1
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Application of the Doppler Spectrum of the Backscattering Microwave Signal for Monitoring of Ice Cover: A Theoretical View. REMOTE SENSING 2022. [DOI: 10.3390/rs14102331] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In the radar remote sensing of sea ice, the main informative parameter is the backscattering radar cross section (RCS), which does not always make it possible to unambiguously determine the kind of scattering surface (ice/sea waves) and therefore leads to errors in estimating the area of the ice cover. This paper provides a discussion of the possibility of using the Doppler spectrum of the reflected microwave signal to solve this problem. For the first time, a semi-empirical model of the Doppler spectrum of a radar microwave signal reflected by an ice cover was developed for a radar with a wide antenna beam mounted on a moving carrier at small incidence angles of electromagnetic waves (0°–19°). To describe the Doppler spectrum of the reflected microwave signal, the following parameters were used: shift and width of the Doppler spectrum, as well as skewness and kurtosis coefficients. Research was conducted on the influence of the main parameters of the measurement scheme (movement velocity, width of antenna beam, sounding direction, incidence angle) and the sea ice concentration (SIC) on the parameters of the Doppler spectrum. It was shown that, in order to determine the kind of scattering surface, it is necessary to use a wide or knife-like (by the incidence angle) antenna. Calculations confirmed the assumption that, when measured from a moving carrier, the Doppler spectrum is a reliable indicator of the transition from one kind of scattering surface to another. The advantage of using the coefficients of skewness and kurtosis in the analysis is that it is not necessary to keep the radar velocity unchanged during the measurement process.
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2
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Climate drives long-term change in Antarctic Silverfish along the western Antarctic Peninsula. Commun Biol 2022; 5:104. [PMID: 35115634 PMCID: PMC8813954 DOI: 10.1038/s42003-022-03042-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 12/21/2021] [Indexed: 11/08/2022] Open
Abstract
Over the last half of the 20th century, the western Antarctic Peninsula has been one of the most rapidly warming regions on Earth, leading to substantial reductions in regional sea ice coverage. These changes are modulated by atmospheric forcing, including the Amundsen Sea Low (ASL) pressure system. We utilized a novel 25-year (1993-2017) time series to model the effects of environmental variability on larvae of a keystone species, the Antarctic Silverfish (Pleuragramma antarctica). Antarctic Silverfish use sea ice as spawning habitat and are important prey for penguins and other predators. We show that warmer sea surface temperature and decreased sea ice are associated with reduced larval abundance. Variability in the ASL modulates both sea surface temperature and sea ice; a strong ASL is associated with reduced larvae. These findings support a narrow sea ice and temperature tolerance for adult and larval fish. Further regional warming predicted to occur during the 21st century could displace populations of Antarctic Silverfish, altering this pelagic ecosystem.
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3
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Comparison of Hemispheric and Regional Sea Ice Extent and Area Trends from NOAA and NASA Passive Microwave-Derived Climate Records. REMOTE SENSING 2022. [DOI: 10.3390/rs14030619] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Three passive microwave-based sea ice products archived at the National Snow and Ice Data Center (NSIDC) are compared: (1) the NASA Team (NT) algorithm product, (2) Bootstrap (BT) algorithm product, and (3) a new version (Version 4) of the NOAA/NSIDC Climate Data Record (CDR) product. Most notable for the CDR Version 4 is the addition of the early passive microwave record, 1979 to 1987. The focus of this study is on long-term trends in monthly extent and area. In addition to hemispheric trends, regional analysis is also carried out, including use of a new Northern Hemisphere regional mask. The results indicate overall good consistency between the products, with all three products showing strong statistically significant negative trends in the Arctic and small borderline significant positive trends in the Antarctic. Regionally, the patterns are similar, except for a notable outlier of the NT area having a steeper trend in the Central Arctic, likely related to increasing surface melt. Other differences are due to varied approaches to quality control, e.g., weather filtering and correction of mixed land-ocean grid cells. Another factor, particularly in regards to NT trends with BT or CDR, is the inter-sensor calibration approach, which yields small discontinuities between the products. These varied approaches yield small differences in trends. In the Arctic, such differences are not critical, but in the Antarctic, where overall trends are near zero and borderline statistically significant, the differences are potentially important in the interpretation of trends.
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4
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Yu L, Leng G, Python A. Varying response of vegetation to sea ice dynamics over the Arctic. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 799:149378. [PMID: 34352465 DOI: 10.1016/j.scitotenv.2021.149378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Revised: 07/26/2021] [Accepted: 07/27/2021] [Indexed: 06/13/2023]
Abstract
Recent reduction of sea ice may have contributed to vegetation growth over the Arctic through albedo feedback effects to atmospheric warming. Understanding the varying response of vegetation to sea ice dynamics is critical for predicting future climate change over the Arctic and middle-high latitudes. Instead of looking at the direct response characteristics, we perform a systematic analysis of the time-lag and time-cumulation responses of vegetation to sea ice dynamics, using a long-term Arctic Normalized Difference Vegetation Index (NDVI) dataset and three sea ice indices (sea ice concentration (SIC), sea ice area (SIA) and sea ice extent (SIE)) from 1982 to 2015. The results show that annual NDVI in the Arctic has exhibited a significant (p < 0.05) increase during 1982 to 2015, while a significant (p < 0.05) decrease is detected for annual SIC, SIA and SIE. The results of a regression analysis on NDVI identify a lag time of 7-months, 8-months and 9-months for vegetation response to SIC, SIA and SIE in February, March and April, respectively, while no evident lag response is observed in summer except for August. For the cumulation response, NDVI in February, March and April shows the largest response to the previous 5, 7 and 9 months of sea ice variations, respectively, while a short cumulation response of 1 to 3 months is found in summer. The differences in the spatial patterns of lagged time are usually not statistically significant in autumn and winter. A shorter lag response (1-3 month) is found in the Yamalia region in June. Further analysis suggests that vegetation response to sea ice dynamics depends on bio - climatic characteristics and soil pH, with vegetation responding faster to sea ice changes in acidic soil. This study provides observational evidences on the varying response of vegetation to sea ice dynamics over the Arctic, which has great implications for predicting vegetation-climate feedback and climate change.
