1/3 total USA UN Environ Prog What makes the Arctic hot? Local communities subsistence Arctic Shipping Routes? Decreasing Ice cover Sept 2007 -ice extent (Pink=1979-2000 mean min) Source: NSIDC Oil/Gas Exploration Links to Global Climate (albedo, CO2, circulation, permafrost and CH4) Northwest Passage - southern route open since 2007 - northern route open 2007, 2010, 2011 Northeast Passage - open since 2008 Sept Ice extent (Magenta = 1979-2000) from: Arctic Report Card 2012 www.arctic.noaa.gov/reportcard INFLOWS OUTFLOWS Through - Pacific, and surface waters - deep (0-2600m) - order 10 Sv - comparatively salty - warm Pacific Water through the - shallow (0-50m) - order 1 Sv - comparatively fresh - seasonally warm/cold Water through the and the - deep (0-2600m) - order 10 Sv - comparatively salty - warm - All into (Some short term southward flow through the ) Through the - Pacific and surface waters - shallow (0 few hundred m) - order 1 Sv - comparatively fresh 1
OTHER INPUTS/OUTPUTS E-P, rivers Summary: Arctic Ocean INPUTS RIVERS (n and US) - order 3000 km 3 /yr freshwater Broad, Shallow Shelves Deep Basins Evaporation-Precipitation - order 2000 km 3 /yr freshwater ( order 2500 km 3 /yr) OUTPUTS: Ice Export through the - equivalent to order 2000 km 3 /yr freshwater Serreze et al., 2006, JGR From the Pacific You are here USA From the To the To the Shallow entrance from the Pacific Medium and Deep connections to the About the size of the USA! Chart from IBCAO ATLANTIC LAYER - warm, salty - largest volume input PACIFIC WATER - nutrient rich - source of heat and freshwater (waters above 0 deg C deeper than 200m) - 2 branches (, ) - roughly 200-800m - follows slopes and ridges - quite weak (strongest flows=eddies) - separates from slopes.. somehow - cools somewhat during transit - transit time 1 or more decades (high nutrient waters) - multiple routes, switches with atmospheric forcing?? - roughly 0-200m - does not always follow topography, more driven by surface forcing - eddies may be significant part of flow - cools to freezing during transit - transit time order a decade 2
Arctic -Ice Climatology MINIMUM (September) Ice Motion (growth and melt) The International Arctic Buoy Program (run from UW) Rigor, et al Satellites (SSM/I, AMSR), NASA and others MAXIMUM (February) http://nsidc.org IABP movie Rigor, Ortmeyer et al, UW Photo D. Barton,1992 Buoy set in ice, reports position, air pressure and temperature to satellite http://iabp.apl.washington.edu The Polar Vortex Arctic Storm Tracks Limited penetration into Arctic except through North due to fairly zonal steering and blocking by land masses Location of tropospheric jet streams Polar jet and midtroposphere pressure courtsey of Maksym courtsey of Maksym, BAS 3
MEAN 1979-1998 Beaufort High Arctic Surface Air Pressure (i.e. Surface Wind) Shorthand atmospheric circulation the Arctic Oscillation (AO) SEA LEVEL PRESSURE = MEAN + VARIABILITY BUT ANY PARTICULAR DAY CAN LOOK VERY DIFFERENT, e.g. WHAT THE ARCTIC SEES Beaufort High Covariance of Level Pressure with AO index (hpa/30 years) Rigor et al., 2002 From D.Thompson, based on Thompson and Wallace 1998 HIGH AO LOW AO from National Geographic Magazine, March 2000 4
Changes in Arctic Climate are related to the Arctic Oscillation (AO) AO Index 1950-2012 (www.cpc.ncep.noaa.gov) Covariance of Level Pressure with AO index (hpa/30 years) A New Dipole pattern?? Hi AO small Beaufort Gyre strong Influence Lo AO large Beaufort Gyre weaker Influence In the Arctic Ocean, the AO explains - 52% of winter SLP variance, and - 36% of summer SLP variance.. but.. From D.Thompson, based on Thompson and Wallace 1998 Courtesy of I.Rigor http://www.arctic.noaa.gov/reportcard/atmosphere.html Arctic Surface Air Temperature (over land) Arctic Ozone Loss 2011 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 5