# Lab 5: Obtaining and Working With Radar Data

In-Class Laboratory 5a and 5b: Due Wednesday April 27, 2011

Resources: Class Handouts, Simplified Radar Equation

1. The WSR-88D transmits pulses of energy rather than a continuous stream so target _______ can be determined.

a. range
b. shape
c. reflectivity
d. composition

2. The beam of the WSR-88D is a volume bounded by the points where the power ______ to ______ the peak power.

a. increases, one-half
b. increases, one-third
c. decreases, one-half
d. decreases, one-third

3. Increased sensitivity of the WSR-88D at close ranges, as compared to distant ranges, is the result of __________ at close ranges.

a. more power transmitted
b. more attenuation
c. greater power density
d. less ground clutter contamination

4. Two sample volumes are located at 50 nm and 70 nm from a radar. They contain the same number and size particles. The power returned from 70 nm will be _______ from 50 nm. The reflectivity from 50 nm will be _______ from 70 nm.

a. greater than, less than
b. less than, greater than
c. greater than, the same as
d. less than, the same as

5. The amount of power returned to a WSR-88D radar is _______ related to the power transmitted and _______ related to the target range.

See handout.

a. directly, directly
b. directly, inversely
c. inversely, directly
d. inversely, inversely

6. The beamwidth for WSR-88D radars varies between 0.87° and 0.96° and is a function of the transmission wavelength and antenna diameter. If a radar has an antenna dish diameter of 28 ft and transmits at a frequency of 2800 MHZ, the beam width is approximately _______.

See equation.

a. 0.88°
b. 0.90°
c. 0.92°
d. 0.96°

7. Incomplete beam filling will result in the WSR-88D displaying reflectivity values _________ what the actual drop-size distribution would produce.

See handout.

a. higher than
b. lower than
c. identical to
d. comparable to

8. If Rmax = 250 nm and a target actually located at 275 nm was detected by the WSR-88D, the target would be displayed at ______ nm range on a 250 nm range Base Reflectivity Product.

a. 25
b. 27
c. 248
d. 275

5b: Obtaining and Plotting Radar Data

2. Order the HAS Radar Data for KUEX for May 22, 2004 for your use at home (in other words, do this at home)

3. Using the ordered radar dara (or downloaded from HAS here at SFSU) for the WSR-88D radar site in Hastings, Nebraska, for 23:41 UTC May 22, 2004 as listed below. Create the 1/2 degree reflectivity plot first, and you will see two hook echoes near the Nebraska/Kansas border. Zoom until the two echoes basically fill the left side of the screen and the Hastings radar cross hair is on the right margin.

Create plots of:

• 1/2 degree base reflectivity (unsmoothed and with NEXRAD smoothing set to 10) (N0R)
• 3.4 degree base reflectivity (unsmoothed and with NEXRAD smoothing set to 10) (N3R)
• 1/2 degree base velocity (unsmoothed) (N0V)
• 1/2 degree storm relative velocity (unsmoothed) (N0S)