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Affiliation(s)
- Linfei Yu
- Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Science and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guoyong Leng
- Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Science and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Andre Python
- Center for Data Science, Zhejiang University, Hangzhou 310058, China; Big Data Institute, University of Oxford, Oxford OX3 7LF, UK
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5
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Using correlative and mechanistic niche models to assess the sensitivity of the Antarctic echinoid Sterechinus neumayeri to climate change. Polar Biol 2021. [DOI: 10.1007/s00300-021-02886-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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6
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Hillebrand FL, Bremer UF, de Freitas MWD, Costi J, Mendes Júnior CW, Arigony-Neto J, Simões JC, da Rosa CN, de Jesus JB. Statistical modeling of sea ice concentration in the northwest region of the Antarctic Peninsula. ENVIRONMENTAL MONITORING AND ASSESSMENT 2021; 193:74. [PMID: 33469714 DOI: 10.1007/s10661-021-08843-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 01/04/2021] [Indexed: 06/12/2023]
Abstract
Sea ice is one of the main components of the cryosphere that modifies the exchange of heat and moisture between the ocean and atmosphere, regulating the global climate. In this sense, it is important to identify the concentration of sea ice in different regions of Antarctica in order to measure the impact of environmental changes on the region's ecosystem. The objective of this study was to evaluate the performance of the multiple linear regression and Box-Jenkins methods for predicting the concentration of sea ice along the northwest coast of the Antarctic Peninsula. Sea ice concentration data from May to November for the period 1979-2018 were extracted from passive remote sensors including a scanning multichannel microwave radiometer, special sensor microwave imager, and special sensor microwave imager/sounder. Meteorological variables from the atmospheric reanalysis model ERA5 of the European Center for Medium-Range Weather Forecasts were used as predictor variables, and the leave-one-out cross-validation technique was used to calibrate and validate the models. It was found that both statistical models have similar performance when analyzing residual analysis results, root mean square error of cross-validation, and final accuracy and residual standard deviation, these responses being related to the regionalization of the study area and to the Box-Jenkins presents strong, homogeneous, and stable correlations in the time series modeled for each pixel.
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Affiliation(s)
- Fernando Luis Hillebrand
- Programa de Pós-Graduação em Sensoriamento Remoto, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
- Centro Polar e Climático, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
| | - Ulisses Franz Bremer
- Programa de Pós-Graduação em Sensoriamento Remoto, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
- Centro Polar e Climático, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Marcos Wellausen Dias de Freitas
- Programa de Pós-Graduação em Sensoriamento Remoto, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
- Instituto de Geociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Juliana Costi
- Programa de Pós-Graduação em Modelagem Computacional, Universidade Federal do Rio Grande, Rio Grande, Brazil
| | - Cláudio Wilson Mendes Júnior
- Programa de Pós-Graduação em Sensoriamento Remoto, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
- Instituto de Geociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Jorge Arigony-Neto
- Instituto de Oceanografia, Universidade Federal do Rio Grande, Rio Grande, Brazil
| | - Jefferson Cardia Simões
- Centro Polar e Climático, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
- Climatic Change Institute, University of Maine, Orono, ME, USA
| | - Cristiano Niederauer da Rosa
- Programa de Pós-Graduação em Sensoriamento Remoto, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
- Centro Polar e Climático, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Janisson Batista de Jesus
- Programa de Pós-Graduação em Sensoriamento Remoto, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
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Kumar A, Yadav J, Mohan R. Global warming leading to alarming recession of the Arctic sea-ice cover: Insights from remote sensing observations and model reanalysis. Heliyon 2020; 6:e04355. [PMID: 32775711 PMCID: PMC7394866 DOI: 10.1016/j.heliyon.2020.e04355] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Revised: 03/16/2020] [Accepted: 06/24/2020] [Indexed: 11/28/2022] Open
Abstract
The present study quantifies the magnitude of Arctic sea-ice loss in the boreal summer (July–September), especially in September at different timescales (daily, monthly, annual and decadal). The investigation on the accelerated decline in the Arctic sea-ice was performed using different datasets of passive microwave satellite imagery and model reanalysis. Arctic sea-ice declined rapidly in the boreal summer (-10.2 ± 0.8 %decade−1) during 1979–2018, while, the highest decline in sea-ice extent (SIE) (i.e., 82,300 km2 yr−1/-12.8 ± 1.1 %decade−1) is reported in the month of September. Since late 1979, the SIE recorded the sixth-lowest decline during September 2018 (4.71 million km2). Incidentally, the records of twelve lowest extents in the satellite era occurred in the last twelve years. The loss of SIE and sea-ice concentration (SIC) are attributed to the impacts of land-ocean warming and the northward heat advection into the Arctic Ocean. This has resulted in considerable thinning of sea-ice thickness (SIT) and reduction in the multiyear ice (MYI) for summer 2018. Global and Arctic land-ocean temperatures have increased by ~0.78 °C and ~3.1 °C, respectively, over the past 40 years (1979–2018) while substantial warming rates have been identified in the Arctic Ocean (~3.5 °C in the last 40-year) relative to the Arctic land (~2.8 °C in the last 40-year). The prevailing ocean-atmospheric warming in the Arctic, the SIE, SIC and SIT have reduced, resulting in the decline of the sea-ice volume (SIV) at the rate of -3.0 ± 0.2 (1000 km3 decade−1). Further, it observed that the SIV in September 2018 was three times lower than September 1979. The present study demonstrates the linkages of sea-ice dynamics to ice drifting and accelerated melting due to persistent low pressure, high air-ocean temperatures, supplemented by the coupled ocean-atmospheric forcing.
