Name:___________________________________ 5 November 2015
ATMS 410 INDIVIDUAL EXAM#02
Choose the single best answer in Questions (1) – (15), each question is worth four points.
Questions (16) - (18) together are worth 40 points. EXAM#02 is worth 100 total points.
(1) A baroclinically unstable disturbance has parcels that move with slopes ________ than the slope of the zonal mean potential temperature surface and is indicative of warm air ________ and cold air ________.
(a) greater, rising, sinking
(b) greater, sinking, rising
(c) less, rising, sinking, LP#5, slide#11
(d) less, sinking, rising
(2) That vertical stretching of an air column is exactly balanced by horizontal ________ is a statement originating from the ________ equation.
(a) divergence, continuity, LP#5, slide#21
(b) divergence, hypsometric
(c) rotation, continuity
(d) rotation, hypsometric
(3) Flow can be confluent but have no convergence .
True, LP#5, slide#29
False
(4) ________ balance is a concept that succinctly captures both ________ and ________ balance conditions common to synoptic-scale flow in the mid-latitudes.
(a) Geostrophic, hydrostatic, thermal wind
(b) Gradient, hydrostatic, thermal wind
(c) Hydrostatic, thermal wind, geostrophic
(d) Thermal wind, geostrophic, hydrostatic, LP#5, slide#37
Fig A.
Use the figure above to answer Problems (5) – (7) for a Northern Hemisphere location.
(5) In which direction would one move to walk toward lower pressure?
(a) toward the east
(b) toward the north, LP#6, slide#117
(c) toward the south
(d) toward the west
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Name:___________________________________ 5 November 2015
ATMS 410 INDIVIDUAL EXAM#02
(6) The actual flow depicted in Fig A is ________, in which the actual wind ( V ) is directed toward ________ pressure.
(a) subgeostrophic, higher
(b) subgeostrophic, lower, LP#5, slides#39-42
(c) supergeostrophic, higher
(d) supergeostrophic, lower
(7) The Coriolis force acting on the ageostrophic component will be directed toward the
________, thereby ________ the wind component parallel to the isobars.
(a) northeast, accelerating, LP#5, slide#41
(b) northeast, decelerating
(c) southwest, accelerating
(d) southwest, decelerating
(8) In the figure above, the thermal wind vector ( V
T
) is indicating that cold air is located toward the ________ and the winds are indicating ________ air advection.
(a) northeast, cold
(b) northeast, warm, LP#5, slide#52
(c) southwest, cold
(d) southwest, warm
(9) Horizontally ________ heating in a layer of air next to the surface eventually results in ________ surface pressure under the region of heating.
(a) homogeneous, decreased
(b) homogeneous, increased
(c) inhomogeneous, decreased, LP#6, slides#7-18
(d) inhomogeneous, increased
(10) In a developing cyclone, upper-level ________ must be ________ than low-level convergence.
(a) convergence, greater
(b) convergence, less
(c) divergence, greater, LP#6, slide#20
(d) divergence, less
2

Name:___________________________________ 5 November 2015
ATMS 410 INDIVIDUAL EXAM#02
(11) Relative vorticity ________ are typically located near upper-level troughs and relative vorticity ________ are typically located near upper-level ridges. Hence, cyclonic vorticity advection (CVA) is the greatest downstream of the ________ and upstream of the ________.
(a) maxima, minima, ridge, trough
(b) maxima, minima, trough, ridge, LP#6, slide#42
(c) minima, maxima, ridge, trough
(d) minima, maxima, trough, ridge
(12) Based on quasi-geostrophic theory, one would expect rising vertical motion in regions of ________ air advection, typical of the ________ region of a mid-latitude surface cyclone.
(a) cold, eastern
(b) cold, western
(c) warm, eastern, LP#6, slides#61-64
(d) warm, western
(13) Under ________ conditions, ________ changes in the upper and lower troposphere are strongly coupled.
(a) nearly neutral, temperature
(b) nearly neutral, vorticity, LP#6, slide#85
(c) strongly stable, temperature
(d) strongly stable, vorticity
(14) Moist processes are most important for ________ vertical motion in ________ systems having a relatively unstable environment.
(a) damping, large
(b) damping, small
(c) enhancing, large
(d) enhancing, small, LP#6, slide#93
(15) The approximate form of the Petterssen Development Equation states that ________ vorticity advection at the 500 hPa level and lower tropospheric ________ air advection both contribute to cyclogenesis at the 1000 hPa level.
(a) anticyclonic, cold
(b) anticyclonic, warm
(c) cyclonic, cold
(d) cyclonic, warm, LP#6, slide#101
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Name:___________________________________ 5 November 2015
ATMS 410 INDIVIDUAL EXAM#02
(16) 10 points
Figure 16. Geostrophic relative vorticity contours (dashed) and geopotential height contours (solid) at the 700 hPa level for a location in the Northern Hemisphere.
A geostrophic relative vorticity minimum at the 700 hPa level is located northeast of a station whose location is marked by the “X”. Indicate the directions of the appropriate vectors for assessing the vorticity advection at the station on the diagram above and determine whether CVA or AVA is occurring above the station using the appropriate dot product relationship. You must indicate whether the angle between the two vectors is [1] less than 90 o or [2] between 90 and 270 o and do a sign analysis (“+” or “
 ”) to support your answer of CVA or of AVA. Assume that the advection of planetary vorticity is negligible.


