thermal response of climate system weather update finish seasons and solar elevation at noon heat...
TRANSCRIPT
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