1. Visibility is a measure of:
a. the opacity of the atmosphere b. molecular motion of the air c. heat capacity d. atmospheric density Answer
2. Match the following terms with their definition:
_____ prevailing visibility a. visibility determined from the airport control tower at stations that also report surface visibility _____ sector visibility b. visibility determined from the usual point of observation _____ surface visibility c. visibility in a specified direction that represents at least a 45 degree arc of the horizon circle _____ tower visibility d. visibility that is considered representative of visibility conditions at a station Answer
3. If the airport tower is considered the "usual point of observation" for visibility, the visibility reported by the tower is considered the:
a. sector visibility b. surface visibility c. tower visibility d. ATCT visibility Answer
4. Which of the following is not true of visibility from automated sensors:
a. it is considered the equivalent of prevailing visibility b. it is based on a standard algorithm c. it is an instantaneous value, not a mean d. it is considered representative of the visibility in the vicinity of the airport Answer
5. List one object that can be used for manually determining visibility.
Answer
6. Prevailing visibility is defined as the greatest distance that can be seen throughout at least _____ the horizon circle, not necessarily continuous.
a. 1/4 b. 1/3 c. 1/2 d. 2/3 Answer
7. For variable visibility to be reported, which of the following criteria need to be satisfied (more than one answer):
_____ visibility is less than 3 miles _____ visibility is between 2 and 4 miles _____ visibility is rapidly increasing and decreasing by mile or more _____ visibility changes by 1 miles or more Answer
8. The arcs used to evaluate sector visibility must be at least _____ degrees in width.
a. 180 b. 90 c. 60 d. 45 Answer
9. Visibility is measured in:
a. nautical miles b. statute miles c. kilometers d. light years Answer
10. If the actual visibility falls halfway between two reportable values, the _____ reportable value is transmitted.
a. lower b. higher c. average d. first Answer
11. When a variable visibility is observed, minimum and maximum values are:
a. reported in the body of METAR b. reported in the remarks of METAR c. not reported in METAR/SPECI d. averaged to determine the variable value Answer
12. When a meteorological discontinuity sensor is present, its visibility value is:
a. reported in the body of METAR b. reported in the remarks of METAR c. not reported in METAR/SPECI d. averaged with the other sensors to determine sector visibility Answer
13. One criteria for reporting sector visibility is:
a. prevailing visibility is less than 3 miles b. sector visibility is more than 3 miles c. prevailing and sector visibility have the same reportable value d. three automated sensors are present Answer
14. Automated surface visibility represents _____ minutes of sensor output.
a. 1 b. 2 c. 5 d. 10 Answer
1. a [6.1]
2. prevailing visibility - d
sector visibility - c
surface visibility - b
tower visibility - a [6.3]
3. b [6.4]
4. c [6.1, 6.4]
5. .. dark objects against the horizon sky
.. unfocused lights of moderate intensity [6.4.2]
6. c [6.3, 6.4.4]
7. Yes visibility is less than 3 miles
No visibility is between 2 and 4 miles
Yes visibility is rapidly ...
No visibility changes ... [6.4.5]
8. d [6.4.6]
9. b [6.5.1]
10. a [6.5.2]
11. b [6.5.3]
12. b [6.5.6]
13. a [6.5.7]
14. d [Table 6-2]