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Precision, accuracy, and temporal resolution are key to making full use of atmospheric trace gas records in ice cores. These aspects will become especially crucial for ice cores that aim to extend the ice core record to the last 1.5?Myr, i.e., across the Mid-Pleistocene Transition…
This Summary for Policymakers uses information and infographics from the research articles, updated with other more recent research articles, to provide the following information: 1.
Seven passive acoustic surveys for marine mammal sounds were conducted by deploying sonobuoys along ship tracks during Antarctic voyages spanning years 2006-2021. These surveys included nearly 330° of longitude throughout Antarctic (south of 60°S) and sub-Antarctic (between 50-60°S) latitudes. Here…
Sub-Antarctic islands and Antarctic coastal regions provide valuable sites for investigating environmental processes in the Southern Ocean.
Net sea-ice extent (SIE) and sea-ice area (SIA) were well below or at record-low levels for all of 2022 (based on satellite passive-microwave ice concentration data since 1979 when the near-homogenous satellite record began; Cavalieri et al. 1996). Indeed…
Net sea ice areal extent was well above average during the first few months of 2015 (Fig. 6.8a). Monthly record extents were observed in January (7.46 × 106 km2), April (9.06 × 106 km2), and May (12.1 × 106 km2).
The spreading of dense shelf water (DSW) from Antarctic coastal margins to lower latitudes plays a vital role in the ocean thermohaline circulation and the global climate system. Through enhanced localized sea ice production in Antarctic coastal polynyas…
Contrasting regional changes in Southern Ocean sea ice have occurred over the last 30 years with distinct regional effects on ecosystem structure and function.
Investigating ecological relationships between predators and their environment is essential to understand the response of marine ecosystems to climate variability and change. This is particularly true in polar regions, where sea ice (a sensitive climate variable)…
Deriving the snow depth on Antarctic sea ice is a key factor in estimating sea-ice thickness distributions from space or airborne altimeters. Using a linear regression to model snow depth from observed 'total freeboard'…
In 2012, Antarctic sea-ice coverage was marked by weak annual-mean climate anomalies that consisted of opposing anomalies early and late in the year (some setting new records) which were interspersed by near-average conditions for most of the austral autumn and winter. Here…
Snow on Antarctic sea ice plays a complex and highly variable role in air-sea-ice interaction processes and the Earth's climate system. Using data collected mostly during the past 10 years, this paper reviews the following topics:
In late winter-early spring 2012, the second Sea Ice Physics and Ecosystems Experiment (SIPEX II) was conducted off Wilkes Land, East Antarctica, onboard R/V Aurora Australis. The sea-ice conditions were characterized by significantly thick first-year ice and snow…
During 2021, and following on from 2020, net Antarctic sea ice coverage continued to exhibit strong variability (Fig. 6.11a), with distinct regional and seasonal contributions (Fig. 6.11b). The year began with below-average overall sea ice extent (SIE) in January through February (Fig. 6.11a)…
Blue whale populations each produce distinctive repeated songs that are stable over periods of decades, and can be used to identify where each population resides and moves. In the Southern Hemisphere and northern Indian Ocean, there are at least seven distinct populations based on their songs…
Individual life-history traits, such as age and sex, influence vital rates in most large vertebrate species. Developmental differences are especially profound in polygamous mating systems. One of the most polygamous of all mammals, the southern elephant seal (Mirounga leonina)…
Estimates of the distribution and density of Antarctic krill (Euphausia superba Dana, 1850) were derived from a large-scale survey conducted during the austral summer in the Southwest Atlantic sector of the Southern Ocean and across the Scotia Sea in 2018–19, the '2018–19 Area 48 Survey'.
During late March to early April 2019, the annual random stratified trawl survey (RSTS) around Heard Island and McDonald Islands (HIMI) was conducted in CCAMLR Division 58.5.2, with the completion of 150 stations. The survey was conducted on the FV Atlas Cove.
Catch rates or catch per unit of effort (CPUE) are used for data-poor exploratory fisheries without integrated assessments in the CPUE by seabed area method to estimate stock biomass in the interim of collecting sufficient tag recaptures. Here, we address the two questions: (1)…
In this paper, we report on fish by-catch during exploratory fishing activities undertaken in Divisions 58.4.1 and 58.4.2 during the period 2014 to 2020. Fish by-catch comprised 12 species or groups of species. In 2019 and 2020, exploratory fishing occurred exclusively in research block 58.4.
Recommendations … (1) That this research plan with a revised sampling design within six existing research blocks in Division 58.4.1 and one existing research block in Division 58.4.2 be adopted. (2) If directed fishing was not allowed in Division 58.4.1 in 2021/22…
In this paper, we report on fish bycatch during exploratory fishing activities undertaken in Divisions 58.4.1 and 58.4.2 during the period 2016 to 2022. Fish bycatch was composed of at least 14 species or species groups. In 2021 and 2022, exploratory fishing occurred in Division 58.4.2 only…
Exploratory fishing for Antarctic toothfish (Dissostichus mawsoni) in East Antarctica (Divisions 58.4.1 and 58.4.2) began in 2003. Since 2017/18, exploratory fishing has been conducted under successive research plans by Australia, France, Japan, Republic of Korea and Spain. Here…
Exploratory fishing for Antarctic toothfish (Dissostichus mawsoni) in East Antarctica (Divisions 58.4.1 and 58.4.2) began in 2003. While preliminary integrated stock assessments have been developed for these Divisions…
The zonal wavenumber spectrum of planetary waves in the atmosphere above Antarctica was studied in two contrasting years: in 2019 when there was a sudden stratospheric warming (SSW), and in 2020 when the Antarctic stratospheric vortex was unusually strong and long-lived.