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Transcript of A Climate Senior Project Presentation
Simulating Climate UsingA Simple Model
Jonathan Fivelsdal
May 12, 2010
Jonathan Fivelsdal Simulating Climate Using A Simple Model 1/44
General Outline
• Introduction
• Basic Facts About Climate
• Climate Model Equation
• Results
• Future Work
Jonathan Fivelsdal Simulating Climate Using A Simple Model 2/44
Introduction
• My Research Focuses on Global Climate
• I use a Computer Model of a 1-D EBM
• I Investigate How Land Configs Affect TemperatureChange Across the Globe
• Simulation Runs Over 1-Year Period
Jonathan Fivelsdal Simulating Climate Using A Simple Model 3/44
Introduction
• My Research Focuses on Global Climate
• I use a Computer Model of a 1-D EBM
• I Investigate How Land Configs Affect TemperatureChange Across the Globe
• Simulation Runs Over 1-Year Period
Jonathan Fivelsdal Simulating Climate Using A Simple Model 3/44
Introduction
• My Research Focuses on Global Climate
• I use a Computer Model of a 1-D EBM
• I Investigate How Land Configs Affect TemperatureChange Across the Globe
• Simulation Runs Over 1-Year Period
Jonathan Fivelsdal Simulating Climate Using A Simple Model 3/44
Introduction
• My Research Focuses on Global Climate
• I use a Computer Model of a 1-D EBM
• I Investigate How Land Configs Affect TemperatureChange Across the Globe
• Simulation Runs Over 1-Year Period
Jonathan Fivelsdal Simulating Climate Using A Simple Model 3/44
Introduction
• My Research Focuses on Global Climate
• I use a Computer Model of a 1-D EBM
• I Investigate How Land Configs Affect TemperatureChange Across the Globe
• Simulation Runs Over 1-Year Period
Jonathan Fivelsdal Simulating Climate Using A Simple Model 3/44
1-D Energy Balance Model
1-D Energy Balance Model
• Used to Examine Properties of Earth’s Climate System
• Based on Equilibrium Condition
• Considers Temperature Variations Across Lines of LatitudeOnly
Jonathan Fivelsdal Simulating Climate Using A Simple Model 4/44
Physics of Heat Exchange
• Energy is the ability to do work
• Heat flux is the process of energy transfer from one body toanother
• Example: Earth Receives Energy From the Sun and inResponse to the Energy Exchange Heats Up
Jonathan Fivelsdal Simulating Climate Using A Simple Model 5/44
Physics of Heat Exchange
• Energy is the ability to do work
• Heat flux is the process of energy transfer from one body toanother
• Example: Earth Receives Energy From the Sun and inResponse to the Energy Exchange Heats Up
Jonathan Fivelsdal Simulating Climate Using A Simple Model 5/44
Physics of Heat Exchange
• Energy is the ability to do work
• Heat flux is the process of energy transfer from one body toanother
• Example: Earth Receives Energy From the Sun and inResponse to the Energy Exchange Heats Up
Jonathan Fivelsdal Simulating Climate Using A Simple Model 5/44
Specific Heat
C =ΔQ
mΔT
• Specific heat capacity: heat energy required to raise thetemperature of a substance
Terms DescriptionΔQ Heat required to raise substance to a given temperaturem Mass of a given substanceΔT Amount of temperature change in a given substanceC Specific Heat Capacity
Jonathan Fivelsdal Simulating Climate Using A Simple Model 6/44
Specific Heat (Examples)
• specific heat of rock is 850 J (kg K)−1
• specific heat of water 4186 J (kg K)−1
• Since the specific heat of water > specific heat of rock;more energy to increase temp of oceans vs. land
Jonathan Fivelsdal Simulating Climate Using A Simple Model 7/44
Specific Heat (Examples)
