An Improved Snow Scheme for the ECMWF Land Surface Model: Description and Offline Validation

A new snow scheme for the European Centre for Medium-Range Weather Forecasts (ECMWF) land surface model has been tested and validated. The scheme includes a new parameterization of snow density, incorporating a liquid water reservoir, and revised formulations for the subgrid snow cover fraction and snow albedo. Offline validation (covering a wide range of spatial and temporal scales) includes simulations for several observation sites from the Snow Models Intercomparison Project-2 (SnowMIP2) and global simulations driven by the meteorological forcing from the Global Soil Wetness Project-2 (GSWP2) and by ECMWF Re-Analysis ERA-Interim. The new scheme reduces the end of season ablation biases from 10 to 2 days in open areas and from 21 to 13 days in forest areas. Global GSWP2 results are compared against basinscale runoff and terrestrial water storage. The new snow density parameterization increases the snow thermal insulation, reducing soil freezing and leading to an improved hydrological cycle. Simulated snow cover fraction is compared against NOAA/National Environmental Satellite, Data, and Information Service (NESDIS) with a reduction of the negative bias of snow-covered area of the original snow scheme. The original snow scheme had a systematic negative bias in surface albedo when compared against Moderate Resolution Imaging Spectroradiometer (MODIS) remote sensing data. The new scheme reduces the albedo bias, consequently reducing the spatial- and time-averaged surface net shortwave radiation bias by 5.2 W m 22 in 14% of the Northern Hemisphere land. The new snow scheme described in this paper was introduced in the ECMWF operational forecast system in September 2009 (cycle 35R3).

[1]  H. Luijting,et al.  Use of atmospheric radiation measurement program data from Barrow, Alaska, for evaluation and development of snow-albedo parameterizations , 2008 .

[2]  D. Verseghy,et al.  Class—A Canadian land surface scheme for GCMS. I. Soil model , 2007 .

[3]  Steven Platnick,et al.  Northern Hemisphere five-year average (2000-2004) spectral albedos of surfaces in the presence of snow: Statistics computed from Terra MODIS land products , 2007 .

[4]  Sergio M. Vicente-Serrano,et al.  The impact of snow depth and snowmelt on the vegetation variability over central Siberia , 2005 .

[5]  Dara Entekhabi,et al.  Hemispheric-scale climate response to Northern Eurasia land surface characteristics and snow anomalies , 2007 .

[6]  David A. Robinson,et al.  Snow Mass over North America: Observations and Results from the Second Phase of the Atmospheric Model Intercomparison Project , 2005 .

[7]  P. Kushner,et al.  Stratosphere-troposphere coupling and links with eurasian land surface variability , 2007 .

[8]  E. Brun,et al.  A numerical model to simulate snow-cover stratigraphy for operational avalanche forecasting , 1992, Journal of Glaciology.

[9]  A. Pitman,et al.  The validation of a snow parameterization designed for use in general circulation models , 1998 .

[10]  Kelly Elder,et al.  Evaluation of forest snow processes models (SnowMIP2) , 2009 .

[11]  B. Ramsay,et al.  The interactive multisensor snow and ice mapping system , 1998 .

[12]  Marc Lynch-Stieglitz,et al.  The development and validation of a simple snow model for the GISS GCM , 1994 .

[13]  Kelly Elder,et al.  An Evaluation of Forest Snow Process Simulations , 2009 .

[14]  David R. Easterling,et al.  Contemporary Changes of the Hydrological Cycle over the Contiguous United States: Trends Derived from In Situ Observations , 2004 .

[15]  Xiao-dong Liu,et al.  Influence of Eurasian spring snow cover on Asian summer rainfall , 2002 .

[16]  Jean-François Mahfouf,et al.  The representation of soil moisture freezing and its impact on the stable boundary layer , 1999 .

[17]  Howard E. Epstein,et al.  The thermoinsulation effect of snow cover within a climate model , 2008 .

[18]  B. Hurk,et al.  The Torne-Kalix PILPS 2(e) experiment as a test bed for modifications to the ECMWF land surface scheme , 2003 .

[19]  Taikan Oki,et al.  The Second Global Soil Wetness Project (GSWP-2) , 2003 .

[20]  G. Stenchikov,et al.  Changes of Snow Cover, Temperature, and Radiative Heat Balance over the Northern Hemisphere , 1994 .

[21]  Pedro Viterbo,et al.  An Improved Land Surface Parameterization Scheme in the ECMWF Model and Its Validation. , 1995 .

[22]  Jan-Gunnar Winther,et al.  Intercomparison and validation of snow albedo parameterization schemes in climate models , 2005 .

[23]  Robert J. Gurney,et al.  The Radiative Effect of a Fir Canopy on a Snowpack , 2006 .

[24]  Thomas R. Karl,et al.  Observed Impact of Snow Cover on the Heat Balance and the Rise of Continental Spring Temperatures , 1994, Science.

[25]  R. Armstrong,et al.  Snow and Climate: Physical Processes, Surface Energy Exchange and Modeling , 2010 .

