Chapter 17 Moisture, Clouds, and Precipitation

What is relative humidity at the dew point ?

100%

orographic lifting question Figure shows air that begins with a temperature of 25 c and relative humidity 50 % flowing from the ocean over the coastal mountain range.

A.temp 25C Dew point 15c 25C= 20g( from check water vapor capacity table 25c how much air hold?) RH=50% x/20gX100%=50 current content=10 g Check table H2O content saturation( grams)= what temperature 10g to saturate? 15c, so dew point 15c-At point A, Air doesn't reach the dew point, because temp 25c and dew point 15c. When we rise up from point A to B, it is used dry adiabatic rate=10c=1000 meters(1 c=100 m) B.Temp 15c Dew point 15C At point B, the temperature is (25 - 10) = 15o C since the dry adiabatic rate is 10oC/1000 m. Temp 15c dew point 15c now temp= dew point is the same= air is full. C. Temp 10 C Dew point 10c At point B, the air is full, so we use a wet adiabatic rate of 5c/1000 At point C, the temperature is (15 - 5) = 10o C since the wet adiabatic rate (as the air parcel is saturated) is 5oC/1000 m. Dew point never ever will be higher than temperature. reach the dew point and then keep cooling down, moisture starts to come out as rain or clouds (precipitation). So the dew point will drop and match the temp. so the dew point is 10 C D.temp:5 C Dew point:5C the temperature is (10 - 5) = 5o C since the wet adiabatic rate (as the air parcel is saturated) is 5oC/1000 m. E.temp:15 Dew:5 Air is going down the other side of the mountain. Air is above =the whole way down =temp goes up and the air is compressed At point E, the temperature is (5 + 10) = 15o C since as the air parcel descends it warms at the dry adiabatic rate which is 10oC/1000 m. F.Temp :25 Dew: 5 At point F, the temperature is (15 + 10) = 25o C since as the air parcel descends it warms at the dry adiabatic rate which is 10oC/1000 m. G. Temp:35 Dew:5 At point G, the temperature is (25 + 10) = 35o C since as the air parcel descends it warms at the dry adiabatic rate which is 10oC/1000 m. the windward, dew point changes because we have rain and clouds. But leeward, we lost much moisture, the only way makes dew point charges add or take away water vapor. leeward is no condesation= not add water vapor. Dew point on leeward simply stays the same. leeward is hotter,dryer because it lost much of mosture on leeward.

What are the two ways relative humidity can be changed?

Add or subtract moisture to the air or change the air temp

What does humidity 100% mean ?

Air is full RH=water vapor content (how much you have) ------------------------ x 100 %=. % water vapor capacity( how much air can hold both numbers ( H2o content and H2O capacity) are the same= 100 %

What term is used to describe clouds found in the mid-altitude height range?

Alto

What does relative humidity change at constant water vapor content ?

Any decrease temperature, RH increase and then reaches 100%= Air is full. Keeping dropping temp moisture comes out of air and cause condensation ( gas- liquid)

At the dew point temperature, _______________________. A.the air is not saturated B.the water vapor content of the air is equal to the water vapor capacity C.the air temperature must always be lower than the dew point temperature D.the relative humidity is less than 100% E.none of these answers

B.the water vapor content of the air is equal to the water vapor capacity

Why we don't see so much condensation in winter ?

Because air is too dry, so it doesn't have moisture.

Why is relative humidity a poor indicator of the amount of water vapor in the air?

Because it is temperature dependent and it is inversely proportional to air temperature. So it is not accurate.

What are fronts?

Boundary between air masses( cold and warm)

What are condensation surfaces in the atmosphere ?

Condensation nuclei-tiny particles like dust, smoke, ocean salt crystals that provide a source for water vapor to condense on. Water vapor condense- it becomes saturated- bump into condensation nuclei- condense onto these nuclei.-Condensation nuclei provide the non-gaseous surface necessary for water vapor to condense into cloud droplets. As droplets join together they grow larger and eventually fall as precipitation

Cooling the air below the dew point results in what?

