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ESTIMATING SEA ICE TRANSPORT INTO THE NORTH ATLANTIC USING THE AMSR-E SATELLITE SENSOR

ESTIMATING SEA ICE TRANSPORT INTO THE NORTH ATLANTIC USING THE AMSR-E SATELLITE SENSOR. Tom A. Agnew, Climate Research Branch, Meteorological Service of Canada and Jared Vandeweghe University of Toronto Toronto, Canada. OUTLINE.

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ESTIMATING SEA ICE TRANSPORT INTO THE NORTH ATLANTIC USING THE AMSR-E SATELLITE SENSOR

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  1. ESTIMATING SEA ICE TRANSPORT INTO THE NORTH ATLANTIC USING THE AMSR-E SATELLITE SENSOR Tom A. Agnew, Climate Research Branch, Meteorological Service of Canada and Jared Vandeweghe University of Toronto Toronto, Canada

  2. OUTLINE • How Arctic freshwater cycles through the Global Climate System • Canadian Archipelago Through-flow Study (CATS) and how we can use satellites to estimate sea ice transport. • Results using the Advanced Microwave Scanning Radiometer (AMSR-E) to estimate the rate of sea-ice transport into the North Atlantic.

  3. Freshwater Cycle Salt Stratified Ocean Temperature Stratified Ocean Courtesy of Eddie Carmack, IOS

  4. Sea ice export into the North Atlantic

  5. Canadian Archipelago Through-flow Study (CATS) Activities Objective: To estimate the rate of transport of freshwater through the Canadian Archipelago into Baffin Bay/Labrador Sea • NSF/SEARCH - funded study for 5–year 2002 to 2007 • 2003 Ocean expeditions to set up moorings (currents, salinity, ice draft, pressure, tracers) • Ocean Surveys (tracers, hydrography, velocity) • Remote Sensing (AMSR-E*, MODIS, AVHRR) • Modeling (sub-mesoscale winds) Investigators Kelly Falkner, Roger Samelson, Marta Torres, Oregon State University (OSU) Andreas Münchow, Kuo Wong, University of Delaware (UDel) Humfrey Melling, Fiona McLaughlin, Robie Macdonald, Eddy Carmack, Institute of Ocean Sciences (IOS), Canada Tom Agnew, Atmosphere & Environment, Canada Peter Jones, John N. Smith, Bedford Institute of Oceanography (BIO), Canada Andrew Weaver, University of Victoria (Uvic), Canada

  6. Sea Ice Motion from AMSR-E Image Pairs January 9-13, 2003

  7. AMSR-E Sea Ice motion and Buoy Comparison * Negative mean underestimation compared to drifting buoys

  8. Daily Sea Ice Area Transport across flux gates Ice Area Flux = ∑ ci ui Δx gate a gate c

  9. Estimating Daily Sea Ice Area Flux Error 1. Error in estimating ui is 2.49 km/day Error in estimating ci is 10% ci ui is σe = 2.53 km/day 2. Error in daily flux: σf = σe L/(Ns) ½ = 320 km2/day where Ns = independent estimates = 10 and L = 400 km 3. Monthly error: σ T = σf (Nd) ½ = 1752 km2 /month 4. Winter error estimate: ~ 5000 km2/winter 5. For previous sensor: 17,000 – 25,000 km2/winter

  10. Sea Ice Area Transport Winter 02/03 and 03/04 651,000 km2 594,000 km2

  11. Estimated Volume of FreshwaterFlux in Winter

  12. Summary Average winter sea ice area transport through Fram Strait for 02/03 and 03/04 winter is 594,000 km2 (the average of 754,000 km2 found by Kwok et al. 2004). The error in estimating the winter ice flux is ~ 5000 km2 for the AMSR-E sensor. This error estimate is a considerable improvement over estimates using earlier passive microwave sensors which range from 17,000 and 25,000 km2 The sea ice area flux across the widest part of Baffin Bay is 651,000 km2 which is 20% higher than the area flux across Fram Strait. However, when you include ice thickness Fram Strait ice volume export is 2400 km3 compared to 975 km3 for Baffin Bay. Using the improved accuracy of AMSR-E we hope in future to estimate sea ice area flux in the main channels of the Canadian Arctic Islands and compare results with ocean moorings set up in these channels under CATS.

  13. Acknowledge: Canadian PERD US NSF/SEARCH NSIDC IABP THANK YOU

  14. Maximum Cross Correlation Method • Uses the cross correlation coefficient as a measure of similarity between patches or sub-regions in the two images. • Select a sub-region or patch in the first image. Then search in the second image using the same size patch until you maximizes the cross-correlation between patches in the two images. • Ice motion is the spatial offset between the two patches • patch size is 6 pixels by 6 pixels (37.5 km x 37.5 km) + + First Image Second Image

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