• specific heat of rock is 850 J (kg K)−1
• specific heat of water 4186 J (kg K)−1
• Since the specific heat of water > specific heat of rock;more energy to increase temp of oceans vs. land
Jonathan Fivelsdal Simulating Climate Using A Simple Model 7/44
Albedo
Albedo (�)
• ratio of radiation reflected by a surface
• 0 ≤ � ≤ 1
• Net Albedo of Earth is determined by factors such as % ofland vs. ocean and glacier coverage
• Earth’s Average Albedo is .3
Jonathan Fivelsdal Simulating Climate Using A Simple Model 8/44
Blackbody Radiation
• A blackbody is a surface that completely absorbs allincident radiation
• Earth absorbs most of the radiation it receives (about 70%)
• Earth can be approximately described as a blackbody
• The amount of energy released by a blackbody over agiven area is obtained by the Stefan-Boltzmann law
Jonathan Fivelsdal Simulating Climate Using A Simple Model 9/44
Blackbody Radiation
• A blackbody is a surface that completely absorbs allincident radiation
• Earth absorbs most of the radiation it receives (about 70%)
• Earth can be approximately described as a blackbody
• The amount of energy released by a blackbody over agiven area is obtained by the Stefan-Boltzmann law
Jonathan Fivelsdal Simulating Climate Using A Simple Model 9/44
Blackbody Radiation
• A blackbody is a surface that completely absorbs allincident radiation
• Earth absorbs most of the radiation it receives (about 70%)
• Earth can be approximately described as a blackbody
• The amount of energy released by a blackbody over agiven area is obtained by the Stefan-Boltzmann law
Jonathan Fivelsdal Simulating Climate Using A Simple Model 9/44
Blackbody Radiation
• A blackbody is a surface that completely absorbs allincident radiation
• Earth absorbs most of the radiation it receives (about 70%)
• Earth can be approximately described as a blackbody
• The amount of energy released by a blackbody over agiven area is obtained by the Stefan-Boltzmann law
Jonathan Fivelsdal Simulating Climate Using A Simple Model 9/44
Stefan Boltzmann LawAmount of Energy Emitted by a Blackbody
E = ��T 4
• E: Flux Density• �: Emissivity (Ability to radiate as a blackbody (�bb = 1)• �: Stefan-Boltzmann Constant *• T: Temperature
* � = 5.67 ⋅ 10−8 Wm−2 K−4
Jonathan Fivelsdal Simulating Climate Using A Simple Model 10/44
Greenhouse Effect
• Ability of Atmosphere to Absorb and Reflect Heat RadiatedFrom Earth’s Surface
• Atmosphere is a layer of gas
• (ie. 78% Nitrogen,21% Oxygen, and < 1% Carbon Dioxide)
• Thicker Atmosphere Absorbs Heat More Effectively
Jonathan Fivelsdal Simulating Climate Using A Simple Model 11/44
Greenhouse Effect
• Ability of Atmosphere to Absorb and Reflect Heat RadiatedFrom Earth’s Surface
• Atmosphere is a layer of gas
• (ie. 78% Nitrogen,21% Oxygen, and < 1% Carbon Dioxide)
• Thicker Atmosphere Absorbs Heat More Effectively
Jonathan Fivelsdal Simulating Climate Using A Simple Model 11/44
Greenhouse Effect
• Ability of Atmosphere to Absorb and Reflect Heat RadiatedFrom Earth’s Surface
• Atmosphere is a layer of gas
• (ie. 78% Nitrogen,21% Oxygen, and < 1% Carbon Dioxide)
• Thicker Atmosphere Absorbs Heat More Effectively
Jonathan Fivelsdal Simulating Climate Using A Simple Model 11/44
Greenhouse Effect
Jonathan Fivelsdal Simulating Climate Using A Simple Model 12/44
Facts About Earth’s Temperature
• Earth’s Effective Blackbody Temperature (No Atmosphere)is 255 K
• Freezing Temperature of Water 273 K
• Earth’s Temperature With Atmosphere (Actual) is 288 K
• Earth’s Temperature With Atmosphere (Model) is 303 K