Condensation= moisture has to come out of the air, fog, dew, or cloud formation

Saturated air means

Content equals capacity (the air can't hold any more) and has 100% relative humidity

What is steam fog?

Cool air moves over warm water and moisture is added to the air. Water has a steaming appearance. a type of evaporation fog that forms because of the addition of moisture to a layer of air. The air is usually cool or cold and already near saturation.

What is the most important process of cloud formation in the atmosphere?

Cooling by expansion of air

One type of cloud doesn't fit any category. That cloud starts (build-up)really low(3-4000 feet) and goes up to 10 miles? vertical development. What is it called?

Cumulonimbus This cloud is a classic thunderstorm. hail, gusty winds, and lighting are associated with this cloud. The top of cloud is called Anvil

On a calm, clear autumn night here in Illinois, ____________ fog may result from rapid nighttime cooling A. upslope B. advection C.steam or evaporation D.radiation E.precipitation

D.radiation

A sling psychrometer is used to determine relative humidity by measuring A.water vapor content B.electrical currents in the air C.dew points D.temperature changes caused by evaporation E.temperature ch

D.temperature changes caused by evaporation

The cloud form that consists of sheets or layers with rain falling from it is called ____________. A.cumulonimbus B.cirrus C.stratus D.cumulus E. nimbostratus

E. nimbostratus

Relative humidity values in the atmosphere will ___________ as the air temperature __________. A.none of these - relative humidity is not related to temperature B.decrease; remains constant C.increase; increases D.decrease; decreases E.decrease; increases

E.decrease; increases

What is radiation fog?

Earth's surface cools rapidly, forms during cool, clear, calm nights the warm earth starts to cool at night.

What involves when ice is processing into convert into liquid water as melt? Do those changes involve? What involves when the conversion of water from one state to another

Energy Huge amount of energy. Energy is absorbed - ice in water gets less and less

What season represents saturated atmosphere ?

Fall actually represents saturated atmosphere.

The lowest water vapor contents generally occur during the summer months T or F

False

When air rises in the atmosphere, it is compressed and the temperature cools. T or F

False

When is relative humidity the highest?

First in the morning Why? Earth is cooling off all the night along.

What is called when liquid( water) changes to a solid ?

Freezing( crystallization) crystlize

What meteorological event occurs when supercooled raindrops freeze on contact with solid objects?

Glaze forms when raindrops become supercooled as they fall through cold air and turn to ice upon colliding with solid objects.

What kind of air has a greater capacity for water vapor? (Hot/Cold)

Hot

Air has the limits -

How much water vapor air can hold.

What does our atmosphere get a huge amount of energy from which conversion of water from one thing to another?

Hurricane, tornade, and thunderstorms

In winter, temperature between. 20-30 F. What is the atmosphere ?

It is so dry. We don't get condensation in the winter.= there is no so much water to condense out.

What is a cumulus cloud?

Latin for "piles", a cloud that looks like a pile or accumulates. globular (shaped like a cotton ball)cloud mass often associated with fair weather. made out of water droplets

Startus

Latin for layer- sheets or layers that cover much of the sky. The edges appear fussy and the color is gray. Low-level clouds closed to the ground made out of water-droplets

cloud droplets

Less than 20 micrometers(0.02 millimeter) in diameter. fall incredibly slowly

Where are there dry states in the U.S ?

Nevada, Arizona, Utah.

How about the other gases like Carbon dioxide and Nitrogen ? Do these gases have 3 states like water ?

No. Carbon Dioxide -gas in the air How to make it into a solid?-We have to freeze it Nitrogen- how to get it freeze ?- We have to make it.

Does relative Humidity (RH) reach more than 100% if cool off air keeping down temperature ?

No. It can't be 102 or 103% and more. It is impossible. water vapor or moisture will come out of the air.

