1. What is Rohwer's Formula Constant?

Rohwer's Formula Constant refers to an empirical coefficient used in Rohwer's equation to estimate evaporation rates, adjusting for local climatic conditions. It helps in accurately predicting evaporation losses from water surfaces.

2. How Does the Calculator Work?

The calculator uses Rohwer's formula:

Where:

• \( C' \) — Rohwer's Formula Constant
• \( E \) — Evaporation Loss per Day (m)
• \( P_a \) — Atmospheric Pressure (cm Hg)
• \( u \) — Mean Wind Velocity (m/s)
• \( \delta V \) — Change in Vapour Pressure (cm Hg)

Explanation: The formula calculates the empirical constant by considering evaporation loss, atmospheric conditions, wind velocity, and vapor pressure changes.

3. Importance of Rohwer's Formula

Details: Rohwer's formula is crucial for estimating evaporation rates from water bodies, which is essential for water resource management, irrigation planning, and hydrological studies.

4. Using the Calculator

Tips: Enter evaporation loss in meters, atmospheric pressure in cm Hg, mean wind velocity in m/s, and change in vapor pressure in cm Hg. All values must be positive and valid.

5. Frequently Asked Questions (FAQ)

Q1: What is the typical range for Rohwer's constant?
A: The constant typically ranges between 0.5-0.8, but can vary based on local climatic conditions.

Q2: Why is wind velocity important in evaporation calculations?
A: Wind helps remove saturated air from the water surface, allowing more evaporation to occur.

Q3: How does atmospheric pressure affect evaporation?
A: Lower atmospheric pressure generally increases evaporation rates as it reduces the boiling point of water.

Q4: What factors influence vapor pressure change?
A: Temperature, humidity, and air movement are the primary factors affecting vapor pressure changes.

Q5: When is Rohwer's formula most accurate?
A: The formula works best for open water surfaces under moderate climatic conditions and may need calibration for extreme environments.