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Affiliation(s)
- Avinash Kumar
- National Centre for Polar and Ocean Research (NCPOR), Ministry of Earth Science, Government of India, Vasco-da-Gama, Goa, India
| | - Juhi Yadav
- National Centre for Polar and Ocean Research (NCPOR), Ministry of Earth Science, Government of India, Vasco-da-Gama, Goa, India
| | - Rahul Mohan
- National Centre for Polar and Ocean Research (NCPOR), Ministry of Earth Science, Government of India, Vasco-da-Gama, Goa, India
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8
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Assessment of the Stability of Passive Microwave Brightness Temperatures for NASA Team Sea Ice Concentration Retrievals. REMOTE SENSING 2020. [DOI: 10.3390/rs12142197] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Gridded passive microwave brightness temperatures (TB) from special sensor microwave imager and sounder (SSMIS) instruments on three different satellite platforms are compared in different years to investigate the consistency between the sensors over time. The orbits of the three platforms have drifted over their years of operation, resulting in changing relative observing times that could cause biases in TB estimates and near-real-time sea ice concentrations derived from the NASA Team algorithm that are produced at the National Snow and Ice Data Center. Comparisons of TB histograms and concentrations show that there are small mean differences between sensors, but variability within an individual sensor is much greater. There are some indications of small changes due to orbital drift, but these are not consistent across different frequencies. Further, the overall effect of the drift, while not definitive, is small compared to the intra- and interannual variability in individual sensors. These results suggest that, for near-real-time use, the differences in the sensors are not critical. However, for long-term time series, even the small biases should be corrected for. The strong day-to-day, seasonal, and interannual variability in TB distributions indicate that time-varying algorithm coefficients in the NASA team algorithm would lead to improved, more consistent sea ice concentration estimates.
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9
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Abstract
Abstract
The development of the technologies of remote sensing of the ocean was initiated in the 1970s, while the ideas of observing the ocean from space were conceived in the late 1960s. The first global view from space revealed the expanse and complexity of the state of the ocean that had perplexed and inspired oceanographers ever since. This paper presents a glimpse of the vast progress made from ocean remote sensing in the past 50 years that has a profound impact on the ways we study the ocean in relation to weather and climate. The new view from space in conjunction with the deployment of an unprecedented amount of in situ observations of the ocean has led to a revolution in physical oceanography. The highlights of the achievement include the description and understanding of the global ocean circulation, the air–sea fluxes driving the coupled ocean–atmosphere system that is most prominently illustrated in the tropical oceans. The polar oceans are most sensitive to climate change with significant consequences, but owing to remoteness they were not accessible until the space age. Fundamental discoveries have been made on the evolution of the state of sea ice as well as the circulation of the ice-covered ocean. Many surprises emerged from the extraordinary accuracy and expanse of the space observations. Notable examples include the determination of the global mean sea level rise as well as the role of the deep ocean in tidal mixing and dissipation.
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10
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The Characteristics of Surface Albedo Change Trends over the Antarctic Sea Ice Region during Recent Decades. REMOTE SENSING 2019. [DOI: 10.3390/rs11070821] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Based on a long-time series (1982–2015) of remote sensing data, we analyzed the change in surface albedo (SAL) during summer (from December to the following February) for the entire Antarctic Sea Ice Region (ASIR) and five longitudinal sectors around Antarctica: (1). the Weddell Sea (WS), (2). Indian Ocean, (3). Pacific Ocean (PO), (4). Ross Sea, and (5). Bellingshausen–Amundsen Sea (BS). Empirical mode decomposition was used to extract the trend of the original signal, and then a slope test method was utilized to identify a transition point. The SAL provided by the CM SAF cloud, Albedo, and Surface Radiation dataset from AVHRR data-Second Edition was validated at Neumayer station. Sea ice concentration (SIC) and sea surface temperature (SST) were also analyzed. The trend of the SAL/SIC was positive during summer over the ASIR and five longitudinal sectors, except for the BS (−2.926% and −4.596% per decade for SAL and SIC, correspondingly). Moreover, the largest increasing trend of SAL and SIC appeared in the PO at approximately 3.781% and 3.358% per decade, respectively. However, the decreasing trend of SAL/SIC in the BS slowed down, and the increasing trend of SAL/SIC in the PO accelerated. The trend curves of the SST exhibited a crest around 2000–2005; thus, the slope lines of the SST showed an increasing–decreasing type for the ASIR and the five longitudinal sectors. The evolution of summer albedo decreased rapidly in the early summer and then maintained a relatively stable level for the whole ASIR. The change of it mainly depended on the early melt of sea ice during the entire summer. The change of sea ice albedo had a narrow range when compared with composite albedo and SIC over the five longitudinal sectors and reached a stable level earlier. The transition point of SAL/SIC in several sectors appeared around the year 2000, whereas that of the SST for the entire ASIR occurred in 2003–2005. A high value of SAL/SIC and a low value of the SST existed in the WS which can be displayed by the spatial distribution of pixel average. In addition, the lower the latitude was, the lower the SAL/SIC and the higher the SST would be. A transition point of SAL appeared in 2001 in most areas of West Antarctica. This transition point could be illustrated by anomaly maps. The spatial distribution of the pixel-based trend of SAL demonstrated that the change in SAL in East Antarctica has exhibited a positive trend in recent decades. However, in West Antarctica, the change of SAL presented a decreasing trend before 2001 and transformed into an increasing trend afterward, especially in the east of the Antarctic Peninsula.
