PROGRAM TITLE:	High Latitude Dynamics, Arctic Ice Dynamics 
SCIENCE ELEMENT:	Climate and Hydrologic Systems


SCIENTIFIC MERIT:  The ice cover of the Arctic Ocean 
significantly impacts climate. Vertical fluxes of mass, momentum 
and energy within the air-ice-ocean system are critical to prediction 
of the global heat budget. Air-sea fluxes are concentrated by 
fracture within the ice plate, a scale dependent process related 
to nonlinear stress and strain. Radiation is a major factor in the heat 
and mass balance of the ice pack, the thermohaline structure of the 
upper ocean, and biological activity. The full spectral radiation field 
in the snow-ice-water system depends on complex scattering and 
absorption mechanisms under investigation. Coupled air-ice-ocean 
models with adequate resolution to test the sensitivity of feedback 
mechanisms are being formulated. The water mass structure of the 
Arctic Ocean may be maintained by lateral advection/mixing from 
the broad continental shelves bordering the polar basin. Export of 
dense shelf water is being related to the thermodynamics of ice 
formation, the mechanics of ice divergence and cross shelf transport 
mechanisms.  Arctic marginal seas (Greenland, Iceland, Norwegian, 
Barents, Kara, Laptev, Bering, Okhotsk) have effects far beyond their 
boundaries. In winter, deep convection, the pump that drives global 
deep ocean circulation, is possible at high latitudes due to the 
marginal stability of the water column and intense surface cooling. 
Circulation in the Fram Strait region is under study to determine 
transport between ocean basins that preconditions deep convection. 
In summer, the polar light cycle produces the global maximum open 
ocean primary productivity in the marginal ice zone.  Principal 
questions include:  how to incorporate leads and ridges (time-
variable discontinuities) in continuum based ice dynamics models; 
how can temperature, albedo, and clouds be measured and 
incorporated in radiative transfer models to determine the surface 
heat balance; what observations are necessary to accurately predict 
polar ice cap melting; how do circulation and water masses in the 
Arctic Ocean pre-condition deep convection in the North Atlantic; 
how do atmospheric polar lows form and trigger deep convection; 
what are the relative roles of biological and physical mechanisms 
in regulating marginal ice zone biological productivity. The 
research community is ready to address these issues further now 
with focused initiatives to reduce current uncertainties. Error 
estimates (e.g., trends in ice cap melting, regional warming, deep 
convective activity) will be reduced significantly with five to ten 
years of sustained effort. Performance and quality is measured by 
peer-reviewed publications in quality journals.

STAKEHOLDERS: This program links to the international WCRP Sea 
Ice and Climate Program, the Canadian RADARSAT Program, the NSF 
ARCSS Initiative, the developing GOOS Program, DOE's AMAP 
Program and NASA's Alaska SAR Facility Program. The research 
directly addresses the need to know the concentration and thickness 
distribution of ice in the Arctic basin and the movement of the ice 
edge in Arctic marginal seas, impacting from 20% of the world's 
commercial fisheries. Through a better understanding of the surface 
heat budget, improved prediction of high latitude weather and 
global climate change will be achieved.  Results will also impact 
design of the optimal observational network to maintain forecasting 
skill. Benefits also include improved algorithms for satellite 
remote sensing, assessment of contaminant dispersal, design of 
offshore platforms and pipelines and transportation safety and 

POLICY RELEVANCE: This activity contributes directly to the 
high priority issues of Climate Change and Global Warming and 
Seasonal and Interannual Prediction. Models predict global warming 
will first be detected in the Arctic. This research provides 
early warning signs and initial estimates of the rate of 
warming,indicating how fast control measures must be 
implemented. It is also an essential element of the national research 
plan mandated by the Interagency Arctic Research and Policy Act 

PROGRAM CONTACT: Dr. Thomas B. Curtin, ONR/Code 324AR, 800 N 
Quincy Street, Arlington, VA 22217, 703-696-4118.