Overview
The questions will be like this. Please finish all the questions in the file.
- A weather balloon measures the following temperatures and altitudes. The ambient lapse rate is plotted in the following figure.
| Temperature (oC) | Adiabatic Lapse Rate (km) | Ambient Lapse Rate (km) |
| 30 | 0 | 0 |
| 25 | 0.5 | 0.7 |
| 20 | 1 | 1.5 |
| 15 | 1.5 | 2 |
| 10 | 2 | 2.3 |
| 5 | 2.5 | 2.5 |
| 0 | 3 | 2.6 |
- (5pts) For a parcel of air on the ground (at 0km altitude and 30oC) fill in the dry adiabatic lapse rate values in the table if you were to raise the parcel till it cooled to 0oC.
- (5pts) Based on this figure what is the mixing depth of the atmosphere under these conditions?
- (10pts) Assuming an average wind speed of 2m/s what is the ventilation coefficient (Vc)? Is there a high potential for air pollution?
- (10pts) For which altitudes is the atmosphere stable? For which altitudes is the atmosphere unstable? (Hint: Compare ambient slopes to the dry adiabatic lapse rate)
2.) (20pts) On a clear night with winds blowing at 2m/s, a bonfire emits CO at a rate of 20g/s. Assume the effective stack height of the fire is 6m. What would you estimate the ground-level concentration of CO to be 400m directly downwind?
3.)(25pts) A line of burning agricultural waste emits 0.3 g/m*s of PM10 on a clear fall afternoon with wind blowing at 3m/s perpendicular to the burning line. What do you estimate the ground-level concentration of PM10 to be 900m downwind?
4.) (25pts) Consider the airshed over a city with 100,000m on each side and a mixing depth of 1,200m. Assuming clean air blows into the airshed at an average speed of 4m/s and SO2 is emitted within the airshed at a rate of 20kg/s, estimate the steady-state concentration of SO2 in the airshed. Assume SO2 is conservative. (Hint: set this up just like our box models from lecture 2 using the conservation of mass principles). Make sure to include a diagram of the model.