DRAFT AND MOVEMENT OF PACK ICE IN THE BEAUFORT SEA: A TIME-SERIES PRESENTATION APRIL 1990 - AUGUST 1999

iv Resume iv Acknowledgements v Introduction 1 Observational Programme 2 Instrumentation 4 Moorings 4 Profiling Sonar for the Measurement of Ice Draft 6 WASP Sonar for the Measurement of Echoes 7 Doppler Sonar for the Measurement of Ice Drift 8 Other Data 9 Data Processing 11 Ice Draft from Echo Range and Pressure 11 Common Challenges in the Processing of Range Data from the IPS 12 Identifying Ice-free Waters 12 Loss of Echoes 12 Spurious Echoes 12 Wind Waves in Leads 12 Ice Displacement from Doppler Tracking 13 Common Challenges in the Processing of Ice-drift Data from the ADCP 14 Signal Degradation in Ice-free Waters 14 Signal Degradation under Stationary Smooth Ice 14 Preparation of Pseudo-spatial Series of Ice Draft 14 Uncertainty in Calibration 16 Ice Draft 16 Ice Drift 17 Ice Draft Time Series for the World Data Centre A Glaciology 18 Monthly Summaries of Time-series Data (1990-1999) 20 Mean Drift Speed 20 Mean Ice Draft 20 Percentiles of Ice Draft 21 References 23