scholarly journals Temporal Means and Variability of Arctic Sea Ice Melt and Freeze Season Climate Indicators Using a Satellite Climate Data Record

2018 ◽  
Vol 10 (9) ◽  
pp. 1328 ◽  
Author(s):  
Ge Peng ◽  
Michael Steele ◽  
Angela Bliss ◽  
Walter Meier ◽  
Suzanne Dickinson
Keyword(s):  
Sea Ice ◽  
Arctic Sea Ice ◽  
Climate Data ◽  
Ice Melt ◽  
Climate Indicators ◽  
Arctic Sea ◽  
Data Record ◽  
Climate Data Record ◽  
Snow And Ice Melt ◽  
Snow And Ice

Information on the timing of Arctic snow and ice melt onset, sea ice opening, retreat, advance, and closing, can be beneficial to a variety of stakeholders. Sea ice modelers can use information on the evolution of the ice cover through the rest of the summer to improve their seasonal sea ice forecasts. The length of the open water season (as derived from retreat/advance dates) is important for human activities and for wildlife. Long-term averages and variability of these dates as climate indicators are beneficial to business strategic planning and climate monitoring. In this study, basic characteristics of temporal means and variability of Arctic sea ice climate indicators derived from a satellite-based climate data record from March 1979 to February 2017 melt and freeze seasons are described. Our results show that, over the Arctic region, anomalies of snow and ice melt onset, ice opening and retreat dates are getting earlier in the year at a rate of more than 5 days per decade, while that of ice advance and closing dates are getting later at a rate of more than 5 days per decade. These significant trends resulted in significant upward trends for anomalies of inner and outer ice-free periods at a rate of nearly 12 days per decade. Small but significant downward trends of seasonal ice loss and gain period anomalies were also observed at a rate of −1.48 and −0.53 days per decade, respectively. Our analyses also demonstrated that the means of these indicators and their trends are sensitive to valid data masks and regional averaging methods.

Unexpectedly high dimethyl sulfide concentration in high-latitude Arctic sea ice melt ponds

2019 ◽  
Vol 21 (10) ◽  
pp. 1642-1649 ◽  
Author(s):  
Keyhong Park ◽  
Intae Kim ◽  
Jung-Ok Choi ◽  
Youngju Lee ◽  
Jinyoung Jung ◽  
...  
Keyword(s):  
Sea Ice ◽  
High Latitude ◽  
Dimethyl Sulfide ◽  
Arctic Sea Ice ◽  
Sulfide Concentration ◽  
Sea Ice Concentration ◽  
Ice Melt ◽  
Melt Ponds ◽  
Arctic Sea ◽  
Ice Concentration

Dimethyl sulfide (DMS) production in the northern Arctic Ocean has been considered to be minimal because of high sea ice concentration and extremely low productivity.

scholarly journals Physical and optical characteristics of heavily melted “rotten” Arctic sea ice

2019 ◽  
Vol 13 (3) ◽  
pp. 775-793 ◽  
Author(s):  
Carie M. Frantz ◽  
Bonnie Light ◽  
Samuel M. Farley ◽  
Shelly Carpenter ◽  
Ross Lieblappen ◽  
...  
Keyword(s):  
Light Scattering ◽  
Sea Ice ◽  
Pore Space ◽  
Total Porosity ◽  
Arctic Sea Ice ◽  
Micro Computed Tomography ◽  
Structural Anisotropy ◽  
Scattering Coefficients ◽  
Ice Melt ◽  
Arctic Sea

Abstract. Field investigations of the properties of heavily melted “rotten” Arctic sea ice were carried out on shorefast and drifting ice off the coast of Utqiaġvik (formerly Barrow), Alaska, during the melt season. While no formal criteria exist to qualify when ice becomes rotten, the objective of this study was to sample melting ice at the point at which its structural and optical properties are sufficiently advanced beyond the peak of the summer season. Baseline data on the physical (temperature, salinity, density, microstructure) and optical (light scattering) properties of shorefast ice were recorded in May and June 2015. In July of both 2015 and 2017, small boats were used to access drifting rotten ice within ∼32 km of Utqiaġvik. Measurements showed that pore space increased as ice temperature increased (−8 to 0 ∘C), ice salinity decreased (10 to 0 ppt), and bulk density decreased (0.9 to 0.6 g cm−3). Changes in pore space were characterized with thin-section microphotography and X-ray micro-computed tomography in the laboratory. These analyses yielded changes in average brine inclusion number density (which decreased from 32 to 0.01 mm−3), mean pore size (which increased from 80 µm to 3 mm), and total porosity (increased from 0 % to > 45 %) and structural anisotropy (variable, with values of generally less than 0.7). Additionally, light-scattering coefficients of the ice increased from approximately 0.06 to > 0.35 cm−1 as the ice melt progressed. Together, these findings indicate that the properties of Arctic sea ice at the end of melt season are significantly distinct from those of often-studied summertime ice. If such rotten ice were to become more prevalent in a warmer Arctic with longer melt seasons, this could have implications for the exchange of fluid and heat at the ocean surface.

