Factors affecting atmospheric pressure Atmospheric pressure at a location varies primarily with which of the following?

Introduction / Context:
Atmospheric pressure is the force per unit area exerted by the weight of the air column above the point of measurement. It is an important boundary condition in many hydraulic problems (e.g., cavitation, siphons, barometers).

Given Data / Assumptions:

• Standard meteorological behaviors.
• No extreme phenomena (e.g., hurricanes) beyond typical variability.

Concept / Approach:
Pressure decreases with altitude as there is less overlying air mass. Temperature changes modify air density; warmer air expands (lower density) reducing pressure aloft, while cooler air increases density. Weather systems (highs/lows) reflect large-scale variations in atmospheric mass distribution, shifting local pressure up or down.

Step-by-Step Solution:

Verification / Alternative check:
Barometric readings demonstrate daily and seasonal variations due to these factors; aviation altimeters require corrections for all three.

Why Other Options Are Wrong:

• Any single-factor choice ignores other well-established contributors.

Common Pitfalls:
Assuming only altitude matters; forgetting temperature/pressure corrections used in fluid property tables.

Final Answer:
all of the above