How to calculate standard altitude gradiant?

The standard altitude gradient is the rate at which the altitude changes with respect to distance traveled horizontally. It is typically expressed in feet per mile or meters per kilometer.

To calculate the standard altitude gradient, you can use the following formula:

Altitude Gradient = (Ending Altitude - Starting Altitude) / Distance Traveled

For example, if you start at an altitude of 1000 feet and end at an altitude of 2000 feet after traveling a distance of 5 miles, the altitude gradient would be:

Altitude Gradient = (2000 - 1000) / 5 = 1000 feet per mile

This means that for every mile traveled horizontally, the altitude increases by 1000 feet.

Calculating Standard Altitude Gradient

The standard altitude gradient is the rate at which atmospheric temperature decreases with altitude. It is typically expressed in degrees Celsius per 100 meters.

Formula:

Standard Altitude Gradient = -6.49 K/100 m

Steps to Calculate:

1. Convert the gradient to degrees Celsius: Multiply -6.49 K/100 m by 1, as 1 degree Celsius = 1 Kelvin. This gives:

Standard Altitude Gradient = -6.49 °C/100 m

2. Adjust for actual conditions: The standard altitude gradient is an average value and may vary slightly with conditions such as air pressure and humidity.

Adjusted Altitude Gradient:

Adjusted Altitude Gradient = Standard Altitude Gradient - Correction Factor

Correction Factors:

- Air Pressure: 0.002 °C/100 m per 1 hPa increase
- Humidity: 0.02 °C/100 m per 1% increase in relative humidity

Example:

To calculate the adjusted altitude gradient for an area with an air pressure of 1010 hPa and a relative humidity of 60%:

- Air Pressure Correction: 0.002 °C/100 m - (1010 hPa - 1000 hPa) = 0.2 °C/100 m
- Humidity Correction: 0.02 °C/100 m - 60% = 1.2 °C/100 m
- Adjusted Altitude Gradient: -6.49 °C/100 m + 0.2 °C/100 m + 1.2 °C/100 m = -5.09 °C/100 m