Do 100% of dew point in the winter morning and 100% of dew point in summer morning mean they hold the same moisture?

No. widely different number because winter doesn't have moisture.

____________ is air that is filled with water vapor to capacity.

Saturated air- It can hold no more water vapor. The maximum quantity of water vapor that the air can hold at any given temperature and pressure.

What is a wintertime form of precipitation that consists of small ice particles?

Sleet

Which form of precipitation is likely to occur as the cloud droplets fall from a layer of warmer air with temperatures above freezing through a colder subfreezing layer closer to the ground?

Sleet

Which season is always the highest water vapor ?

Summer

Relative humidity will always change as temperature changes, assuming that the water vapor content of the atmosphere remains constant. T or F

T

What is relative humidity (RH)?

Tells us how much water vapor is in the air compared to how much air hold at the temperature. water vapor content (how much you have) ------------------------ x 100 %=. % water vapor capacity( how much air can hold) RH always shows as a percentage. this number is not absolute, but relative ( ratio) The ratio of the air's water-vapor content to its water-vapor capacity.

What is humidity?

The amount of water vapor in the air( atmosphere)

What is the dew point temperature?

The temp the air needs to be cooled to in order to reach saturation(RH=100%) The temperature where air can not hold additional moisture, and condense will begin. the temperature at which the water vapor in the air becomes saturated and condensation begins.

Why does fall represent saturated atmosphere ?

The temperature is cold. The capacity of air is getteing smaller.

What does relative humidity change at constant Temperature show?

These experiment shows RH increase all the way up to 100 % by adding more water vapor to the Air. but It doesn't represent the atmosphere. Why? We don't have the constant of temperature.

When do water molecues begin to slow down ?

They hit cold air and then collide and begin to condensation.( gas→liquid)

Water vapor adds pressure to air. What is it called ? The part of the total atmospheric pressure attributable to water-vapor content.

Vapor pressure

What means capacity is temperature dependent ?

Warm air can hold much more water vapor than cold air. Molecules move faster

What is the only substance that occurs in all three states on Earth's surface?

Water

liquid water

Water molecules separate. bunch of them still stick together but move more freely.

What is called when air form a gas ?

Water vapor Thermal energy( heat) -Water molecules zipping around so fast- going off( explore) into the air.

What happens at the dew point temperature?

Water vapor condenses to a liquid.

What is condensation ? example ?

Water vapor(gas ) to Liquid ( water) about 600 cal released) the surface of a beer glass. Condensation, fog, dew, or cloud formation

Under what circumstances could the relative humidity exceed 100 percent without producing condensation in the air?

When there are no condensation nuclei When there are no condensation nuclei present, a relative humidity well in excess of 100 percent is needed to produce clouds.

Melting and evaporation (absorb/release) heat?

absorb

Water is the only substance ( compound) that exists in ___________ on the Earth.

all three states water occurs 3 states such as gas, water, and liquid.

What are middle clouds and what is the height?

altostratus(alto-middle), altocumulus, 2000-6000 meters made out of droplets and thicker.

Hundreds of water evaporate out the Ocean and put water vapor in the air every single day. Constant cycle of water through atmosphere never stops- why is it so important ?

because of stored energy

All the energy that drives the process our atmosphere comes from _____________________.

changing the states of water

What are high clouds and what is the height?

cirrus(wispy hair), cirrostratus(stratus sheet-like), cirrocumulus, over 6000 meters

What is a sling psychrometer?

compares the wet and dry bulb temperatures(current air temp) the greater the difference between the thermometer readings(wet-bulb and dry-bulb), the lower the RH-used to determine both relative humidity and dew point

Formation of precipitation

complex process that involves both ice crystal and collision of water droplets.

What is frontal wedging?

cool air acts as a barrier to warm air, the fronts are part of the storm (systems called middle-latitude cyclones) Warm air ( hold more moisture) is pushed by cold air ↓ rise up and exapnad( adiabatic cooling) bounaries get precipitation like storm.

