About the disk

The disk contains material obtained from the numerical model output. Results from the high resolution regional ocean and sea ice model forced with realistic daily atmospheric forcing for the 1979-2002 period are presented. The model is maintained at the Naval Postgraduate School in Monterey, CA. The numerical grid of the model is configured at 1/12° (~9 km) and 45 levels, and the domain includes the Arctic Ocean and subarctic seas.

 

The primary objective of this work is to present, in a simple form, our efforts of modeling the region of Chukchi and Beaufort seas. This region is investigated within the framework of the Western Arctic Shelf-Basin Interaction (SBI) project. This disk is a result of collaboration within the SBI project. Dr. Wieslaw Maslowski of Naval Postgraduate School (NPS) in Monterey provided the model output; Dr. Waldemar Walczowski from the Institute of Oceanology Polish Academy of Sciences (IO PAS), Sopot, performed the analysis. 

 

 Monthly means as well as daily snapshots of model output are used. Several different forms of presentation are included:

• mean horizontal distributions of single properties;

• combined distributions of mean current vectors and mean tracers (temperature, salinity) at different levels;

• transports across several sections;

• time series of horizontal distributions as movies;

• Empirical Orthogonal Functions analysis of SSH, temperature and salinity fields.

 

 Transports across sections are presented as:

·        23-year mean volume, heat and freshwater transports calculated from monthly mean model output;

·       climatological annual cycles of volume transport, water temperature and salinity;

·        time series of volume, heat and fresh water transports calculated from monthly mean model output.

 

Correlations between flows across several sections are presented.

 

Heat transport was calculated against the reference temperature -0.1 °C; the reference salinity in the freshwater transport calculations is 34.8 psu.

 

Two movies show the entire Arctic Ocean, the rest presents the larger SBI region. Monthly means were used to prepare movies. Two movies were prepared using model daily snapshots. Please note that due of use of monthly means for calculations of eddy kinetic energy (EKE) those values are underestimated; they represent ~15 % of estimates based on calculations from daily model snapshots (Marble, 2001).

 

All movies are made of images in Graphics Interchange Format (gif).

 

Empirical Orthogonal Functions (EOFs) analysis are used to show spatial and temporal variability of modelled fields. This is an efficient tool for investigation of large amount of information obtained from a numerical model and for compression into space-time patterns of variability. The model results were evaluated using Principal Component method. EOFs of the Sea Surface Height, temperature and salinity anomalies are presented. Temperature and salinity anomalies were normalized by their standard deviations. Time series of the first three Principal Components as well as the horizontal distributions of EOFs (eigenvectors) are presented.

 

Principal Axes (PA) of currents at different levels were computed as well. The 1^st (major) Principal Axis at each point of the model grid shows the direction of maximum variance of current velocity. Regions over the slope, where the 1^st PA is perpendicular to the isobaths are potential places of the most intensive cross-slope exchanges and shelf-basin interactions.