Jonathan Fivelsdal Simulating Climate Using A Simple Model 13/44
More Facts About Earth’sTemperature
• Difference Between Actual Mean Temperature (288 K) andEffective (255 K) is 30 K
• The Temp Difference is due to the Greenhouse Effect
Jonathan Fivelsdal Simulating Climate Using A Simple Model 14/44
Incoming Solar Radiation
• Amount of Solar Radiation Earth Receives in Units Wm−2
• Solar Radiation is also referred to as Short Wave(SW)
Jonathan Fivelsdal Simulating Climate Using A Simple Model 15/44
Incoming Solar Radiation
• Amount of SW that reaches Top of Atmosphere is 1380Wm−2
• Total Amount of SW Received by an Average Point onEarth is 343 Wm−2
Jonathan Fivelsdal Simulating Climate Using A Simple Model 16/44
Incoming Solar Radiation
• Amount of SW that reaches Top of Atmosphere is 1380Wm−2
• Total Amount of SW Received by an Average Point onEarth is 343 Wm−2
Jonathan Fivelsdal Simulating Climate Using A Simple Model 16/44
Incoming Solar Radiation
• Amount of SW that reaches Top of Atmosphere is 1380Wm−2
• Total Amount of SW Received by an Average Point onEarth is 343 Wm−2
Jonathan Fivelsdal Simulating Climate Using A Simple Model 16/44
Incoming Solar Radiation
• Only 25 % of the SW at the Top of the Atmosphere(TOA)Reaches Earth’s Surface
• This is because Earth’s Sphericity and only half of theearth is lit by the sun
• (ie. day and night)
Solar Radiation ValuesRadiation at TOA 1380 Wm−2
Incoming Radiation 343 Wm−2
Jonathan Fivelsdal Simulating Climate Using A Simple Model 17/44
Geographic Features and Climate
Geographic Features that Affect Climate are
• Distribution of Land and Sea• Ocean Currents• Orientation of Land Masses
Jonathan Fivelsdal Simulating Climate Using A Simple Model 18/44
Climate Models
Advantages of Simple Climate Models VS Complex Models
• Easier to Interpret• Less Computationally Expensive• Easier to Implement
• Complex Models use Systems of PDE’s• My Model is Based on 1 Partial Differential Equation
Jonathan Fivelsdal Simulating Climate Using A Simple Model 19/44
The Model Equation
Climate Model Equation
∂T
∂t=
1
�cpℎ[Qs(1− �)− I +D]
Model Parameters Description�cpℎ Thermal Capacity FactorQ Insolations = s(y) Latitude Distribution� AlbedoI OLRD Difffusion
Jonathan Fivelsdal Simulating Climate Using A Simple Model 20/44
Model Parameters Explained
∂T
∂t=
1
�cpℎ[Qs(1− �)− I +D]
• Q = 343 Wm−2: (Incoming Solar Radiation)• s(y): Describes How Solar Radiation is Distributed Over
Latitudes• y = sin(�): where � is Latitude• (1-�): Ratio Solar Radiation Absorbed by the Earth• I: Outgoing Long Wave Radiation• D: Diffusion (Heat Transport Term)
Jonathan Fivelsdal Simulating Climate Using A Simple Model 21/44
Outward Longwave Radiation
Since �rock ≈ 1 and �water ≈ 1 we represent I as
I = ��T 4
= (1)�T 4
= �T 4
Jonathan Fivelsdal Simulating Climate Using A Simple Model 22/44
Thermal Capacity Factor
∂T
∂t=
1
�cpℎ[Qs(1− �)− I +D]
• �cpℎ is the thermal capacity factor
• Amount of Heat Per Unit Surface Area needed to Raise theSurface Temperature of the Earth by 1∘ C
• Units are in J K−1 m−2
Jonathan Fivelsdal Simulating Climate Using A Simple Model 23/44
Thermal Capacity Factor
∂T
∂t=
1
�cpℎ[Qs(1− �)− I +D]
• �cpℎ is the thermal capacity factor
• Amount of Heat Per Unit Surface Area needed to Raise theSurface Temperature of the Earth by 1∘ C
• Units are in J K−1 m−2
Jonathan Fivelsdal Simulating Climate Using A Simple Model 23/44
Thermal Capacity Factor
∂T
∂t=
1
�cpℎ[Qs(1− �)− I +D]
• �cpℎ is the thermal capacity factor
• Amount of Heat Per Unit Surface Area needed to Raise theSurface Temperature of the Earth by 1∘ C
