gas ice to gas

Classifying Clouds

Height then shape Cumulus - spans multiple Cirro-highest Alto-middle Strato - lowest Cirrus- whispy stratus- layered cumulus-clumpy nimbus-precipitation producing

Air with Higher/lower temperature can evaporate more water vapor than air at a lower temp?

Higher

Which TWO the following phase changes generate the GREATEST change in bond energy? Both correct answers, and no incorrect answers, must be chosen in order to receive credit.

Ice sublimating to water vapor Water vapor depositing to ice

If one air sample has a relative humidity of 50% and the second air sample has a relative humidity of 75%, which of the following is true?

It is unknown which air sample has a higher actual water vapor content. Because relative humidity does not measure actual water vapor content. it measures how close the air is to becoming saturated.

Transpiration

Liquid water is transported via the roots of plants from groundwater to their leaves, and evaporates through the pores of the leaves and enters the atmosphere as water vapor.

When water goes from a gas to a liquid, is it gaining or losing energy?

Losing

The CLOSER the spacing of isobars on a weather map, the ​[?] the PGF, and consequently the ​[?] the horizontal wind speed.

Stronger faster

What is latent heat?

The energy responsible for phase changes at a CONSTANT TEMPERATURE

Assume one air sample has a temperature of 95°F and a dewpoint of 70°F. Assume a second air sample has a temperature of 70°F and a dewpoint of 65°F. Which of the following is a true statement?

The first air sample has more actual water vapor in it than the second air sample. BECAUSE DEWPOINT IS HIGHER

When does the greatest change in energy occur?

The greatest change in energy occurs when a solid changes directly to a gas or vice-versa An ice changing to a vapor therefore consists of the largest energy change for all possible answers listed above.

T/F: Air that is COLDEST is represented by the LOWEST isoheight values on an isobaric map, and is where one will find an upper-level low pressure center

True

T/F: The majority of clouds that form over the continental United States are cold clouds that produce precipitation via the Bergeron-Findeisen-Wegener process.

True

T/F: air that is WARMEST on an isobaric map is represented by the LARGEST isoheight values, and is where one will find an upper-level high pressure center

True

If the atmosphere surrounding an air parcel is COLDER than the air parcel, the atmosphere is (stable/ unstable)

Unstable

Phase changes in which LATENT heat is released into the air by the molecules changing phase.

Vapor to Liquid Liquid to Ice Vapor to Ice

Condensation

Vapor to liquid

Aerosols

Very small airborne solid and liquid particles that must be present for liquid droplets and ice crystals to form on their surfaces.

Lower LCL has a (warmer/cooler) temp at a certain height compared to a parcel with a higher LCL.

Warmer

when water molecules undergoing a phase change RELEASE latent heat to the surrounding air, we can expect that the absorbed energy would ​[?] the surrounding air.

Warms

Gradient

a change in some quantity of interest measured over a distance.

centrifugal force

a force exerted on air as it travels in a curved path always points outward, away from the center of curved motion. Therefore, the centrifugal force pulls air outward from the center of its curved

If the temperature of a sample of ice was to increase from -10°C to -5°C, the water molecules of the sample would be ​[?] in the form of ​[?] heat:

absorbing energy from the surrounding air, sensible

Level of Free Convection (LFC)

altitude is where the atmosphere first becomes unstable to rising air parcels

Coriolis force

causes horizontally moving air to make a rightward deflection in the Northern Hemisphere and a leftward deflection in the Southern Hemisphere.

heterogeneous nucleation.

cloud droplets that form on (natural or man-made) non-water CCN

When the air is supersaturated, what occurs at a faster rate than evaporation

condensation

Geostrophic winds

correspond to a pattern where horizontal upper-level winds are not accelerating; that is, they are traveling in a straight-line path without changing their speed or direction FOUND in regions BETWEEN the peaks of ridges and the bases of troughs

dewpoint depression

difference in value between the actual air temperature and the dewpoint (T-Td) The larger the dewpoint depression, the more subsaturated the air is, and the more the air temperature must cool in order to reach saturation while maintaining its mixing ratio.

Isobaric Maps

each map is drawn at a constant pressure level rather than at a constant altitude.

