Use of atmospheric radiation measurement program data from Barrow, Alaska, for evaluation and development of snow-albedo parameterizations

Mölders, Nicole; Luijting, Hanneke; Sassen, Kenneth

doi:10.1007/s00703-007-0271-6

Cited by 19 publications

(16 citation statements)

References 70 publications

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“…threshold, and its definition, has been reported as a drawback in this type of snow albedo parameterization (Pedersen and Winther 2005;Molders et al 2008), which is also used in other NWP models. To reduce the importance of the threshold a continuous reset was implemented:…”

Section: ) Snow Albedomentioning

confidence: 99%

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

Dutra

Balsamo

Viterbo³

et al. 2010

Journal of Hydrometeorology

265

259

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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).

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Section: ) Snow Albedomentioning

confidence: 99%

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

Dutra

Balsamo

Viterbo³

et al. 2010

Journal of Hydrometeorology

265

259

View full text Add to dashboard Cite

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“…The albedo of snow over land also shows seasonal variation due to a variety of factors, especially melting and refreezing (e.g., Marshall and Oglesby 1994;Mö lders et al 2008). We use a simple formulation here to represent the seasonal change.…”

Section: Polar Wrfmentioning

confidence: 99%

Development and Testing of Polar WRF. Part III: Arctic Land*

et al. 2011

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A version of the state-of-the-art Weather Research and Forecasting model (WRF) has been developed for use in polar climates. The model known as ''Polar WRF'' is tested for land areas with a western Arctic grid that has 25-km resolution. This work serves as preparation for the high-resolution Arctic System Reanalysis of the years 2000-10. The model is based upon WRF version 3.0.1.1, with improvements to the Noah land surface model and snow/ice treatment. Simulations consist of a series of 48-h integrations initialized daily at 0000 UTC, with the initial 24 h taken as spinup for atmospheric hydrology and boundary layer processes. Soil temperature and moisture that have a much slower spinup than the atmosphere are cycled from 48-h output of earlier runs. Arctic conditions are simulated for a winter-to-summer seasonal cycle from 15 November 2006 to 1 August 2007. Simulation results are compared with a variety of observations from several Alaskan sites, with emphasis on the North Slope. Polar WRF simulation results show good agreement with most near-surface observations. Warm temperature biases are found for winter and summer. A sensitivity experiment with reduced soil heat conductivity, however, improves simulation of near-surface temperature, ground heat flux, and soil temperature during winter. There is a marked deficit in summer cloud cover over land with excessive incident shortwave radiation. The cloud deficit may result from anomalous vertical mixing of moisture by the turbulence parameterization. The new snow albedo parameterization for WRF 3.1.1 is successfully tested for snowmelt over the North Slope of Alaska.

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“…(4) was increased from 0.3 to 0.6. This was motivated by the findings of Pedersen and Winther (2005) and Mölders et al (2008), who note that for ECHAM5's snow albedo parameterization, and also for ECHAM4 for which α sn, min = 0.4, snow albedo decreases too early and too fast during snowmelt.…”

Section: Alb2 and Alb2_ndgmentioning

confidence: 99%

Evaluation of North Eurasian snow-off dates in the ECHAM5.4 atmospheric general circulation model

et al. 2014

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Abstract. The timing of springtime end of snowmelt (snowoff date) in northern Eurasia in version 5.4 of the ECHAM5 atmospheric general circulation model (GCM) is evaluated through comparison with a snow-off date data set based on space-borne microwave radiometer measurements and with Russian snow course data. ECHAM5 reproduces well the observed gross geographical pattern of snow-off dates, with earliest snow-off (in March) in the Baltic region and latest snow-off (in June) in the Taymyr Peninsula and in northeastern parts of the Russian Far East. The primary biases are (1) a delayed snow-off in southeastern Siberia (associated with too low springtime temperature and too high surface albedo, in part due to insufficient shielding by canopy); and (2) an early bias in the western and northern parts of northern Eurasia. Several sensitivity experiments were conducted, where biases in simulated atmospheric circulation were corrected through nudging and/or the treatment of surface albedo was modified. While this alleviated some of the model biases in snow-off dates, 2 m temperature and surface albedo, especially the early bias in snow-off in the western parts of northern Eurasia proved very robust and was actually larger in the nudged runs.A key issue underlying the snow-off biases in ECHAM5 is that snowmelt occurs at too low temperatures. Very likely, this is related to the treatment of the surface energy budget. On one hand, the surface temperature T s is not computed separately for the snow-covered and snow-free parts of the grid cells, which prevents T s from rising above 0 • C before all snow has vanished. Consequently, too much of the surface net radiation is consumed in melting snow and too little in heating the air. On the other hand, ECHAM5 does not include a canopy layer. Thus, while the albedo reduction due to canopy is accounted for, the shielding of snow on ground by the overlying canopy is not considered, which leaves too much solar radiation available for melting snow.

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Use of atmospheric radiation measurement program data from Barrow, Alaska, for evaluation and development of snow-albedo parameterizations

Cited by 19 publications

References 70 publications

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

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

Development and Testing of Polar WRF. Part III: Arctic Land*

Evaluation of North Eurasian snow-off dates in the ECHAM5.4 atmospheric general circulation model

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