SAN FRANCISCO STATE UNIVERSITY                                                               Meteorology 430 DEPARTMENT OF GEOSCIENCES                                                      Fall 2010
























Exam #1

250 Points








Name _______________________________________________



                        1.         For questions involving use of equations or calculations, lay out all equations                                                            carefully, show all units, show all steps, number equations sequentially.


                        2.         For questions involving analysis or mapping techniques, use proper color                                                                 conventions, use proper mapping techniques (NO grease pencil on final copies).


                        3.         This examination is open book, open notes.


                        4.         Answer on separate sheets or on back of exam.         

Part A.  Map Set 1 (70 pts)


1,  Attached find the WXP analyses of 200 mb and 1000 mb convergence and 500 mb vertical velocities (in x, y, p coordinates) forecast by the NAM 12Z 21 October 2010.  Note the location indicated by the square off the California coast.


The simplified continuity equation is




Assuming Dines Compensation, compute the vertical velocity at 500 mb that would be associated with the divergence at 200 mb. (40 pts)


You will note the following:


(a)        the 200 mb is near the tropopause and the divergence at the point at that level  is 1.0 X 10-5 s-1;

(b)       200 mb divergence is representative of the net divergence in the layer from the Level of Non-                                   divergence (LND) to the tropopause;

(c)        the vertical velocity at the tropopause is zero;

(d)       the tropopause is at the 200 mb level (11880 m)  and the LND is at the 500 mb level (5700 m).

(e)        the 1000 mb divergence at the same point is -4.25 X  10-5 s-1 (Note:  it is not necessary to know this to answer this question, but it will help you in forming your answer for (2) below.


Show all work and lay out all steps.


2.  Briefly explain to what extent the charts given in Map Set 1 GENERALLY  illustrate the principle of Dines Compensation (at the location where the small box is drawn).  (25 pts)


3.  Print the following (starting at 8:30AM)  for the date, time, and region indicated on the black board: 42.5N, 130W, 48 hr forecast if you are doing a forecast chart.   Several of you will be printing charts for 12 UTC today and don't need the latitude and longitude information (10 pts)



500 mb vertical velocity


300 mb chart with observations (12 UTC 10/22/10)


200 mb convergence


500 mb chart with observations(12 UTC 10/22/10)


200 mb vertical velocity


1000 mb vertical velocity


Simple surface chart with observations (12 UTC 10/22/10)


700 mb chart with observations(12 UTC 10/22/10)


850 mb chart with observations(12 UTC 10/22/10)


700 mb vertical velocity

Xiu Ping

1000 mb convergence



Map Set 1



Part B.  Map Set 2 (60 pts)


Attached find the 850 mb, 700 mb, 500 mb and 200 mb charts for12Z 22 October 2004. Also included is the Eta initialization for surface isobars and 1000-500 mb thickness.


1. Discuss why the trough over the central portions of the country “tilts” towards the west (in this case).


2. Draw advection arrows and fronts for the cyclone in the midsection of the country.

Map Set 2



Part C.  Map Set 3 (80 pts)


Attached find sfcplot and a plot of unanalyzed surface observations for 12Z 22 October 2004


Analyze the surface plot inside the solid lines, using proper isobar intervals, color conventions, frontal/trough symbols etc. (no isotherms or isodrosotherms).  Use the 1000-500 mb thickness analysis from Part B to help you to complete the frontal analysis. (70 POINTS)



Map Set 3



Part D.  Map Set 4 (40 pts)


Attached find the 12UTC soundings for Davenport, Iowa and Albuquerque, New Mexico; and the surface isobars and 1000/500 mb Thickness for 12Z 22 October 2004.


Do the following sets of questions:


1.   Note the locations of Albuquerque and Davenport labeled A and B, respectively. 


(a)       Plot the 1000 mb geostrophic wind vector at each location with a solid arrow.                                               (You will have to qualitatively estimate the length of the vector).

(b)      Plot the thermal wind vector at the same locations with dashed arrows.  (Again, you will have to qualitatively estimate the length of the vector..make it 4 times the length of the 1000 mb geostrophic wind vector you did in (a)).

(c)       Now, on the back of this sheet, replot these vectors in a manner that will allow                                             you to estimate the 500 mb geostrophic wind vector.  Replot the 500 mb                                                     geostrophic wind vector on the map.


2.         Describe how the thermal structure and wind profiles evident on the sounding/wind plot for Davenport and Albuquerque is consistent with your frontal analyses.



Map Set 4