Definition
A digital communication system that transmits information between aircraft and ground stations, or between aircraft, using radio or satellite signals. In the context of weather, datalink delivers near real-time products such as radar imagery, METARs, TAFs, AIRMETs, SIGMETs, and winds aloft directly to the cockpit.
Plain English
A wireless data connection that sends weather information and other messages straight to the cockpit display, so the pilot can see it without talking on the radio.
Context Anchor
Seen in upper-air weather observations, especially when a weather balloon carries instruments upward and sends the readings back to a ground station.
Derivation
From 'data' (information) and 'link' (a connection between two points). The name simply describes what it does: a connection that carries data, as opposed to a voice radio link that carries speech.
Why Pilots Care
It reduces voice radio congestion and provides a written record of instructions and data.
Intuition Check
Do not read DataLink as the weather data itself. Here, it means the communication path that carries the data from the airborne instrument to the ground.
Example Sentence 1
On the cross-country, the pilot used datalink weather to monitor a line of storms developing ahead of the route.
Example Sentence 2
Controllers can issue a route amendment directly to the aircraft via datalink.