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11
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Maksym T. Arctic and Antarctic Sea Ice Change: Contrasts, Commonalities, and Causes. ANNUAL REVIEW OF MARINE SCIENCE 2019; 11:187-213. [PMID: 30216739 DOI: 10.1146/annurev-marine-010816-060610] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Arctic sea ice has declined precipitously in both extent and thickness over the past four decades; by contrast, Antarctic sea ice has shown little overall change, but this masks large regional variability. Climate models have not captured these changes. But these differences do not represent a paradox. The processes governing, and impacts of, natural variability and human-induced changes differ markedly at the poles largely because of the ways in which differences in geography control the properties of and interactions among the atmosphere, ice, and ocean. The impact of natural variability on the ice cover is large at both poles, so modeled ice trends are not entirely inconsistent with contributions from both natural variability and anthropogenic forcing. Despite this concurrence, the coupling of natural climate variability, climate feedbacks, and sea ice is not well understood, and significant biases remain in model representations of the ice cover and the processes that drive it.
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Affiliation(s)
- Ted Maksym
- Department of Applied Ocean Physics and Engineering, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA;
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12
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Goldstein MA, Lynch AH, Zsom A, Arbetter T, Chang A, Fetterer F. The step-like evolution of Arctic open water. Sci Rep 2018; 8:16902. [PMID: 30442979 PMCID: PMC6237816 DOI: 10.1038/s41598-018-35064-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 10/31/2018] [Indexed: 11/09/2022] Open
Abstract
September open water fraction in the Arctic is analyzed using the satellite era record of ice concentration (1979-2017). Evidence is presented that three breakpoints (shifts in the mean) occurred in the Pacific sector, with higher amounts of open water starting in 1989, 2002, and 2007. Breakpoints in the Atlantic sector record of open water are evident in 1971 in longer records, and around 2000 and 2011. Multiple breakpoints are also evident in the Canadian and Russian halves. Statistical models that use detected breakpoints of the Pacific and Atlantic sectors, as well as models with breakpoints in the Canadian and Russian halves and the Arctic as a whole, outperform linear trend models in fitting the data. From a physical standpoint, the results support the thesis that Arctic sea ice may have critical points beyond which a return to the previous state is less likely. From an analysis standpoint, the findings imply that de-meaning the data using the breakpoint means is less likely to cause spurious signals than employing a linear detrend.
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Affiliation(s)
- Michael A Goldstein
- Climate Change Research Center, University of New South Wales, Sydney, NSW, 2052, Australia. .,Finance Division, Babson College, Babson Park, MA, 02457, USA.
| | - Amanda H Lynch
- Institute at Brown for Environment and Society, Brown University, Providence, RI, 02912, USA.,Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI, 02912, USA
| | - Andras Zsom
- Data Science Practice, Computing & Information Services, Brown University, Providence, RI, 02912, USA
| | - Todd Arbetter
- Institute at Brown for Environment and Society, Brown University, Providence, RI, 02912, USA
| | - Andres Chang
- Institute at Brown for Environment and Society, Brown University, Providence, RI, 02912, USA
| | - Florence Fetterer
- National Snow and Ice Data Center, Cooperative Institute for Research in the Environmental Sciences, University of Colorado, Boulder, CO, 80309, USA
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13
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Gaps Analysis and Requirements Specification for the Evolution of Copernicus System for Polar Regions Monitoring: Addressing the Challenges in the Horizon 2020–2030. REMOTE SENSING 2018. [DOI: 10.3390/rs10071098] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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14
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Shepherd A, Fricker HA, Farrell SL. Trends and connections across the Antarctic cryosphere. Nature 2018; 558:223-232. [DOI: 10.1038/s41586-018-0171-6] [Citation(s) in RCA: 101] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 03/21/2018] [Indexed: 11/09/2022]
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15
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Hegyi BM, Taylor PC. The unprecedented 2016-17 Arctic sea ice growth season: the crucial role of atmospheric rivers and longwave fluxes. GEOPHYSICAL RESEARCH LETTERS 2018; 45:5204-5212. [PMID: 33479551 PMCID: PMC7816819 DOI: 10.1029/2017gl076717] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 05/04/2018] [Indexed: 05/31/2023]
Abstract
The 2016-17 Arctic sea ice growth season (October-March) exhibited the lowest end-of-season sea ice volume and extent of any year since 1979. An analysis of MERRA2 atmospheric reanalysis data and CERES radiative flux data reveals that a record warm and moist Arctic atmosphere supported the reduced sea ice growth through two pathways. First, numerous regional episodes of increased atmospheric temperature and moisture, transported from lower latitudes, increased the cumulative energy input from downwelling longwave surface fluxes. Second, in those same episodes, the efficiency that the atmosphere cooled radiatively to space was reduced, increasing the amount of energy retained in the Arctic atmosphere and reradiated back toward the surface. Overall, the Arctic radiative cooling efficiency shows a decreasing trend since 2000. The results presented highlight the increasing importance of atmospheric forcing on sea ice variability demonstrating that episodic Arctic atmospheric rivers, regions of elevated poleward water vapor transport, and the subsequent surface energy budget response is a critical mechanism actively contributing to the evolution of Arctic sea ice.
