Maximum Vapour Pressure Given Evaporation Loss Per Month Calculator

Formula Used:

\[ V = v + \frac{E_m}{C \times (1 + \frac{u}{16})} \]

Actual Vapour Pressure:

cm Hg

Evaporation Loss per Month:

Meyer's Constant:

Mean Wind Velocity:

m/s

Maximum Vapour Pressure:

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is Maximum Vapour Pressure?

The Maximum Vapour Pressure refers to the highest pressure exerted by a vapour in equilibrium with its liquid at a given temperature, often measured in cm Hg or kPa. It represents the saturation point where evaporation and condensation rates are equal.

2. How Does the Calculator Work?

The calculator uses the Meyer's formula:

\[ V = v + \frac{E_m}{C \times (1 + \frac{u}{16})} \]

Where:

\( V \) — Maximum Vapour Pressure (cm Hg)
\( v \) — Actual Vapour Pressure (cm Hg)
\( E_m \) — Evaporation Loss per Month (m)
\( C \) — Meyer's Constant (1.1 for deep water, 1.5 for shallow water)
\( u \) — Mean Wind Velocity (m/s)

Explanation: The formula accounts for the relationship between actual vapour pressure, evaporation loss, wind velocity, and water body characteristics to determine the maximum vapour pressure.

3. Importance of Maximum Vapour Pressure Calculation

Details: Calculating maximum vapour pressure is crucial for hydrological studies, water resource management, evaporation rate estimation, and climate modeling. It helps in understanding water balance in reservoirs and natural water bodies.

4. Using the Calculator

Tips: Enter actual vapour pressure in cm Hg, evaporation loss per month in meters, select appropriate Meyer's constant based on water depth, and mean wind velocity in m/s. All values must be valid and non-negative.

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between actual and maximum vapour pressure?
A: Actual vapour pressure represents current atmospheric moisture content, while maximum vapour pressure is the saturation point at a given temperature where no more evaporation can occur.

Q2: Why are there different Meyer's constants?
A: Different constants account for varying evaporation characteristics - 1.1 for deep water (slower evaporation) and 1.5 for shallow water (faster evaporation due to greater surface area exposure).

Q3: How does wind velocity affect vapour pressure?
A: Higher wind velocities increase evaporation rates by removing saturated air from the water surface, allowing more water molecules to evaporate.

Q4: What are typical values for evaporation loss per month?
A: Evaporation rates vary by climate, typically ranging from 0.1-0.3 m/month in temperate regions to 0.3-0.6 m/month in arid regions.

Q5: When is this calculation most useful?
A: This calculation is particularly valuable for water resource engineers, hydrologists, and climate scientists working on reservoir management, irrigation planning, and climate change impact assessments.