Definition
ASDAR is an automated system that collects upper-air weather data — such as wind, temperature, and pressure — from sensors on commercial aircraft in flight and relays that data to ground-based meteorological centers via satellite. It supplements traditional weather balloon (radiosonde) observations by providing frequent, real-time atmospheric readings from along busy air routes.
Plain English
Airliners already measure the air around them as they fly. ASDAR is the setup that automatically sends those measurements up to a satellite, which then passes them down to weather forecasters on the ground.
Context Anchor
Seen in discussions of upper-air observations and how weather services collect data above the surface.
Derivation
The name describes the data path: the Aircraft gathers the data, a Satellite acquires it, and the satellite then relays it down to a ground station. Reading the acronym in that order makes the system easy to picture.
Why Pilots Care
ASDAR data feeds the upper-wind and temperature forecasts pilots rely on for flight planning, fuel calculations, and turbulence avoidance. More frequent aircraft reports mean more accurate winds aloft forecasts than balloon launches alone could provide.
Analogy
It is like a car automatically reporting road and temperature conditions as it drives, except the aircraft is reporting conditions in the air to weather services.
Grounding Statement
An ASDAR-equipped aircraft can gather weather information during a normal flight and send it out automatically without the pilot making a special report.
Intuition Check
ASDAR is not a pilot radio call or a weather report you normally create by hand. It is an automated data collection and relay system installed on certain aircraft.
Example Sentence 1
Upper-air observations come from several sources, including weather balloons and ASDAR-equipped airliners flying along high-altitude routes.
Example Sentence 2
Forecasters used ASDAR data to refine upper-level wind forecasts for the next day's departure planning.