Variations of Ice Cover and Thermohaline Structure in the Arctic-GIN Sea Basin. Analysis of Model Results for the 1986-1990 Period.
Abstract
Thermodynamic changes in the Arctic ice cover and ocean have been investigated for the years 1986-1990 with a coupled ice-ocean numerical model. The model basin includes the Barents and GIN (Greenland-Iceland-Norwegian) Seas on a polar stereographic grid with 127 km resolution. The coupled model consists of the Hibler ice model, a 3-D advective turbulent mixed layer model based on the Mellor-Yamada level 2.5 closure scheme, and a diagnostic inverse model for the geostrophic currents. The pressure gradients for the geostrophic flow are derived from the Levitus climatology, as are the influxes of heat and salt at the open boundaries. The atmospheric momentum and heat fluxes were derived from 6.hourly Navy Operational Global Atmospheric Prediction System (NOGAPS) output for the years 19861990. Analysis has focused on interannual variations of the total ice volume, ice edge position and ice circulation, the thermohaline structure, and the turbulent energy associated with the inertial Ekman currents available for mixing. These variations have been computed for the whole model domain, as well as in the Arctic Basin proper, the GIN Sea and the Greenland Sea (the MIZEX zone). The range of interannual variations for the ice cover is found to be much greater in the summer than in the winter, with magnitudes up to 50% and 10% of the mean seasonal variation. The summer minima of the total ice volume and ice covered area form a half period of an oscillating cycle: 1986 and 1990 having minima of about the same strength and 1988 a maximum. There is a negative correlation between these cycles and the annual wind strengths, which have maxima in the years 1986 and 1990.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 26, 1996
- Accession Number
- ADA304887
Entities
People
- Richard Allard
- Steve A. Piacsek
Organizations
- United States Naval Research Laboratory