大兴安岭北部兴安落叶松林雪水文特征

目的研究大兴安岭北部地区兴安落叶松林雪水文特征，为今后积雪蒸发测定和区域水资源调控提供更为科学的数据支撑和理论基础。方法对观测期内16场降雪的大气降雪量以及对林内积雪深度、积雪密度以及雪水当量进行了周期性观测与统计分析。结果(1) 随着降雪级别的减少，兴安落叶松林的截留率呈现逐渐增加的趋势，分别为6.50%(暴雪)、9.04%(大雪)、9.8%(中雪)、15.7%(小雪)。可见，兴安落叶松林降雪截留最大截留率出现在小雪，暴雪时截留率则最小。(2)兴安落叶松林内积雪深度和林外相比差异不大，其中落叶松林林内积雪深度最深为68.6cm，林外空地积雪深度最深为74.8cm。(3)林内和林外的积雪密度在观测初期会随降雪的输入而降低，无降雪期有相应升高。融雪期随着气温的升高，雪密度减少速度会加快。在4月24—29日达到最大值，减少量分别为0.07和0.11g/cm3。(4)雪水当量速率减少量在4月24—29日达到最大值，分别为30.2和46.4mm。结论和林外空地相比，兴安落叶松林对积雪深度、积雪密度及雪水当量影响不大，说明兴安落叶松林在雪水文过程中对积雪特征影响尽管存在，但并不明显。该区雪蒸发日变化呈单峰曲线变化规律，积雪期的日蒸发量和蒸发速率均值分别为0.04mm和0.2×10-3mm/h，日蒸发量波动幅度在0.02~0.14mm之间，在融雪期间，日蒸发量和蒸发速率的均值分别为0.38mm和1.51×10-3mm/h，采用灰色关联度对各因子进行分析，得出净辐射是影响兴安落叶松林内积雪蒸发的主要因素。 

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.