Homework Questions for Chapter 10 - Global Circulation
Consult Syllabus for Due Date
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. Draw a 60 knot west wind using the standard symbols on a weather map. If this wind is observed at 700 mb, draw in the height lines and directions of the relevant forces creating the wind assuming it is geostrophic. CLEARLY label the forces and the relative values of the height lines.
2. Draw a 20 knot northwest wind that is observed at the surface. Now, draw in isobars and the relevant forces that are creating this wind. CLEARLY label the forces and the relative values of the isobars.
3. Draw a diagram below to help explain why air must circulate around an area of low pressure (hurricane) cyclonically (CCW) in the northern hemisphere.
4. Write out the units of pressure in terms of mass (kg), distance (m), and time (s).
5. On the map below (print it out, or copy and paste it into your homework), indicate the approximate wind direction at Chicago, IL and central PA.
6. A parcel at 0 km is moving west to east and approaches a mountain chain that is 4 km tall. If the initial temperature and dewpoint of the parcel is 20ºC and 12ºC, respectively, what is the final temperature and dew point of this parcel on the other side of the mountain after it has descended to its original altitude? How do the final temperature and dewpoint compare to the original values? Assume that the parcel of air descends dry adiabatially.
7. Here at LSC, the pressure decreases to the west by 4 mb over a distance of 200 km at 5 km MSL.
a. Assuming the flow is geostrophic, what is the wind direction?
b. What is the magnitude of the pressure gradient force?
c. What is the speed of this geostrophic wind?
8. In meteorology, we use the concept of finite differences a lot to examine how a meteorological variable is changing over some distance. Check out this diagram for an illustration of how to compute finite differences.
If the air temperature at Hanover, NH is 20 degrees Celsius while 125 km to the north, it is 30 degrees Celsius here at LSC,
a. draw an accurate picture of this meteorological situation
b. What is DT? What is Dy? What is DT/Dy?
c. Given that a surface temperature gradient (change) creates the polar jet, what would the direction of the resultant polar jet stream winds created by the above surface temperature gradient?
d. If DU/Dz is 0.005 s-1, then what is the west-east wind speed at 5 km above the ground? Assume that the wind speed at the ground is 5 ms-1. Note that U is the west-east component of the wind.
EXTRA CREDIT: Create a vertical cross section of wind speed and temperature across the polar front with model data that we receive in the met lab. On your cross section indicate the location of the polar front and the upper-level jet stream. Discuss the relationship between the polar front and the upper-level jet stream.
