A new melt onset algorithm is developed using high resolution SAR (RADARSAT).
Mean melt onset date was found on YD 164 in northern CAA from 1997 to 2014.
No significant melt onset trend was found for this 18-year period.
20">Earlier melt onset was associated with lighter September sea ice coverage.
25">RADARSAT estimates were more robust than passive microwave and scatterometer.