2012 Changing Arctic Ocean 506E/497E - Lecture 1 - Woodgate
What makes the Arctic “hot”? Local communities UN Environ subsistence Prog 1/3 total USA Arctic Shipping Routes?
Oil/Gas Exploration Decreasing Ice cover Links to Global Climate (albedo, CO2, circulation, permafrost and CH4) Sept Sea Ice extent (Magenta = 1979-2000)
Northwest Passage - southern route open since 2007 - northern route open 2007, 2010, 2011
Northeast Passage Sept 2007 Sea-ice extent - open since 2008 (Pink=1979-2000 mean min) Source: NSIDC from: Arctic Report Card 2012 www.arctic.noaa.gov/reportcard
INFLOWS OUTFLOWS Through Fram Strait - Pacific, Atlantic and surface waters - deep (0 - 2600m)
Russia Russia - order 10 Sv 80N 80N - comparatively salty Barents Sea Barents Sea - warm
Fram Fram Strait Greenland Strait Greenland Sea Sea Bering Bering Strait Strait
Greenland Greenland Alaska Canadian Alaska Canadian Archipelago Atlantic Water through the Archipelago Pacific Water through the Fram Strait and the Barents Sea Through the Canadian Archipelago Bering Strait - deep (0 - 2600m) - Pacific and surface waters - shallow (0 - 50m) - order 10 Sv - All into Atlantic - shallow (0 – few hundred m) - order 1 Sv - comparatively salty (Some short term southward flow - order 1 Sv - comparatively fresh - warm - seasonally warm/cold through the Bering Strait) - comparatively fresh
1 2012 Changing Arctic Ocean 506E/497E - Lecture 1 - Woodgate
OTHER INPUTS/OUTPUTS – E-P, rivers Summary: Arctic Ocean
Russia Broad, Shallow Shelves INPUTS RIVERS (Russian and US) - order 3000 km3/yr freshwater Deep Basins
Evaporation-Precipitation (Bering Strait order Shallow entrance from - order 2000 km3/yr freshwater 2500 km3/yr) Barents Sea the Pacific From the Atlantic From the Medium and Deep Pacific Fram connections to the Strait Atlantic Russia 80N Barents Sea OUTPUTS: Bering To the Strait Atlantic Greenland Fram StraitGreenland Ice Export through the Fram Strait Sea Canadian Bering 3 You are About the size Strait - equivalent to order 2000 km /yr Archipelago freshwater here Greenland To the of the USA! Alaska Canadian Archipelago USA Atlantic Chart from IBCAO Serreze et al., 2006, JGR
ATLANTIC LAYER PACIFIC WATER - warm, salty - nutrient rich Russia Russia 80N - largest volume input 80N - source of heat and freshwater Barents Sea Barents Sea
Fram Fram Strait Greenland Strait Greenland Sea Sea Bering Bering Strait Strait (high nutrient waters) Greenland - multipleGreenland routes, switches with (waters above 0 deg C deeper than 200m) Alaska Canadian Alaska Canadian atmospheric forcing?? Archipelago- 2 branches (Fram Strait, Barents Sea) Archipelago - roughly 0-200m - roughly 200-800m - does not always follow topography, - follows slopes and ridges more driven by surface forcing - quite weak (strongest flows=eddies) - eddies may be significant part of flow - separates from slopes .. somehow - cools to freezing during transit - cools somewhat during transit - transit time “order a decade” - transit time “1 or more decades”
2 2012 Changing Arctic Ocean 506E/497E - Lecture 1 - Woodgate
Arctic Sea-Ice Sea Ice Motion (growth and melt)
Climatology The International Arctic Buoy Program (run from UW) Rigor, et al MINIMUM (September)
Satellites (SSM/I, AMSR), NASA and others MAXIMUM (February) Buoy set in ice, reports position, IABP movie air pressure and http://nsidc.org Rigor, Ortmeyer et al, UW temperature to satellite http://iabp.apl.washington.edu Photo D. Barton,1992
The Polar Vortex Arctic Storm Tracks Limited penetration into Arctic except through North Atlantic due to fairly zonal steering and blocking by land masses
Location of tropospheric jet Polar jet and mid- streams troposphere pressure
courtsey of Maksym courtsey of Maksym, BAS
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MEAN 1979-1998 Arctic Surface Air Shorthand atmospheric circulation Beaufort High Pressure (i.e. – the Arctic Oscillation (AO)
Surface Wind) SEA LEVEL PRESSURE = MEAN + VARIABILITY
BUT ANY PARTICULAR DAY CAN Beaufort High LOOK VERY DIFFERENT, e.g. WHAT THE ARCTIC SEES
Covariance of Sea Level Pressure with AO index (hPa/30 years)
From D.Thompson, based on Thompson and Wallace 1998 Rigor et al., 2002
HIGH AO LOW AO
from National Geographic Magazine, March 2000
4 2012 Changing Arctic Ocean 506E/497E - Lecture 1 - Woodgate
Changes in Arctic Climate are related to A New Dipole pattern?? the Arctic Oscillation (AO) AO Index 1950-2012 Covariance of Sea Level Pressure (www.cpc.ncep.noaa.gov) with AO index (hPa/30 years)
Hi AO – small Beaufort Gyre strong Atlantic Influence Lo AO – large Beaufort Gyre weaker Atlantic Influence
In the Arctic Ocean, the AO explains - 52% of winter SLP variance, and - 36% of summer SLP variance From D.Thompson, based on Thompson and Wallace 1998 .. but .. http://www.arctic.noaa.gov/reportcard/atmosphere.html Courtesy of I.Rigor
Arctic Surface Air Arctic Ozone Temperature Loss 2011 (over land) Comparable to Antarctic loss Cause - cold, long-lasting vortex.
General warming trend 2009, 2010 colder
Arctic Report Card, Overland et al, 2011 Arctic Report Card, Bernhard et al, 2011
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