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Quiz Chapter 24Quiz Chapter 24
1.1. SublimationSublimation
2.2. Latent heatLatent heat
3.3. HumidityHumidity
4.4. SaturatedSaturated
5.5. Relative humidityRelative humidity
6.6. PsychrometerPsychrometer
7.7. Hair hygrometerHair hygrometer
8.8. Specific humiditySpecific humidity
9.9. Dew pointDew point
10.10.DewDew
04/21/2304/21/23describe how relative humidity is describe how relative humidity is
measuredmeasured
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This is due at the end of classThis is due at the end of classWarm up question:Warm up question: How does relative How does relative
• Explain how water vapor enters the Explain how water vapor enters the air.air.
• Explain the meaning of humidity and Explain the meaning of humidity and describe how it is measured.describe how it is measured.
• Describe what happens when the Describe what happens when the temperature of air decreases at or temperature of air decreases at or below the dew point.below the dew point.
• Water in the air is Water in the air is called water vapor: called water vapor: it is tasteless, it is tasteless, odorless, and odorless, and invisible gasinvisible gas
• Water in the air Water in the air can also be in the can also be in the form of ice or form of ice or water dropletswater droplets
• Water in the form of ice is Water in the form of ice is held in a CRYSTALLINE held in a CRYSTALLINE STRUCTURE STRUCTURE
• Evaporation occurs when Evaporation occurs when water molecules rotate and water molecules rotate and vibrate fast enough to vibrate fast enough to overcome forces of overcome forces of attractionattraction
• Can ice become vapor Can ice become vapor without first becoming without first becoming water?water?– Sublimation: process where Sublimation: process where
water in a solid form (ice) water in a solid form (ice) goes directly to a gas phasegoes directly to a gas phase
• Though most water Though most water enters atmosphere enters atmosphere through EVAPORATION, through EVAPORATION, some water does enter some water does enter through SUBLIMATIONthrough SUBLIMATION– Where does most Where does most
sublimation occur? (hint: sublimation occur? (hint: where is there a lot of where is there a lot of ice???)ice???)
• Latent Heat: “Hidden” Latent Heat: “Hidden” heatheat– Given off during Given off during
evaporationevaporation– Taken out during freezingTaken out during freezing
•HumidityHumidity • Humidity: amount of Humidity: amount of water in the atmospherewater in the atmosphere– When the air CANNOT hold When the air CANNOT hold
anymore water, the air is anymore water, the air is considered to be considered to be SATURATEDSATURATED
• The higher the The higher the temperature of air – THE temperature of air – THE MORE WATER IT CAN MORE WATER IT CAN HOLDHOLD– As the temperature As the temperature
decreases, so does the decreases, so does the ability of air to hold water ability of air to hold water vaporvapor
• Relative HumidityRelative Humidity • Relative Humidity is a Relative Humidity is a RATIORATIO
MASS OF WATER IN AIRMASS OF WATER IN AIR
POTENTIAL MASS OF WATERPOTENTIAL MASS OF WATER
• Potential mass of water Potential mass of water that air can hold changes that air can hold changes with the temperature of with the temperature of the airthe air– Hotter - more water vapor Hotter - more water vapor
contentcontent– Colder – less water vapor Colder – less water vapor
• Wet Bulb – Dry Bulb Wet Bulb – Dry Bulb MethodMethod– Dry bulb takes temperature Dry bulb takes temperature
of air with the amount of of air with the amount of moisture presentmoisture present
– Wet Bulb takes Wet Bulb takes temperature of air temperature of air SIMULATING A SATURATED SIMULATING A SATURATED ATMOSPHEREATMOSPHERE
– Using both measurements, Using both measurements, estimate humidity based on estimate humidity based on Relative Humidity ChartRelative Humidity Chart
• Dew pointDew point • This is the temperature This is the temperature at which air is saturated at which air is saturated with water . Below this with water . Below this temperature liquid or temperature liquid or solid water forms.solid water forms.
• Dew may also form on a Dew may also form on a surface via surface via condensationcondensation
• If the dew point is below If the dew point is below freezing frost will formfreezing frost will form
• Cloud formationCloud formation • The water needs The water needs something to something to condense onto, condense onto, dust.dust.
• The air must be at The air must be at or below the dew or below the dew point to cause point to cause cloud formation or cloud formation or saturated.saturated.
04/21/2304/21/23list the conditions that must exist list the conditions that must exist
• Convective coolingConvective cooling • As air rises it As air rises it expands and cools, expands and cools, due to the release due to the release of energy.of energy.
• This process of This process of cooling and cooling and heating to rising heating to rising and falling air is and falling air is called adiabaticcalled adiabatic
04/21/2304/21/23list the conditions that must exist list the conditions that must exist
• Convective coolingConvective cooling • Warms at a steady Warms at a steady rate of 1rate of 100C for every C for every 100 M the air 100 M the air descends. The descends. The cooling is effected cooling is effected by the condensation by the condensation process and process and averages .7averages .700C per C per 100 M the air rises.100 M the air rises.
04/21/2304/21/23list the conditions that must exist list the conditions that must exist
• Convective coolingConvective cooling • The level at which The level at which the clouds form is the clouds form is called the called the condensation level.condensation level.