• Units are in J K−1 m−2
Jonathan Fivelsdal Simulating Climate Using A Simple Model 23/44
Properties of Rock and Water
• Rock radiates heat differently from water
• Specific Heat of Rock (cpr) is 850 J K−1 kg−1
• Specific Heat of Water (cpw) is 4198 J K−1 kg−1
• Specific Heat of Water is about 5 times larger than SpecificHeat of Rock
Jonathan Fivelsdal Simulating Climate Using A Simple Model 24/44
Properties of Rock and Water
• Rock radiates heat differently from water
• Specific Heat of Rock (cpr) is 850 J K−1 kg−1
• Specific Heat of Water (cpw) is 4198 J K−1 kg−1
• Specific Heat of Water is about 5 times larger than SpecificHeat of Rock
Jonathan Fivelsdal Simulating Climate Using A Simple Model 24/44
Properties of Rock and Water
• Rock radiates heat differently from water
• Specific Heat of Rock (cpr) is 850 J K−1 kg−1
• Specific Heat of Water (cpw) is 4198 J K−1 kg−1
• Specific Heat of Water is about 5 times larger than SpecificHeat of Rock
Jonathan Fivelsdal Simulating Climate Using A Simple Model 24/44
Properties of Rock and Water
• Rock radiates heat differently from water
• Specific Heat of Rock (cpr) is 850 J K−1 kg−1
• Specific Heat of Water (cpw) is 4198 J K−1 kg−1
• Specific Heat of Water is about 5 times larger than SpecificHeat of Rock
Jonathan Fivelsdal Simulating Climate Using A Simple Model 24/44
Capacity Factors: Rock and Water
∂T
∂t=
1
�cpℎ[Qs(1− �)− I +D]
Rock Thermal Capacity Factor
rc = �rcprℎr
Water Thermal Capacity Factor
wc = �wcpwℎw
Jonathan Fivelsdal Simulating Climate Using A Simple Model 25/44
Radiative Imbalance
• Excess Radiation (Tropics) Deficit (Poles)
Jonathan Fivelsdal Simulating Climate Using A Simple Model 26/44
Hadley Circulation
• A Physical Manifestation of Heat Transport
• Large Scale Circulations Develop in the Atmosphere due toUneven Heating
• 1. Air Rises Near The Equator
• 2. Then Air Flows Poleward and Cools
• 3. Air Sinks Near The Poles
• 4. Air Flows Close to Surface Back Towards Equator
Jonathan Fivelsdal Simulating Climate Using A Simple Model 27/44
Gulf Stream
• Series of Fast Moving Ocean Currents in the Atlantic• Carry Warm Air Poleward• Results in Mild Climates in North America and Europe• The Diffusion term (D) Represents this Process
Jonathan Fivelsdal Simulating Climate Using A Simple Model 28/44
Model Diffusion Compared toRealistic Diffusion
• Model Diffusion is Given by the equation D = C(T − T )
• Realistic Diffusion is Represented by
D ∝ ∂2T
∂x
Jonathan Fivelsdal Simulating Climate Using A Simple Model 29/44
Model Diffusion Compared toRealistic Diffusion
Figure:Dark Line ≡ Temp. DistributionA,B ≡ Specfic Temps.Dotted ≡ Mean Temperature
Jonathan Fivelsdal Simulating Climate Using A Simple Model 30/44
Model Diffusion Compared toRealistic Diffusion
• With Model Diffusion A and B are Treated the Same• Due to (T − T ) for A equaling (T − T ) for B
Jonathan Fivelsdal Simulating Climate Using A Simple Model 31/44
Model Diffusion Compared toRealistic Diffusion
• With Realistic Diffusion Negative Diffusion at A andPositive Diffusion at B
• A: Neg. Curvature and B: Pos. CurvatureJonathan Fivelsdal Simulating Climate Using A Simple Model 32/44
Land Configurations
Land Types
• Type 1: Land in Poles Only (land > 55 S and land > 55 N)
• Type 2: Land in Poles and Tropics
• Type 3: Land in Tropics Only (23.5 S < land < 23.5 N)
• Type 4: Land mostly in Northern Hemisphere (MostlyAbove the Equator)
• Land types were run for each initial temperature
Jonathan Fivelsdal Simulating Climate Using A Simple Model 33/44
