光化学臭氧日变化特征与其前体物关系的探讨

应用大气光化学模式研究了日最大臭氧体积分数及其出现时刻与其前体物NMHC、NOx体积分数及NMHC／NOx比值的关系。结果表明，影响日最大臭氧体积分数（ψ03max）脊线位置（EKMA图，Empirical Kinetic Modeling Approach）的关键因子是NMHC成份组成比例；日臭氧体积分数达到最大值需要的时间（τ03max）与NMHC／NOx比值及NMHC成份组成比例有关，与NMHC、NOx体积分数关系不大。此外，利用该结果解释了近20a北京日最大臭氧体积分数出现时刻具有不断提前的变化趋势的原因。     

区域性光化学模式与LLA-C机制的模拟性能比较

以LLA-C机制为基准,在[NOx]比率分别为1.79、7.14、28.6条件下测试了区域性光化学模式（ROS）的模拟性能。结果表明ROS模式在上述三种初值条件下均能从总体趋势上给出与LLA-C机制相似的结果,但只有当非甲烷烃浓度较高（[NMHC]/[NOx]>12）时ROS模式模拟值与LLA-C机制预测值比较接近。在这种条件下,ROS模型对OH的预测值有待改进。我国大气中相当高的[NMHC]/[NOx]比率说明ROS模式用于全国范围内的空气质量趋势模拟是可行的。     

近地面O3变化化学反应机理的数值研究

利用中尺度气象模式（MM5）及区域化学模式（RADM）对中国地区近地面O3变化化学反应机理进行了数值模拟研究。主要研究了近地面O3变化与其主要前体物NMHC（非甲烷烃）、NOx、CO等之间复杂相互作用关系。主要结论为:（1） 污染地区近地面O3变化主要受光化学作用控制;而清洁地区地面O3变化主要受大气背景O3浓度影响。（2）NMHC和NOx的变化对HO2和OH自由基的影响是十分复杂的,O3的反馈作用对自由基的影响是不可忽视的。（3）在高NOx污染地区的地面上空可能出现高O3污染。（4）在O3光化学反应机理中同样存在线性相关关系。     

对流层氮氧化物光化学转化特征研究

应用大气光化学模式研究了日间影响NOx光化学转化率的主要物理化学因子.探讨了在不同NMHC/NOx比值时,NOx光化学特征及其转化产物的变化规律.结果表明,影响NOx转化率的主要因子是阳光辐射强度和NMHC/NOx比值.但在NMHC/NOx比值很低时,光强的增加并不能显著提高NOx转化率.温度和初始臭氧浓度对NOx转化率的影响次之.相对湿度对NOx转化率的影响较小.在不同NMHC/NOx比值下,NOx转化特征和产物有很大区别.NMHC/NOx比值高时,产物中PAN＞HNO3.NMHC/NOx比值中(低)时,产物主要是HNO3,PAN等有机氮不到10%(1%).最后初步比较了模拟和观测的NOy组成.     

高NOx条件下非甲烷烃体积分数的变化对O3生成量的影响

利用ＬＬＡ－Ｃ光化学反应机制,在ＮＯＸ保持高值不变时,模拟分布范围很广的８种初始［ＮＭＨＣ］／［ＮＯｘ］（１０９／１０９）（１．０、３．０、７．１、１４．３、２８．６、５７．２、１００．０、２００．０）条件下臭氧体积分数的变化。模拟结果表明,当［ＮＭＨＣ］／［ＮＯｘ］≥１５．０时,臭氧生成量对ＮＭＨＣ的改变不大敏感而主要依赖于ＮＯｘ的大小。但是,当非甲烷烃与氮氧化物的比北较低（＜７．０）时,臭氧生成量紧密地依赖于非甲烷烃体积分数。进一步的验证工作还有待于加强。     

大气甲烷浓度长期变化及未来趋势

应用初步建立的全球二维大气化学模式,对工业革命以来甲烷的长期变化进行了模拟研究。模式将CH4、CO和NOx排放源方案进行了参数化。在考虑了CH4排放源以及对OH浓度有重要影响的CO和NOx排放源的长期变化的基础上,模拟了CH4和OH浓度自1840年到20世纪90年代的长期变化趋势。结果表明,工业革命前的大气甲烷体积分数和年排放总量分别为760×10-9和280Tg,1991年大气甲烷的体积分数和年排放总量分别为1611.9×10-9和533.9Tg。而对流层中OH的数密度则由1840年的7.17×105cm-3变化到1991年的5.79×105cm-3,下降了19%。如果CH4、CO及NOx这三种排放源继续按给定的方案增长,那么到2020年大气甲烷的体积分数和年排放总量将增加为2090.7×10-9和966.2Tg,而OH的数密度将为5.47×105cm-3,比1840年降低24%。     

光化学烟雾的控制试验

利用MM5与RADM的耦合模式,设计了3个削减源排放的试验,用以探讨控制光化学污染的有效途径。试验结果表明,在NMHC/NOx比值很大的前提条件下,NOx地面源排放的削减对降低大气中O3含量的作用最显著,而削减NMHC对降低大气中PAN含量的作用明显,同时削减NMHC和NOx是降低大气光化学污染强度的最佳途径。     

大气中一氧化碳浓度变化的模拟研究

应用全球二维大气化学模式,模拟了CO、CH4和OH自由基等成分自工业革命到2020年的长期变化.模拟的全球CO平均体积分数在1840年、1991年和2020年分别为27×10-6、76×10-6和105×10-6.从1840到1991年,OH自由基数浓度从7.17×105个分子/cm3下降到5.79×105个分子/cm3,降低了19%.模拟的CH4长期变化与冰芯资料相符.模拟的20世纪80年代CO体积分数年增长率为1.03%～1.06%.大气中CO在20世纪90年代前是增长的,而到90年代初观测到CO体积分数突然下降.应用二维大气化学模式对此原因进行了模拟研究,结果表明,CO排放源的减少是CO体积分数下降的主要因子,平流层臭氧减少是另一个重要因子.尽管CO排放源的减少对大气CH4增长率的变化有较大影响,而CH4排放源减少对CO体积分数变化却几乎没有影响.     

