Energy and water cycles in Siberian biosphere

西伯利亚生物圈的能量和水循环

基本信息

批准号：
11201206
负责人：
OHTA Takeshi
金额：
$ 37.7万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research on Priority Areas (B)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

项目摘要

1. The sum of the turbulent fluxes was generally in good agreement with the available energy flux, except when the latent heat flux was large, when the total turbulent fluxes often exceeded the available energy flux ; this bias in the energy balance was affected by the wind direction. Although the reasons for this phenomenon at this site are not clear, it might be an effect of the larch forest surrounding the site.2. The seasonal variation and magnitude of the latent heat flux (IE) were similar to those of the sensible heat flux (H) ; both were maximal in June, Consequently, the Bowen ratio was around 1.0 on many days during the study period. On some clear days just after rainfall events, IE was very large, and the sum of H and IE exceeded the net all-wave radiation.3. Remarkably, from 7 to 22 July 2000, which corresponded to a long rainless period, IE decreased and was smaller than H. Considering the diurnal change in the saturation deficit and soil moisture for the same period, it is thought that IE was affected by the atmosphere rather than by the soil.4. The contribution of understory evapotranspiration (Eu) to the evapotranspiration from the entire ecosystem (Et) was 25-50% of Et throughout the period analyzed, and a similar relationship was obtained for overstory transpiration (Eo). These results suggest that Eu plays a very important role in the water cycle at this site.5. Significant differences in the water and energy exchanges of the pine and larch forests at Spasskaya Pad occurred just after the snowmelt season. This could have been due to the difference in species (evergreen versus deciduous forest) or in soil thawing conditions. Consequently, the shape of the seasonal variation in the Bowen ratio over the course of the study period at the pine site was markedly different from that in the larch forest.

1. 湍流通量之和一般与可用能通量吻合较好，但当潜热通量较大时，湍流通量总和往往超过可用能通量；能量平衡的这种偏差受到风向的影响。虽然该地点出现这种现象的原因尚不清楚，但可能是该地点周围落叶松林的影响。 2．潜热通量（IE）的季节变化和大小与感热通量（H）相似；两者均在 6 月份达到最大值，因此，在研究期间的许多天，Bowen 比率都在 1.0 左右。在降雨后的一些晴天，IE很大，H和IE之和超过了净全波辐射。3．值得注意的是，2000 年 7 月 7 日至 22 日，对应着长时间的无雨期，IE 有所下降，并且小于 H。考虑到同期饱和度亏差和土壤湿度的日变化，可以认为 IE 受到了大气而不是土壤。4。在整个分析期间，林下蒸散量 (Eu) 对整个生态系统蒸散量 (Et) 的贡献为 Et 的 25-50%，并且对于上层蒸腾量 (Eo) 也得出了类似的关系。这些结果表明Eu在该站点的水循环中发挥着非常重要的作用。5．斯帕斯卡亚帕德的松林和落叶松林的水和能量交换在融雪季节之后出现了显着差异。这可能是由于物种差异（常绿林与落叶林）或土壤解冻条件造成的。因此，在研究期间，松林地区鲍文比的季节变化形状与落叶松林明显不同。