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Affiliation(s)
- Bradley M. Hegyi
- NASA Langley Research Center, Climate Science Branch, Hampton, Virginia, USA
| | - Patrick C. Taylor
- NASA Langley Research Center, Climate Science Branch, Hampton, Virginia, USA
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16
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Sensitivity Analysis of Arctic Sea Ice Extent Trends and Statistical Projections Using Satellite Data. REMOTE SENSING 2018. [DOI: 10.3390/rs10020230] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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17
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Garcia-Eidell C, Comiso JC, Dinnat E, Brucker L. Satellite Observed Salinity Distributions at High Latitudes in the Northern Hemisphere: A Comparison of Four Products. JOURNAL OF GEOPHYSICAL RESEARCH. OCEANS 2017; 122:7717-7736. [PMID: 33101824 PMCID: PMC7580809 DOI: 10.1002/2017jc013184] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Global surface ocean salinity measurements have been available since the launch of SMOS in 2009 and coverage was further enhanced with the launch of Aquarius in 2011. In the polar regions where spatial and temporal changes in sea surface salinity (SSS) are deemed important, the data has not been as robustly validated because of the paucity of in situ measurements. This study presents a comparison of four SSS products in the ice-free Arctic region, three using Aquarius data and one using SMOS data. The accuracy of each product is assessed through comparative analysis with ship and other in situ measurements. Results indicate RMS errors ranging between 0.33 and 0.89 psu. Overall, the four products show generally good consistency in spatial distribution with the Atlantic side being more saline than the Pacific side. A good agreement between the ship and satellite measurements were also observed in the low salinity regions in the Arctic Ocean, where SSS in situ measurements are usually sparse, at the end of summer melt seasons. Some discrepancies including biases of about 1 psu between the products in spatial and temporal distribution are observed. These are due in part to differences in retrieval techniques, geophysical filtering, and sea ice and land masks. The monthly SSS retrievals in the Arctic from 2011 to 2015 showed variations (within ~1 psu) consistent with effects of sea ice seasonal cycles. This study indicates that spaceborne observations capture the seasonality and interannual variability of SSS in the Arctic with reasonably good accuracy.
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Affiliation(s)
- Cynthia Garcia-Eidell
- NASA Goddard Space Flight Center,Cryospheric Sciences Laboratory, Greenbelt, MD 20771, USA
- Wyle Science Technology and Engineering, 2400 NASA Parkway, Houston, TX 77058, USA
| | - Josefino C. Comiso
- NASA Goddard Space Flight Center,Cryospheric Sciences Laboratory, Greenbelt, MD 20771, USA
| | - Emmanuel Dinnat
- NASA Goddard Space Flight Center,Cryospheric Sciences Laboratory, Greenbelt, MD 20771, USA
- Center of Excellence in Earth Systems Modeling and Observation, Chapman University, Orange, CA 92866, USA
| | - Ludovic Brucker
- NASA Goddard Space Flight Center,Cryospheric Sciences Laboratory, Greenbelt, MD 20771, USA
- Universities Space Research Association, Goddard Earth Sciences Technology and Research Studies and Investigations, Columbia, MD 21044, USA
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18
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Comiso JC, Gersten RA, Stock LV, Turner J, Perez GJ, Cho K. Positive Trend in the Antarctic Sea Ice Cover and Associated Changes in Surface Temperature. JOURNAL OF CLIMATE 2017; 30:2251-2267. [PMID: 32699487 PMCID: PMC7375258 DOI: 10.1175/jcli-d-16-0408.1] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The Antarctic sea ice extent has been slowly increasing contrary to expected trends due to global warming and results from coupled climate models. After a record high extent in 2012 the extent was even higher in 2014 when the magnitude exceeded 20×106 km2 for the first time during the satellite era. The positive trend is confirmed with a newly reprocessed sea ice data that addressed inconsistency issues in the time series. The variability in sea ice extent and ice area was studied alongside surface ice temperature for the 34-year period starting 1981 and the result of the analysis show a strong correlation of -0.94 during the growth season and -0.86 during the melt season. The correlation coefficients are even stronger with a one-month lag in surface temperature at -0.96 during the growth season and -0.98 during the melt season suggesting that the trend in sea ice cover is strongly influenced by the trend in surface temperature. The correlation with atmospheric circulation as represented by the Southern Annular Mode (SAM) index appears to be relatively weak. A case study comparing the record high in 2014 with a relatively low ice extent in 2015 also shows strong sensitivity to changes in surface temperature. The results suggest that the positive trend is a consequence of the spatial variability of global trends in surface temperature and that the ability of current climate models to forecast sea ice trend can be improved through better performance in reproducing observed surface temperatures in the Antarctic region.
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Affiliation(s)
| | - Robert A Gersten
- Cryospheric Sciences Laboratory, NASA Goddard Space Flight Center
- Wyle Science Technology and Engineering
| | - Larry V Stock
- Cryospheric Sciences Laboratory, NASA Goddard Space Flight Center
- Stinger Graffarian Technologies (SGT)
| | | | - Gay J Perez
- Cryospheric Sciences Laboratory, NASA Goddard Space Flight Center
- University of the Philippines Diliman
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Dinnat EP, Brucker L. Improved Sea Ice Fraction Characterization for L-Band Observations by the Aquarius Radiometers. IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING : A PUBLICATION OF THE IEEE GEOSCIENCE AND REMOTE SENSING SOCIETY 2017; 55:1285-1304. [PMID: 32742050 PMCID: PMC7394339 DOI: 10.1109/tgrs.2016.2622011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Radiometers operating at L-band (1.4 GHz) are used to retrieve sea surface salinity over ice-free oceans and have been used recently to study the cryosphere. One hindrance of their use in the high latitudes is the preponderance of mixed scenes, where seawater and sea ice are both present in the sensor's field of view (FOV). Accurately characterizing the scene is crucial for oceanographic and cryospheric applications. To that end, a sea ice fraction model, composed of passive microwave sea ice concentration retrievals and an instrument simulator that integrates radiative power coming from all around the antenna, is used. We investigate the model currently used operationally to derive the ice fraction affecting the Aquarius observations and show that it can be significantly improved. On the one hand, the current model tends to overestimate sea ice fraction in the marginal ice zone where observations are used for salinity retrievals. On the other hand, the current model underestimates ice fraction within the ice pack where observations are used to derive sea ice properties. For the northern hemisphere, we also find evidence of the sea ice type impact on L-band radiometric observations. We present a model to derive sea ice fractions that are in better agreement with Aquarius radiometric observations using the Advanced Microwave Scanning Radiometer 2 Bootstrap algorithm for sea ice concentration and using high-resolution integration over the sensor's FOV.
