WMO code FM 42-IX (Aircraft Meteorological DAta Relay). Reports from selected aircraft carrying ASDAR or ACARS automatic data-collection systems. (The AMDAR code replaced the ASDAR code in March 1992.) Some of the reports are received in BUFR and others in character code.
Hourly observations from aircraft during all stages of flight giving globally coverage in around 160,000 reports a day.
Data are extracted for the 4 principal synoptic periods (00-06, 06-12, 12-18 and 18-00 UT) and delivered to the BADC at the following times (all in GMT):
| Synoptic period | Delivery to BADC |
| 0000-0559 | 1330 |
| 0600-1159 | 1930 |
| 1200-1759 | 0130 |
| 1800-2359 | 0730 |
Ingest scripts run at the BADC every 20 minutes, converting the incoming files to the self describing BADC-CSV format, but neither the processed or raw data are placed into archive until the following day.
The table below provides the list of available parameters in the column order that they appear in the BADC-CSV files in the archive.
| Column number | ParameterUnit | |
|---|---|---|
| 1 | YEAR | year |
| 2 | MONTH | month |
| 3 | DAY | day |
| 4 | HOUR | hour |
| 5 | MINUTE | minute |
| 6 | Second | second |
| 7 | TIME OF RECEIPT YEAR | year |
| 8 | TIME OF RECEIPT MONTH | month |
| 9 | TIME OF RECEIPT DAY | day |
| 10 | TIME OF RECEIPT HOUR | hour |
| 11 | TIME OF RECEIPT MINUTE | minute |
| 12 | Aircraft registration number | 1 |
| 13 | Aircraft identifier | 1 |
| 14 | LATITUDE | degrees |
| 15 | LONGITUDE | degrees |
| 16 | Altitude | m |
| 17 | Original specification of lat/long | 1 |
| 18 | Collecting centre | 1 |
| 19 | Aircraft navigational system | 1 |
| 20 | Type of aircraft data relay system | 1 |
| 21 | Aircraft roll angle | degrees |
| 22 | Pressure | Pa |
| 23 | Phase of flight | 1 |
| 24 | Wind measurement instrument type | 1 |
| 25 | Wind direction | degrees |
| 26 | Wind speed | ms-1 |
| 27 | Vertical gust velocity | ms-1 |
| 28 | Vertical gust acceleration | ms-2 |
| 29 | Degree of turbulence | |
| 30 | Precision of temperature observation | K |
| 31 | Air temperature | K |
| 32 | Dew point temperature | K |
| 33 | Relative humidity | % |
| 34 | Mixing ratio (from 18/06/07) | kg/kg |
| 35 | Degree of air frame icing | 1 |