基于XGBoost算法的WRF-Chem模式优化模拟

采用人工智能算法XGBoost结合大气化学模式WRF-Chem,利用北京地区大气污染物的模拟结果及站点监测数据,构建XGBoost统计预报算法模型,并对两种大气污染物（PM_2.5和O₃）进行优化模拟,同时分析其特征贡献要素.结果表明,该统计预报模型能够很好地优化大气化学模式模拟的大气污染物浓度,降低模拟误差,对于北京地区站点模拟浓度优化呈现出城区>近郊>远郊的优化特点,且算法模型对O₃浓度优化程度更高,优化后相关系数提高达128%.此外,通过特征要素的贡献量分析表明,CO是影响O₃优化的重要特征变量,城郊区特征贡献得分均高达1000以上,Q2（近地面2m比湿）是影响PM_2.5优化的重要气象特征变量,城郊区特征贡献得分分别为950和824.     

Ecological Change and the Challenges for Monitoring

Anthropogenic activities are changing the chemical composition of the global atmosphere. This results in changes to the physical properties as well, such as the radiation balance. These properties are important input variables for biospheric processes. This paper discusses a number of documented ecological changes that have occurred in response to the changing atmosphere. Much of the information has been derived from data collected at integrated monitoring sites. The changing atmosphere is expected to result in many more ecological changes to resources of economic as well as environmental value. Defining and understanding these changes will be necessary for managing sustainable development and poses major challenges for monitoring programs in general and for integrated sites in particular.     

Chemical leasing: cooperative business models for sustainable chemicals management. Summary of research projects commissioned by the Austrian Federal Ministry of Agriculture, Forestry, Environment and Water Management

- Sustainable chemistry - Section editors: Klaus Günter Steinhäuser, Steffi Richter, Petra Greiner, Jutta Penning, Michael AngrickBackground, Aim and Scope Chemicals play a vital role in the day-to-day life of industrialised societies. Their use is not restricted to the chemical enterprises per se, but is a crucial part of production processes in a lot of industrial sectors. Traditional instruments of environmental policy (such as bans, restrictions) can only deal with the most hazardous substances. The Johannesburg Implementation Plan of 2002 calls for more sustainable patterns of production and consumption, and sets the year of 2020 as a goal to use chemicals in a way that human health and the environment are not endangered. Political instruments should not only gather more knowledge about the properties of chemicals, but should also stimulate the environmentally sound use of chemicals. Existing business models should therefore be reviewed in relation to this strategic approach to encourage marketing options with respect to the environmental focus.Main Features Business models were examined for their effects on the consumption of chemicals and amount of waste emissions in relation to their economic potential. Different possibilities for cooperation of supplier, user and disposal companies were elaborated and examined with a view to the specific situation in Austria.Results and Discussion A range of cooperative models – summarised under the term ‘chemical leasing’ - was identified, which can contribute to a more efficient use of resources. 12 main possible application areas (cleaning, lubrication, paint stripping and others) have been identified in Austria. If chemical leasing models were applied in these areas, the amounts of chemicals currently used could be reduced by one third (53,000 tonnes per year). Cost reductions of up to 15 % can be expected.Conclusion The application of chemical leasing models can contribute considerably to achieving more sustainable and resource-efficient patterns of production. The Austrian Ministry for Environment has therefore decided to subsidise the further practical implementation of these new service-oriented business models. Pilot projects in 4 enterprises, which are supervised by consulting companies, are currently being carried out. Recommendation and Outlook The experiences of the pilot projects will serve as valuable building blocks for the wider use of chemical leasing models. Furthermore, the UNIDO Cleaner Production Centres have expressed their clear interest and will examine the possibility to use chemical leasing as a part of their Cleaner Production Programmes.     