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Affiliation(s)
- Emmanuel P Dinnat
- Cryospheric Sciences Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771 USA, and also with the Center of Excellence in Earth Systems Modeling and Observations, Chapman University, Orange, CA 92866 USA
| | - Ludovic Brucker
- Cryospheric Sciences Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771 USA, and also with the Universities Space Research Association, Goddard Earth Sciences Technology and Research Studies and Investigations, Columbia, MD 21044 USA
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Aksenov Y, Karcher M, Proshutinsky A, Gerdes R, de Cuevas B, Golubeva E, Kauker F, Nguyen AT, Platov GA, Wadley M, Watanabe E, Coward AC, Nurser AJG. Arctic pathways of Pacific Water: Arctic Ocean Model Intercomparison experiments. JOURNAL OF GEOPHYSICAL RESEARCH. OCEANS 2016; 121:27-59. [PMID: 27818853 PMCID: PMC5070528 DOI: 10.1002/2015jc011299] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Accepted: 10/13/2015] [Indexed: 06/01/2023]
Abstract
Pacific Water (PW) enters the Arctic Ocean through Bering Strait and brings in heat, fresh water, and nutrients from the northern Bering Sea. The circulation of PW in the central Arctic Ocean is only partially understood due to the lack of observations. In this paper, pathways of PW are investigated using simulations with six state-of-the art regional and global Ocean General Circulation Models (OGCMs). In the simulations, PW is tracked by a passive tracer, released in Bering Strait. Simulated PW spreads from the Bering Strait region in three major branches. One of them starts in the Barrow Canyon, bringing PW along the continental slope of Alaska into the Canadian Straits and then into Baffin Bay. The second begins in the vicinity of the Herald Canyon and transports PW along the continental slope of the East Siberian Sea into the Transpolar Drift, and then through Fram Strait and the Greenland Sea. The third branch begins near the Herald Shoal and the central Chukchi shelf and brings PW into the Beaufort Gyre. In the models, the wind, acting via Ekman pumping, drives the seasonal and interannual variability of PW in the Canadian Basin of the Arctic Ocean. The wind affects the simulated PW pathways by changing the vertical shear of the relative vorticity of the ocean flow in the Canada Basin.
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Affiliation(s)
| | | | | | | | | | - Elena Golubeva
- Institute of Computational Mathematics and Mathematical Geophysics, Siberian Branch of Russian Academy of Sciences Novosibirsk Russia; Department of Mathematics and Mechanics Novosibirsk State University Novosibirsk Russia
| | | | - An T Nguyen
- Massachusetts Institute of Technology Cambridge Massachusetts USA
| | - Gennady A Platov
- Institute of Computational Mathematics and Mathematical Geophysics, Siberian Branch of Russian Academy of Sciences Novosibirsk Russia; Department of Mathematics and Mechanics Novosibirsk State University Novosibirsk Russia
| | - Martin Wadley
- School of Mathematics University of East Anglia Norwich UK
| | - Eiji Watanabe
- Japan Agency for Marine-Earth Science and Technology Kanagawa Japan
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Gutt J, Alvaro MC, Barco A, Böhmer A, Bracher A, David B, De Ridder C, Dorschel B, Eléaume M, Janussen D, Kersken D, López-González PJ, Martínez-Baraldés I, Schröder M, Segelken-Voigt A, Teixidó N. Macroepibenthic communities at the tip of the Antarctic Peninsula, an ecological survey at different spatial scales. Polar Biol 2015. [DOI: 10.1007/s00300-015-1797-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Rogers AD, Yesson C, Gravestock P. A Biophysical and Economic Profile of South Georgia and the South Sandwich Islands as Potential Large-Scale Antarctic Protected Areas. ADVANCES IN MARINE BIOLOGY 2015; 70:1-286. [PMID: 26296718 DOI: 10.1016/bs.amb.2015.06.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The current hiatus in the establishment of a network of marine protected areas (MPAs) in the Antarctic means that other routes to conservation are required. The protection of overseas territories in the Antarctic and sub-Antarctic represents one way to advance the initiation of such a network. This review of the physical and biological features of the United Kingdom (U.K.) overseas territories of South Georgia and South Sandwich Islands (SGSSI) is undertaken to estimate the importance of the islands in terms of marine conservation in the Southern Ocean and globally. The economy and management of SGSSI are also analysed, and the question of whether the islands already have sufficient protection to constitute part of an Antarctic network of MPAs is assessed. The SGSSI comprise unique geological and physical features, a diverse marine biota, including a significant proportion of endemic species and globally important breeding populations of marine predators. Regardless of past exploitation of biotic resources, such as seals, whales and finfish, SGSSI would make a significant contribution to biological diversity in an Antarctic network of MPAs. At present, conservation measures do not adequately protect all of the biological features that render the islands so important in terms of conservation at a regional and global level. However, a general lack of data on Antarctic marine ecosystems (particularly needed for SGSSSI) makes it difficult to assess this fully. One barrier to achieving more complete protection is the continuing emphasis on fishing effort in these waters by U.K. government. Other non-U.K. Antarctic overseas territories of conservation importance are also compromised as MPAs because of the exploitation of fisheries resources in their waters. The possible non-use values of SGSSI as well as the importance of ecosystem services that are indirectly used by people are outlined in this review. Technology is improving the potential for management of remote MPAs, particularly in the context of incursion by illegal fishing activities and use of satellite surveillance for enforcement of fisheries and conservation regulations. The conflict between commercial exploitation and conservation of Antarctic marine living resources is explored.
