Rohwers formula (1931) Calculator

✖Atmospheric Pressure or mean barometric pressure (mm of mercury).ⓘ Atmospheric Pressure [P_a]			+10% -10%
✖Mean Wind Velocity at Ground Level in km/hr which can be taken to be the velocity at 0.6m height above the ground.ⓘ Mean Wind Velocity at Ground Level [u₀]			+10% -10%
✖Saturation Vapour Pressure at Water Surface (mm of mercury) is defined as the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases at a given temperature.ⓘ Saturation Vapour Pressure [e_s]			+10% -10%
✖Actual Vapour Pressure is the air in mm of mercury is the vapour pressure exerted by the water in the air.ⓘ Actual Vapour Pressure [e_a]			+10% -10%

✖Lake Evaporation is a sensitive indicator of the hydrological response to climate change. Variability in annual lake evaporation is assumed to be controlled by the surface solar radiation.ⓘ Rohwers formula (1931) [E_lake]

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Rohwers formula (1931) Solution

STEP 0: Pre-Calculation Summary

Formula Used

Lake Evaporation = 0.771*(1.465-0.00073*Atmospheric Pressure)*(0.44+0.0733*Mean Wind Velocity at Ground Level)*(Saturation Vapour Pressure-Actual Vapour Pressure)
E_lake = 0.771*(1.465-0.00073*P_a)*(0.44+0.0733*u₀)*(e_s-e_a)
This formula uses 5 Variables

Variables Used

Lake Evaporation - Lake Evaporation is a sensitive indicator of the hydrological response to climate change. Variability in annual lake evaporation is assumed to be controlled by the surface solar radiation.
Atmospheric Pressure - (Measured in Millimeter Mercury (0 °C)) - Atmospheric Pressure or mean barometric pressure (mm of mercury).
Mean Wind Velocity at Ground Level - (Measured in Kilometer per Hour) - Mean Wind Velocity at Ground Level in km/hr which can be taken to be the velocity at 0.6m height above the ground.
Saturation Vapour Pressure - (Measured in Millimeter Mercury (0 °C)) - Saturation Vapour Pressure at Water Surface (mm of mercury) is defined as the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases at a given temperature.
Actual Vapour Pressure - (Measured in Millimeter Mercury (0 °C)) - Actual Vapour Pressure is the air in mm of mercury is the vapour pressure exerted by the water in the air.

STEP 1: Convert Input(s) to Base Unit

Atmospheric Pressure: 4 Millimeter Mercury (0 °C) --> 4 Millimeter Mercury (0 °C) No Conversion Required
Mean Wind Velocity at Ground Level: 4.3 Kilometer per Hour --> 4.3 Kilometer per Hour No Conversion Required
Saturation Vapour Pressure: 17.54 Millimeter Mercury (0 °C) --> 17.54 Millimeter Mercury (0 °C) No Conversion Required
Actual Vapour Pressure: 3 Millimeter Mercury (0 °C) --> 3 Millimeter Mercury (0 °C) No Conversion Required

STEP 2: Evaluate Formula

Substituting Input Values in Formula

E_lake = 0.771*(1.465-0.00073*P_a)*(0.44+0.0733*u₀)*(e_s-e_a) --> 0.771*(1.465-0.00073*4)*(0.44+0.0733*4.3)*(17.54-3)

Evaluating ... ...

E_lake = 12.3778766785784

STEP 3: Convert Result to Output's Unit

12.3778766785784 --> No Conversion Required

FINAL ANSWER

12.3778766785784 ≈ 12.37788 <-- Lake Evaporation

(Calculation completed in 00.020 seconds)

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Rohwers formula (1931)

LaTeX Go Lake Evaporation = 0.771*(1.465-0.00073*Atmospheric Pressure)*(0.44+0.0733*Mean Wind Velocity at Ground Level)*(Saturation Vapour Pressure-Actual Vapour Pressure)

Meyers formula (1915)

LaTeX Go Lake Evaporation = Coefficient Accounting for Other Factors*(Saturation Vapour Pressure-Actual Vapour Pressure)*(1+Monthly Mean Wind Velocity/16)

Dalton-Type Equation

LaTeX Go Lake Evaporation = Coefficient*Wind Speed Correction Factor*(Saturation Vapour Pressure-Actual Vapour Pressure)

Dalton's Law of Evaporation

LaTeX Go Evaporation from Water Body = Proportionality Constant*(Saturation Vapour Pressure-Actual Vapour Pressure)

Rohwers formula (1931) Formula

LaTeX Go

What is Evaporation?

