Difference between revisions of "ESE315 Assignment 2"
From atmoschem
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'''''Required:''''' | '''''Required:''''' | ||
| − | # Mars is 2.3e8 km away from the Sun; its albedo is 0.15. Its only source of heat is solar radiation. (a) Calculate the effective temperature of Mars. (b) The temperature observed at the surface of Mars is 220 K. What do you conclude about the Martian atmosphere? | + | # (10 credits) Mars is 2.3e8 km away from the Sun; its albedo is 0.15. Its only source of heat is solar radiation. (a) Calculate the effective temperature of Mars. (b) The temperature observed at the surface of Mars is 220 K. What do you conclude about the Martian atmosphere? |
| − | # The "Faint Young Sun" paradox has been puzzling scientists since the 1970s. Assuming that the distance between the Sun and the Earth has not changed significantly since the time of the Earth's formation 4.6 billion years ago. Use python to make a 2-D contour plot of the Earth's effective temperature (Te) for a range of solar | + | # (20 credits) The "Faint Young Sun" paradox has been puzzling scientists since the 1970s. Assuming that the distance between the Sun and the Earth has not changed significantly since the time of the Earth's formation 4.6 billion years ago. Use python to make a 2-D contour plot of the Earth's effective temperature (Te) for a range of solar constants and a range of albedos. |
| − | # | + | # (20 credits) Use the [http://climatemodels.uchicago.edu/modtran/ MODTRAN model] to simulate the terrestrial infrared radiation spectrum at a location on Earth. Use the following present-day conditions: CO2=400 ppm; CH4=1.7 ppm; tropospheric ozone=28 ppb; stratospheric ozone scale=1; water vapor scale=1; freon scale=1; temperature offset=0C; No clouds or rain; altitude 70 km; looking down. |
| + | ## why | ||
| + | |||
'''''Extra credit:''''' | '''''Extra credit:''''' | ||
| − | The following questions are not part of the assignment that you are required to hand in. You can do them | + | The following questions are not part of the assignment that you are required to hand in. You can do any ONE (but only ONE) of them to get 10 extra credits. Or, you can use these as inspiration for your term project. |
Based on the MODTRAN model: | Based on the MODTRAN model: | ||
| − | * Demonstrate the [http://www.kaltura.com/index.php/extwidget/preview/partner_id/1090132/uiconf_id/20652192/entry_id/1_etyzlvw7/embed/auto? Band Saturation Effect] by making a plot of Iout as a function of a greenhouse gas concentration, from say 0 to 1000 ppm, with lots of points at low concentrations. | + | * Demonstrate the [http://www.kaltura.com/index.php/extwidget/preview/partner_id/1090132/uiconf_id/20652192/entry_id/1_etyzlvw7/embed/auto? Band Saturation Effect] by making a plot of Iout as a function of a greenhouse gas concentration, from say 0 to 1000 ppm, with lots of points at low concentrations. Explain this phenomenon. |
| − | * Calculate the average temperature that the Earth radiates to space by setting the model Iout to epsilon sigma T4 and solving for T. What altitude is this (assuming the light is coming from the troposphere, the lowermost region in the temperature profile plot)? How does this altitude change as you change the greenhouse gas concentration? | + | * Calculate the average temperature that the Earth radiates to space by setting the model Iout to epsilon sigma T4 and solving for T. What altitude is this (assuming the light is coming from the troposphere, the lowermost region in the temperature profile plot)? How does this altitude change as you change the greenhouse gas concentration? Explain this phenomenon. |
| − | * What is the effect of clouds on the upwelling IR to space, and to the downwelling IR seen from the ground? | + | * What is the effect of clouds on the upwelling IR to space, and to the downwelling IR seen from the ground? Explain this phenomenon. |
| − | * Compare CO2 vs. methane as greenhouse gases. Which would be the stronger if they had the same concentrations? Which is stronger given their current concentrations? | + | * Compare CO2 vs. methane as greenhouse gases. Which would be the stronger if they had the same concentrations? Which is stronger given their current concentrations? Explain this phenomenon. |
| − | Simulate the temperature response to greenhouse gas IR forcing by adjusting the ground temperature to maintain a constant Iout as you increase the gas concentration. Demonstrate the water vapor feedback effect by doing this using both options of constant vapor pressure and constant relative humidity. | + | * Simulate the temperature response to greenhouse gas IR forcing by adjusting the ground temperature to maintain a constant Iout as you increase the gas concentration. Demonstrate the water vapor feedback effect by doing this using both options of constant vapor pressure and constant relative humidity. Explain this phenomenon. |
Revision as of 20:02, 23 September 2019
Required:
- (10 credits) Mars is 2.3e8 km away from the Sun; its albedo is 0.15. Its only source of heat is solar radiation. (a) Calculate the effective temperature of Mars. (b) The temperature observed at the surface of Mars is 220 K. What do you conclude about the Martian atmosphere?
- (20 credits) The "Faint Young Sun" paradox has been puzzling scientists since the 1970s. Assuming that the distance between the Sun and the Earth has not changed significantly since the time of the Earth's formation 4.6 billion years ago. Use python to make a 2-D contour plot of the Earth's effective temperature (Te) for a range of solar constants and a range of albedos.
- (20 credits) Use the MODTRAN model to simulate the terrestrial infrared radiation spectrum at a location on Earth. Use the following present-day conditions: CO2=400 ppm; CH4=1.7 ppm; tropospheric ozone=28 ppb; stratospheric ozone scale=1; water vapor scale=1; freon scale=1; temperature offset=0C; No clouds or rain; altitude 70 km; looking down.
- why
Extra credit:
The following questions are not part of the assignment that you are required to hand in. You can do any ONE (but only ONE) of them to get 10 extra credits. Or, you can use these as inspiration for your term project.
Based on the MODTRAN model:
- Demonstrate the Band Saturation Effect by making a plot of Iout as a function of a greenhouse gas concentration, from say 0 to 1000 ppm, with lots of points at low concentrations. Explain this phenomenon.
- Calculate the average temperature that the Earth radiates to space by setting the model Iout to epsilon sigma T4 and solving for T. What altitude is this (assuming the light is coming from the troposphere, the lowermost region in the temperature profile plot)? How does this altitude change as you change the greenhouse gas concentration? Explain this phenomenon.
- What is the effect of clouds on the upwelling IR to space, and to the downwelling IR seen from the ground? Explain this phenomenon.
- Compare CO2 vs. methane as greenhouse gases. Which would be the stronger if they had the same concentrations? Which is stronger given their current concentrations? Explain this phenomenon.
- Simulate the temperature response to greenhouse gas IR forcing by adjusting the ground temperature to maintain a constant Iout as you increase the gas concentration. Demonstrate the water vapor feedback effect by doing this using both options of constant vapor pressure and constant relative humidity. Explain this phenomenon.
