Homework Questions for Chapter 11 - Air Masses and Fronts
Consult Syllabus for Due Date
Questions 1 and 2 will be turned in for a grade.
SHOW ALL WORK , CIRCLE THE CORRECT ANSWER, PLEASE BE NEAT AND STAPLE YOUR HOMEWORK!
ALSO, PLEASE USE A SPREADSHEET FOR ALL GRAPHS
Follow the Problem solving steps discussed in class
1. A warm front is moving northward at a speed of 15 knots. The front has a slope of 1:50. South of the front, the surface air has a temperature of 30 degrees Celsius and a dew point temperature of 18 degrees Celsius.
a. Assuming that the air south of the front is moving northward at 30 knots and will move up and over the warm frontal surface, how far north of the surface frontal position will you begin to see clouds form?
b. From the time that the warm southerly air reaches the surface warm frontal position, how long will it take for the air to produce mid level clouds at 5 km above the surface?
2. One measure of the strength of a front is the magnitude of the temperature difference across the front (DT). If we assume that the frontal orientation is N-S, as in the case of an eastward moving cold front, the frontal strength (FS) is related to the magnitude of the temperature difference by:
where DT is the change in temperature over a distance Dx across the front.
(a) What are the units of frontal strength?
(b) On a given day, it is sunny on the warm side of the front and cloudy (low stratus) on the cold-air side. At 8 AM, the temperature 30 km east of the front is 20 degrees Celsius while 20 km west of the front it is 10 degrees Celsius. By 2 PM that afternoon, the temperature 30 km east of the front has increased to 35 degrees Celsius (sunny) while the temperature 20 km west of the front is still 10 degrees Celsius (cloudy). How did the frontal strength change during the day? Quantitatively explain your answer.
3. Suppose an mP air mass moving eastward from the Pacific Ocean travels across the United States. Describe all of the modifications that could take place as this air mass moves eastward in winter. In summer.
4. Explain how an anticyclone during autumn can bring record-breaking low temperatures and cP air to the south-eastern states and only several days later very high temperatures and mT air.
5. Explain why freezing rain more commonly occurs with warm fronts than with cold fronts.
6. Sketch the relative positions of a low and its attendant cold and warm fronts that would be observed in the southern hemisphere. How would the winds shift during the passage of the cold front?
7. Why does the same cold front produce more rain over Kentucky than over western Kansas?
a. Sketch representative soundings (temperature and winds) ahead and behind a cold front
b. Sketch representative soundings (temperature and winds) ahead and behind a warm front
8. You are in Ithaca, NY and observe the wind shifting from East to South accompanied by a sudden rise in both the air temperature and dewpoint temperature. What type of front passed?
9. If Lake Erie froze over in January, is it still possible to lave lake-effect snows off Lake Erie in February? Why or why not?
10. In winter, cold frontal weather is typically more violent than warm-front weather. Why? Explain why this is not necessearily true in summer.
11. Thunderstorms have formed along a cold front producing rain showers on the cold-air side of the front. Assuming that the air on the cold-air side of the front is initially subsaturated, will the rain showers increase the temperature difference across the front (frontogenesis) or decrease the temperature difference across the front (frontolysis)? Explain your answer.
EXTRA CREDIT:
Consider a cold front during late fall moving south from Canada passing over the Great Lakes. Will the front likely be stronger or weaker once it has passed over the Great Lakes. With the aid of a diagram, explain you answer.
or
Find an example of a cold frontal passage in a forecast meteogram for Burlington, VT. Indicate:
- which model produced the meteogram
- the time of cold frontal passage on the forecast meteogram.
- the time when the front was observed to pass through Burlington.