长白山阔叶红松林冬季雪面蒸发特征

Characteristics of evaporation over broadleaved Korean pine forest in Changbai Mountains, Northeast China during snow cover period in winter

利用2002—2005年冬季积雪期涡度相关水汽通量和微气象观测资料,对长白山阔叶红松林雪面蒸发动态及其与气象因子的关系进行分析.结果表明:该涡度相关观测系统积雪期能量平衡闭合度为79.9%,潜热通量占净辐射的21.4%.研究期间,该区蒸发日变化呈单峰曲线形式,蒸发速率在融雪期大于稳定积雪期.30min平均蒸发速率与净辐射呈线性关系,与气温呈二次曲线关系;蒸发日总量与净辐射呈二次曲线关系,与气温呈指数关系.积雪期蒸发日总量呈下降-稳定-上升的动态变化趋势,且上升期>下降期>稳定期,蒸发日总量最大值为0.73mm·d-1,最小值为0.004mm·d-1.2002—2003、2003—2004和2004—2005年积雪期蒸发总量分别为27.6、25.5和22.9mm,占同期降水量的37.9%、19.5%和30.0%,平均蒸发日总量分别为0.17、0.19和0.17mm·d-1.

Based on the measurement data of water vapor flux by open-path eddy covariance and of the micrometeorological factors in broad-leaved Korean pine forest in Changbai Mo system untains during the snow cover period from 2002 to 2005, this paper analyzed the dynamics of snow cover evaporation and the relationships between the evaporation and meteorological factors. The energy balanced ratio during the snow cover period was 79.9%, and the latent heat flux accounted for 21.4% of net radiation. The diurnal variation of the evaporation presented a single-peak curve, and the evaporation rate during snow-melting period was higher than that during stable snow cover peri- od. The half-hour evaporation presented liner relationship with net radiation and quadratic relation- ship with air temperature. The daily evaporation presented quadratic relationship with net radiation and exponential relationship with air temperature. The daily evaporation presented a dynamic trend of decreasing-stable-increasing, with the maximum at increasing stage and the minimum at stable stage. The maximum value of the daily evaporation was 0.73 mm·d^-1 , and the minimum value was 0.004 mm·d^-1. During the snow cover periods of 2002-2003, 2003-2004 and 2004-2005, the annual evaporation was 27.6, 25.5, and 22.9 mm, accounting for 37.9%, 19.5%, and 30. 0% of the precipitation in the same periods, respectively. The mean value of the daily evaporation in the three periods was 0.17, 0.19, and 0.17 mm·d^-1 , respectively.