Snow hydrological characteristics of Larix gmelinii forest in northern Daxing'an Mountains of northeastern China

ObjectiveTo provide more scientific data support and theoretical basis for the future snow cover evaporation measurement and regional water resurces requlation, the snow hydrological characteristics in the natural forest of Larix gmelinii was studied in northern Daxing'an Mountains of northeastern China. The snowfall interception and snow cover characteristics were systematically studied from the end of October 2015 to the beginning of May 2016.

MethodDuring the observation period, the snowfall of 16 snowfalls, as well as the snow depth, snow density and snow water equivalent in the forest were periodically observed and statistically analyzed.

Result(1) With the decreasing of snowfall level, the interception rate of Larix gmelinii forest showed a gradual increasing trend, which was 6.50% (blizzard), 9.04% (heavy snow), 9.8% (moderate snow), 15.7% (light snow). It can be seen that the maximum interception rate of snowfall in Larix gmelinii forest occurred in light snow, and the smallest occurred in blizzard. (2) The difference between the depth of snow inside Larix gmelinii forest and that outside the forest was not significant. Among them, the deepest snow depth in larch forest was 68.6cm, and that in outer space was 74.8cm. (3) The density of snow inside and outside the forest decreased with the input of snowfall in the early stage of observation, and did not increase in the absence of snowfall. Snowmelt as the temperature rises, the snow density will decrease faster. (4) Reaching the maximum between April 24 and April 29, with a decrease of 0.07 and 0.11g/cm³, respectively; the reduction of snow equivalent rate reached the maximum between April 24 and April 29, 30.2 and 46.4mm, respectively.

ConclusionCompared with the open space outside the forest, the Larix gmelinii forest has little effect on the snow depth, snow cover density and snow water equivalent, indicating that the effect of Larix gmelinii forest on the hydrological characteristics of snow cover is not obvious. The daily change of snow evapotranspiration in this area showed a single-peak curve variation. The daily evaporation and evaporation rates in the snow-covered period were 0.04mm and 0.2×10^-3mm/h, respectively. Daily evaporation fluctuated between 0.02-0.14mm. During the snowmelt period, the average daily evaporation and evaporation rates were 0.38mm and 1.51×10^-3mm/h, respectively, and the factors were analyzed using the grey correlation degree. It is concluded that net radiation is the main factor influencing snowcover evaporation in Larix gmelinii forest.