Revising the Bering Strait Freshwater Flux into the Arctic Ocean

Rebecca A Woodgate and Knut Aagaard

ONR logo  
ONR N00014-99-1-0345
NSF logo
NSF  0125082

Published in Geophysical Research Letters, January 2005
Woodgate, R. A., and K. Aagaard (2005), Revising the Bering Strait freshwater flux into the Arctic Ocean, Geophys. Res. Lett., 32, L02602, doi:10.1029/2004GL021747. 
Copyright 2005 American Geophysical Union. Further reproduction or electronic distribution is not permitted.

Preprint (downloadable as pdf)


Back to Bering Strait
Back to High Latitude Dynamics

Please contact Rebecca Woodgate ( for use of any of this material

   The  freshwater  flux  through the Bering  Strait  into  the Arctic Ocean is important regionally and globally, e.g.  for Chukchi  Sea  hydrography, Arctic Ocean stratification,  the global  freshwater cycle, and the stability of the  Atlantic overturning   circulation.  Aagaard   and   Carmack   [1989] estimated  the Bering Strait freshwater flux as 1670  km3/yr (relative  to  34.8 psu), assuming an annual mean  transport (0.8  Sv)  and salinity (32.5 psu). This is ~ 1/3rd  of  the total freshwater input to the Arctic. Using long-term moored measurements and ship-based observations, we show that  this is  a  substantial  underestimate of  the  freshwater  flux. Specifically, the warm, fresh Alaskan Coastal Current in the eastern  Bering  Strait  may  add  ~  400  km3/yr.  Seasonal stratification  and  ice transport may  add  another  ~  400 km3/yr.  Combined,  these corrections are  larger  than the interannual variability observed by near-bottom measurements and  near-surface measurements will be necessary to quantify this flux and its interannual variability.

© Polar Science Center, University of Washington, 2004

  For details, see paper

Figure  1.  The Bering Strait region, with mooring locations (A1 -  65.90°N  169.43°W, water depth 50 m;  A2  -  65.78°N 168.59°W,  53 m; A3 - 66.29°N 168.97°W, 56 m; A3' -  68.17°N 168.97°W, 59 m; A4 - 65.75°N 168.26°W, 59 m) as black  dots, showing  sea  surface  temperature  for 26th  August   2004 (MODIS/Aqua  level  1  image courtesy of Ocean  Color  Data Processing Archive, NASA/Goddard Space Flight Center). Arrow marks  the  Diomede  Islands  ~ 65.8°N 168°W.  White  areas  indicate clouds.

Figure  2. Thirty-day running mean of hourly time-series  of  salinity  9  m  above bottom at sites A1  (western  channel,  cyan),  A2  (eastern  channel, blue), A3  (north  of  Bering  Strait,  black), and A4 (the Alaskan Coastal Current,  red).  Not  all  moorings are deployed each year.   Between  summer  1992  and  summer 1995, A3' (thin black line)  was  deployed  instead   of   A3  (see  Figure  1).   Record  mean   (i.e.,  approximately annual mean from summer to summer)  salinities  (S,  black)  (errors  ~  0.2 psu) and freshwater  transports  (errors  ~  300  km3/yr)  are  estimated  from  A3  records,  assuming  no  stratification in  velocity  or  density  (FW,  green) and with the correction of 800 km3/yr (FW+, red).

Figure  3.  July 2003 CTD salinity section across the eastern channel of the Bering Strait from the Diomede islands (left) to  Alaska  (right). Black dots indicate moored  instrument locations. Note the fresh (warm) ACC on the Alaskan coast.

Figure  4. Hourly time-series data from A2 and A4  for  July  2002  to  2003.   (a)  Principal component  of  velocity  (~  northward velocity) at A2 (47 m, blue) and A4 (34 m, red; 24  m, yellow; and 14 m, green). (b) Salinity at A2 (48 m, blue) and A4 (39 m, red).  Thick black line marks times when near- bottom  temperatures at A2 and A4 are at the freezing  point  (Julian  days 360 to 482, i.e., late December 2002  to  late  April 2003).

© Polar Science Center, University of Washington, 2004

We gratefully acknowledge financial support for this work from  the Office of Naval Research (ONR), High Latitude Dynamics program.

Back to Bering Strait Homepage

Back to High Latitude Dynamics Homepage