Publication:
Causality and Evolution of Summer Polynyas off the Coast of Northern Greenland

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Authors
Lee, Younjoo
Maslowski, Wieslaw
Osinski, Robert
Kinney, Jaclyn Clement
Craig, Anthony
Cassano, John
Nijssen, Bart
Seefeldt, Mark
Subjects
Advisors
Date of Issue
2020
Date
Publisher
EGU
Language
Abstract
The summer polynya along the northern coast of Greenland has been observed only six months later after the winter polynya in 2018, which has prompted concerns about the stability of some of the thickest sea-ice in the Arctic region. This study combines retrospective remotely sensed sea-ice measurements with results from the Regional Arctic System Model (RASM) to examine the causes, eect, and evolution of open-water areas/polynyas in the region. RASM is a limited-domain, fully-coupled climate model, consisting of the atmosphere (Weather Research and Forecasting, WRF3.7), ocean (Los Alamos National Laboratory Parallel Ocean Program, POP2), sea-ice (Community Sea Ice Model, CICE5), land hydrology (Variable Inltration Capacity, VIC4) and streamow routing (RVIC) components. The ocean and sea- ice models are congured with the horizontal resolution of 1/12-degree with 45 vertical levels and 5 sea-ice thickness categories, respectively. The atmosphere and land hydrology components are set up on a 50-km grid with 40-vertical levels and 3-soil layers, respectively. The Climate Forecast System Reanalysis (CFSR) and version 2 (CFSv2) output are used as boundary conditions for dynamic downscaling. Analysis of the sea-ice conditions o the coast of northern Greenland revealed that RASM, in agreement with satellite measurements, has simulated ve summer polynya events, i.e. in August of 1984, 1985, 2002, 2004 and 2018, over the 39-year period (1980-2018). All these events were primarily dynamically forced, with the thermodynamic forcing playing the secondary, yet still important role. While the thermodynamically driven sea-ice melting exhibited a relatively little year-to-year variability, between 87 km3 and 115 km3, its relative contribution to the total sea-ice loss increased by 2.5 times, from 16% in 1984 to 40% in 2018. This implies that with continuing thinning of sea-ice, increasingly less mechanical forcing may be required to generate and maintain a polynya or open water north of Greenland in summers to come.
Type
Presentation
Abstract
Description
The article of record as published may be found at https://doi.org/10.5194/egusphere-egu2020-6076
EGU General Assembly 2020
Series/Report No
Department
Oceanography
Organization
Naval Postgraduate School (U.S.)
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NPS Report Number
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Funder
Format
6 slides
Citation
Lee, Y., Maslowski, W., Osinski, R., Clement Kinney, J., Craig, A., Cassano, J., Nijssen, B., and Seefeldt, M.: Causality and Evolution of Summer Polynyas o the Coast of Northern Greenland, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-6076, https://doi.org/10.5194/egusphere-egu2020-6076, 2020
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This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.
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