5A-2 Radar

Question 0

Which wavelength is best when you are trying to detect light to moderate rain?

Answer 0

3 cm

Question 1

An electrical current passing through a wire coiled around a metal bar that induces a magnetic field is called

Answer 1

Electromagnetism

Question 2

Which wavelength would be best for you to use when large thunderstorm or hurricanes frequently occur?

Answer 2

10.7 cm

Question 3

The number of cycles per a given unit of time is called

Answer 3

Frequency

Question 4

As electromagnetism waves are emitted from radar and travel through the atmosphere, some of their energy is lost. What is the loss of energy because of the interaction with atmospheric phenomena called?

Answer 4

Attenuation

Question 5

What are the two related factors that attenuation of radar waves depends on?

Answer 5

Wavelength of the emitted radio waves and size and composition of the particle encountered by these waves

Question 6

The amount of time it takes the radar to send one pulse is known as

Answer 6

Pulse length

Question 7

What decides the minimum range of the radar?

Answer 7

Pulse length

Max range is listening time

Question 8

Another term for second-trip echoes is

Answer 8

Range folding

Question 9

How does the radar beam width vary with the wavelength; how does it vary with the diameter of the parabolic reflector of the antenna?

Answer 9

Radar beam width and wavelength DIRECTLY proportional

Radar beam width and diameter of reflector INVERSELY proportional

Question 10

Sample volume is equal to

Answer 10

One-half the pulse length and beam diameter

Question 11

What kind of resolution is it called when the radar can distinguish between two targets at the same range but different directions from the radar?

Answer 11

Bearing resolution

Question 12

The ability of the radar to differentiate between two closely spaced targets at the same range and bearing but at different elevations depends on

Answer 12

Beam width

Question 13

Range resolution depends on

Answer 13

Pulse length

Question 14

Side lobes can cause certain side effects. Which is a side effect?

Answer 14

Ground clutter

Question 15

Superrefraction is when the curvature of the radar beam is

Answer 15

Greater than the earth’s curvature

Question 16

Another effect of superrefraction is the displayed height values are

Answer 16

Overestimated

Question 17

Straightening of the radar beam upward best defines

Answer 17

Subrefraction

Question 18

What does subrefraction do?

Answer 18

Reduces the maximum range of detection of low-level targets

Question 19

Computation of the equivalent reflectivity factor (Ze) depends on

Answer 19

Average returned power, range to target, and a set of known factors called the “radar constant”

Question 20

While performing a radar METWATCH, the operator notices a storm that had increased from 40 tom43 dBZs at one elevation slice. The operator must assume the intensity of this storm has

Answer 20

Doubled

Question 21

The factor that allows a Doppler radar to remember the frequency of transmitted energy for later comparison to returning energy is

Answer 21

Coherency

Question 22

The WSR-88D has only one antenna, it only measures the component of wind that is

Answer 22

Parallel to the radar beam

Question 23

Which action is an effective means of decreasing velocity aliasing?

Answer 23

Increase the pulse repetition frequency

Question 24

The Doppler dilemma is a trade off between

Answer 24

Range and velocity

Question 25

What kind of pulse repetition frequencies (PRF) are required for high velocity measurements and long ranges?

Answer 25

High PRFs are required for high velocity measurements, and low PRFs are required for long ranges

Question 26

What's the Doppler spectrum?

Answer 26

The distribution of power received by the radar at each frequency within a sample volume

Question 27

The spectral slope of the Doppler spectrum of a large thunderstorm with hail appear

Answer 27

Broad and flat

Question 28

The spectrum width product is useful for the early detection of thunderstorm development because

Answer 28

The detection of high spectrum widths may be indicative of currents present in a convective atmosphere

Question 29

Widespread low spectrum width values with isolated areas of higher values is most likely indicative of

Answer 29

Embedded storms

Question 30

The beam width of the WSR-88D is approximately

Answer 30

1.0 degree

Question 31

Which sub component of the radar data acquisition (RDA) takes raw analog data from the receiver and process it into a digital base data?

Answer 31

Signal processor

Question 32

Solid (ground clutter) return has very low spectrum width values ranging from

Answer 32

0.1 to 0.5 m/sec

Question 33

Data thresholding occurs at the

Answer 33

Radar data acquisition (RDA)

Question 34

How many elevation slices does both volume coverage pattern (VCP) 31 and VCP 32 (clear air mode) complete in ten minutes?

