DEPARTMENT OF GEOSCIENCES Name ____________________
San Francisco State University Metr. 201
Metr 201 -- Synoptic Metr
Quiz #4 100 pts.
(Test will be collected at 10:40 AM)
1. Fill in the Blank. (4 points each for a total of 20 points in this section).
(a) The 500 mb level is found typically at what height (either in decameters or feet) _18000 ft_(564 dm)
(b) The 700 mb level is found typically at what height (either in decameters or feet) _10000 ft_(330 dm)
(c) The 300 mb level is found typically at what height (either in decameters or feet) __30000 ft__(1000 dm)
(d) A contour of constant wind speed (or current speed) is known as an _isotach
(f) The development of cold air downdrafts, precipitation at ground level, the anvil and lightning appear roughly simultaneously when a cumulus congestus cloud becomes cumulonimbus. This is apparently related to the formation of ____hail_____________ at the portion of the cloud at or near the freezing level.
2. Units. Provide the metric units used conventionally for the following (4 pts each for a total of 20 pts)
Vg (Geostrophic Wind Speed) ___m s-1 or knots or km h-1
Æz/Æn _ dimensionless
frictional acceleration m s-2
500 mb height _decameters or meters
Coriolis parameter (f=2½sin¿) __s-1 _
3. 500 mb chart (30 pts).
Examine the 500 mb chart given below. Note the locations given at A, B, C and D. (5 points each answer for a total of 30 points in this section).
a. The strongest winds would be found at location ____ C_____ . Why? _
According to the geostrophic wind relationship, the wind speed is directly proportional to the pressure or height gradient. On a weather map, this appears where the isobars or height contours are closest together. The height contours on the chart above are closest together at C.
b. The wind direction (please use the direction designation that meteorologists use, e.g., southerly) at location A is __northwesterly__ and at location B is __southwesterly___ .
c. If the wind speed at C is 55 knots, plot the correct meteorological symbol for that wind information right on the chart.
d. Locate one trough axis and one ridge axis, by placing the correct symbols on the chart.
4. Surface chart. On the surface chart below, note the Pressure System, and the three Lines that are indicated. (30 pts)
a. Annotate the chart with the correct symbols for the pressure system (indicate whether it is a High or a Low, by placing the correct word or letter in the correct color convention) and the boundaries at Lines 1, 2 and 3 with the correct boundary symbols and color conventions, (6 points each for a total of 24 points).
b. Briefly state why the pressure system is not only a cyclone, but a special type of cyclone termed "wave cyclone" (6 points).
This is a low pressure area completely encircled by at least one isobar, and in which fronts are found in a wavelike configuration. Hence, it is a wave cyclone.