scholarly journals Observation of perennial Arctic sea ice melt and freeze-up using passive microwave data

1998 ◽  
Vol 103 (C12) ◽  
pp. 27753-27769 ◽  
Author(s):  
Douglas M. Smith
Keyword(s):  
Sea Ice ◽  
Arctic Sea Ice ◽  
Passive Microwave ◽  
Ice Melt ◽  
Arctic Sea ◽  
Microwave Data

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

2019 ◽  
Vol 13 (1) ◽  
pp. 1-20 ◽  
Author(s):  
Abigail Smith ◽  
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 match the physics underlying the passive microwave observations.

Estimation of melt pond fraction over high-concentration Arctic sea ice using AMSR-E passive microwave data

2016 ◽  
Vol 121 (9) ◽  
pp. 7056-7072 ◽  
Author(s):  
Yasuhiro Tanaka ◽  
Kazutaka Tateyama ◽  
Takao Kameda ◽  
Jennifer K. Hutchings
Keyword(s):  
Sea Ice ◽  
Arctic Sea Ice ◽  
Passive Microwave ◽  
High Concentration ◽  
Melt Pond ◽  
Arctic Sea ◽  
Microwave Data

scholarly journals Recent changes in the Arctic melt Season

2006 ◽  
Vol 44 ◽  
pp. 367-374 ◽  
Author(s):  
Julienne Stroeve ◽  
Thorsten Markus ◽  
Walter N. Meier ◽  
Jeff Miller
Keyword(s):  
Sea Ice ◽  
Arctic Sea Ice ◽  
Significant Trend ◽  
Passive Microwave ◽  
The Arctic ◽  
Regional Variability ◽  
Arctic Sea ◽  
Microwave Data

AbstractMelt-season duration, melt-onset and freeze-up dates are derived from Satellite passive microwave data and analyzed from 1979 to 2005 over Arctic Sea ice. Results indicate a Shift towards a longer melt Season, particularly north of Alaska and Siberia, corresponding to large retreats of Sea ice observed in these regions. Although there is large interannual and regional variability in the length of the melt Season, the Arctic is experiencing an overall lengthening of the melt Season at a rate of about 2 weeks decade–1. In fact, all regions in the Arctic (except for the central Arctic) have Statistically Significant (at the 99% level or higher) longer melt Seasons by >1 week decade–1. The central Arctic Shows a Statistically Significant trend (at the 98% level) of 5.4 days decade–1. In 2005 the Arctic experienced its longest melt Season, corresponding with the least amount of Sea ice Since 1979 and the warmest temperatures Since the 1880s. Overall, the length of the melt Season is inversely correlated with the lack of Sea ice Seen in September north of Alaska and Siberia, with a mean correlation of –0.8.

scholarly journals Snow Depth Retrieval on Arctic Sea Ice From Passive Microwave Radiometers—Improvements and Extensions to Multiyear Ice Using Lower Frequencies

2018 ◽  
Vol 123 (10) ◽  
pp. 7120-7138 ◽  
Author(s):  
Philip Rostosky ◽  
Gunnar Spreen ◽  
Sinead L. Farrell ◽  
Torben Frost ◽  
Georg Heygster ◽  
...  
Keyword(s):  
Sea Ice ◽  
Snow Depth ◽  
Arctic Sea Ice ◽  
Passive Microwave ◽  
Arctic Sea ◽  
Microwave Radiometers ◽  
Multiyear Ice ◽  
Lower Frequencies

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.

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