Contemporary estimates of Pan‐Arctic freshwater discharge from GRACE and reanalysis

Streamflow from Arctic river basins has been increasing in recent decades in response to warming climate. In addition to being a sensitive indicator of global change, Arctic discharge is a critical component of the freshwater budget of the Arctic Ocean, where increasing freshwater flows may slow rates of North Atlantic Deep Water formation and heat transport by the thermohaline circulation. However, quantifying rates of freshwater discharge from the entire Pan-Arctic drainage has been troublesome using traditional stream gauging methods. Here we use satellite measurements of variations in continental water storage from the GRACE mission to present first estimates of monthly freshwater discharge from the entire Pan-Arctic for the period 2003–2005. Results show that rates of Pan-Arctic discharge for this time period (3588 ± 257 km3 yr−1) are significantly larger than those suggested by gauge-based estimates (3238 km3yr−1), and furthermore, may indicate that discharge rates are accelerating.

[1]  A. Venkitaraman.  Water cycle shifts gear , 2005 .

[2]  Eric F. Wood,et al.  A pan‐arctic evaluation of changes in river discharge during the latter half of the 20th century , 2005 .

[3]  Daqing Yang,et al.  Compatibility evaluation of national precipitation gage measurements , 2001 .

[4]  J. Wahr,et al.  Measurements of Time-Variable Gravity Show Mass Loss in Antarctica , 2006, Science.

[5]  Matthew Rodell,et al.  Detectability of variations in continental water storage from satellite observations of the time dependent gravity field , 1999 .

[6]  Christoph C. Raible,et al.  Climate change: Water cycle shifts gear , 2005, Nature.

[7]  D. Chambers.  Evaluation of new GRACE time‐variable gravity data over the ocean , 2006 .

[8]  Matthew Rodell,et al.  Total basin discharge for the Amazon and Mississippi River basins from GRACE and a land‐atmosphere water balance , 2005 .

[9]  F. Portmann,et al.  Discharge Observation Networks in Arctic Regions: Computation of the River Runoff into the Arctic Ocean, Its Seasonality and Variability , 2000 .

[10]  D. Lettenmaier,et al.  Streamflow simulations of the terrestrial Arctic domain , 2005 .

[11]  Kevin E. Trenberth,et al.  Estimates of Freshwater Discharge from Continents: Latitudinal and Seasonal Variations , 2002 .

[12]  Vincent R. Gray.  Climate Change 2007: The Physical Science Basis Summary for Policymakers , 2007 .

[13]  S. Swenson,et al.  Accuracy of GRACE mass estimates , 2006 .

[14]  Roger G. Barry,et al.  Spatial and temporal variability in active layer thickness over the Russian Arctic drainage basin , 2005 .

[15]  C. Vörösmarty,et al.  Assessment of contemporary Arctic river runoff based on observational discharge records , 2001 .

[16]  M. Dyurgerov,et al.  Observational Evidence of Increases in Freshwater Inflow to the Arctic Ocean , 2004 .

[17]  J. Wahr,et al.  Acceleration of Greenland ice mass loss in spring 2004 , 2006, Nature.

[18]  David M. Lawrence,et al.  A projection of severe near‐surface permafrost degradation during the 21st century , 2005 .

[19]  R. Reynolds,et al.  The NCEP/NCAR 40-Year Reanalysis Project , 1996, Renewable Energy.

[20]  Wolfgang Grabs,et al.  High‐resolution fields of global runoff combining observed river discharge and simulated water balances , 2002 .

[21]  Richard B. Lammers,et al.  THE DYNAMICS OF RIVER WATER INFLOW TO THE ARCTIC OCEAN , 2000 .

[22]  D. Bromwich,et al.  The Atmospheric Hydrologic Cycle over the Arctic Basin from Reanalyses. Part I: Comparison with Observations and Previous Studies* , 2000 .

[23]  Victor Zlotnicki,et al.  Time‐variable gravity from GRACE: First results , 2004 .

[24]  Richard B. Lammers,et al.  Increasing River Discharge to the Arctic Ocean , 2002, Science.

[25]  M. Watkins,et al.  GRACE Measurements of Mass Variability in the Earth System , 2004, Science.

[26]  L. D. Hinzman,et al.  Disappearing Arctic Lakes , 2005, Science.

[27]  D. Bromwich,et al.  Large‐scale hydro‐climatology of the terrestrial Arctic drainage system , 2002 .

[28]  The Global Water Cycle , 2013 .

[29]  Dennis P. Lettenmaier,et al.  Tracking Fresh Water from Space , 2003, Science.

[30]  T. Prowse,et al.  Arctic River Flow: A Review of Contributing Areas , 2000 .