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Affiliation(s)
- Alex D Rogers
- Department of Zoology, University of Oxford, Oxford, United Kingdom.
| | - Christopher Yesson
- Institute of Zoology, Zoological Society of London, London, United Kingdom
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Woolfe KF, Sabra KG. Variability of the coherent arrivals extracted from low-frequency deep-ocean ambient noise correlations. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2015; 138:521-532. [PMID: 26328669 DOI: 10.1121/1.4923447] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Correlation processing of ocean noise can be used to develop totally passive ocean monitoring methods. Using various hydrophone pair orientations, this study investigates the frequency dependence, seasonal variability, and emergence rate of coherent arrivals from cross-correlations of low frequency ambient noise (f < 40 Hz) recorded on triangular hydrophones arrays. These arrays are located at five existing hydroacoustic stations of the International Monitoring System (IMS), situated in the deep-sound channel, and distributed across the Atlantic, Pacific, and Indian Ocean basins. For the majority of studied sites, persistent and fast-emerging coherent arrivals are reliably obtained if the axis connecting the selected hydrophone pair has a direct line-of-sight with regions of the globe containing stable and diffuse noise sources (e.g., polar-ice or seismic noise). Furthermore, for this favorable orientation, the emergence rate of coherent arrivals extracted between hydrophone pairs separated by long ranges (here ∼130 km) can be approximated based on measurements made between hydrophone pairs separated by short ranges (∼2 km) in the Atlantic Ocean. Hence, results from this study, obtained using existing hydrophone configurations of the IMS hydroacoustic stations, could be used to guide the placement of other hydrophone arrays over the globe for future long-range passive ocean monitoring experiments.
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Affiliation(s)
- Katherine F Woolfe
- Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Karim G Sabra
- Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
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Turner J, Hosking JS, Bracegirdle TJ, Marshall GJ, Phillips T. Recent changes in Antarctic Sea Ice. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2015; 373:rsta.2014.0163. [PMID: 26032320 DOI: 10.1098/rsta.2014.0163] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
In contrast to the Arctic, total sea ice extent (SIE) across the Southern Ocean has increased since the late 1970s, with the annual mean increasing at a rate of 186×10(3) km(2) per decade (1.5% per decade; p<0.01) for 1979-2013. However, this overall increase masks larger regional variations, most notably an increase (decrease) over the Ross (Amundsen-Bellingshausen) Sea. Sea ice variability results from changes in atmospheric and oceanic conditions, although the former is thought to be more significant, since there is a high correlation between anomalies in the ice concentration and the near-surface wind field. The Southern Ocean SIE trend is dominated by the increase in the Ross Sea sector, where the SIE is significantly correlated with the depth of the Amundsen Sea Low (ASL), which has deepened since 1979. The depth of the ASL is influenced by a number of external factors, including tropical sea surface temperatures, but the low also has a large locally driven intrinsic variability, suggesting that SIE in these areas is especially variable. Many of the current generation of coupled climate models have difficulty in simulating sea ice. However, output from the better-performing IPCC CMIP5 models suggests that the recent increase in Antarctic SIE may be within the bounds of intrinsic/internal variability.
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Affiliation(s)
- John Turner
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET, UK
| | - J Scott Hosking
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET, UK
| | - Thomas J Bracegirdle
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET, UK
| | - Gareth J Marshall
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET, UK
| | - Tony Phillips
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET, UK
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Abrahamsen EP. Sustaining observations in the polar oceans. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2014; 372:rsta.2013.0337. [PMID: 25157189 PMCID: PMC4150293 DOI: 10.1098/rsta.2013.0337] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Polar oceans present a unique set of challenges to sustained observations. Sea ice cover restricts navigation for ships and autonomous measurement platforms alike, and icebergs present a hazard to instruments deployed in the upper ocean and in shelf seas. However, the important role of the poles in the global ocean circulation provides ample justification for sustained observations in these regions, both to monitor the rapid changes taking place, and to better understand climate processes in these traditionally poorly sampled areas. In the past, the vast majority of polar measurements took place in the summer. In recent years, novel techniques such as miniature CTD (conductivity-temperature-depth) tags carried by seals have provided an explosion in year-round measurements in areas largely inaccessible to ships, and, as ice avoidance is added to autonomous profiling floats and gliders, these promise to provide further enhancements to observing systems. In addition, remote sensing provides vital information about changes taking place in sea ice cover at both poles. To make these observations sustainable into the future, improved international coordination and collaboration is necessary to gain optimum utilization of observing networks.
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Affiliation(s)
- E P Abrahamsen
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET, UK
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Marshall J, Armour KC, Scott JR, Kostov Y, Hausmann U, Ferreira D, Shepherd TG, Bitz CM. The ocean's role in polar climate change: asymmetric Arctic and Antarctic responses to greenhouse gas and ozone forcing. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2014; 372:20130040. [PMID: 24891392 PMCID: PMC4032509 DOI: 10.1098/rsta.2013.0040] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In recent decades, the Arctic has been warming and sea ice disappearing. By contrast, the Southern Ocean around Antarctica has been (mainly) cooling and sea-ice extent growing. We argue here that interhemispheric asymmetries in the mean ocean circulation, with sinking in the northern North Atlantic and upwelling around Antarctica, strongly influence the sea-surface temperature (SST) response to anthropogenic greenhouse gas (GHG) forcing, accelerating warming in the Arctic while delaying it in the Antarctic. Furthermore, while the amplitude of GHG forcing has been similar at the poles, significant ozone depletion only occurs over Antarctica. We suggest that the initial response of SST around Antarctica to ozone depletion is one of cooling and only later adds to the GHG-induced warming trend as upwelling of sub-surface warm water associated with stronger surface westerlies impacts surface properties. We organize our discussion around 'climate response functions' (CRFs), i.e. the response of the climate to 'step' changes in anthropogenic forcing in which GHG and/or ozone-hole forcing is abruptly turned on and the transient response of the climate revealed and studied. Convolutions of known or postulated GHG and ozone-hole forcing functions with their respective CRFs then yield the transient forced SST response (implied by linear response theory), providing a context for discussion of the differing warming/cooling trends in the Arctic and Antarctic. We speculate that the period through which we are now passing may be one in which the delayed warming of SST associated with GHG forcing around Antarctica is largely cancelled by the cooling effects associated with the ozone hole. By mid-century, however, ozone-hole effects may instead be adding to GHG warming around Antarctica but with diminished amplitude as the ozone hole heals. The Arctic, meanwhile, responding to GHG forcing but in a manner amplified by ocean heat transport, may continue to warm at an accelerating rate.
