摘要:利用珠海凤凰山陆气相互作用观测塔站2014年11月至2016年5月的观测数据，对比分析了干湿季森林下垫面能量通量和气象要素的变化特征，分析了在不同稳定度下3个风向范围（315°～45°、45°～135°和135°～225°）的动量和感热交换系数随冠层表面风速的变化特征，并对动量和感热交换系数进行了参数化研究。结果表明：干季感热和潜热通量值相当，湿季潜热远大于感热。干季和湿季的夜晚都出现负感热现象，感热从大气向森林输送。相对湿度的变化幅度大，与该地气象状况密切相关，相对湿度的垂直梯度夜晚较大，白天较小。干季的气温垂直梯度比湿季的明显。风速在冬季变化平缓，夏季变化剧烈，低层风速随高度变化梯度明显，高层较紊乱。各高度风向差异不大。中性和近中性状态下，在风向为315°～45°、45°～135°和135°～225°时，动量交换系数Cdn分别为0.05、0.0055和0.022，感热交换系数Chn分别为0.0055、0.003和0.004。在稳定和不稳定状态下，动量交换系数Cd、感热交换系数Ch随冠层表面风速v明显发生变化，稳定条件下，Cd、Ch随v的增大而增大；不稳定条件下，Cd、Ch随v的增大而减小。分不同风向对森林冠层Cd、Ch在稳定和不稳定条件下与v的关系进行了拟合，得到了参数化公式。
关键词:陆气相互作用/
动量交换系数/
感热交换系数/
参数化
Abstract:The variation characteristics of the energy flux and meteorological elements of the underlying surface of the forest during the wet and dry seasons were compared and analyzed by using observation data obtained from November 2014 to May 2016 from the Zhuhai Phoenix Mountain Land–Atmosphere Interaction Observation Tower Station. The variation characteristics of the momentum and sensible heat exchange coefficients in three wind direction ranges (315°–45°, 45°–135°, and 135°–225°) along with the canopy?surface wind speed under different stability conditions, as well as the parameterizations of these coefficients were analyzed. The sensible heat and latent heat fluxes in the dry season were equivalent, whereas in the wet season latent heat is much higher than the sensible heat. Negative sensible heat occurs during the night in both the dry and wet seasons, with the sensible heat being transported from the atmosphere to the forest. The variation range of the relative humidity is large and is closely related to the meteorological conditions in the area. The vertical gradient of the relative humidity is larger at night and smaller during the day. The vertical gradient of the air temperature in the dry season is more significant than that in the wet season. The wind speed changes gently in winter but violently in summer. There is an obvious gradient in the low-level wind speed with height, whereas the high-level wind is chaotic. The wind direction at different heights does not differ significantly. In neutral and near-neutral states, the momentum exchange coefficients Cdn are 0.05, 0.0055, and 0.022, respectively, when the wind directions are 315°–45°, 45°–135°, and 135°–225°, and the sensible heat exchange coefficients Chn are 0.0055, 0.003, and 0.004, respectively. Under stable and unstable conditions, the momentum exchange coefficient Cd and the sensible heat exchange coefficient Ch obviously change with the wind velocity v on the canopy surface. Under stable conditions, Cd and Ch increase with increases in v, and under unstable conditions, Cd, and Ch decrease with increases in v. We fitted the relationships between Cd, Ch in the forest canopy and v under stable and unstable conditions in different wind directions, and obtained the parameterized formula.
Key words:Land–atmosphere interaction/
Momentum exchange coefficient/
Sensible heat exchange coefficient/
Parameterization
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