Course Quiz #5
14 November 2003
13 Respondents
1) When considering Quasi-Linear Convective Systems, radar-detectable circulation signatures most often begin below 3 km height and grow upward with respect to height and time (True or False).
9525
True
0115
False
8791
True.
3688
True
1626
True
3331
True
0402
False they grow from the mid levels down
9425
false
5410
True.
8336
True
7990
True
1565
True
2) Regarding the conceptual model of favorable proximity soundings; which soundings would promote the formation of "mini-supercells" associated with tropical cyclones within or near its outer-rainbands (choose the best answer):
a) High moisture values throughout
the column, with the amplitude of parcel buoyancy
generally large in the presence of weak vertical wind
shear through a deep tropospheric layer.
b) Low
moisture values throughout the column, with the amplitude
of parcel buoyancy generally small in the presence
of strong vertical wind shear through a deep
tropospheric layer.
c) High moisture values throughout
the column, with the amplitude of parcel buoyancy
generally small, but concentrated in a strongly-sheared
lower-tropospheric layer.
d) High moisture values throughout
the column, with the amplitude of parcel buoyancy
generally small, but concentrated in a weakly-sheared
lower-tropospheric layer.
9525
c
0115
D
8791
C
3688
c
1626
c
3331
C
0402
c)
9425
C no question
5410
c.
8336
(c)
7990
C
1565
C
3) Assuming the noninductive charging mechanism, please briefly explain how cloud electrification(charging) occurs and give the atmospheric temperature levels at which the charging takes place.
9525
Do not recall
0115
Cloud electrification occurs, with respect to noniductive charging mechanisms, by polarized particles in close proximity stripping off or shedding charges, such as different sizes of graupel or water droplets. The charge seperations cause an excess of positive/negative charge in the local cloud region, until the electrical potential overcomes the resistance of the atmosphere. The temperature at which this becomes most favorable is -10 degrees C.
8791
Collision of different drop sizes occurs, or more likely larger graupel interacts with smaller water droplets. The larger drops/graupel "capture" electrons from the smaller ones. This will tend to occur between -10 C and -20 C where mixed phase precip generally exists.
3688
Charging of clouds occur when graupel and snow collide within the cloud. Lighter flakes tend to positively charge the upper portions of the cloud while graupel tend to negatively charge the low portions of the cloud. These collisions usually occur in the sub-freezing level of the cloud at a temperature range of -30 0 degrees C.
1626
Electrification occurs when liquid and ice particles collide, graple must be present.
3331
ice crystals collide with graupel at levels below freezing (-8 to -14 c). after the collision, the ice crystals have a positive charge and the graupel has a negative charge. the small ice crystal particles ( charge) are carried to higher parts of the cloud, while heavier pcpn particles (and negative charge) becomes concentrated in the lower parts of the cloud. This is the very basic electrification mechanism in CBs. There is a third concentration of charge near or below the freezing level.
0402
Water and ice (graupel) particles collide with each other, typically in updrafts regions, allowing for a transfer of charge. This typically occurs in the -10 C to -20 C range.
9425
geessshhh. the charging occurs by the collision (interaction) between ice particles and graupel. The collisions are responsible for removing charge from some particles and adding to others (in an updraft environment. I believe the from the base upwards the average charge is negative-positive-negative, with the central positive charge occuring around -10 C...of course, I could have this reversed.
5410
Charging occurs as heavier graupel particles strip charge from the liquid water drops they encounter as they circulate in the cloud. The ideal temperature range is between -8 C to -13 C or the mixed-phased region.
8336
Charging occurs between graupel and ice, in the presence of supercooled liquid, generally at temperatures lower than -10 degrees C.
7990
Charign occurs in the presence of graupel and supercooler water droplets, whereby negative charge associated with the water droplets moves to the middle/bottom part of the storm, while positively charged graupel increasingly moves to the upper part of the storm. The temperature range where most charge separation occurs is from -10 to -16 C.
1565
Both graupel and ice particles are needed for this kind of charging mechanism, which generally takes place around the -10 C to -20 C level. As the graupel forms and is pushed upward, it carries with it a general negative charge. It then interacts with an ice crystal, and a positive charge is exchanged and deposited on the graupel...to balance out it's charge. This leaves the ice with a positive charge. Once this positive charge higher up in the cloud becomes large enough, you initiate lightning from this area to the middle of the cloud where the charge was more negative.
4) Different types of frozen precipitation particles produce different types of microbursts. ____________ are needed to produce strong dry microbursts, and _____________ are needed to produce strong wet microbursts (Fill in the Blanks).
9525
Snow Ice Crystals
0115
Small water droplets, dendrites
8791
Small raindrops and/or snow; graupel
3688
Snowflakes 0 0 0 Hail
1626
Snow near the cloud layer falling into a dry adiabatic layer produce dry microburst. Hail falling through dry air over humid air produce wet microburst.
