Numerical Model Derived Altimeter Correction Maps for Non-Standard Atmospheric Temperature and Pressure

Abstract

Altimeter corrections for non-standard temperature pose a challenge because accurate calculations require detailed knowledge of the temperature structure of the atmosphere between the surface and the aircraft. By applying basic hypsometric formulae to high resolution numerical model temperature and moisture output, detailed maps of current and forecasted corrected D-values are created. Corrected D-values provide the altitude difference between the true altitude and the indicated altitude from a pressure altimeter. Unlike standard D-values, the corrected D-value corrects for non-standard pressure in addition to non-standard temperature and is therefore useful for flights below class A airspace. Maps of corrected D-value may help provide increased situational awareness for pilots during cold-weather operations as well as a useful educational tool for quantifying the effects of non-standard temperature on pressure altimetry.