1. What is Pressure Gradient Force (PGF)?

Definition: PGF is the force that results from differences in atmospheric pressure, causing air to move from high to low pressure.

Purpose: This calculator computes the PGF vector components and magnitude based on density and pressure gradient.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( \text{PGF} \) — Pressure gradient force vector (m/s²)
• \( \rho \) — Air density (kg/m³)
• \( \nabla P \) — Pressure gradient vector (Pa/m)

Explanation: The negative sign indicates the force is directed from high to low pressure. The force is inversely proportional to density.

3. Importance of Pressure Gradient Force

Details: PGF is fundamental in meteorology, driving wind patterns and atmospheric circulation. It's one of the primary forces in the equations of motion for atmospheric flow.

4. Using the Calculator

Tips:

• Enter air density (default 1.225 kg/m³ for sea level at 15°C)
• Input pressure gradient components in x and y directions
• Density must be > 0

5. Frequently Asked Questions (FAQ)

Q1: Why is the PGF inversely proportional to density?
A: For the same pressure difference, less dense air experiences greater acceleration (F=ma).

Q2: What are typical pressure gradient values?
A: In weather systems, typical values range from 1-5 Pa/km (0.001-0.005 Pa/m).

Q3: How does PGF relate to wind speed?
A: PGF is the primary force initiating wind, but actual wind is affected by Coriolis force and friction.

Q4: What units are used for the pressure gradient?
A: Pascals per meter (Pa/m), where 1 hPa/km = 0.1 Pa/m.

Q5: Why is the result in m/s²?
A: PGF is an acceleration (force per unit mass) in the equations of motion.