3331
snow, graupel/hail
0402
Snow, Hail (graupel)
9425
snow for dry microbursts hail for wet microbursts
5410
Ice crystals/Virga, graupel/hail
8336
snowflakes, hailstones
7990
graupel, hail
1565
Snow > dry microbursts Hail > wet microbursts
5) The following Near-Term Improvements (FY-03-FY07) are associated with improving NWS tornado warnings (choose all that apply):
a) Training: Weather
Events Simulator (WES)
b) Integrate FAA weather
radars into NWS operations
c) NEXRAD Open Radar
Data Acquisition (ORDA)
d) Satellite Total
Lightning Mapping
e) NEXRAD Dual Polarization
f)
9525
a,c,d,e,f
0115
A,B,C,E
8791
A, B, C, D (E and F are around FY07 or beyond)
3688
a,b,c
1626
a,b,c
3331
A, B, C, D, E, F
0402
a), b), c) ? e)
9425
I would have to say all of the above although it is questionable whether all can be done in the time period stated.
5410
a f, though integration of Dual Polarization may not occur until 2007 at the earliest.
8336
(a) and (c)
7990
a, b, c
1565
A, B, C, F
6) Which of the following are true statements about flash floods (choose all that apply):
a)
Pre-saturation of soils is important, but not a necessary
condition.
b) They are always the result of non-severe
convection.
c) Flash flood storms always have high
precipitation efficiency.
d) The drainage area is small
with respect to the intense precipitation area.
e)
Rainfall rate is often more important then total
accumulation.
9525
a,d,e
0115
A,C,E
8791
A, D, E
3688
a,d,e
1626
a,c,e
3331
A, D, E
0402
a), d), e)
9425
a,d,e...and possibly c.
5410
a, c, d, e
8336
(a), (d), and (e)
7990
a, d, e
1565
A, C, E
7) Place the "Down" and "Up" or "Both" next to the following phrases to identify characteristics most directly associated with downwind, upwind, or both downwind and upwind MCS propagation:
a)
Quasi-stationary gust fronts
b) Fast, largely unidirectional
flow
c) Large temperature-dewpoint spreads in the
boundary layer
d) "Deep" tropospheric moisture
9525
a)Both b)Down c)Down d) Both
0115
A. Up B. Down C. Both D. Both
8791
A: Both B: Down C: Down D: Up
3688
a) Up b) Both c) Down d) Up
1626
a. Up b. Down c. Both d. Both
3331
a) up; b) both; c)down; d)up
0402
a) Both b) Down c) Down d) Up
9425
a.up b.down c.both d.down
5410
quasi-stationary gust fronts upwind fast, largely unidirectional flow both large temp-dewpoint spreads in the boundary layer down deep tropospheric moisture both
8336
(a) up (b) both (c) down (d) up
7990
a up b down c down d both
1565
A UPWIND B BOTH C DOWN D UPWIND
8) Which of the following are true statements about freshwater flooding associated with tropical cyclones (choose all that apply):
a) Rainfall rates
typically reach 8 in/hr.
b) Interaction between a
tropical cyclone and a polar front usually decreases the
heavy precipitation potential.
c) Long duration of
heavy rain is the result of slow forward motion and/or
a large precipitating area.
d) Intense
rainfall may occur more than 100 miles from the center of
circulation.
e) Rainfall patterns often become asymmetric as a
storm transitions into an extra-tropical cyclone.
9525
a,c,d,e
0115
C,D,E
8791
A, C, D (especially weakening TCs), E
3688
c,d,e
1626
c,d,e
3331
C, D
0402
a), c), d), e)
9425
b,c,d,e
5410
d,e
8336
(c), (d), and (e)
7990
c, d, e
1565
C, D, E
9) What are the two main inputs that create the Tropical Rainfall Potential (TraP ) product?
9525
windshear and precipitable water
0115
Estimated Rainfall rate and Tropical Storm motion
8791
Satellite rain rate and TPC track forecast
3688
Microwave Satellite Imagery and
1626
Microwave sensor, ?
3331
microwave satellite-derived rainfall estimates and TPC storm track
0402
1 ) IR brightness temperatures 2 ) Tropical storm motion (direction and speed)
9425
forecast track and forward speed (besides the satellite derived rainfall rates)
5410
1 Estimated rainfall rate from POES microwave radiometer. 2 Model forecast track.
8336
Microwave satellite information System motion
7990
1 forecast storm motion 2 rain rate from satellite microwave sensors
1565
The two inputs are: 1 The forecast track/speed of the system from the tropical cyclone warning center 2 A recent satellite derived rainfall intensity measurement...generally from polar orbiting microwave sensors.
10) R-CLIPER is a tropical cyclone rainfall model that deals with QPF by combining intensity and duration. Climatology and track forecast are used to project swaths of rainfall. R-CLIPER assumptions are: 1) rainfall rates vary with radii from the tropical cyclone center, and 2) the greatest rates are closer to the center with rates decreasing with increasing radii. (True or False)
9525
False
0115
True
8791
True
3688
True
1626
False
3331
True
0402
False greatest rates may be away from the center
9425
true
5410
True.
8336
True
7990
True
1565
True