Thermal Response of Climate System

Weather Update

Finish Seasons and Solar Elevation at Noon

Heat Transfer Processes

Latent Heat Transfer

Heating Imbalances

For Next Classs: Read Christopherson Ch. 4 (pp. 101-116) available on AsUlearn

Climate Newshttp://nc-climate.ncsu.edu/climateblog?id=118&h=d9f95ad7

http://www.washingtonpost.com/blogs/capital-weather-gang/wp/2015/01/16/scientists-react-to-warmest-year-2014-underscores-undeniable-fact-of-human-caused-climate-change/

RUC Forecast Soundingshttp://rucsoundings.noaa.gov/

Annual March of the Seasons

Figure 2.15

11:30 P.M. in the Antarctic

Figure 2.16

Insolation at Top of Atmosphere

Figure 2.10

Solar Elevation at Noon

Figure 2.18

Solar Elevation at Noon (SEN)

SEN is the angle of the noon sun above the horizon SEN = 90˚ - ArcDistance ArcDistance = number of degrees of latitude between location

of interest and sun’s noontime vertical rays If the latitude of location of interest and sun are in opposite

hemispheres, add to get ArcDistance If they are in the same hemisphere, subtract from the larger of

the two values

SEN Example

What is the SEN on June 21 for Boone (36 N)

SEN = 90 – ArcDistance Where are the sun’s noontime

vertical rays? ArcDistance = 36 – 23.5 ArcDistance = 12.5 SEN = 90 – 12.5 SEN = 77.5˚

Analemma

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Chapter 4: Driving Question

What are the causes and consequences of heat transfer within Earth’s climate system?

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Heat Transfer Processes

Radiation• Both a form of energy and a means of energy transfer• Radiational heating: object absorbs radiation at a greater

rate than it emits radiation Internal energy increases, temperature rises

• Radiational cooling: object emits radiation at a greater rate than it absorbs radiation

Internal energy decreases, temperature drops

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Heat Transfer Processes

Conduction and Convection• Conduction: the transfer of kinetic energy of atoms or

molecules via collisions between neighboring atoms or molecules

• Heat Conductivity: the ratio of the rate of heat transport across an area to the temperature gradient

Substances with a higher heat conductivity have greater rates of heat transport

• Solids are better conductors than liquids, liquids are better conductors than gases

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Heat Transfer Processes

Conduction and Convection• Convection: the vertical transport of heat within a fluid via

motions of the fluid itself Generally only occurs in liquids or gases (fluids) Convection in the atmosphere consequence of

differences in air density Advection is the horizontal transport of heat

• Sensible Heating: combination of conduction and convection

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Convection currents transport heat conducted from Earth’s surface into the troposphere

A fresh layer of snow is a good heat insulator

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Heat Transfer Processes

Phase Changes of Water• Water occurs naturally in all three phases

(solid, liquid, gas)• Depending on phase changes, either

absorbs or releases heat to or from environment

• Latent heat: quantity of heat involved in phase changes of water

• Latent heating: the transport of heat from one location to another as a consequence of changes in the phase of water

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Heat Transfer Processes

Phase Changes of Water• Heat absorbed from environment

during changes to higher energy states melting, evaporation, sublimation

• Heat released to environment during changes to lower energy states

freezing, condensation, deposition

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Thermal Response and Specific Heat

Specific Heat: amount of heat that will raise the temperature of 1 gram of a substance by 1 Celsius degree• Measured relative to liquid water

Water has the greatest specific heat of any naturally occurring substance

• Variation in specific heat from one substance to another implies that different materials have different capacities for storing internal energy

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Thermal Response and Specific Heat

Maritime and Continental Climates• Maritime climates: immediately

downwind of the ocean, and experience much less contrast between average winter and summer temperature

• Continental Climates: well inland, experience a much greater contrast between winter and summer temperature

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Heat Imbalance: Atmosphere vs. Earth’s Surface

Latent Heating• Transfer of heat energy from one place to another as a

consequence of phase changes of water• Heat is transferred from Earth’s surface to the troposphere

through latent heating• Large quantities of heat are required to bring about phase

changes of water as compared to phase changes of other naturally occurring substances

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Heat Imbalance: Atmosphere vs. Earth’s Surface

Latent Heating• Latent heat of fusion: amount of heat required to convert

a solid at its melting point to a liquid without a change in temperature

• Latent heat of vaporization: amount of heat required to convert a liquid to a gas without a change in temperature

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Heat Imbalance: Atmosphere vs. Earth’s Surface

Sensible Heating• Transport of heat from one

location or object to another via conduction, convection or both

• Often combines with latent heating to channel heat from Earth’s surface into the troposphere

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Heat Imbalance: Atmosphere vs. Earth’s Surface

Sensible Heating• The Bowen Ratio compares

how heat at the Earth’s surface is divided between sensible heating and latent heating

Varies from one place to another

Depends on amount of surface moisture

Surface energy budget through the course of a year