Percentage Land Vs. Water
Land Type: Type 1 Type 2 Type 3 Type 4Land 39% 65% 26% 39%Water 61 % 35 % 74 % 61%
• Notice: Land Type 3 has the most water
Jonathan Fivelsdal Simulating Climate Using A Simple Model 34/44
Initial Condition 1
Annual Average Temperatures With Initial Temperature 255 K
250
255
260
265
270
275
280
285
290
-90 -75 -60 -45 -30 -15 0 15 30 45 60 75 90
Latitude
Tem
pera
ture
(Kel
vin)
Land Type 1Land Type 2Land Type 3Land Type 4Initial Temp
Jonathan Fivelsdal Simulating Climate Using A Simple Model 35/44
Results for Initial Condition 1
• Land Type 3 Changes the Least From the InitialTemperature of 255 K
• This is because Land Type 3 has the most water and thehigh heat capacity of water
• Land Type 2 Changes the Most Since it has the Most Land• Land Type 1 and 4 have similar Temp. Distributions since
same amount of land
Land Type: Type 1 Type 2 Type 3 Type 4Land 39% 65% 26% 39%Water 61 % 35 % 74 % 61%
Jonathan Fivelsdal Simulating Climate Using A Simple Model 36/44
Initial Condition 2
Annual Average Temperatures With Initial Temperature 273 K
260
265
270
275
280
285
290
-90 -75 -60 -45 -30 -15 0 15 30 45 60 75 90
Latitude
Tem
pera
ture
(Kel
vin)
Land Type 1Land Type 2Land Type 3Land Type 4Initial Temp
Jonathan Fivelsdal Simulating Climate Using A Simple Model 37/44
Results for Initial Condition 2
Land Type 3 Changes the Least From the Initial Temp.
Again this is likely due to the higher heat capacity of water
Land Type: Type 1 Type 2 Type 3 Type 4Land 39% 65% 26% 39%Water 61 % 35 % 74 % 61%
Jonathan Fivelsdal Simulating Climate Using A Simple Model 38/44
Initial Condition 3
Annual Average Temperatures With Initial Temperature 288 K
260
265
270
275
280
285
290
295
-90 -75 -60 -45 -30 -15 0 15 30 45 60 75 90
Latitude
Tem
pera
ture
(Kel
vin)
Land Type 1Land Type 2Land Type 3Land Type 4Initial Temp
Jonathan Fivelsdal Simulating Climate Using A Simple Model 39/44
Results for Initial Condition 3
Land Type: Type 1 Type 2 Type 3 Type 4Average Temps. 279.30 K 278.88 K 282.20 K 279.25 KΔ Initial Temp. -8.7 K -9.12 K -5.8 K -8.75 K
• Land types 1,2, and 4 have average temperatures about 10K less than 288 K.
• Land type 3 has an average temperature about 6 K lessthan 288 K
• Therefore Land Type 3 changes the least from the initialtemperature
Jonathan Fivelsdal Simulating Climate Using A Simple Model 40/44
Initial Condition 4
Annual Average Temperatures With Initial Temperature 303 K
260
265
270
275
280
285
290
295
300
305
-90 -75 -60 -45 -30 -15 0 15 30 45 60 75 90Latitude
Tem
pera
ture
(Kel
vin)
Land Type 1Land Type 2Land Type 3Land Type 4Initial Temp
Jonathan Fivelsdal Simulating Climate Using A Simple Model 41/44
Results for Initial Condition 4
One difference from other graphs is all temp. distributions liebelow initial temp.
Jonathan Fivelsdal Simulating Climate Using A Simple Model 42/44
Discussion
All temp. distributions have a similar shape (indicatesdominance of solar term Qs(y))
Every temp. distribution has cold temperatures in poles andwarm temperatures in tropics
Land Type 3 is the most distinct distribution
Land Type 3 Changes Least from Initial Temperature (has themost water)
Jonathan Fivelsdal Simulating Climate Using A Simple Model 43/44
Future Work
Test if large percent of water coverage is sole reason for smalltemp. changes
Method 1: Keep ratio of land to water constant but changedistributions of land
Method 2: Keep land distribution constant but change ratio ofland to water
Jonathan Fivelsdal Simulating Climate Using A Simple Model 44/44