SEIB–DGVM: A new Dynamic Global Vegetation Model using a spatially explicit individual-based approach

We report the development of a new spatially explicit individual-based Dynamic Global Vegetation Model (SEIB–DGVM), the first DGVM that can simulate the local interactions among individual trees within a spatially explicit virtual forest. In the model, a sample plot is placed at each grid box, and then the growth, competition, and decay of each individual tree within each plot is calculated by considering the environmental conditions for that tree as it relates to the trees that surround it. Based on these parameters only, the model simulated time lags between climate change and vegetation change. This time lags elongated when original biome was forest, because existing trees prevent newly establish trees from receiving enough sunlight and space to quickly replace the original vegetation. This time lags also elongated when horizontal heterogeneity of sunlight distribution was ignored, indicating the potential importance of horizontal heterogeneity for predicting transitional behavior of vegetation under changing climate. On a local scale, the model reproduced climate zone-specific patterns of succession, carbon dynamics, and water flux, although on a global scale, simulations were not always in agreement with observations. Because the SEIB–DGVM was formulated to the scale at which field biologists work, the measurements of relevant parameters and data comparisons are relatively straightforward, and the model should enable more robust modeling of terrestrial ecosystems.     

Using equation discovery to revise an Earth ecosystem model of the carbon net production

Equation discovery approaches to automated modeling from observed data usually derive equation-based models from scratch rather than from an initial model already established in the domain of use. In this paper, we present an approach that uses new or recent observational data to improve an existing equation-based model. The approach is used to reduce the error of the Earth ecosystem model of the net production of carbon in the atmosphere. We revise the initial ecosystem model in two directions. First, we calibrate the values of the constant parameters in the model on new observational data. Second, we allow the use of alternative equation structures for some of the sub-models of the initial model and use our approach to choose among them. Experiments show that both revision of values of the constant parameters and revision of the structures of sub-models can considerably reduce the error of the initial model.     

环境信息系统中关于办公自动化的探讨

在简要介绍环境信息系统概况的同时 ,重点在办公自动化系统上提出了一些体会 ,并从开发、应用等几方面说明了办公自动化系统作为一项系统工程在目前信息中的作用     

石墨炉原子吸收法测定大气中锡的研究

研究了１０种基体改进剂和不同石墨管对石墨炉法测定锡的影响，结果表明，使用热解涂层石墨管并采用铁－抗坏血酸作基体改进剂，可获得最高的灵敏度和最好的回收率，用此法对锡标准样品进行测定，所得结果与定值吻合，相对误差为３．０％￣４．０％，相对标准偏差为２．０％￣４．８％，检出限为０．４０μｇ／Ｌ。     

环境质量灰色评价模型及其应用

根据灰色关联分析的地质，构造目标函数，运用拉格朗日乘数法求极值，建立了一种新的环境质量评价模型．结合实例说明了该模型的具体应用．与其它方法进行了对比，结果完全一致．该模型数学推导严谨、科学合理、分辩率高、可靠性强．     

湿地可持续发展与经济损益的理论分析

文章分析了中国湿地可持续发展的基本内涵和人为干扰的限制因子，建立了湿地人为干扰破坏损益分析技术路线，提出了经济损益分析理论模型及损益度计量模型。     

石河子市大气中氮氧化物与气象条件的关系

用实测数据分析了石河子市大气中ＮＯｘ与气温，湿度和风速等气象因子的关系，得出结论是气温升高，风速增强，使大气中ＮＯｘ浓度值降低，相对湿度在７０％～８０％之间，其ＮＯｘ浓度较高，为此，气象条件诸如水平风速，大气温度，湿度和大气层结构的稳定与否均大对气污染物浓度产生重要影响。     

灰色聚类法在大气环境污染区划中的应用

灰色聚类法,对于大气环境污续多因子区划评价简便易行,是一种具有实用意义的新方法,结果直观,切合实际,令人满意。     

降水对金属材料的大气腐蚀速率影响研究

对甘肃省陇南地区、兰州市和新疆独山子的金属材料的大气腐蚀速率进行了分析测定,研究并比较了酸雨和非酸雨区的大气腐蚀速率,研究和探讨了相互关系。     

用灰色系统理论对乌鲁木齐市大气降水pH值进行预测分析

运用灰色系统理论建立灰色模型ＧＭ，对该模型进行了检验和残差修正。并用其模型分析和预测乌鲁木齐市１９９４＝１９９８年大气降水ｐＨ值。