1. What is Pressure Gradient Force?

Definition: The pressure gradient force is the force that results when there is a difference in pressure across a surface, causing movement from high to low pressure.

Purpose: It's a fundamental concept in meteorology and fluid dynamics that explains wind patterns and fluid movements.

2. How Does the Formula Work?

The calculator uses the formula:

Where:

• \( PGF \) — Pressure gradient force (m/s²)
• \( \nabla P \) — Pressure gradient (Pa/m)
• \( \rho \) — Density of the fluid (kg/m³)

Explanation: The negative sign indicates the force is directed from high to low pressure. The force increases with greater pressure differences and decreases with higher density.

3. Importance in Atmospheric Science

Details: The pressure gradient force is one of the primary forces that drive atmospheric circulation and wind patterns, balanced by Coriolis force and friction.

4. Using the Calculator

Tips: Enter the pressure gradient (change in pressure per meter) and fluid density (default 1.225 kg/m³ for air at sea level). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why is the formula negative?
A: The negative sign indicates the force acts from high to low pressure areas.

Q2: What's a typical pressure gradient in weather systems?
A: In mid-latitude weather systems, typical gradients are about 1-2 hPa per 100 km (0.001-0.002 Pa/m).

Q3: How does density affect the PGF?
A: For the same pressure gradient, less dense fluids experience greater acceleration.

Q4: What units should I use?
A: Use Pascals per meter (Pa/m) for pressure gradient and kg/m³ for density to get m/s² for the force.

Q5: How does this relate to wind speed?
A: While PGF initiates motion, actual wind speed is determined by balance with other forces (Coriolis, friction).