1928 research outputs found
Sort by
Characteristics of hydrogen/oxygen isotopes in water masses and implications for spatial distribution of freshwater in the Amundsen Sea, Southern Ocean
Full text linkAntarctica’s marginal seas are of great importance to atmosphere–ocean–ice interactions and are sensitive to global climate change. Multiple factors account for the freshwater budget in these regions, including glacier melting, seasonal formation/decay of sea ice, and precipitation. Hydrogen (H) and oxygen (O) isotopes represent useful proxies for determining the distribution and migration of water masses. We analyzed the H and O isotopic compositions of 190 seawater samples collected from the Amundsen Sea during the 34th Chinese Antarctic Research Expedition in 2017/2018. The upper-oceanic structure (3%) of freshwater generally lie in the upper ~50 m and extend from Antarctica to ~65°S in the meridional direction (anomalously low freshwater proportion occurred between 68°S and 71°S). Winter Water mainly occupied the layer between 50 and 150 m south of 71°S in the western Amundsen Sea. The water structure and spatial distribution of freshwater in the upper Amundsen Sea were found influenced mainly by the rates of basal and surficial melting of ice shelves, seasonal alternation of sea ice melt/formation, wind forcing, and regional bathymetry. Owing to the distance between heavy sea ice boundary (HSIB) and ice shelves is much shorter in the western HSIB than the east HSIB, the western part of the heavy sea ice boundary includes a higher proportion of freshwater than the eastern region. This study, which highlighted the distribution and extent of freshwater derived from ice (ice shelves and sea ice) melt, provides important evidence that the offshore drift pathway of cold and fresh Antarctic continental shelf water is likely interrupted by upwelled UCDW in the Amundsen Sea
Tensile strength of sea ice using splitting tests based on the digital image correlation method
Full text linkThe splitting test is a competitive alternative method to study the tensile strength of sea ice owing to its suitability for sampling. However, the approach was questioned to the neglect of local plastic deformation during the tests. In this study, splitting tests were performed on sea ice, with 32 samples subjected to the regular procedure and 8 samples subjected to the digital image correlation method. The salinity, density, and temperature were measured to determine the total porosity. With the advantage of the digital image correlation method, the full-field deformation of the ice samples could be determined. In the loading direction, the samples mainly deformed at the ice–platen contact area. In the direction vertical to the loading, deformation appears along the central line where the splitting crack occurs. Based on the distribution of the sample deformation, a modified solution was derived to calculate the tensile strength with the maximum load. Based on the modified solution, the tensile strength was further calculated together with the splitting test results. The results show that the tensile strength has a negative correlation with the total porosity, which agrees with previous studies based on uniaxial tension tests
3rd Arctic Science Ministerial Report - Knowledge for a Sustainable Arctic
Full text linkTo strengthen international cooperation and respond to the severe threat of climate change and biodiversity loss in the Arctic, the Icelandic Ministry of Education, Science and Culture and the Japanese Ministry of Education, Culture, Sports, Science and Technology co-organized the 3rd Arctic Science Ministerial (ASM3) which was held in Tokyo on 08-09 May 2021.
Delegates from 27 different countries and the European Commission, as well as representatives from Arctic Indigenous Peoples’ Organizations, gathered in Tokyo and online to discuss developments in international research and commit to future cooperation. This meeting was built on the themes initiated by the first Arctic Science Ministerial hosted by the United States and held in Washington, D.C. in 2016, and the second Arctic Science Ministerial co-hosted by the European Commission, Finland and Germany and held in Berlin in 2018.
Knowledge for a Sustainable Arctic was the overarching theme for ASM3 and included four sub-themes under the titles: Observe, Understand, Respond, Strengthen. These reflect elements of the previous ASM themes and reintroduce an emphasis on education which appeared in the first Ministerial
The White/Wiphala Paper on Indigenous Peoples’ food systems
Full text linkOur life depends on nature and we contribute to nature through nurturing. This symbiotic relationship is something all of us are beginning to understand more and more.
