Maritime snowpack

Figure 1 Typical stratigraphies of the taiga, tundra and maritime snowpacks, with photomicrographs of typical snow crystal types. Scale bars 1 mm. Bold numbers next to the stratigraphies are density values, in g.cm. ...

Temperate maritime areas are usually forested, resulting in low wind speeds. The mild temperatures, combined with a thick snowpack, lead to a very low temperature gradient, of the order of 2 to 5 °C.m except near the surface, where daily temperature variations can lead to elevated transient gradients that change sign during the day. The density of the maritime snowpack usually increases monotonously with depth. 

The Alpine and maritime snowpacks have many similarities. A specific figure is not necessary here and can be found in Sturm et al, " Alpine snowpacks form in regions slightly colder than the maritime snowpack and signs of melting are less frequent. The temperature gradient in late fall can be sufficient to form a depth hoar layer 5 to 20 cm... 

Bower JP, Hood E, Hoferkamp LA (2008) Major solutes, metals, and alkylated aromatic compounds in high-latitude maritime snowpacks near the Trans-Alaska pipeline terminal, Valdez, Alaska. Environ Res Lett 3 045010... 

Among several existing classifications of seasonal snowpacks, we use that of Sturm et al. " that describes the tundra, taiga, Alpine, maritime, prairie and ephemeral snowpacks. Sturm et al. also mention the mountain snowpack, that displays such large spatial variations that it... 

At the beginning of the snow season, ground temperatures are usually close to 0°C, so that the temperature gradient is determined by the atmospheric temperature. In temperate areas with a maritime or Alpine snowpack, the temperature gradient will usually be less than 10" C.m while in subarctic or Arctic areas, it will usually be greater than 20°C.m ... 

The impact of the temperature gradient on metamorphism explains many of the features of Figure 1. The typical HGM-type metamorphism of the taiga snowpack eventually transforms most of the snowpack into depth hoar, " while the QIM-type metamorphism of the maritime and Alpine snowpacks forms, in the absence of melting, layers of small rounded grains 0.2 to 0.4 mm in diameter. However, considering the effects of other climate variables such as wind speed is necessary to explain features such as the presence of windpacks formed of small rounded grains in the tundra snowpack. 

---