What kind of cloud is vertical low to high altitude?

cumulonimbus- often produces rain showers and thunderstorms

The change of state from a gas to a solid is called ____________.

deposition

rain

droplets have at least a 0.5 mm diameter

Drizzle

droplets have less than 0.5 mm diameter Precipitation from stratus clouds consisting of tiny droplets.

What climate does sublimation occur ?

dry climate ( dry air) For example, Utah is really dry air. There is snow on the ground but sun comes up. Later there is no snow or puddles on the ground. Why? because of air is dry. Sublimation occurs.

adiabatic temperature changes doesn't occur ________________

due to addition or less of heat.

What is orographic lifting?

elevated terrains act as a barrier( to the flow of air, force the air to ascend ) Move up- temp drops- causing water vapor-air to cool off and reach the dew point and begin to condense-form clouds, precipitation. After the top of the mountain, lose moisture, Air sinking, temp starts to go up means Relative Humility goes down-means air does out-get desert, called rain shadow desert the result can be rainshadow desert (usually from a mountain) air is lifted over an obstacle occurs when there is a change in temperature of a gas caused by expansion or contraction of the gas without the use of heat

It takes more energy to evaporate or melt

evaporate about 600 cal absorbed melt 80 cal absorbed

What does dew point temperature tell us?

exactly how much water vapor in the air. Higher temp - more moisture Lower temp- less moisture

What is deposition? Example?

gas to solid without condensation process -black ice: directly true into ice ( about 680 cal released) example :ice on bridge and road

hail

hard rounded pellets concentric shells most diameter range from 1 to 5cm

Adiabatic temperature (heating/cooling) occurs when.. (2 answers)

heating air is compressed when air is warm= motion of air molecules increase.(= they speed up and collide) ↓ produce heat= temp goes up atmosphere Descending(sinking) air is compress due to increasing air pressure. cooling Air expands when the air will cool. Molecules slow down→ air expands→ temp drops atmosphere rising air will expand due to decreasing air pressure. Molecules are less to collide with one another= so the temp will drop and reach the dew point=cause condensation.= forms clouds, rain, and fog, etc

What is a cirrus cloud?

high(20,000 feet from the ground), white, thin(made out of ice), wispy( like feathery appearance ) cloud which is made of ice crystals

What is upslope fog?

humid air moves up a slope, adiabatic cooling occurs. warm air is force up over a mountain.

snow

ice crystal, or* aggregates of ice crystal *to combine into a single group or toal A solid form of precipitation produced by the sublimation of water vapor.

glaze or freezing rain

impact with a solid causes freezing. Rain that freezes on contact

What is latent heat?

in order to accomplish that state change, movement that moves from one area to another without causing a change in temperature. The energy absorb or released during a change in a state such as a conversion from one state to another. The energy needed to change the state of a substance For example, ice in the mixture(beaker cup) The temperature of the mixture stays the same 32 F to melt. Even add energy, the energy goes into molecular between water molecules in the ice cubes. - the heat used to melt ice(causing ice to melt) does not produce a temperature change. The energy absorbed or released during a change in state.

What is a hygrometer?

instrument used to measure relative humidity

Temperature and relative humidity have what kind of relationship?

inverse( opposite in relation) For example, temp goes up, RH goes down.

What does the table show ? Temp C (F). water-vapor content at saturation (grams) -40(-40). 0.1 -30(-22). 0.3

it shows how much air hold water vapor= capacity content= how much you have ?

Freezing releases 80 calories per gram to the surrounding environment as _________.

latent heat of fusion

What is an electrical hygrometer?

measures electrical current (influenced by water vapor)

Fronts are part of the storm systems called___________.

middle-latitude cyclones cold air is always heavier than warm air. so it tend to slide underneath the warm air. so cold air pushes warm air upward so warm air- expand-cool off- reach the dew point so band of precipitation and could along cold front along a cold front, we have intense local thunderstorms or rainstorms.