Answer 34

Five

Question 35

How many hours does the JAZ drive have the capability to hold?

Answer 35

450 hours

Question 36

Control of the radar product generator (RPG) is accomplished from a computer terminal known as the

Answer 36

Master system control function (MSCF)

Question 37

Who owns the MSCF at a majority of the CONUS locations?

Answer 37

National Weather Service (NWS)

Question 38

How is data transferred from the radar product generator (RPG) to an Open Principal User Processor (OPUP)?

Answer 38

By the wideband communications link

Question 39

What is the maximum number of workstations a large OPUP can consist of?

Answer 39

10

Question 40

Which system supports direct connections to up to seven WSR-88Ds?

Answer 40

Medium OPUP

Question 41

The OPUP uses which operating system and user interaction is done through the common desktop environment (CDE) Graphic User Interface (GUI) by

Answer 41

Unix; keyboard and mouse

Question 42

The OPUP product display window can display up to how many windows per screen?

Answer 42

12

Question 43

Which value is considered non-precipitable and are often just cloud droplets?

Answer 43

+18 dBZ

Question 44

Where would you look for a hook echo signature?

Answer 44

In the right rear quadrant of the trailing half of the parent echo

Question 45

Embedded thunderstorms are detected by the WSR-88D quite well because

Answer 45

It's 10 cm wavelength can see through the stratiform precipitation because less attenuation occurs

Question 46

Outflow boundaries may be seen on the WSR-88D even when no clouds are present because

Answer 46

Of the gradient in the refractive index

Question 47

Which product is used to detect and locate motions in and around potentially severe weather producing storms?

Answer 47

Base mean radial velocity

Question 48

When the Doppler zero line has a noticeable S-shaped pattern, winds are considered

Answer 48

Veering with height

Question 49

When the radar detects pure cyclonic rotation, the Doppler zero line is oriented

Answer 49

Parallel to the viewing direction

Question 50

The spectrum width product is most effective when

Answer 50

Used with other products

Question 51

The spectrum width product is useful for the early detection of thunderstorm development because

Answer 51

The detection of high spectrum widths may be indicative of currents present in a convective atmosphere

Question 52

Data collected for generation of the composite reflectivity product is derived from

Answer 52

All elevation slices

Question 53

Which statement is NOT a use of the composite reflectivity (CR) product?

Answer 53

It can be used to show 3-D structure of the reflectivity pattern USES: First step in identifying sig weather features Quick check on overall reflectivity pattern Provides instant snapshot of most imp reflectivity patterns

Question 54

The melting level is displayed on the composite reflectivity product as

Answer 54

Multiple rings of enhanced reflectivity around the RDA

Question 55

Which procedure is a primary use for the layered composite reflectivity maximum (LRM) product?

Answer 55

Quickly identifying stronger storms and areas with a greater potential for convection

Question 56

Which condition indicates an intense updraft and strong likelihood for severe weather on the layered composite reflectivity product?

Answer 56

Strong reflectivity values (>50 dBZ) in the high altitude layer

Question 57

What is the minimum depth layer for the layered composite reflectivity pattern?

Answer 57

1000 ft

Question 58

What is the major difference between composite reflectivity and user selectable composite reflectivity?

Answer 58

Composite reflectivity is produced by using the entire volume scan

Question 59

Which is a true statement concerning ground clutter?

Answer 59

Ground clutter principally affects lower elevations, and has low radial velocity and spectrum width

Question 60

Identify the three processing regions of the layered composite reflectivity maximum (LRM) anomalous propagation removed (APR) algorithm.

Answer 60

Omit all, accept if, and reject if

Question 61

As the strength of the updraft in a storm increases, the vertically integrated liquid (VIL) values of that storm

Answer 61

Increase

Question 62

Vertically integrated liquid (VIL) algorithm display VIL values for storms based on

Answer 62

Reflectivity data converted to liquid water content values

Question 63

A strongly tilted storm may cause what mind of vertically integrated liquid (VIL) values to be displayed?

Answer 63

Lower

Question 64

The echo tops (ET) product is based on data from what other product?

Answer 64

Base reflectivity

Question 65

The echo tops (ET) product computes echo top height by using

Answer 65

2.2 x 2.2 nm grid boxes

Question 66

What is the function of the tilt test in the hybrid scan reflectivity (HSR) algorithm?

