Mean Wind Velocity At Ground Level Given Evaporation Loss Per Day Calculator

Mean Wind Velocity Formula:

\[ u = \frac{\left(\frac{E}{C' \times (1.465 - (0.00732 \times P_a)) \times (V - v)}\right) - 0.44}{0.0732} \]

Evaporation Loss Per Day (E):

Meter

Rohwer's Formula Constant (C'):

Atmospheric Pressure (P_a):

cm Hg

Maximum Vapor Pressure (V):

cm Hg

Actual Vapor Pressure (v):

cm Hg

Mean Wind Velocity (u):

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1. What Is The Mean Wind Velocity Formula?

The Mean Wind Velocity formula calculates wind speed at ground level based on evaporation loss, atmospheric conditions, and vapor pressure differences using Rohwer's empirical equation.

2. How Does The Calculator Work?

The calculator uses Rohwer's formula:

\[ u = \frac{\left(\frac{E}{C' \times (1.465 - (0.00732 \times P_a)) \times (V - v)}\right) - 0.44}{0.0732} \]

Where:

\( u \) — Mean Wind Velocity (cm/s)
\( E \) — Evaporation Loss Per Day (m)
\( C' \) — Rohwer's Formula Constant
\( P_a \) — Atmospheric Pressure (cm Hg)
\( V \) — Maximum Vapor Pressure (cm Hg)
\( v \) — Actual Vapor Pressure (cm Hg)

Explanation: This empirical formula relates wind velocity to evaporation rates and atmospheric conditions, accounting for pressure and humidity effects.

3. Importance Of Wind Velocity Calculation

Details: Accurate wind velocity estimation is crucial for evaporation studies, agricultural water management, meteorological forecasting, and environmental monitoring applications.

4. Using The Calculator

Tips: Enter all values in the specified units. Ensure vapor pressure values are consistent and all inputs are positive values greater than zero.

5. Frequently Asked Questions (FAQ)

Q1: What is Rohwer's Formula Constant?
A: Rohwer's Formula Constant is an empirical coefficient that varies based on local climatic conditions and surface characteristics, typically ranging from 0.5 to 0.8.

Q2: Why use this specific formula?
A: Rohwer's formula provides a reliable empirical relationship between wind velocity and evaporation rates, particularly useful for agricultural and hydrological applications.

Q3: What are typical wind velocity values?
A: Mean wind velocities at ground level typically range from 50-500 cm/s (0.5-5 m/s), depending on location, time of day, and weather conditions.

Q4: How accurate is this calculation?
A: The accuracy depends on the precision of input measurements and the appropriateness of the Rohwer constant for specific local conditions.

Q5: Can this be used for all locations?
A: While generally applicable, local calibration of the Rohwer constant may be needed for optimal accuracy in specific geographic regions.