Name:___________________________________
ATMS 411
14 April 2015
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) ________ are a source of ________ energy for ________.
(a) cyclones, baroclinic, frontogenesis
(b) cyclones, barotropic, frontogenesis
(c) fronts, baroclinic, cyclogenesis, LP#4, slide#3
(d) fronts, barotropic, cyclogenesis
(2) Which of the following is not a criterion for locating a front on a surface weather
map?
(a) a relative minimum in pressure
(b) changes in the dew point
(c) sharp temperature changes over a short distance
(d) strong lateral anticyclonic wind shear along the front, LP#4, slide#7
(3) Because gradients in atmospheric properties along the front are typically several
orders of magnitude ________ than the cross-front gradients, researchers often consider
fronts as two-dimensional and display vertical cross sections oriented ________ the front.
(a) larger, normal to
(b) larger, parallel to
(c) smaller, normal to, LP#4, slide#9
(d) smaller, parallel to
(4) A low level jet, associated with the ________ conveyor belt near the 850 hPa level
located just ahead of the surface ________ front transports substantial amounts of
moisture and heat.
(a) cold, cold
(b) cold, warm
(c) warm, cold, LP#4, slide#20
(d) warm, warm
(5) Which term contributes primarily to frontolysis above the boundary layer in the
strong maritime cold front case study of Bond and Fleagle (1985)?
(a) confluence
(b) diabatic heating
(c) shearing deformation
(d) tilting, LP#4, slide#41
Name:___________________________________
ATMS 411
14 April 2015
INDIVIDUAL EXAM#02
(6) Frontogenesis rates refer to frontogenesis ________, the ________ perspective.
(a) at a fixed location, Eulerian
(b) at a fixed location, Lagrangian
(c) following an air parcel, Eulerian
(d) following an air parcel, Lagrangian, LP#4, slides#29, 42, 43
(7) Air parcels can move through the frontal zone.
True, LP#4, slides#42 and 46
False
(8) The cloud structures associated with ________ fronts is typically driven by
________-scale dynamics, hence, the associated frontogenetical forcing is strong.
(a) cold, meso, LP#4, slide#51
(b) cold, synoptic
(c) warm, meso
(d) warm, synoptic
(9) The ageostrophic advection of temperature at ________ and ________ is strongly
frontogenetical and, consequently, the front should develop more of a tilt to the
________ with time.
(a) A, C, right
(b) A, C, left, LP#4, slide#74
(c) B, D, right
(d) B, D, left
(10) Divergence of Q-vectors indicates ________ vertical motion and the Q-vectors point
in the same direction as the ageostrophic wind in the ________ layers.
(a) rising, lower
(b) rising, upper
(c) sinking, lower, LP#4, slides#80-86, 91
(d) sinking, upper
Name:___________________________________
ATMS 411
14 April 2015
INDIVIDUAL EXAM#02
(11) The geostrophic winds and isotherms plotted on the figure above indicate a situation
in which the Q-vector at “X” would be pointing toward the ________, assuming that the
geostrophic winds are changing only in the east-west direction.
(a) east
(b) west, LP#4, slide#79
(c) north
(d) south
(12) Inertial instability in the Northern Hemisphere occurs when the absolute vorticity of
the basic flow is ________, meaning that the relative vorticity ________.
(a) negative, can be positive or negative
(b) negative, must be negative, LP#4, slide#110
(c) positive, can be positive or negative
(d) positive, must be negative
(13) Slantwise instability can be identified in a vertical cross section if the ________
surfaces are standing more vertical and the ________ surfaces are oriented closer to the
horizontal so that a parcel will tend to ________ its original position.
(a) absolute momentum, potential temperature, move away from
(b) absolute momentum, potential temperature, return to
(c) potential temperature, absolute momentum, move away from, LP#4, slide#112
(d) potential temperature, absolute momentum, return to
(14) The planetary boundary layer (PBL) depth can vary from 30 m (very ________
PBL) to 3 km (very ________ PBL), but is ________ km in depth on average in the midlatitudes.
(a) stable, unstable, 1, LP#5, slide#31
(b) stable, unstable, 2
(c) unstable, stable, 1
(d) unstable, stable, 2
(15) Turbulent eddies generally transport ________ toward the ground and transport
________ and ________ away from the ground in the PBL.
(a) heat, moisture, momentum
(b) moisture, momentum, heat
(c) momentum, heat, moisture, LP#5, slides#28 & 47
(d) noodles, marshmallows, apple sauce
Name:___________________________________
ATMS 411
14 April 2015
INDIVIDUAL EXAM#02
(16) 15 points
Figure 16. Vertical cross section of an entrance or exit region of a straight jet streak (solid contour at
“jet alt.”) located in the Northern Hemisphere. The altitude of the jet streak is labeled “jet alt.” and
the horizontal position of the jet streak is labeled “XJ”. The location of horizontal divergence at “jet
alt.” is labeled “DIV” and the location of an isentrope next to the ground is labeled “ ”.
