Barometric Formula:
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Definition: This calculator estimates altitude based on atmospheric pressure using the barometric formula, which relates pressure to height in an isothermal atmosphere.
Purpose: It's used in aviation, meteorology, and altitude measurements when direct altitude measurement isn't available.
The calculator uses the barometric formula:
Where:
Explanation: The formula calculates the altitude where the pressure would be P, given a sea-level pressure P₀ and constant temperature T.
Details: Accurate altitude measurement is crucial for aviation safety, weather forecasting, and scientific research.
Tips: Enter temperature in Kelvin (default 288.15K ≈ 15°C), sea level pressure in Pascals (default 101325 Pa = 1 atm), and current pressure in Pascals. Current pressure must be less than sea level pressure.
Q1: Why use Kelvin for temperature?
A: The gas law requires absolute temperature. Kelvin is the SI unit for thermodynamic temperature.
Q2: What's a typical sea level pressure?
A: Standard atmospheric pressure is 101325 Pa (1 atmosphere), but actual pressure varies with weather conditions.
Q3: How accurate is this formula?
A: It assumes constant temperature (isothermal atmosphere). For more accuracy, use the International Standard Atmosphere model.
Q4: Can I use hPa or mmHg instead of Pascals?
A: Yes, but convert to Pascals first (1 hPa = 100 Pa, 1 mmHg ≈ 133.322 Pa).
Q5: What's the maximum altitude this can calculate?
A: The formula works best below 11 km (tropopause). Above that, temperature isn't constant.