How to Use the ISA Temperature Calculator
- Enter the sea level temperature (typically around 15°C for standard conditions)
- Enter the sea level pressure (typically 1013.25 hPa for standard conditions)
- Enter the altitude in meters for which you want to calculate the temperature
- Click the "Calculate" button to compute the temperature and pressure at the specified altitude
International Standard Atmosphere (ISA) Model
The International Standard Atmosphere (ISA) is a model that represents the average atmospheric conditions of the Earth. It assumes a linear temperature lapse rate of 6.5°C per kilometer above sea level.
Temperature Calculation Formula
The temperature at a given altitude in the ISA model is calculated as:
T = T₀ - L × h
Where:
- T = Temperature at altitude (K)
- T₀ = Sea level temperature (K)
- L = Temperature lapse rate (6.5 °C/km or 0.0065 °C/m)
- h = Altitude (m)
Pressure Calculation Formula
The pressure at a given altitude in the ISA model is calculated using the barometric formula:
P = P₀ × (T / T₀)^(-gM / (R×L))
Where:
- P = Pressure at altitude (Pa)
- P₀ = Sea level pressure (Pa)
- T = Temperature at altitude (K)
- T₀ = Sea level temperature (K)
- g = Gravitational acceleration (9.80665 m/s²)
- M = Molar mass of dry air (0.0289644 kg/mol)
- R = Universal gas constant (8.314 J/(mol·K))
- L = Temperature lapse rate (6.5 °C/km or 0.0065 °C/m)
Applications
This calculator is useful for:
- Aerospace engineering and aviation
- Weather forecasting
- Altitude measurement calibration
- Calculating air density for various applications