A COMPARISON OF SEA ICE PARAMETERS COMPUTED FROM ADVANCED VERY HIGH-RESOLUTION RADIOMETER AND LANDSAT SATELLITE IMAGERY AND FROM AIRBORNE PASSIVE MICROWAVE RADIOMETRY

The advanced very high resolution radiometer (AVHRR), flying on the NOAA polar-orbiting weather satellites, can be used to map both sea ice concentration and ice edge, under cloud-free conditions. In order to evaluate the accuracy and reliability of these AVHRR ice parameters, we have compared AVHRR-derived sea ice parameters from the Bering Sea with those computed from nearly coincident (within 6 hours) Landsat multispectral scanner (MSS) imagery and from the aircraft multichannel microwave radiometer (AMMR) flown on the NASA DC-8. The higher spatial and spectral resolutions of the Landsat data make them appropriate to use as a reference for the AVHRR inferred sea ice parameters while the lower-altitude aircraft microwave sensor also provides a good source of comparison data. Both the AVHRR near-infrared (channel 2) and thermal infrared (channel 4) images were used to compute ice concentration. Mean ice concentration differences between the channel 2 AVHRR and Landsat MSS data (Landsat-AVHRR) ranged from -0.8 to 1.8% with a mean value of 0.5%. Root-mean-square (rms) differences ranged from 6.8 to 17.7%. Mean differences were larger for the channel 4 AVHRR ice concentrations ranging from -2.2 to 8.4% with rms differences from 8.6 to 26.8%. Mean differences between AVHRR channel 2 concentrations and the AMMR data (AMMR-AVHRR) ranged from -19.7 to 18.9% while rms values went from 17.0 to 44.8%. Mean ice edge differences between the Landsat and AVHRR images were 1.8 km for channel 2 and 2.9 km for channel 4 with rms differences of 3.2 km and 4.4 km, respectively. The AVHRR ice edge was south and west of the Landsat edge.