ACE 106 SURFACE
OBSERVATION
FUNDAMENTALS
PRACTICE EXAM
Question 1: What type of report is a routine hourly meteorological observation used primarily for aviation?
Choices:
1) TAF
2) METAR
3) SIGMET
4) PIREP
Correct Answer: METAR
Explanation: A METAR (Aviation Routine Weather Report) is an hourly or semi-hourly routine observation of surface weather conditions at an airport.Page 1
Question 2: Which automated system code 'AO2' indicates on a surface weather
observation report?
Choices:
1) Automated station with a precipitation discriminator 2) Automated station without a precipitation discriminator 3) Manual station with backup observer 4) Satellite-only monitoring system
Correct Answer: Automated station with a precipitation discriminator
Explanation: AO2 indicates an automated station equipped with a precipitation discriminator that can di�erentiate between rain and snow.Question 3: What type of lines on a surface weather chart connect areas of equal barometric pressure?
Choices:
1) Isotherms 2) Isotachs 3) Isobars 4) Isodrosotherms
Correct Answer: Isobars
Explanation: Isobars are lines drawn on a weather map connecting points of equal atmospheric pressure.Page 2
Question 4: If isobars on a surface weather chart are closely spaced, what does this indicate?
Choices:
1) A weak pressure gradient and light winds 2) A steep pressure gradient and high wind speeds 3) An approaching warm front with stable air 4) High relative humidity and imminent fog
Correct Answer: A steep pressure gradient and high wind speeds
Explanation: Closely spaced isobars represent a steep pressure gradient, which drives higher wind velocities.
Question 5: What fundamental force causes surface winds to cross isobars at an
angle rather than blowing parallel to them?
Choices:
1) Coriolis force 2) Pressure gradient force 3) Centrifugal force 4) Surface friction
Correct Answer: Surface friction
Explanation: Friction slows wind near the surface, decreasing the Coriolis e�ect and allowing the pressure gradient force to push air across isobars.Page 3