Evaluation of accumulation process of total nitrogen in the forested watershed by using the satellite remote sensing data and the vegetation database

采用野外观测和GIS分析方法，结合遥感资料和森林清单，研究了我国少数森林山区植被特征与总氮平衡的关系。结果总结如下：1。建立了大气中全氮平衡的数学模型，以评估大气通过雨水向森林山区提供的全氮。大气中全氮积累过程的控制因素是大气中全氮的平流和降水对全氮的去除，较长测量周期获得的雨水中全氮浓度的季节变化可以很好地估计。在森林流域中，与植被活动相对应的生长速率和与生物量相对应的树木茎体积较大，溪流中TN的负荷一般较小，树木对氮的同化变得活跃。由于径流过程非常缓慢，径流中全氮的季节变化不大。提出了一种利用遥感数据的多重概率分布估计生物量和植被活动相关植被特征分布的新方法。利用Landsat/TM数据和森林进行适用性调查，结果表明该方法优于ISODATA方法。良好的水环境必须通过物质循环系统的连续性来创造，森林经营的控制和防止连续性的人类活动成为流域管理。为了保持物质的持续流通，居民在流域内建立监测系统，管理机构或研究机构收集各种水环境数据变得非常重要。

The relationship between the total nitrogen (TN) balance and the vegetation characteristics in a few forested mountain areas was investigated by field observations and GIS analysis of the forest lists and the satellite remote sensing data. The results were summarized as follows.1. A mathematical model of TN balance in the atmosphere was developed to evaluate the supplied TN from the atmosphere into the forested mountain area through the rainwater. The governing factors of the accumulation process of TN in the atmosphere were advection of TN in the atmosphere and the removal of TN by the precipitation, and the seasonal variation of TN concentration in the rainwater, which were obtained during the longer measurement period, could be estimated well.2. TN loading in the stream water was generally small and the assimilation of nitrogen in trees become active in the forest watershed in which the growth rate corresponding to the vegetation activity and the stem volume of tree corresponding to the biomass were large. Seasonal variations of TN in the stream water were not large because the runoff process of TN was very slow.3. A new method to estimate the distributions of vegetation characteristics related to the biomass and vegetation activities is proposed by using multiple probability distributions of remotely sensed data. The applicability was investigated by using Landsat/TM data and the forest, and it was better than the ISODATA method.4. A sound water environment must be created by the keeping continuity on the material circulation system and the control of the forest management and the human activities preventing the continuity becomes the watershed management. To keep the continuous material circulation it becomes important for residence to establish the monitoring system in the watershed and for organizations of administrations or research institutes to collect Various water environmental data.