1. What is Actual Vapor Pressure?

Actual vapor pressure (e) is the partial pressure of water vapor in the air, calculated from the saturation vapor pressure (e_s) and relative humidity (RH). It represents the real amount of water vapor present in the air.

2. How Does the Calculator Work?

The calculator uses the equation:

Where:

• \( e \) — Actual vapor pressure (hPa)
• \( e_s \) — Saturation vapor pressure (hPa)
• \( RH \) — Relative humidity (percentage)

Explanation: The equation converts relative humidity (a percentage) into actual vapor pressure by scaling the saturation vapor pressure.

3. Importance of Actual Vapor Pressure

Details: Actual vapor pressure is crucial for understanding atmospheric moisture content, calculating dew point, and in various meteorological and agricultural applications.

4. Using the Calculator

Tips: Enter saturation vapor pressure in hPa and relative humidity as a percentage (0-100). Both values must be valid (e_s > 0, RH between 0-100).

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between actual and saturation vapor pressure?
A: Saturation vapor pressure is the maximum possible vapor pressure at a given temperature, while actual vapor pressure is the real amount present.

Q2: What are typical values for actual vapor pressure?
A: In normal conditions, actual vapor pressure ranges from about 5 hPa in dry conditions to 30 hPa in very humid tropical conditions.

Q3: How does temperature affect vapor pressure?
A: Temperature primarily affects saturation vapor pressure (e_s), which increases exponentially with temperature.

Q4: What units should I use?
A: This calculator uses hectopascals (hPa), which are equivalent to millibars (mb) in meteorology.

Q5: Can I use this for dew point calculations?
A: Yes, actual vapor pressure is directly used in dew point temperature calculations.