Seasonal transitions of Arctic sea ice over the satellite era in CMIP6 models

2020 ◽  
Author(s):  
Abigail Smith ◽  
Alexandra Jahn ◽  
Muyin Wang
Keyword(s):  
Sea Ice ◽  
Seasonal Change ◽  
Arctic Sea Ice ◽  
Ice Thickness ◽  
Large Ensemble ◽  
Model Biases ◽  
Early Results ◽  
Climate Indicators ◽  
Large Spread ◽  
Arctic Sea

<p>Projections of Arctic sea ice area show substantial model spread in CMIP3, CMIP5 and early results from CMIP6. Here we assess how simulated seasonal transitions in Arctic sea ice may be contributing to the large inter-model spread. For this we make use of CMIP6 models, the CESM Large Ensemble and the new Arctic Sea Ice Seasonal Change and Melt/Freeze Climate Indicators satellite dataset. Spring ice loss and fall ice growth can be characterized by various metrics (melt onset, break-up, opening, freeze onset, freeze-up, closing). By assessing numerous metrics of seasonal sea ice transitions, we evaluate a range of ice loss and gain processes in CMIP6 models, as well as biases that may contribute to the large spread in model projections of Arctic sea ice. We show that model biases in seasonal sea ice transitions can compensate for other unrealistic aspects of the sea ice, such as very low ice thickness, resulting in acceptable September sea ice areas for the wrong reasons. Furthermore, we find that the metrics of seasonal sea ice change, while often used interchangeably, are not related to ice area and thickness in the same ways.</p>

scholarly journals Meltwater sources and sinks for multiyear Arctic sea ice in summer

2021 ◽  
Vol 15 (9) ◽  
pp. 4517-4525
Author(s):  
Don Perovich ◽  
Madison Smith ◽  
Bonnie Light ◽  
Melinda Webster
Keyword(s):  
Sea Ice ◽  
Heat Budget ◽  
Arctic Sea Ice ◽  
Sources And Sinks ◽  
Ice Melt ◽  
Ice Surface ◽  
Melt Ponds ◽  
Arctic Sea ◽  
Ice Mass Balance ◽  
Surface Heat Budget

Abstract. On Arctic sea ice, the melt of snow and sea ice generate a summertime flux of fresh water to the upper ocean. The partitioning of this meltwater to storage in melt ponds and deposition in the ocean has consequences for the surface heat budget, the sea ice mass balance, and primary productivity. Synthesizing results from the 1997–1998 SHEBA field experiment, we calculate the sources and sinks of meltwater produced on a multiyear floe during summer melt. The total meltwater input to the system from snowmelt, ice melt, and precipitation from 1 June to 9 August was equivalent to a layer of water 80 cm thick over the ice-covered and open ocean. A total of 85 % of this meltwater was deposited in the ocean, and only 15 % of this meltwater was stored in ponds. The cumulative contributions of meltwater input to the ocean from drainage from the ice surface and bottom melting were roughly equal.

scholarly journals Physical and optical characteristics of heavily melted "rotten" Arctic sea ice

2018 ◽  
Author(s):  
Carie M. Frantz ◽  
Bonnie Light ◽  
Samuel M. Farley ◽  
Shelly Carpenter ◽  
Ross Lieblappen ◽  
...  
Keyword(s):  
Light Scattering ◽  
Sea Ice ◽  
Pore Space ◽  
Total Porosity ◽  
Arctic Sea Ice ◽  
Micro Computed Tomography ◽  
Structural Anisotropy ◽  
Scattering Coefficients ◽  
Ice Melt ◽  
Arctic Sea

Abstract. Field investigations of the properties of heavily melted "rotten" Arctic sea ice were carried out on shorefast and drifting ice off the coast of Utqiaġvik (formerly Barrow), Alaska during the melt season. While no formal criteria exist to qualify when ice becomes "rotten", the objective of this study was to sample melting ice at the point where its structural and optical properties are sufficiently advanced beyond the peak of the summer season. Baseline data on the physical (temperature, salinity, density, microstructure) and optical (light scattering) properties of shorefast ice were recorded in May and June 2015. In July of both 2015 and 2017, small boats were used to access drifting "rotten" ice within ~ 32 km of Utqiaġvik. Measurements showed that pore space increased as ice temperature increased (−8 °C to 0 °C), ice salinity decreased (10 ppt to 0 ppt), and bulk density decreased (0.9 g cm-3 to 0.6 g cm-3). Changes in pore space were characterized with thin-section microphotography and X-ray micro-computed tomography in the laboratory. These analyses yielded changes in average brine inclusion number density (which decreased from 32 mm-3 to 0.01 mm-3), mean pore size (which increased from 80 μm to 3 mm) as well as total porosity (increased from 0 % to > 45 %) and structural anisotropy (variable, with values generally less than 0.7). Additionally, light scattering coefficients of the ice increased from approximately 0.06 cm-1 to > 0.35 cm-1 as the ice melt progressed. Together, these findings indicate that Arctic sea ice at the end of melt season is physically different from the often-studied summertime ice. If such rotten ice were to become more prevalent in a warmer Arctic, this could have implications for the exchange of fluid and heat at the ocean surface.