[26]  Stéphane Bélair,et al.  Operational Implementation of the ISBA Land Surface Scheme in the Canadian Regional Weather Forecast Model. Part II: Cold Season Results , 2003 .

[27]  Donald G. Baker,et al.  Snow Depth Required to Mask the Underlying Surface , 1991 .

[28]  Yongkang Xue,et al.  A simple snow-atmosphere-soil transfer model , 1999 .

[29]  Alan H. Strahler,et al.  Validation of the MODIS bidirectional reflectance distribution function and albedo retrievals using combined observations from the aqua and terra platforms , 2006, IEEE Transactions on Geoscience and Remote Sensing.

[30]  D. Mocko,et al.  Simulation of high latitude hydrological processes in the Torne-Kalix basin : PILPS phase 2(e) - 2: Comparison of model results with observations , 2003 .

[31]  Crystal B. Schaaf,et al.  Accuracy assessment of the MODIS 16-day albedo product for snow: comparisons with Greenland in situ measurements , 2005 .

[32]  N. Rutter,et al.  Evaluation of the NOHRSC Snow Model (NSM) in a One-Dimensional Mode , 2008 .

[33]  Pedro M. A. Miranda,et al.  An offline study of the impact of lakes on the performance of the ECMWF surface scheme , 2010 .

[34]  E. Anderson,et al.  A point energy and mass balance model of a snow cover , 1975 .

[35]  F. Chauvin,et al.  Sensitivity of the hydrological cycle to increasing amounts of greenhouse gases and aerosols , 2002 .

[36]  P. Kushner,et al.  The dynamical response to snow cover perturbations in a large ensemble of atmospheric GCM integrations. , 2008 .

[37]  E. Martin,et al.  An Energy and Mass Model of Snow Cover Suitable for Operational Avalanche Forecasting , 1989, Journal of Glaciology.

[38]  Jean-François Mahfouf,et al.  A new snow parameterization for the Météo-France climate model , 1995 .

[39]  S. Seneviratne,et al.  Seasonal Variations in Terrestrial Water Storage for Major Midlatitude River Basins , 2006 .

[40]  K. Davis,et al.  The MODIS (Collection V005) BRDF/albedo product: Assessment of spatial representativeness over forested landscapes , 2009 .

[41]  Pedro M. A. Miranda,et al.  Deriving an effective lake depth from satellite lake surface temperature data: a feasibility study with MODIS data , 2010 .

[42]  Pierre Etchevers,et al.  An Intercomparison of Three Snow Schemes of Varying Complexity Coupled to the Same Land Surface Model: Local-Scale Evaluation at an Alpine Site , 2001 .

[43]  B. Hurk,et al.  A Revised Hydrology for the ECMWF Model: Verification from Field Site to Terrestrial Water Storage and Impact in the Integrated Forecast System , 2009 .

[44]  Lifeng Luo,et al.  Snow process modeling in the North American Land Data Assimilation System (NLDAS): 1. Evaluation of model‐simulated snow cover extent , 2003 .

[45]  R. Koster,et al.  The Rhône-Aggregation Land Surface Scheme Intercomparison Project: An Overview , 2002 .

[46]  H. Douville,et al.  Sensitivity of the Asian summer monsoon to an anomalous Eurasian snow cover within the Météo-France GCM , 1996 .

[47]  Matthias Drusch,et al.  ECMWF's Global Snow Analysis: Assessment and Revision Based on Satellite Observations , 2004 .

[48]  Andreas Roesch,et al.  Assessment of Snow Cover and Surface Albedo in the ECHAM5 General Circulation Model , 2006 .

[49]  B. Ramsay,et al.  Published online in Wiley InterScience (www.interscience.wiley.com) DOI: 10.1002/hyp.6720 Enhancements to, and forthcoming developments in the Interactive Multisensor Snow and Ice Mapping System (IMS) † , 2022 .

[50]  Pedro Viterbo,et al.  Impact on ECMWF forecasts of changes to the albedo of the boreal forests in the presence of snow , 1999 .

[51]  Josef M. Oberhuber,et al.  Snow cover model for global climate simulations , 1993 .

[52]  Alan H. Strahler,et al.  Quality assessment of BRDF/albedo retrievals in MODIS operational system , 2008 .

[53]  A. K. Betts,et al.  O ine validation of the ERA 40 surface scheme , 2000 .

[54]  A. Sterl,et al.  The ERA‐40 re‐analysis , 2005 .

[55]  A. J. Dolman,et al.  The Pilot Phase of the Global Soil Wetness Project , 1999 .

[56]  Zong-Liang Yang,et al.  Validation of the Snow Submodel of the Biosphere-Atmosphere Transfer Scheme with Russian Snow Cover and Meteorological Observational Data , 1997 .

[57]  David A. Robinson,et al.  Land surface conditions over Eurasia and Indian summer monsoon rainfall , 2003 .

[58]  Sonia I. Seneviratne,et al.  Inferring changes in terrestrial water storage using ERA-40 reanalysis data: The Mississippi River Basin , 2004 .