1. What is Pressure Gradient Force (PGF)?

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: In meteorology and geography, it's fundamental for understanding wind patterns and atmospheric circulation.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( PGF \) — Pressure Gradient Force (m/s²)
• \( \nabla P \) — Pressure gradient (Pa/m)
• \( \rho \) — Air density (kg/m³)

Explanation: The negative sign indicates the force is directed from high to low pressure. Greater pressure differences or lower densities result in stronger forces.

3. Importance in Geography and Meteorology

Details: PGF is the primary force initiating atmospheric motion, driving winds and storms. It's balanced by Coriolis and friction forces in large-scale flows.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: Why is the result negative?
A: The negative sign indicates direction from high to low pressure. The magnitude is what's important for force strength.

Q2: What's a typical pressure gradient value?
A: In meteorology, gradients are often 1-2 hPa/100 km (0.0001-0.0002 Pa/m) but can be much stronger in storms.

Q3: How does altitude affect the calculation?
A: Air density decreases with altitude, so the same pressure gradient produces stronger PGF at higher elevations.

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

Q5: How does PGF relate to wind speed?
A: PGF creates wind acceleration, but actual wind speed depends on other forces (Coriolis, friction) and duration.