Indicate on the diagram above:
[1] the location of cold air next to the ground (labeled “COLD”),
[2] the wind direction of the jet streak, into the page (labeled with a “ × ” in the
oval) or out of the page (labeled with a “ · ” in the oval),
[3] the anti-cyclonic (labeled “AC”) and cyclonic (labeled “CYCL”) shear side of
the jet streak,
[4] the tropopause location (labeled “TROP”) on both the AC and CYCL shear
sides of the jet streak,
[5] locations of relatively warm (labeled “W”) and cold (labeled “K”) air at two
locations above the jet streak altitude (jet alt.), on the (i) AC and (ii) CYCL shear sides of
the jet streak,
[6] location of convergence (labeled “CON”) at the jet streak altitude (jet alt.),
[7] the direction of the ageostrophic wind component blowing normal to the jet
streak wind direction (with an arrow) at the jet streak altitude (jet alt.), and
[8] your conclusion regarding the jet streak region being an entrance or an exit
region. EXIT, ageostrophic wind direction indicates decelerating air parcels at jet core
Name:___________________________________
ATMS 411
14 April 2015
INDIVIDUAL EXAM#02
(17) 10 points
The geostrophic winds blow into the page in the surface frontal scenario depicted in the
diagram above. Assume that the geostrophic wind speeds (Vgb and Vgt) are such that
their magnitudes increase with altitude (|Vgb| < |Vgt|). Given what you know about the
slope of fronts near the surface, deduce weather you expect the frontal surface to go from
the location aloft near Vgt through location x1 or through location x2. Assume the front is
located in the Northern Hemisphere.
Be sure to apply the appropriate frontal slope equation to support your answer and state
very clearly what you know about the slope of fronts near the surface.
Appropriate equation:
This equation is based on thermal wind balance which states that (in the Northern
Hemisphere) the thermal wind (vertical shear of the geostrophic wind) is directed such
that cold air is to the left. Based on the given information we’d have to deduce that the
thermal wind is pointing into the page, hence, cold air is to the left of the Vg locations in
the diagram. We know that near the surface fronts slope towards cold air and/or fronts
have positive slope, so that the +y axis in Eq. (6.1) is directed to the left (+x axis is
directed into the page) and the frontal surface must be extending from location x2 upward
to the location aloft near Vgt.
Name:___________________________________
ATMS 411
14 April 2015
INDIVIDUAL EXAM#02
(18) 15 points
Figure 18. A portion of the U.S. East Coast is shown above for a wintertime situation in which the
pressure gradient force (PGF) at 1000 hPa is everywhere constant and is directed parallel to the
coastline (toward the south). Locations “1”-“5” are at the center of the nearby “+”. Note that
locations “1”, “3”, “4”, and “5” are over the water.
Use the figure to draw and to determine the following,
[a] draw and label two isoheights (one on each side of location “3”) consistent with the
given 1000 hPa level PGF orientation {2 points},
[b] draw and label several isotherms consistent with the winter season and the geographic
location, indicating clearly the location of the relatively cold and warm air {3 points},
[c] draw the 1000 hPa winds at locations “1”, “2”, “4”, and “5” assuming a balanced flow
state unique to an ocean surface (no friction) and a land surface (much friction), being
careful to indicate differences in relative speed and direction {4 points}, and
[d] determine the contribution of the horizontal flow to frontogenesis or frontolysis at
location “3” using the simplest form of the frontogenesis equation being certain to name
the term likely giving the greatest contribution for the given horizontal flow{6 points}.
[a] isoheights have east-west orientation w/ decreasing values toward the south
[b] isotherms (isentropes, same at 1000 hPa level) are directed parallel to the coast with cold air toward the
left (west)
[c] winds at the over-water points (1, 3, 4, 5) blow toward the west and are in geostrophic balance, wind at
2 blows toward the southwest due to the impact of significant friction
[d]
term #3 on RHS is represented by figure  confluence, dominates the contribution in Eq (6.2)
+y point toward cold air (to the left or to the west), so +x points toward the north (top of figure), flow on
cold air side has small v>0, flow on warm air side has large v>0, hence; dv/dy < 0,  decreases as one
moves toward the +y (west) direction, hence; d/dy < 0, their product is positive  frontogenesis
Name:_____________________________________
Work to be included for Problem _____ of Exam _____ in class ATMS _____