Radar
Correlation Coefficient Radar Guide: Debris, Hail, Rain, and Mixed Targets
What correlation coefficient shows on dual-pol radar, why low values can indicate mixed targets, and how it helps identify debris or hail.
Quick answer: Correlation coefficient helps show how similar radar targets are, which can flag mixed objects such as debris, hail, or non-meteorological echoes.
What it measures
Rain drops tend to look more similar to radar than tumbling debris or mixed precipitation.
Lower values can mean the radar is seeing a messy mixture of shapes and sizes.
Tornado debris context
A low correlation coefficient area near strong rotation can support a tornado debris signature.
Location and velocity context are essential.
Other uses
Correlation coefficient can help distinguish rain, hail, melting snow, birds, insects, and clutter.
It is one radar clue, not a standalone answer.