Simulation of Northern Eurasian Local Snow Depth, Mass, and Density Using a Detailed Snowpack Model and Meteorological Reanalyses

Abstract

The Crocus snowpack model within the Interactions between Soil-Biosphere-Atmosphere (ISBA) land surface model was run over northern Eurasia from 1979 to 1993, using forcing data extracted from hydrometeorological datasets and meteorological reanalyses. Simulated snow depth, snow water equivalent, and density over open fields were compared with local observations from over 1000 monitoring sites, available either once a day or three times per month. The best performance is obtained with European Centre for Medium-Range Weather Forecasts (ECMWF) Interim Re-Analysis (ERA-Interim). Provided blowing snow sublimation is taken into account, the simulations show a small bias and high correlations in terms of snow depth, snow water equivalent, and density. Local snow cover durations as well as the onset and vanishing dates of continuous snow cover are also well reproduced. A major result is that the overall performance of the simulations is very similar to the performance of existing gridded snow products, which, in contrast, assimilate local snow depth observations. Soil temperature at 20-cm depth is reasonably well simulated. The methodology developed in this study is an efficient way to evaluate different meteorological datasets, especially in terms of snow precipitation. It reveals that the temporal disaggregation of monthly precipitation in the hydrometeorological dataset from Princeton University significantly impacts the rain-snow partitioning, deteriorating the simulation of the onset of snow cover as well as snow depth throughout the cold season.

The growth of sublimation crystals and surface hoar on the Antarctic plateau

“…The mean bias over the three days of simulation is 0.3 K, the root mean square deviation is 1.49 K. Given the potential errors of measuring temperature from IR emission, in part due to errors of snow emissivity (Bintanja and Vandenbroeke, 1995), this shows that Crocus provides a reasonable estimate of the snow surface temperature. A similar conclusion was reached by Brun et al (2011) andFreville et al (2014) Figure 3 presents the modeled vertical profiles of temperature for the upper layers of the snowpack for different times of the day for 18 and 19 January 2009. The evolution of the vertical profile is similar for both days with maximum surface temperature around noon.…”

“…The vertical resolution in the snow is not fixed since it corresponds to the layering of the snowpack controlled by the model (Vionnet et al, 2012). Despite these rather simplistic assumptions, as demonstrated in Brun et al (2011), Crocus allows a good simulation of the vertical sub-surface temperature profile at Dome C and surface temperature in Antarctica (Freville et al, 2014). Finally, Crocus takes as input the meteorological variables that constrain the surface mass and energy balance of the snowpack: air temperature, specific humidity, wind speed, shortwave and long-wave incoming radiation and precipitation amount and phase.…”

“…Finally, Crocus takes as input the meteorological variables that constrain the surface mass and energy balance of the snowpack: air temperature, specific humidity, wind speed, shortwave and long-wave incoming radiation and precipitation amount and phase. Brun et al (2011) have carried out Crocus simulations at Dome C. In their study two types of simulations were done, i.e., stand alone simulations forced by local meteorological variables over a period of ten days and coupled simulations with the atmospheric model AROME. They showed that the model reproduces the observed downward propagation of the diurnal heat wave into the upper 50 cm of the snowpack and the snow surface temperature reasonably well.…”

“…These data are provided on a 3 h time step and have been processed as in Brun et al (2013). Operational analyses from the European Centre for Medium-Range Weather Forecasts (ECMWF) similar to ERA-Interim have been evaluated at Dome C with respect to field measurements of temperature, humidity and wind speed at different levels on a 45 m tower by Genthon et al (2010).…”

“…A first Crocus simulation was initialized with a 30 m thick snowpack with similar snow physical properties as in Brun et al (2011). This simulation was performed over two years (1 January 2007 to 1 January 2009) to initialize properly the deep snowpack temperature profile.…”