Publication:
Assessment of the Regional Arctic System Model Intra-Annual Ensemble Predictions of Arctic Sea Ice

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Authors
Maslowski, Wieslaw
Lee, Younjoo
Craig, Anthony
Seefeldt, Mark
Osinski, Robert
Cassano, John
Kinney, Jaclyn Clement
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Advisors
Date of Issue
2020
Date
Publisher
EGU
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Abstract
The Regional Arctic System Model (RASM) has been developed and used to investigate the past to present evolution of the Arctic climate system and to address increasing demands for Arctic forecasts beyond synoptic time scales. RASM is a fully coupled ice-ocean-atmosphere-land hydrology model congured over the pan-Arctic domain with horizontal resolution of 50 km or 25 km for the atmosphere and land and 9.3 km or 2.4 km for the ocean and sea ice components. As a regional model, RASM requires boundary conditions along its lateral boundaries and in the upper atmosphere, which for simulations of the past to present are derived from global atmospheric reanalyses, such as the National Center for Environmental Predictions (NCEP) Coupled Forecast System version 2 and Reanalysis (CFSv2/CFSR). This dynamical downscaling approach allows comparison of RASM results with observations, in place and time, to diagnose and reduce model biases. This in turn allows a unique capability not available in global weather prediction and Earth system models to produce realistic and physically consistent initial conditions for prediction without data assimilation.More recently, we have developed a new capability for an intra-annual (up to 6 months) ensemble prediction of the Arctic sea ice and climate using RASM forced with the routinely produced (every 6 hours) NCEP CFSv2 global 9-month forecasts. RASM intra-annual ensemble forecasts have been initialized on the 1st of each month starting in 2019 with forcing for each ensemble member derived from CSFv2 forecasts, 24-hr apart from the month preceding the initial forecast date. Several key processes and feedbacks will be discussed with regard to their impact on model physics, the representation of initial state and ensemble prediction skill of Arctic sea ice variability at time scales from synoptic to decadal. The skill of RASM ensemble forecasts will be assessed against available satellite observations with reference to reanalysis as well as hindcast data using several metrics, including the standard deviation, root mean square dierence, Taylor diagrams and integrated ice-edge error.
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Abstract
Description
The article of record as published may be found at https://doi.org/10.5194/egusphere-egu2020-12849
EGU General Assembly 2020
Series/Report No
Department
Oceanography
Organization
Naval Postgraduate School (U.S.)
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Format
1 p.
Citation
Maslowski, W., Lee, Y., Craig, A., Seefeldt, M., Osinski, R., Cassano, J., and Clement Kinney, J.: Assessment of the Regional Arctic System Model Intra-Annual Ensemble Predictions of Arctic Sea Ice , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-12849, https://doi.org/10.5194/egusphere-egu2020-12849, 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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