1. What is the Magnus Formula?

The Magnus formula is an empirical relationship that calculates the saturation vapor pressure of water over liquid water as a function of temperature. It provides an accurate estimation of vapor pressure in meteorological and environmental applications.

2. How Does the Calculator Work?

The calculator uses the Magnus formula:

Where:

• \( e_s \) — Saturation vapor pressure (hPa)
• \( T \) — Temperature (°C)
• 6.112 — Reference vapor pressure at 0°C (hPa)
• 17.67 and 243.5 — Empirical constants

Explanation: The formula describes how the maximum amount of water vapor that air can hold increases exponentially with temperature.

3. Importance of Vapor Pressure Calculation

Details: Vapor pressure calculation is essential for weather forecasting, humidity measurement, climate studies, and various industrial processes involving air-water systems.

4. Using the Calculator

Tips: Enter temperature in degrees Celsius. The calculator will compute the saturation vapor pressure in hectopascals (hPa).

5. Frequently Asked Questions (FAQ)

Q1: What is the range of validity for the Magnus formula?
A: The formula is valid for temperatures between -45°C and 60°C, though it's most accurate between 0°C and 50°C.

Q2: How does vapor pressure relate to humidity?
A: Relative humidity is the ratio of actual vapor pressure to saturation vapor pressure at the same temperature, expressed as a percentage.

Q3: Why are there different vapor pressure formulas?
A: Different formulas (Magnus, Goff-Gratch, Arden Buck) offer varying accuracy across different temperature ranges and applications.

Q4: How does altitude affect vapor pressure?
A: Vapor pressure itself is not directly affected by altitude, but the relationship between vapor pressure and other humidity measures changes with atmospheric pressure.

Q5: What are typical vapor pressure values?
A: At 20°C, saturation vapor pressure is about 23.4 hPa. At 0°C, it's 6.11 hPa, and at 40°C, it's about 73.8 hPa.