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Affiliation(s)
- John Marshall
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Kyle C Armour
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Jeffery R Scott
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Yavor Kostov
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Ute Hausmann
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - David Ferreira
- Department of Meteorology, University of Reading, Reading, Berkshire, UK
| | | | - Cecilia M Bitz
- Department of Atmospheric Sciences, University of Washington, Seattle, WA, USA
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Statistical Modeling of Sea Ice Concentration Using Satellite Imagery and Climate Reanalysis Data in the Barents and Kara Seas, 1979–2012. REMOTE SENSING 2014. [DOI: 10.3390/rs6065520] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Comiso JC, Hall DK. Climate trends in the Arctic as observed from space. WILEY INTERDISCIPLINARY REVIEWS. CLIMATE CHANGE 2014; 5:389-409. [PMID: 25810765 PMCID: PMC4368101 DOI: 10.1002/wcc.277] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The Arctic is a region in transformation. Warming in the region has been amplified, as expected from ice-albedo feedback effects, with the rate of warming observed to be ∼0.60 ± 0.07°C/decade in the Arctic (>64°N) compared to ∼0.17°C/decade globally during the last three decades. This increase in surface temperature is manifested in all components of the cryosphere. In particular, the sea ice extent has been declining at the rate of ∼3.8%/decade, whereas the perennial ice (represented by summer ice minimum) is declining at a much greater rate of ∼11.5%/decade. Spring snow cover has also been observed to be declining by -2.12%/decade for the period 1967-2012. The Greenland ice sheet has been losing mass at the rate of ∼34.0 Gt/year (sea level equivalence of 0.09 mm/year) during the period from 1992 to 2011, but for the period 2002-2011, a higher rate of mass loss of ∼215 Gt/year has been observed. Also, the mass of glaciers worldwide declined at the rate of 226 Gt/year from 1971 to 2009 and 275 Gt/year from 1993 to 2009. Increases in permafrost temperature have also been measured in many parts of the Northern Hemisphere while a thickening of the active layer that overlies permafrost and a thinning of seasonally frozen ground has also been reported. To gain insight into these changes, comparative analysis with trends in clouds, albedo, and the Arctic Oscillation is also presented. How to cite this article:WIREs Clim Change 2014, 5:389�409. doi: 10.1002/wcc.277.
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A Satellite-Based Surface Radiation Climatology Derived by Combining Climate Data Records and Near-Real-Time Data. REMOTE SENSING 2013. [DOI: 10.3390/rs5094693] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Recent Declines in Warming and Vegetation Greening Trends over Pan-Arctic Tundra. REMOTE SENSING 2013. [DOI: 10.3390/rs5094229] [Citation(s) in RCA: 145] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Smith WO, Ainley DG, Arrigo KR, Dinniman MS. The oceanography and ecology of the Ross Sea. ANNUAL REVIEW OF MARINE SCIENCE 2013; 6:469-487. [PMID: 23987914 DOI: 10.1146/annurev-marine-010213-135114] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The continental shelf of the Ross Sea exhibits substantial variations in physical forcing, ice cover, and biological processes on a variety of time and space scales. Its circulation is characterized by advective inputs from the east and exchanges with off-shelf regions via the troughs along the northern portions. Phytoplankton biomass is greater there than anywhere else in the Antarctic, although nitrate is rarely reduced to levels below 10 μmol L(-1). Overall growth is regulated by irradiance (via ice at the surface and by the depths of the mixed layers) and iron concentrations. Apex predators reach exceptional abundances, and the world's largest colonies of Adélie and emperor penguins are found there. Krill are represented by two species (Euphausia superba near the shelf break and Euphausia crystallorophias throughout the continental shelf region). Equally important and poorly known is the Antarctic silverfish (Pleuragramma antarcticum), which is also consumed by most upper-trophic-level predators. Future changes in the Ross Sea environment will have profound and unpredictable effects on the food web.
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Affiliation(s)
- Walker O Smith
- Virginia Institute of Marine Science, College of William & Mary, Gloucester Point, Virginia 23062;
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Kurtz NT, Markus T. Satellite observations of Antarctic sea ice thickness and volume. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2012jc008141] [Citation(s) in RCA: 129] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Mårtensson S, Meier HEM, Pemberton P, Haapala J. Ridged sea ice characteristics in the Arctic from a coupled multicategory sea ice model. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2010jc006936] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Fogt RL, Wovrosh AJ, Langen RA, Simmonds I. The characteristic variability and connection to the underlying synoptic activity of the Amundsen-Bellingshausen Seas Low. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011jd017337] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Kinnard C, Zdanowicz CM, Fisher DA, Isaksson E, de Vernal A, Thompson LG. Reconstructed changes in Arctic sea ice over the past 1,450 years. Nature 2011; 479:509-12. [PMID: 22113692 DOI: 10.1038/nature10581] [Citation(s) in RCA: 242] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2010] [Accepted: 09/21/2011] [Indexed: 11/09/2022]
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Aoki T, Kuchiki K, Niwano M, Kodama Y, Hosaka M, Tanaka T. Physically based snow albedo model for calculating broadband albedos and the solar heating profile in snowpack for general circulation models. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010jd015507] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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38
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Comiso JC, Kwok R, Martin S, Gordon AL. Variability and trends in sea ice extent and ice production in the Ross Sea. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010jc006391] [Citation(s) in RCA: 110] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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39
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Smith WO, Comiso JC. Influence of sea ice on primary production in the Southern Ocean: A satellite perspective. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2007jc004251] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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