V g
  p
 g
 

V g
  p
 g
 

V g
 p
 g cos
    
0 [ positive ] geostrophic wind points toward the northeast, geostrophic relative vorticity gradient vector points toward the southwest (from low values to high values, normal to the local
GRV contours) so that the angle is between 90 and 270 o and the cosine of the angle is negative. A positive advection indicates CVA at the 700 hPa level.
4

Name:___________________________________ 5 November 2015
ATMS 410 INDIVIDUAL EXAM#02
(17) 15 points
Figure 17. Geostrophic relative vorticity contours (dashed) and geopotential height contours (solid) at the 500 hPa level for a location in the Northern Hemisphere.
A geostrophic relative vorticity maximum at the 500 hPa level is located northeast of a station whose location is marked by the “X”. Indicate the directions of the appropriate vectors for assessing the vorticity advection at the station on the diagram above and determine whether CVA or AVA is occurring above the station using the appropriate dot product relationship. You must indicate whether the angle between the two vectors is [1] less than 90 o or [2] between 90 and 270 o and do a sign analysis (“+” or “  ”) to support your answer of CVA or of AVA. Assess the vertical motion (“rising” or “sinking”) at the 600 hPa level over the station using Eq. (3.13), the contribution due to differential vorticity advection of the Quasi-Geostrophic Omega Equation, and your results from Problem (16). Assume that the advection of planetary vorticity is negligible and that static stability is positive.


V g
  p
 g
 

V g
  p
 g
 

V g
 p
 g cos
    
0 [ negative ] geostrophic wind points toward the northeast, geostrophic relative vorticity gradient vector points toward the northeast (from low values to high values, normal to the local GRV contours) so that the angle is less than 90 o and the cosine of the angle is positive. A negative advection indicates AVA at the 500 hPa level.
 v
 f

0

 p



V g
  p
 g






CVA

700

AVA
500







(

)


(

)


 



0 [ positive ] positive omega at 600 hPa indicates sinking motion.
5

Name:___________________________________ 5 November 2015
ATMS 410 INDIVIDUAL EXAM#02
(18) 15 points
Use the continuity equation in isobaric coordinates to assess whether you expect to find convergence or divergence near the surface at Station “X” in Problems (16) and (17). Use this finding to determine if the low-level geostrophic relative vorticity can be expected to increase or decrease at Station X as a result of the low-level convergence or divergence using the appropriate quasi-geostrophic equation. Assume that the only mechanism contributing to vertical motion at the 600 hPa level over Station X is due to differential vorticity advection and that vertical motion near the surface is zero. Do not apply any of the Petterssen Development equations in this problem. Use your result from Problem (17) as the vertical motion condition at the upper level over Station X.
Eq. (2.8) is correct form of continuity eqtn:
DIV = -d(omega)/dp =

[(+ - 0) mb/(600-{~1000}) mb]
= - [+/

] > 0, low-level divergence
Eq. (2.20) is the appropriate QG equation, [geostrophic relative vorticity = GRV]: d GRV/ dt =
 f
0
* DIV {contribution due to low-level CONV or DIV}
=

(+) * (+) < 0, can expect a low-level GRV decrease at Station X
6

Name:_____________________________________
Work to be included for Problem _____ of Exam _____ in class ATMS _____
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