Definition
A weather-detection enhancement added to the FAA's ASR-9 airport surveillance radar that processes radar returns to detect wind shear, microbursts, gust fronts, and precipitation in the airport terminal area. When hazardous conditions are identified, alerts are passed to air traffic controllers, who relay them to pilots arriving at or departing from the airport.
Plain English
It is a weather add-on built into the airport's main surveillance radar. The radar already tracks aircraft, and this add-on uses the same returns to spot dangerous wind shifts and microbursts near the airport so controllers can warn pilots.
Context Anchor
Seen in low-level wind shear discussions and at airports where air traffic control can issue wind shear or microburst alerts from radar-based weather equipment.
Derivation
ASR stands for Airport Surveillance Radar, the radar used by approach controllers to track aircraft within roughly 60 miles of an airport. The 9 refers to the ninth-generation model. WSP, Weather Systems Processor, is the software and hardware package added to that radar so it can also analyze weather returns. Knowing the breakdown helps because the term sounds like a standalone system but is really a weather upgrade bolted onto an existing aircraft-tracking radar.
Why Pilots Care
Gives pilots advance warning of wind shear that can cause sudden loss of airspeed and altitude during takeoff or landing.
Analogy
It is like adding a weather warning function to a radar that already watches traffic near the airport: the radar is still there, but the added processor looks for dangerous wind patterns.
Grounding Statement
ASR-9 WSP matters most when an aircraft is close to the runway and the wind suddenly changes strength or direction.
Intuition Check
Do not read ASR-9 WSP as just a normal weather report. In this context, it is a specific radar-based system used to detect hazardous wind shear near an airport.
Example Sentence 1
The tower issued a microburst alert from the ASR-9 WSP, and the arriving flight elected to go around.
Example Sentence 2
Pilots at major airports rely on ASR-9 WSP data to decide whether to continue an approach in gusty conditions.