【作者】 张龚；

【导师】 曾光明； 蒋益民；

【作者基本信息】 湖南大学 ， 环境工程， 2006， 博士

【摘要】 研究地韶山位于中国中南部的湖南省湘潭市韶山蔡家塘,属于亚热带气候,丘陵地貌,年平均降雨量1200~1700 mm,植被类型为亚热带针阔混交林,针叶为主。2000年1月~2003年12月在韶山蔡加塘森林小流域中进行样品采集工作,其样地设置和采样方法及质量控制按EMEP手册的要求进行,对大气、土壤、地表水和土壤水的变化进行监测。森林的水文特征对森林的生产力和营养物质的循环有着重要的影响。林冠层截留损失在森林地蒸散发中通常是非常显著,有时可能成为主要的水分损失源。韶山森林冠层具有二维结构,上部乔木冠层的覆盖率约为82 %;下部灌木亚冠层覆盖率约为41 %。对于韶山森林的二维冠层结构很难一次应用Gash降雨截留解析模型来者模拟冠层截留损失。考虑到Gash模型的本质以及每层林冠的高度和冠层的覆盖率,用原始Gash模型来模拟上部乔木冠层的截留损失,用修正的Gash模型来模拟较为稀疏的下部灌木层的截留损失。2003年乔木冠层截留损失测量值占到年降水量的15.0 %,灌木亚冠层的截留损失占到年降水量的9.0 %,总截留损失占到了年降水量的24.0 %。Penman -Monteith(PM公式)方程算得乔木冠层单位地表面积的平均蒸发率为0.79 mm·h-1,稀疏灌木亚冠层的为0.32 mm·h-1。原始Gash模型模拟的乔木冠层的损失为215.6 mm,高出测量值17.2 %;稀疏Gash模型的模拟值为118.5 mm,高出模拟值7.0 %。韶山森林树枝和树干的蒸发损失所占截留损失较少的比重。解析冠层截留模型在许多环境中得到了成功的应用,但是决定冠层截留损失大小的蒸发速率和空气动力学阻力参数在以往的应用中,均被予以假设(空气动力学阻力参数通常被假设为0)而没有进行实际计算和测量。用7种不同的方法分别计算空气动力学参数值,用PM公式计算蒸发率。稀疏Gash模型模拟的穿透水的值高出测量值1.6 %,模拟的茎干流高出实测值12.4 %。韶山地区的降水属于硫酸性降水。韶山大气降水和森林穿透水中的阳离子浓度在降雨的总离子浓度中所占比重均大于65 %,有的甚至高达82 %。韶山大气降水、穿冠水和地表穿透水的离子是极不平衡的,大气降水中SO42-和NO3-的平均最大浓度都出现在春季,在韶山森林四年的观测年中,穿透雨中弱酸的浓度和通量比起降雨在各个季节均有较大程度的富集。韶山森林植被对酸雨的缓冲作用以及对酸性物质的中和作用是非常明显的,而且作用主要发生在冠层。韶山森林冠层三个空间层次中pH值与SO42-、NO3-以及Ca2+的回归分析和数学模拟结果表明,H+与SO42-的来源一致,主要来源于工业污染。盐基离子总沉降通量在春、更多还原

【Abstract】 Shaoshan forest (Caijiatang catchment) is situated in Xiantan city of Hunan province in central-south China, which is with subtropics and hills and coniferous-deciduous mixed forests. There is an annual mean precipitation of 1200~1700 mm and distinct four seasons in a year in Shaoshan. Monitoring and sampling of atmosphere, soil, surface water and soil water were conducted in Caijiatang catchment in Shaoshan forest from January 2000 to December 2003. The field design and sampling methods and data quality controlling were performed according to the EMEP (European Monitoring and Evaluation Program) manual.Forest hydrology has the important impact on the forest productivity and the nutrient cycling. Canopy interception loss is significant in the evapotranspiration in forests, which, sometimes, is the dominant part in water losses in forests. The Shaoshan forest canopy is of two-layer structure, namely the top-canopy and the sub-canopy. The top-canopy coverage is 82 % and the sub-canopy coverage is about 41 %. It is difficult for Shaoshan forest to simulate the canopy interception losses by using the Gash’s analytical model, which is successfully used in temperate and tropical forests. The original Gash model was used to predict the top-cnaopy interception loss and the sparse Gash model was used to simulate the sub-canopy loss for the nature of the original and the sparse Gash models and the coverage and structure of Shaoshan forest.The top-canopy interception loss accounted for about 15.0 % of the annual precipitation and the sub-canopy loss amounted to 9.0 % of the precipitation, indicating that the total interception losses were about 24.0 %. Average evaporation rate from top-canopy layer per ground unit was calcultaed to be 0.79 mm·h-1 and that from sub-canopy was 0.32 mm·h-1 using the Penman-Monteith equation. Top-canopy interception loss was 215.6 mm by the original Gash model with an 17.2 % overestimation and the sub-canopy loss was 118.5 mm with an 7.0 % overestimation. The evaporation from trunks and stems was not signative. Although the analytical interception model was used with worldwide success, the key parameters as evaporation rate and aerodynamic resistance usually were assumed without calculation and measurement and the aerodynamic resistance was assumed to be zero. The aerodynamic resistance was calculated by seven different methods and the更多还原