4. D. Archer problem #3 Chapter 4 (pg. 41). Note that the model you want to run

Question

4. D. Archer problem #3 Chapter 4 (pg. 41). Note that the model you want to run for this problem is at: http://climatemodels.uchicago.edu/modtran/modtran.html. 15 pts

5. D. Archer problem #4 Chapter 8 (pg. 101). 5 pts

6. D. Archer problem #5 Chapter 8 (pg. 101). 5 pts

g CO2? have as great an impact on the heat balance as a doubling of d) What is the "equivalent CO2" of doubling atmospheric methane? That is to say, how many ppm of would lead to the same change in outgoing IR radiation energy flux as CO2 methane? What is the ratio of ppm co2 change to ppm methane change? 2. CO2 a) Is the direct effect of increasing coa on the energy output at the top of the atmosphere larger in high latitudes or in the tropics? b) Set pco2 to an absurdly high value of 10,000 ppm.You will see a spike in the CO2 absorption band. What temperature is this light coming from? where in the atmosphere do you think this comes from? Now turn on clouds and run the model again. Explain what you see. Why, at night, is it warmer when there are clouds? 3. Water vapor. Our theory of climate presumes that an increase in the temperature a ground level will lead to an increase in the outgoing IR energy flux at the top of the atmosphere a) How much extra outgoing IR would you get by the by 5oc? hat effect raising temperature of the ground and why? does the ground temperature have on the shape of the outgoing spectrum IR b) More water can evaporate into warm air than into cool air. By setting the model to hold the water vapor at constant relative humidity rather than constant vapor pressure (the default, calculate again the change in outgoing IR energy flux that accompanies a 5°C temperature increase. Is it higher or lower? Does water vapor make the Earth more sensitive to CO2 increases or less sensitive? c) Now see this effect in another way. Starting from a base case, record the total outgoing IR flux. Now increase pCO2 to 550 ppm. The temperature in the model stays the same (it's just how the model is written), so the IR flux goes down. Now, using the constant vapor pressure of water option, increase the temperature offset until you get the original IR flux back again. What is the change in T required? Now repeat the calculation but at constant relative humidity. Does the increase in CO2 drive a bigger or smaller temperature change?

Explanation / Answer

1. c.Doubling of CO2 will reduce the upward infrared radiation flux of the atmosphere. It will be decreased from 289.29 W/m2 to 286.054W/m2, a reduction of 3.23W/m2. While doubling of methane will also reduce this IR flux of atmosphere. It will change from 289.29W/m2 to 288.409W/m2 which that there is reduction of about 0.88W/m2

1d. doubling of concentration of CH4 to only 3.4 ppm will reduce the upward IR flux of the atmosphere to 288.409W/m2. To have the same effect the CO2 concentration needs to be increased to about 482 ppm.

2a Increase of CO2 has greater effect on higher latitudes than tropics. This is because increase of temperature will increase the melting of snow or ice present in the polar regions. Also the air of polar regions are dry which means that the amount of water vapour present in the air will be little. In humid regions there is little amount of CO2 into the air whereas in drier regions the concentration of CO2 is significant in the atmosphere.

2b. During the day if the sky is clear or cloudless then the earth will receive more heat from the sun and it will result in warmer temperature. But in the night the effect is opposite. If the night sky is clear then the heat emitted by the earth due to cooling of land surface the heat gets easily escaped to space. Whereas if the sky is cloudy then the cloud will trap some of the emitted heat and then reemit it to earth which will result in warmer temperature.

3.b. The increase in water vapour will make the atmosphere less sensitive to the CO2. Since the concentration of CO2 is very little in the humid air whereas the CO2 concentration is significantly higher in drier air or the air devoid of water vapour.

Related Questions

Navigate

• Browse (All)
• Browse 4
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.