Evaporation is the process in which a liquid changes to the gaseous state as the free surface, below its boiling point, through the transfer of energy.

How to Calculate Rohwers formula (1931)?

Rohwers formula (1931) calculator uses Lake Evaporation = 0.771*(1.465-0.00073*Atmospheric Pressure)*(0.44+0.0733*Mean Wind Velocity at Ground Level)*(Saturation Vapour Pressure-Actual Vapour Pressure) to calculate the Lake Evaporation, The Rohwers Formula (1931) formula is defined as it accounts for the effect of pressure in addition to the wind speed at a height of 0.6 m above free water surface (km/hr). Lake Evaporation is denoted by E_lake symbol.

How to calculate Rohwers formula (1931) using this online calculator? To use this online calculator for Rohwers formula (1931), enter Atmospheric Pressure (P_a), Mean Wind Velocity at Ground Level (u₀), Saturation Vapour Pressure (e_s) & Actual Vapour Pressure (e_a) and hit the calculate button. Here is how the Rohwers formula (1931) calculation can be explained with given input values -> 12.37788 = 0.771*(1.465-0.00073*533.288)*(0.44+0.0733*1.19444444444444)*(2338.46788-399.966).

FAQ

What is Rohwers formula (1931)?

The Rohwers Formula (1931) formula is defined as it accounts for the effect of pressure in addition to the wind speed at a height of 0.6 m above free water surface (km/hr) and is represented as E_lake = 0.771*(1.465-0.00073*P_a)*(0.44+0.0733*u₀)*(e_s-e_a) or Lake Evaporation = 0.771*(1.465-0.00073*Atmospheric Pressure)*(0.44+0.0733*Mean Wind Velocity at Ground Level)*(Saturation Vapour Pressure-Actual Vapour Pressure). Atmospheric Pressure or mean barometric pressure (mm of mercury), Mean Wind Velocity at Ground Level in km/hr which can be taken to be the velocity at 0.6m height above the ground, Saturation Vapour Pressure at Water Surface (mm of mercury) is defined as the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases at a given temperature & Actual Vapour Pressure is the air in mm of mercury is the vapour pressure exerted by the water in the air.

How to calculate Rohwers formula (1931)?

The Rohwers Formula (1931) formula is defined as it accounts for the effect of pressure in addition to the wind speed at a height of 0.6 m above free water surface (km/hr) is calculated using Lake Evaporation = 0.771*(1.465-0.00073*Atmospheric Pressure)*(0.44+0.0733*Mean Wind Velocity at Ground Level)*(Saturation Vapour Pressure-Actual Vapour Pressure). To calculate Rohwers formula (1931), you need Atmospheric Pressure (P_a), Mean Wind Velocity at Ground Level (u₀), Saturation Vapour Pressure (e_s) & Actual Vapour Pressure (e_a). With our tool, you need to enter the respective value for Atmospheric Pressure, Mean Wind Velocity at Ground Level, Saturation Vapour Pressure & Actual Vapour Pressure and hit the calculate button. You can also select the units (if any) for Input(s) and the Output as well.

How many ways are there to calculate Lake Evaporation?

In this formula, Lake Evaporation uses Atmospheric Pressure, Mean Wind Velocity at Ground Level, Saturation Vapour Pressure & Actual Vapour Pressure. We can use 2 other way(s) to calculate the same, which is/are as follows -

Lake Evaporation = Coefficient Accounting for Other Factors*(Saturation Vapour Pressure-Actual Vapour Pressure)*(1+Monthly Mean Wind Velocity/16)
Lake Evaporation = Coefficient*Wind Speed Correction Factor*(Saturation Vapour Pressure-Actual Vapour Pressure)

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