scholarly journals Pollution over the Tibetan Plateau Linked to Sea Ice Loss in the Arctic

Eos ◽  
2020 ◽  
Vol 101 ◽  
Author(s):  
Michael Allen
Keyword(s):  
Tibetan Plateau ◽  
Sea Ice ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
The Tibetan Plateau ◽  
Anthropogenic Aerosol ◽  
Ice Melt ◽  
Arctic Sea ◽  
Aerosol Pollution ◽  
New Research

New research suggests an atmospheric connection between Arctic sea ice melt and anthropogenic aerosol pollution over the Tibetan Plateau.

scholarly journals Definition differences and internal variability affect the simulated Arctic sea ice melt season

2018 ◽  
Author(s):  
Abigail Ahlert ◽  
Alexandra Jahn
Keyword(s):  
Sea Ice ◽  
Internal Variability ◽  
Arctic Sea Ice ◽  
Satellite Observations ◽  
Marine Ecology ◽  
Passive Microwave ◽  
The Arctic ◽  
Season Length ◽  
Ice Melt ◽  
Arctic Sea

Abstract. Satellite observations show that the Arctic sea ice melt season is getting longer. This lengthening has important implications for the Arctic Ocean's radiation budget, marine ecology and accessibility. Here we assess how passive microwave satellite observations of the melt season can be used for climate model evaluation. By using the Community Earth System Model Large Ensemble (CESM LE), we evaluate the effect of multiple possible definitions of melt onset, freeze onset and melt season length on comparisons with passive microwave satellite data, while taking into account the impacts of internal variability. We find that within the CESM LE, melt onset shows a higher sensitivity to definition choices than freeze onset, while freeze onset is more greatly impacted by internal variability. The CESM LE accurately simulates that the trend in freeze onset largely drives the observed pan-Arctic trend in melt season length. Under RCP8.5 forcing, the CESM LE projects that freeze onset dates will continue to shift later, leading to a pan-Arctic average melt season length of 7–9 months by the end of the 21st century. However, none of the available model definitions produce trends in the pan-Arctic melt season length as large as seen in passive microwave observations. This suggests a model bias, which might be a factor in the generally underestimated response of sea ice loss to global warming in the CESM LE. Overall, our results show that the choice of model melt season definition is highly dependent on the question posed, and none of the definitions exactly matches the physics underlying the passive microwave observations.

scholarly journals A long-term and reproducible passive microwave sea ice concentration data record for climate studies and monitoring

2013 ◽  
Vol 6 (1) ◽  
pp. 95-117
Author(s):  
G. Peng ◽  
W. N. Meier ◽  
D. J. Scott ◽  
M. H. Savoie
Keyword(s):  
Sea Ice ◽  
Passive Microwave ◽  
Climate Data ◽  
Concentration Data ◽  
Sea Ice Concentration ◽  
Ice Concentration ◽  
Data Record ◽  
Climate Data Record ◽  
Climate Studies

Abstract. A long-term, consistent, and reproducible satellite-based passive microwave sea ice concentration climate data record (CDR) is available for climate studies, monitoring, and model validation with an initial operation capability (IOC). The daily and monthly sea ice concentration data are on the National Snow and Ice Data Center (NSIDC) polar stereographic grid with nominal 25 × 25 km grid cells in both the Southern and Northern Hemisphere Polar Regions from 9 July 1987 to 31 December 2007 with an update through 2011 underway. The data files are available in the NetCDF data format at http://nsidc.org/data/g02202.html and archived by the National Oceanic and Atmospheric Administration (NOAA)'s National Climatic Data Center (NCDC) under the satellite climate data record program (http://www.ncdc.noaa.gov/cdr/operationalcdrs.html). The description and basic characteristics of the NOAA/NSIDC passive microwave sea ice concentration CDR are presented here. The CDR provides similar spatial and temporal variability as the heritage products to the user communities with the additional documentation, traceability, and reproducibility that meet current standards and guidelines for climate data records. The dataset along with detailed data processing steps and error source information can be found at: doi:10.7265/N5B56GN3.

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