• This starts at the This starts at the bottom of the cloud bottom of the cloud and further and further condensation allow condensation allow the clouds to form the clouds to form up.up.
04/21/2304/21/23list the conditions that must exist list the conditions that must exist
• The mixing of two The mixing of two or more moist air or more moist air masses with masses with different air different air temperatures may temperatures may be enough to get be enough to get below the dew below the dew point.point.
04/21/2304/21/23list the conditions that must exist list the conditions that must exist
• Advective coolingAdvective cooling • This is when warm This is when warm moist air passes moist air passes over a cold body of over a cold body of water or land water or land mass, the heat is mass, the heat is absorbed (dropping absorbed (dropping below the dew below the dew point) and low point) and low clouds form or fog.clouds form or fog.
04/21/2304/21/23list the conditions that must exist list the conditions that must exist
• Classification of Classification of cloudsclouds
• By form and altitudeBy form and altitude
• Forms: Stratus, Forms: Stratus, Cumulus and Cirrus.Cumulus and Cirrus.
• Altitude groups: Low Altitude groups: Low is up to 2,000 M, is up to 2,000 M, Middle is 2,000 to Middle is 2,000 to 6,000 M and High is 6,000 M and High is above 6,000 M above 6,000 M
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• Are sheet like or layered, Are sheet like or layered, they are low to the earth they are low to the earth surface and cover large surface and cover large areas of the sky.areas of the sky.
• Formed when warm air is Formed when warm air is above cool air, give very above cool air, give very little rain.little rain.
• Two other types: Two other types: nimbostratus are dark and nimbostratus are dark and give heavy rain or snow, give heavy rain or snow, altostratus form at middle altostratus form at middle latitudes and little rain latitudes and little rain
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• Are the puffy or popcorn Are the puffy or popcorn clouds, if the form at the clouds, if the form at the middle they are middle they are altocumulus and at lower altocumulus and at lower levels are stratocumulus levels are stratocumulus and cumulus.and cumulus.
• If there are strong rising If there are strong rising winds a cumulonimbus winds a cumulonimbus forms and can produce forms and can produce thunder, lighting and rain.thunder, lighting and rain.
04/21/2304/21/23list the conditions that must exist list the conditions that must exist
• Cirrus CloudsCirrus Clouds • These are the feathery These are the feathery or curly clouds at high or curly clouds at high altitudes.altitudes.
• Normally made of ice Normally made of ice crystals, that can cause crystals, that can cause a halo to form around a halo to form around the sun or moon.the sun or moon.
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• FogFog• Radiation fog or ground fog forms Radiation fog or ground fog forms
close to the ground as it gives off close to the ground as it gives off the heat from the day, more the heat from the day, more common in valleys were the cold common in valleys were the cold air can collect.air can collect.
• Advection fog forms when warm Advection fog forms when warm moist air pushes over a colder moist air pushes over a colder surface.surface.
• Upslope fog is cause by warm air Upslope fog is cause by warm air moving uphill and steam fog is moving uphill and steam fog is when warm air moves over a when warm air moves over a colder body of water.colder body of water.
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• PrecipitationPrecipitation • Moisture that falls Moisture that falls from the sky; from the sky; either as a liquid or either as a liquid or solid. ( rain, snow, solid. ( rain, snow, sleet and hail)sleet and hail)
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• Snow – most common Snow – most common solid form. Smaller in solid form. Smaller in size in lower temp size in lower temp because of lack of because of lack of moisture. moisture.
• Sleet – rain freezes in Sleet – rain freezes in the air as it falls to the the air as it falls to the ground.ground.
• If it freezes when it hits If it freezes when it hits the ground it forms the ground it forms sheet ice or glaze ice.sheet ice or glaze ice.
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• Hail – lumps of ice Hail – lumps of ice that are spherical or that are spherical or irregular in shape.irregular in shape.
• Form in normally in Form in normally in cumulonimbus cumulonimbus clouds, rain gets clouds, rain gets pushed through a pushed through a freeze layer and freeze layer and wind currents push wind currents push it up and down it up and down several times.several times.
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• Water droplets are Water droplets are normally small normally small enough to stay in enough to stay in the air.the air.
• If the size If the size increases 100 increases 100 times from 20 times from 20 micrometers, they micrometers, they will begin to fallwill begin to fall
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• Cloud seedingCloud seeding • They add freezing They add freezing nuclei to the cloud like: nuclei to the cloud like: silver iodine (from silver iodine (from flares or burners) or flares or burners) or powdered dry ice.powdered dry ice.
• Conflicting evidence on Conflicting evidence on effect, it may someday effect, it may someday help end droughts and help end droughts and control storms. control storms.
04/21/2304/21/23list the conditions that must exist list the conditions that must exist
precipitationprecipitation• Three types: a wide funnel Three types: a wide funnel
attached to a cylindrical attached to a cylindrical container, one that dumps container, one that dumps when it reaches a certain level, when it reaches a certain level, and the last weighs the and the last weighs the amount of water in the bucket.amount of water in the bucket.
• Only measure in one small Only measure in one small area.area.
• Snow is measured by depth Snow is measured by depth and water volume, average is and water volume, average is 10cm of snow per 1cm of 10cm of snow per 1cm of waterwater