Multiyear variations in the iceberg amount derived from the dataset were related to the Southern Oscillation Index (SOI) to establish their possible link to El Niño/Southern Oscillation (ENSO) events. In this study we have focused on the Atlantic and Indian ocean sectors of Antarctica where the statistics of available iceberg observations from ships is most extensive. Earlier analysis of this dataset allowed for an improved characterization of the iceberg distribution in a number of regions of Antarctica. This work concentrated primarily on digitizing and quality control of observation records from ship ice logbooks stored at the Arctic and Antarctic Research Institute (AARI), but also involved collection and processing of other available iceberg observation data.
In the last several years we have made an effort to establish the most comprehensive dataset of ship-borne observations of icebergs in Antarctica. As a result earlier studies of iceberg occurrence in Antarctica were based only on limited datasets.
The difficulty in using these data consists in the fact that no standard method of observation and report format have been adopted, the data collection is not centralized, and a large number of reports are still available only as paper records.
GOOGLE MAPS ANOMALY ICEBERG MANUAL
Manual and radar observations from ships present the primary source of information on the distribution of smaller icebergs. Neither of these two latter approaches was able to provide information on the iceberg distribution, concentration and long-term variability. through model simulation of iceberg formation and their subsequent drift and decay. Attempt to establish general patterns of iceberg drifting tracks in Antarctica has been made by Gladstone et al. tagged and monitored individual icebergs to determine prevalent iceberg tracks in Weddell Sea. Smaller icebergs comprise more than 90% of all icebergs, however they are missing in these studies because of inadequate spatial resolution of satellite data. A similar satellite-based approach to locate and track large Antarctic iceberg has been implemented at Brigham Young University. At the National Ice Center (NIC) of National Atmospheric and Oceanic Administration (NOAA) satellite imagery is applied to routinely track icebergs with a size of 10 nautical miles (n mi) and over (see ). During the last three decades satellite observations have been actively used for monitoring of very large Antarctic icebergs. Ocean currents, sea ice and, to a lesser extent, winds determine the iceberg drift, thus information on the iceberg distribution and concentration can help better understand the ocean and atmospheric circulation in the polar region. Safety of navigation as well as the icebergs' effect on the thermohaline structure and on the heat and fresh water balance of the ocean, stimulate studies of iceberg movement and distribution. Having calved off the margin of ice shelves, glacier tongues or ice cliffs at the coast of Antarctica, they drift both along and off the coast line while gradually melting and fracturing. Icebergs present a distinctive feature of the Southern Ocean. The latter is caused by anomalous surface pressure High and associated anti-clockwise circulation around the pressure anomaly developing in the south-eastern part of Pacific Ocean during the negative phase of ENSO. The change in the iceberg amount is explained by an increased iceberg drift into this region from the southern part of Weddell Sea and from Pacific Ocean. The strongest ENSO effect was observed in the region east of Drake Passage where the iceberg concentration increased by about 50% during years of the negative Southern Oscillation Index (SOI) phase.
Several regions in the Atlantic and Indian Ocean sector of Antarctica have been identified where yearly anomalies of the iceberg occurrence exhibit a noticeable correlation with El Niňo/Southern Oscillation (ENSO) events. Large concentration of icebergs was found in the Weddell Sea and north-east of the Antarctic Peninsula. The analysis of the data has revealed a gradual decrease in the iceberg concentration away from the coast of Antarctica and a substantial variation along the coast line. The collected dataset includes more than 40,000 reports predominantly from Russian and Australian research vessels made over the last 36 years (1970–2005). The spatial distribution and multiyear variability of iceberg concentration in the Atlantic and Indian ocean sectors of the Antarctic region have been studied using ship-borne observations of iceberg occurrence.