An air pressure contour line joins locations in a region having the same…
2017
An air pressure contour line joins locations in a region having the same atmospheric pressure. The following is an air pressure contour plot of a geographical region. Contour lines are shown at 0.05 bar intervals in this plot.
If the possibility of a thunderstorm is given by how fast air pressure rises or drops over a region, which of the following regions is most likely to have a thunderstorm?
- A.
P
- B.
Q
- C.
R
- D.
S
Attempted by 69 students.
Show answer & explanation
Correct answer: C
Key idea: thunderstorms are most likely where air pressure changes rapidly over a short distance. On a contour map, rapid pressure change appears where contour lines are closely spaced (a steep pressure gradient).
Interpret contours: The contour interval is 0.05 bar. Closely spaced contours mean a large pressure change per unit distance; widely spaced contours mean a small pressure change per unit distance.
Compare locations: At location R the contour lines are much more tightly packed than at P, Q, or S, so the pressure changes fastest there.
Conclusion: The area most likely to have a thunderstorm is the one with the steepest pressure gradient—location R—because rapid changes in pressure favor storm development.
A video solution is available for this question — log in and enroll to watch it.