Since millennia, Indigenous Peoples have been protecting their environment and biodiversity. Today scientists are telling us that 80 percent of the remaining world’s biodiversity is in our lands and territories. We didn’t know this. Our ancestors did not know about biodiversity, ecology, ecosystem services or CO2 trapping, but they knew that protecting the ecosystems, environment and biodiversity were essential for our wellbeing and sustainability. Our elders, mothers and fathers taught us this as a way to exhibit good behaviour in the community
Traditional Arctic native fish storage methods and their role in the sustainable development of the Arctic
Full text linkThe business of the Arctic has received increased attention owing to climate change. However, resource development and the use of waterways threaten the fragile Arctic ecology. The indigenous people of the Arctic have acquired a vast amount of traditional knowledge about coexisting in harmony with nature over the course of many years. Herein, five types of fish storage facilities that are commonly used by Arctic indigenous people and their working mechanisms are described. The traditional knowledge of the Arctic indigenous people is practically applied in Arctic fish storage systems, which are still common, effective, and environmentally friendly. The traditional fish storage facilities of the aborigines are of significance because they promote the sustainable development of the Arctic
Modelling on seasonal lake ice evolution in central Asian arid climate zone: a case study
Full text linkThe seasonal cycle of ice thickness and temperature in Lake Wuliangsuhai, a typical shallow lake in the central Asian arid climate zone, was simulated using the HIGHTSI model and the MERRA-2 data as the meteorological forcing. The average ice growth rate was 0.64 cm·d−1 and −1.65 cm·d−1 for the growth and melting stage of the ice cover, respectively. The ice thickness agreed well with the field observations conducted in winter 2017, with a correlation coefficient of 0.97. The ice temperature field also agreed with observations in both daily variations and the vertical profile, and a better agreement in the daily amplitude and profile shape of ice temperature could be achieved if field data on physical properties of snow cover and melting ice were available. This study proved the feasibility of both the HIGHTSI model and the MERRA-2 data for modeling the ice cover evolution in Lake Wuliangsuhai, providing a basis for a deep insight into the difference of lake ice evolution between central Asian arid climate zone and polar/sub-polar regions
Agreement to prevent unregulated high seas fisheries in the Central Arctic Ocean
Full text linkThis Agreement aims to prevent unregulated commercial fishing in the high seas portion (waters that are not under the jurisdiction of any country) of the Central Arctic Ocean by implementing precautionary conservation and management measures. It establishes a regional regulatory regime in line with the 1995 UN Fish Stocks Agreement and the Convention on the Law of the Sea. The Parties to this Agreement agree not to engage in commercial fishing activities in the high seas portion of the Central Arctic Ocean for an initial period of 16 years after the agreement enters into force. This period can be extended automatically every 5 years, unless one party objects. The Parties can only authorise vessels registered in their country to carry out commercial fishing if they follow: Internationally recognised conservation and management measures for the sustainable management of fish stocks adopted by one or more regional or subregional fisheries management organisation(s) or arrangement(s); or interim conservation and management measures that may be established by the Parties. The agreement is precautionary — until recently, ice has covered the high seas portion of the Central Arctic Ocean all year round, making fishing in those waters impossible. However, global warming has significantly reduced ice coverage, which may open up this area to fishing in the future. A review of the Agreement and of the scientific information obtained through the joint programme will take place at least every 2 years. Conservation and management measures for exploratory fishing in the area will be established within 3 years of the Agreement coming into force. There shall be compatibility between Parties' management and conservation measures efforts in line with the 1995 Straddling Fish Stocks Agreement
Towards an integrated study of subglacial conditions in Princess Elizabeth Land, East Antarctica
Full text linkRetrievals of Arctic sea ice melt pond depth and underlying ice thickness using optical data
Full text linkMelt pond is a distinctive characteristic of the summer Arctic, which affects energy balance in the Arctic system. The Delta-Eddington model (BL) and Two-strEam rAdiative transfer model (TEA) are employed to retrieving pond depth Hp and underlying ice thickness Hi according to the ratio X of the melt-pond albedo in two bands. Results showed that when λ1 = 359 nm and λ2 = 605 nm, the Pearson’s correlation coefficient r between X and Hp is 0.99 for the BL model. The result of TEA model was similar to the BL model. The retrievals of Hp for the two models agreed well with field observations. For Hi, the highest r (0.99) was obtained when λ1 = 447 nm and λ2 = 470 nm for the BL model, λ1 = 447 nm and λ2 = 451 nm for the TEA model. Furthermore, the BL model was more suitable for the retrieval of thick ice (0 < Hi < 3.5 m, R2 = 0.632), while the TEA model is on the contrary (Hi < 1 m, R2 = 0.842). The present results provide a potential method for the remote sensing on melt pond and ice in the Arctic summer
Marine biogenic aerosols and their effects on aerosol-cloud interactions over the Southern Ocean: a review
Full text linkThe Southern Ocean (SO) plays an important role in the global climate system. Changes in SO biogeochemistry and marine ecosystems may influence the distribution of atmospheric aerosols and clouds and impact the climate system. We reviewed current knowledge on the interactions between marine aerosols and clouds over the SO. We focused on marine primary and secondary organic aerosols and summarized their characteristics, processes and roles as cloud condensation nuclei and ice nuclei. We described in detail the interactions between the marine ecosystem, aerosols and clouds. We discussed marine productivity, formation of marine biogenic aerosols and interactions between aerosols, clouds and climate. We explored the impact of climate change on SO marine ecosystem productivity and aerosol–cloud–climate feedback. Marine biogenic aerosols could impact the radiation budget and oceanic low-level clouds over the SO. This study contributes towards an improved understanding of marine productivity, aerosol-cloud interactions and climate change in the SO. The SO may respond to climate change in varying degrees. More studies are urgently needed to support accurate forecasts of future changes in the SO