USCG Meteorology Practice Exam

The microbarograph is the instrument that provides a continuous measurement of pressure changes. It operates by using a sensitive diaphragm that responds to fluctuations in atmospheric pressure. As external pressure changes, the diaphragm moves, and this movement is converted into an electrical signal that can be recorded continuously over time. This allows for real-time tracking of pressure variations, which is particularly useful in meteorology for observing weather patterns and predicting storm systems.

In contrast, an aneroid barometer and a mercurial barometer are designed for manual readings of atmospheric pressure at a specific moment, rather than providing a continuous record. An aneroid barometer uses a sealed metal box that expands and contracts with pressure changes, while a mercurial barometer relies on the height of a mercury column in a tube to indicate pressure. Both of these instruments require manual interpretation, whereas the microbarograph automates the recording process.

A wind vane, on the other hand, is an instrument designed specifically to measure wind direction, not atmospheric pressure. Therefore, while it is useful for understanding wind patterns, it does not contribute to the measurement of pressure changes.