Answer 66

It compares the areal coverage of echoes at the 0.5 and 1.5 elevation slices

Question 67

The storm total precipitation (STP) product provides continuously updated information on precipitation accumulations within how many nautical miles of the radar?

Answer 67

124

Question 68

A limitation of the STP product is that it

Answer 68

Has trouble with small scale features

Question 69

What information is included in the attribute table that accompanies the user selectable precipitation (USP) product?

Answer 69

The total number of hours used to build the product

Question 70

How long is the database for the user selectable precipitation (USP) product?

Answer 70

30 hours

Question 71

What is the maximum number of hours that the user selectable precipitation product can be generated for?

Answer 71

24 hours

Question 72

When is the only time snow products are useful?

Answer 72

During dry snowfall events

Question 73

What are the typical strength rank values for a well-defined mesocyclone?

Answer 73

Between five and nine

Question 74

The mesocyclone detection (MD) product can be graphically displayed, what symbol is displayed for a circulation having a strength rank less than 5?

Answer 74

A thin yellow open circle

Question 75

The graphic symbol for a tornadic vortex signature (TVS) is a

Answer 75

Red-filled, inverted, isosceles triangle

Question 76

The graphic symbol for an elevated tornadic vortex signature (TVS) is a

Answer 76

Red, open, inverted, isosceles triangle

Question 77

The maximum shear associated with a tornadic vortex signature (TVS) must be at least

Answer 77

36 m/s (=~ 72 knots) anywhere in the circulation

Question 78

Which statement is NOT a limitation of the tornadic vortex signature (TVS) product?

Answer 78

It only identifies TVSs associated with mesocyclones

Question 79

The total number of vertical wind profiles that can be displayed on a single velocity azimuth display winds profile (VWP) is up to

Answer 79

11

Question 80

The velocity azimuth display (VAD) wind profile (VWP) displays

Answer 80

The true wind speed and direction

Question 81

The color-coded root mean square (RMS) of displayed velocity azimuth display (VAD) winds is related to the

Answer 81

Reliability of the winds

Question 82

Data thresholds for the vertical winds profile (VWP) can be changed

Answer 82

By the master system control function (MSCF)

Question 83

The velocity azimuth display (VAD) winds profile (VWP) can detect features such as

Answer 83

Wind shifts and jet streams

Question 84

The SRM/SRR depends on what algorithm?

Answer 84

Storm tracking

Question 85

The velocity cross-section product is limited to a range within

Answer 85

124nm

Question 86

Resolution of cross-section products

Answer 86

Remain constant

Question 87

Which algorithm is the output of the storm cell segments algorithm directly sent to?

Answer 87

Storm cell centroids

Question 88

The Storm Cell Identification and Tracking (SCIT) algorithm can track how many individual storm cells?

Answer 88

100

Question 89

How does the storm cell tracking algorithm handle a storm cell centroid when it can't correlate with a storm cell centroid from a previous volume scan?

Answer 89

It labels the storm as "NEW" and doesn't forecast a track

Question 90

What determines the length of a forecast made by the storm position forecast algorithm?

Answer 90

Accuracy of previous volume scan's forecast

Question 91

The storm track information (STI) product algorithm provides data on

Answer 91

Past, present, and future locations of thunderstorms

Question 92

How many minutes does the linear motion feature enable the radar user to manually compute a forecast position?

Answer 92

60 minutes

Question 93

What are the three estimates that the hail detection algorithm provides?

Answer 93

Probability of hail Probability of severe hail Maximum expected hail size

Question 94

The probability of severe hail algorithm will look for hail

Answer 94

>3/4 inch

Question 95

What information needs to be routinely updated to increase the hail detection algorithm's performance?

Answer 95

Mean sea level (MSL) altitudes for 0 deg C and -20 deg C

Question 96

What is the maximum number of volume scans used for history in the cell trends graphic product?

Answer 96

10

Question 97

Which dual polarization product is the ratio of the reflected horizontal and vertical power returns and is expected in decibels?

Answer 97

Differential reflectivity

Question 98

Which dual polarization product is a dimensionless measure of the similarity between the reflected horizontal and vertical power returns within each radar pulse volume?

Answer 98

Correlation coefficient (CC)

Question 99

The outer dashed circle on the melting layer product represents the

Answer 99

Point along the radial beyond which the beam is entirely above the melting layer