Atmospheric Pressure Given Change In Vapour Pressure Calculator

Atmospheric Pressure Formula:

\[ P_a = \frac{1.456 - \left(\frac{E}{C' \times (0.44 + (0.0732 \times u)) \times \delta V}\right)}{0.00732} \]

Evaporation Loss per Day:

Rohwer's Formula Constant:

Mean Wind Velocity:

m/s

Change in Vapour Pressure:

cmHg

Atmospheric Pressure:

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1. What is Atmospheric Pressure?

Atmospheric pressure refers to the force exerted by the weight of the atmosphere on a surface, typically measured in pascals (Pa), millibars (mb), or inches of mercury (inHg). It is a crucial parameter in meteorology and various engineering applications.

2. How Does the Calculator Work?

The calculator uses the Atmospheric Pressure formula:

\[ P_a = \frac{1.456 - \left(\frac{E}{C' \times (0.44 + (0.0732 \times u)) \times \delta V}\right)}{0.00732} \]

Where:

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

Explanation: This formula calculates atmospheric pressure based on evaporation loss, wind velocity, and vapour pressure changes using Rohwer's empirical approach.

3. Importance of Atmospheric Pressure Calculation

Details: Accurate atmospheric pressure measurement is essential for weather forecasting, aviation, industrial processes, and scientific research where pressure variations significantly impact system performance.

4. Using the Calculator

Tips: Enter evaporation loss in meters, Rohwer's constant, mean wind velocity in m/s, and change in vapour pressure in cmHg. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is Rohwer's Formula Constant?
A: Rohwer's Formula Constant is an empirical coefficient used in Rohwer's equation to estimate evaporation rates, adjusting for local climatic conditions.

Q2: Why is wind velocity measured at 9 meters height?
A: Wind velocity is typically measured at about 9 meters above ground to minimize surface turbulence effects and obtain consistent measurements.

Q3: How does vapour pressure affect atmospheric pressure calculations?
A: Vapour pressure changes indicate humidity variations, which affect evaporation rates and consequently influence atmospheric pressure calculations.

Q4: What are typical values for evaporation loss per day?
A: Evaporation loss varies by climate but typically ranges from 2-10 mm per day in temperate regions, though it can be higher in arid conditions.

Q5: Can this formula be used for all atmospheric conditions?
A: This empirical formula works well for standard conditions but may require adjustments for extreme weather conditions or unusual geographical locations.