About this viewer

This site retrieves AMDAR aircraft soundings from NOAA’s MADIS (Meteorological Assimilation Data Ingest System). Commercial aircraft carry meteorological sensors and report automatically in flight; a climb or descent through the troposphere yields a vertical profile very like a radiosonde ascent, at airports, several times a day.

Most aircraft report temperature and wind. A smaller number carry additional sensors. In a typical six-hour window of about 4,000 aircraft, roughly 400 also report turbulence (eddy dissipation rate) and around 100 report water vapour. These are different fleets — an aircraft reporting turbulence usually is not one reporting moisture.

Where the data comes from

• Aircraft (AMDAR/ACARS) — NOAA MADIS. Aircraft identifiers in the public feed are encrypted by NOAA.
• Radiosondes — US and Canadian ascents from the Iowa Environmental Mesonet (Iowa State University); the rest of the world from IGRA v2.2 (NOAA NCEI).
• Surface observations (METARs) — the NOAA Aviation Weather Center for recent hours, and the IEM ASOS archive for older dates. These are the ground truth for the moisture check described below.
• Model soundings — HRRR and GFS via Open-Meteo (CC BY 4.0).
• Map — Leaflet, with tiles from CARTO and OpenStreetMap contributors.

The 48-hour rule

Aircraft observations are proprietary to the airlines that provide them until they are 48 hours old, after which NOAA releases them publicly. The archive therefore begins where the restriction ends. One welcome side effect: the archive carries every fleet, where the real-time feed carries only the unrestricted subset — so the same hour can show several thousand aircraft from the archive against a few dozen live.

The dewpoint check

MADIS quality-controls aircraft dewpoint only for validity and internal consistency — there is no spatial check on moisture. An aircraft whose humidity sensor has stuck dry therefore reports plausible, self-consistent, far-too-dry values that pass QC indefinitely. This site adds the missing check: each profile is compared against its own airport’s METAR, against neighbouring aircraft, and against a physical test — water vapour must decrease with height, and a stuck sensor makes it appear to increase. Suspect profiles carry a red warning above the Skew-T. Treat the warning as a prompt to look closely, not as a verdict.

Questions, corrections, or a case that looks wrong? Please contact richmamrosh@gmail.com.