Transpiration from plants transfers water to the Earth's atmosphere through the phase change process of:

evaporation

The MAJORITY of water vapor that ends up in the Earth's atmosphere comes directly from:

evaporation from oceans (because most water on Earth is from the oceans)

An air parcel:

expands as it rises and contracts as it sinks

Subgeostrophic horizontal upper-level winds

found rounding the base of a TROUGH of low pressure

Friction Force

horizontal surface winds encounter rough surface landscape barriers (i.e., trees, buildings and other urban development, mountains, etc.). This dynamic results in horizontal surface winds slowing down from their original speeds.

supergeostrophic horizontal upper-level winds

horizontal upper-level winds that round the PEAK of a ridge of high pressure

Pressure Gradient

how much pressure changes over a given distance always points from regions of higher pressure toward regions of lower pressure

Aggregation

ice crystals collide with and stick to each other. Aggregation produces a collection of ice crystals falling together as a single large snowflake. The largest, prettiest snowflakes are formed through the process of aggregation!

Gravity Force

is approximately equal in magnitude and opposite in direction to this vertical component of the PGF this keeps air particles from flying into space

isoheights

lines or curves that connect points on a given pressure surface with equal altitude

Isobars

lines or curves that connect points with equal sea level pressure.

Haze

liquid droplets that form in subsaturated conditions

If the air's relative humidity INCREASES while its temperature stays constant, the air's ​[?]:

mixing ratio must be increasing

Mixing ratio

mixing ratio quantifies the absolute (i.e., the actual) amount of water vapor present in the air. More specifically, the mixing ratio measures the mass of water vapor present in a sample of air divided by the mass of other gases (like N2 and O2) in the same sample of air when the dewpoint increases, the air's actual water vapor content increases (i.e., the air sample's mixing ratio increases)

Upon exiting cloud base, assume that a small rain drop falls for 60 seconds at its terminal velocity of 2.8 m/s before evaporating. In this case, would the drizzle droplet reach the surface before evaporating, if the surface is located 200 meters below the cloud base?

no

Bergeron-Findeisen-Wegener process

primary means of precipitation formation in cold clouds supercooled cloud droplets are attracted to nearby ice crystals. They evaporate and their resulting water vapor deposits directly onto the nearby ice crystals, which consequently grow in size rapidly through this deposition. most rapid growth of ice crystals when the cloud temperature is between -12° C and -17° C.

homogeneous nucleation

process of cloud droplets forming on WATER-based substances

Water precipitation

rain, sleet, snow, freezing rain, and hail.

If the air temperature COOLS while its water vapor content STAYS CONSTANT, the air's ​[?]:

relative humidity must be increasing

Clouds and precipitation most often form through the process of condensation. Thus, the phase change that produces clouds and precipitation:

releases latent heat to the surrounding air (Higher Phase to lower phase)

If water molecules were in the process of transitioning from water vapor to liquid water, they would be ​[?] in the form of ​[?] heat.

releasing energy to the surrounding air, latent

Graupel

soft, small snow pellets.

If the atmosphere surrounding an air parcel is WARMER than the air parcel, the atmosphere is (stable/ unstable)

stable

If the relative humidity of an air sample is 101%, the air sample is ​[?], and ​[?] is the dominant phase change process for water.

supersaturated condensation

Lifting Condensation Level (LCL)

the altitude at which a rising surface-based air parcel first cools to its dewpoint and reaches saturation, and where cloud cover begins The LCL corresponds to the altitude of cloud bases.

Saturation Mixing Ratio

the maximum amount of water vapor that could be present in the air at its current temperature. In other words, the saturation mixing ratio measures the maximum mass of water vapor that could possibly be in a sample of air at a given temperature, relative to the mass of other gases in the same sample of air.

terminal velocity

the maximum speed of a falling object that is reached when air drag deceleration becomes equal to the downward acceleration of gravity. Once a falling particle reaches its terminal velocity, its falling speed no longer increases.

Dewpoint

the temperature to which the air must cool, while maintaining a constant mixing ratio, in order to reach saturation. the actual amount of water vapor present in an air sample (i.e., the absolute water vapor content of the air).

Supercooled

water droplets having tempatures below freezing that remain in liquid state

hygroscopic nuclei

water-attracting CCN like salt

hydrophobic nuclei

water-repelling CCN only develop in very supersaturated environments