What characterizes the standard atmosphere at sea level?

The standard atmosphere at sea level is characterized by a pressure of 29.92 inches of mercury (inHg) and a temperature of 15°C. This definition is widely accepted in aviation and meteorology and serves as a baseline for various calculations related to altitudes, aircraft performance, and weather phenomena.

The significance of the pressure value, 29.92 inHg, is that it represents the average atmospheric pressure at sea level under standard atmospheric conditions, allowing for consistent measurement and comparison in both aviation and scientific fields. Meanwhile, the temperature of 15°C is also critical as it establishes a baseline reference for temperature variations and altimeter settings, crucial for accurate flight operations.

This standard is used globally, which is why it is essential for pilots and meteorologists to understand these values for planning and operations. The other options do not reflect the accepted values for standard atmospheric conditions at sea level, making them unsuitable for this context.