Analysis of Iceberg Frequency in Labrador Sea Using Aerial Reconnaissance Flight Surveys and Satellite Radar Data

Abstract

Recently Nalcor announced the discovery of three newly defined hydrocarbon basins located primarily in deep water in the Labrador Sea, off the east coast of Newfoundland and Labrador, Canada. The basins are Henley, Chidley and Holton Basins and expanded the extent of the Hawke Basin. On behalf of Nalcor Energy, C-CORE recently completed the Offshore Newfoundland and Labrador Metocean Study which summarizes environmental conditions of these regions to support offshore petroleum exploration and development in the Labrador Sea and to outline the resource potential to the global oil and gas industry. Defining iceberg densities was one of the required tasks for the study. Among various environmental conditions, iceberg density is one of the most challenging parameter to define accurately both spatially and temporally. Aerial iceberg reconnaissance flight surveys provided by IIP (International Ice Patrol) and CIS (Canadian Ice Service) were studied, classified and analyzed to compute iceberg density (number of icebergs per square km). Only open water icebergs were considered for analysis because of the difficulty associated with reliably identifying icebergs in pack ice, which may lead to an underestimation of iceberg occurrence. Therefore, aerial reconnaissance data were compared with CIS pack ice charts to eliminate any possibility of iceberg sightings in pack ice being included in the analysis. Satellite radar data acquired using Envisat wide swath mode (WSM) imagery was also used for iceberg detections in order to provide full coverage of the study area. Again, sea ice was outlined in the imagery to ensure no targets in sea ice were counted. The WSM imagery provided a 400 km wide swath with an approximate radar resolution of 150 m, meaning smaller targets were not detected. In order to combine satellite radar data with aerial reconnaissance surveys a non-detection factor was calculated using a comparison of concurrent Envisat and aerial coverage to compensate for missed targets due to the coarser radar resolution. The resulting map of open water iceberg densities will provide a baseline for the region which shall be further refined through an on-going program using high-resolution Sentinel satellite data. Detailed descriptions of the analysis, procedures and results are presented in this paper. Areal density results of the newly defined basins are compared to the other frontier regions, where iceberg risks are higher.