Formation of Hail

occurs in large cumulonimbus clouds with violet up and downdrafts. Layers of freezing rain are caught in up and down drafts in the cloud.

How is a calorie measured?

one calorie is the heat necessary to raise the temperature of 1 gram of water 1 degree celsius. measure that is absorbed or released ( heat), and give in reaction.

Orographic lifting leads to _______________ on windward lopes.

precipitation= orographic rain

What type of fog forms in valleys at night?

radiation fog

sleet

rain that freezes while falling. occurs when warmer air overlies colder air Frozen or semifrozen rain formed when raindrops freeze as they pass through a layer of cold air.

If air depends, it warms, making condensation and precipitation even less. The result can be _____________

rainshadow desert

What is a hair hygrometer?

reads the humidity directly by the expansions/contraction of hair

The ratio of the air's water vapor content to its capacity at that same temperature and pressure is a measure of the air's ___________.

relative humidity

Freezing and condensation (absorb/release) heat?

release

The process of converting a gas to a liquid ____________ heat energy. Possible answers - releases or absorbs. Choose the correct answer.

releases

What are winter time phenomenon ?

sleet, freezing rain

What is sublimation? Example?

solid to gas without melting process. example for dry ice

What are low clouds and what is the height?

stratus, stratocumulus, nimbostratus(nimbus means rainy), nimbostratus is not a thunderstorm cloud below 2,000 meters. made out of water droplets

which season is always the highest water vapor content ?

summer

Water vapor requires what to condense on?

surface

Water vapor requires a ______ to condense on. What are they?

surface Possible condensation surfaces- on the grass, a car window etc.

Water capacity is controlled by what?

temperature

What is a calorie?

the amount of energy needed to raise the temperature of 1 gram of water 1 degree Celsius the amount of energy is absorbed or release , and given in reaction.

Water is constantly cycled through_____________

the atmosphere ( change places from one thing to another).

When is almost the highest humidity at any given day? how about the lowest humidity ?

the first in the morning.Relative humidity is then at its lowest during mid day when it is the hottest outside. early after noon (dividing by a higher number since water vapor capacity is based on air temperature).

What is the mixing ratio?

the mass of water vapor in a unit of air compared to the remaining mass of dry air the weight of water vapor compare to the weight of dry air. often measure in grams per kilogram.

Evaporation is sometimes called a "cooling process" because ____________.

the water temperature usually decreases after Evaporation

Clouds are composed of

tiny water droplets and ice crystals

localized convective lifting

unequal surface heating causes localized pockets of air to rise because of their buoyancy Solar heating hits Earth's surface and warms it. warm air is less dense than the surrounding cool air. As air is warm and this package of air that rises up( thermal) thermal cross the condense level. temp is low, so water vapor is not stable in the air it causes condense out of the air and make clouds

Humidity 92% but the outside is raining. Where is the rain coming from ?

up there somewhere reaches at the dew point and then cause rain.

How does hail form and in what kind of cloud?

violent up and down drafts in large cumulonimbus clouds, formed from freezing rain caught

What is advection fog?

warm, moist air moves over a cool surface.( along the coast)= common on the Pacific Coast.

Condensation

water vapor in the air changes to a liquid & forms dew, fog, or clouds

In summer, temperature between 70-90 F, What does the atmosphere have more?

water vapor= more moisture. Hot air hold more water vapor than cold air.

convergence

where the air is flowing together and rising ( low pressure=rotating counterclockwise =cyclone) As air flows horizontally- meets along the surface of Earth.-it forces upward. it is responsible for hurricanes and cyclones The condition that exists when the distribution of winds in a given area results in a net horizontal inflow of air into the area. Because convergence at lower levels is associated with an upward movement of air, areas of convergent winds are regions favorable to cloud formation and precipitation.