1. What is Vapor Pressure?

Vapor pressure is the pressure exerted by water vapor in the atmosphere. It represents the partial pressure of water vapor in air and is a key parameter in meteorology and humidity calculations.

2. How Does the Calculator Work?

The calculator uses the vapor pressure equation:

Where:

• \( e \) — Vapor pressure (hPa)
• \( T_d \) — Dew point temperature (°C)
• \( \exp \) — Exponential function

Explanation: This empirical equation calculates the saturation vapor pressure at the dew point temperature, which equals the actual vapor pressure in the air.

3. Importance of Vapor Pressure Calculation

Details: Vapor pressure is essential for calculating relative humidity, absolute humidity, and other moisture parameters. It's crucial for weather forecasting, agricultural planning, and industrial processes.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: What is the relationship between vapor pressure and dew point?
A: Dew point temperature is the temperature at which air becomes saturated. Vapor pressure calculated from dew point gives the actual water vapor content in the air.

Q2: What are typical vapor pressure values?
A: Vapor pressure typically ranges from 0 hPa in very dry conditions to about 40 hPa in very humid tropical conditions.

Q3: How is vapor pressure related to relative humidity?
A: Relative humidity = (actual vapor pressure / saturation vapor pressure at air temperature) × 100%

Q4: Why use 6.112 as the constant?
A: 6.112 hPa is the saturation vapor pressure at 0°C, serving as the reference value in this empirical formula.

Q5: Can this formula be used for temperatures below 0°C?
A: Yes, the formula is valid for temperatures below 0°C, though different coefficients are sometimes used for ice vs. water saturation.