Monitoring Long-term Trends in Sulfate and Ammonium in US Precipitation: Results from the National Atmospheric Deposition Program/National Trends Network

Data from the National Atmospheric Deposition Program/National Trends Network (NADP/NTN) indicate significant changes have occurred in precipitation chemistry and the chemical climate in the United States (US). A Seasonal Kendall Trend (SKT) analysis shows statistically significant increases in precipitation ammonium concentrations at 64% of 159 continental US NADP/NTN sites evaluated from Winter 1985 to Fall 2004 (Dec. 1984 – Nov. 2004). Sulfate decreases were widespread, with an SKT analysis indicating statistically significant decreases at 89% of sites evaluated. Ratios of chemical equivalent concentrations of ammonium to sulfate in precipitation have risen to the extent that ammonium now exceeds sulfate over more than half of the continental U.S. on a precipitation-weighted-mean annual basis. These trends in the concentrations of ammonium, sulfate, and other species have been accompanied by significant decreases in the frequency of acidic precipitation (pH < 5.0) in the last decade.     

工科有机化学教学目标与教学改革的探索

工科有机化学是面向工科专业开设的一门基础课,以往的教学只是按章节顺序详细介绍各类反应,内容多,难以记忆,而且各专业间差别不大.随着教改的不断发展,规定的教学时数愈来愈少,如何解决内容多与时间少的矛盾,如何体现专业特点成为我们急待解决的问题.我们主要从教学目标、教学内容、教学手段方面进行了一些尝试,取得了较好的效果.     

成都市干性降落物与道路粉尘的化学组成对比研究

为了弄清大气中微粒子的化学组成的特征，我们自2001年12月在成都市采集了干性降落物和道路粉尘，并对其水溶性阴离子成分进行了比较。通过分析认为干性降落物对道路粉尘的化学组分有影响。同时道路混凝土的污染物亦可进入道路粉尘。     

应用遗传神经网络方法分析我国降水化学数据

收集了１１１组包含Ｃａ＾２＋、Ｍｇ＾２＋等８种离子浓度和ＰＨ值的我国降水化学数据，并用遗传神经网络（Ｇｅｎｅｔｉｃ Ｎｅｕｒａｌ Ｎｅｔ－ｗｏｒｋｓ，ＧＮＮ）方法建立了这些离子浓度和ＰＨ值绵ＢＰ网络模式，运用这些模式计算了各离子浓度对ＰＨ值的贡献，结果表明，我国各地降水ＰＨ值与各地区酸性离子与碱性离子相互用途相关，其中生离子的中和作用起着主导作用。     

废物利用发展油田助剂

油田开发需要大量的化学助剂,由于昂贵的价格影响了成本。为减少耗资,吉林油田利用化工产品的下脚料和煤矸石等研制并合成了油田的化学助剂,例如增产剂、ＣＥＡ解堵剂、吗啉驱油剂、ＰＳ增油剂,以及堵水剂ＨＰＡＮ等。将其应用于生产,保护了生态环境,减少了环境污染,节省了大量资金。为油田废物再利用打开了极其广阔的应用市场。     

浊点萃取在环境化学方面的应用

浊点萃取（ＣＰＥ）是一种新兴的液－液、液－固萃取方法，通过对该方法的相分离行为，改变实验参数如表面活性剂疏水性，平衡温度及时间、离心时间、ｐＨ值、离子强度、萃取物与表面活性剂浓度、添加剂等研究现状，综述了这一方面的原理、操作及其优化，并以ＰＡＨｓ等１７种有机污染物为例示，详细讨论了这一方法对环境样品的前处理技术，以及用于环境污染的进展，最后，探讨了该技术方法的发展前景。     

云下洗脱-Eulerian模式

在Eulerian模式中,在大气氨浓度大于硝酸的条件下,简要讨论了各种污染物对雨水组成的影响.结果表明,在本文考虑的情况下,氨对SO_2气体洗脱和SO~(2-)形成的影响最大,且能抑制雨水的酸化;过氧化氢的作用略小于氨.气溶胶对雨水SO_4~(2-)浓度的贡献小于气体.云下H_2O_2和O_3氧化能力的大小取决于雨水的pH、降落距离和各自的浓度.在雨水pH高,降落距离短和各自浓度小时,O_3的氧化能力大于H_2O_2,反之则H_2O_2大于O_3.对韶关降水酸化的模拟表明,考虑气体污染物补充机制的Eulerian模式可以较好地模拟现场降水酸化过程.