Barometric Pressure

Definition

Barometric pressure is the force exerted by the weight of the atmosphere on a given surface area, typically measured in units like inches of mercury (inHg) or millibars (mb). This measurement is crucial for understanding how atmospheric conditions influence weather patterns and phenomena, such as storms and air stability, as well as for aviation, where accurate pressure readings are vital for flight operations.

5 Must Know Facts For Your Next Test

1. Barometric pressure decreases as altitude increases due to the thinning of the atmosphere; this is why pilots need to adjust their altimeters.
2. Standard sea-level pressure is defined as 29.92 inches of mercury (inHg) or 1013.25 millibars (mb).
3. Rapid changes in barometric pressure can indicate approaching weather systems, such as low-pressure systems associated with storms.
4. High barometric pressure generally indicates clear skies and stable weather, while low pressure is often linked to clouds and precipitation.
5. Barometric pressure measurements are essential for calibrating altimeters in aircraft to ensure accurate altitude readings during flight.

Review Questions

• How does barometric pressure change with altitude and what implications does this have for aviation?
  • As altitude increases, barometric pressure decreases due to the reduced weight of the air above. This is critical for aviation because pilots must adjust their altimeters to reflect these changes, ensuring accurate altitude readings. Incorrectly calibrated altimeters can lead to dangerous situations during takeoff and landing if the true altitude isn't known.
• Discuss the relationship between barometric pressure and weather phenomena such as storms and fronts.
  • Barometric pressure plays a significant role in weather phenomena. Low-pressure systems are often associated with stormy weather, as they allow air to rise and cool, leading to cloud formation and precipitation. In contrast, high-pressure systems typically bring clear skies and stable conditions. Weather fronts also involve shifts in barometric pressure as two different air masses collide, affecting temperature and precipitation patterns.
• Evaluate the importance of accurate barometric pressure readings for both meteorology and aviation safety.
  • Accurate barometric pressure readings are crucial for meteorology as they help forecast weather patterns and track storms effectively. For aviation safety, precise measurements ensure that pilots can navigate safely by providing correct altitude information. A failure to maintain accurate readings could lead to dangerous situations such as controlled flight into terrain or misjudging storm systems, making it essential for both fields to prioritize reliable barometric data.

Related terms

Atmospheric Pressure: The total pressure exerted by the weight of the air above a given point, typically decreases with altitude.

Pressure Altitude: The altitude in the atmosphere at which the atmospheric pressure is equal to a standard reference pressure, usually 29.92 inHg.

Weather Front: A boundary separating two different air masses, which can lead to changes in weather conditions and is often associated with changes in barometric pressure.