应用查表法模拟区域对流层O3、Nox分布和演化的研究

应用STEM-II气相光化学模式探讨了影响对流层O3、NOx气相光化学转化率的各物理、化学因子。表明在我国多数地区光化学污染物特征(NMHC/NOx较高)下,光辐射强度、温度、初始O3浓度和NOx浓度是影响O3、NOx气相光化学转化率的主要因子。将以上因子分档组合,计算并建立了各种情况下O3、NOx气相光化学转化率的查算表,并将之用于模拟区域O3、NOx的演化和分布。结果表明,与光化学模式直接耦合计算法相比,该方法既能显著缩短计算时间,又能基本反映大气化学反应的非线性过程,并与直接耦合法符合得较好。     

冷锋天气大气边界层内臭氧及 氮氧化物的观测研究

利用北京325 m气象塔作为高空平台,于1997年10月观测到一次冷锋过程大气边界层内O3及NOx体积分数的变化,研究了O3及NOx体积分数与气象要素之间的关系,着重讨论了冷锋过境前后O3及NOx的体积分数变化及其与输送过程的关系。研究表明:北京大气边界层中下层存在明显的O3体积分数垂直梯度,O3的垂直输送与风速及温度梯度密切相关。冷锋过程有利于高层O3向低层输送,使O3体积分数垂直梯度明显减小,并使NOx体积分数显著降低。     

全国各省市气象科技期刊文章摘编（33）

1傅里叶相位技术在雷达回波移动矢量特征分析中的应用 《南京气象学院学报》2008年第4期肖现中国科学院大气物理研究院100029     

氨基酸离子液体[bmin]Gly的合成探索及表征

探索两步法合成1-丁基-3-甲基咪唑甘氨酸离子液体([bmim]Gly)的反应条件.第一步,采用阴离子树脂静态交换法由1-丁基-3-甲基咪唑溴盐([bmim]Br)与强碱性阴离子树脂生成中间产物1-丁基-3-甲基咪唑氢氧化物([bmim]OH),通过单因素实验获得其最佳交换条件;第二步,[bmim]OH与甘氨酸(Gly)反应,经脱水、洗涤后得目标产物.对产物进行核磁(¹H NMR)和红外(IR)表征,结果表明产品纯度较高.与动态合成法相比,静态法合成[bmim]Gly操作简便,节水省时,有助于实现氨基酸离子液体合成过程的绿色化和工业化.     

白洋淀水陆不均匀地区能量平衡特征分析

应用2005年9月在河北白洋淀地区进行的大气边界层综合观测实验资料, 对水陆不均匀地表条件下的白洋淀地区陆地的能量平衡特征进行了分析。结果表明: (1) 该地区存在能量不闭合现象。涡动相关法得到的感热、 潜热之和仅为有效能的75%, 其中涡动相关法得到的潜热通量为Bowen比法得到的潜热通量的70%, 而涡动相关法得到的感热通量为Bowen比法得到的感热通量的77% 。 (2) 地表潜热通量和感热通量随着净辐射的变化而变化。但潜热通量明显比感热通量大, 净辐射主要消耗于地表的水汽蒸发。 (3) 该地区白天的Bowen比平均在-0.4~0.4之间, 总体平均为0.131。受天气条件影响较大, 有明显的日变化, 午后15:00以后近地面层会出现逆温, Bowen比变为负值。 (4) 能量闭合程度有一定的日变化, 随着太阳高度角的增大而增大。     

Compound[ing] disasters in Puerto Rico: Pathways for virtual transdisciplinary collaboration to enhance community resilience

Puerto Rico has been subject to complex and compounding effects of multiple disasters, exacerbated by sociopolitical, climactic, and geographical challenges that complicate relief and resilience. Interdisciplinary teams are uniquely suited to traverse emerging challenges in post-disaster settings, but there are few studies that leverage transdisciplinary skill sets and virtual co-production of knowledge to build on local autonomous responses. Communities are key sources of information and innovation which can serve as a model for recovery amidst disaster. Thus, an interdisciplinary team of emerging scholars collaborated with Caras con Causa, a local organization in Cataño, Puerto Rico, to develop processes for enhancing autonomous responses to disaster events through participatory pathways, specifically highlighting local knowledge and preferences. The results of this collaboration include: (1) an iterative process model for transdisciplinary co-production in virtual settings and (2) key highlights from post engagement reflections including community-scale definitions of disaster, and limitations to virtual collaboration amidst disaster. Together, these results yielded critical insights and lessons learned, including recommendations for improved project communication methods within transdisciplinary and virtual collaborations. Collectively, the process, it’s resulting products, and the post-engagement reflections demonstrate a pathway for scholars and community members to engage disaster resilience challenges. These strategies are most effectively practiced through focused collaboration with community stakeholders and are paramount in solving real-world challenges related to the increasing complex of compounding disasters.     

Combined effects of elevated [CO2] and high temperature on leaf mineral balance in Coffea spp. plants

Modelling studies predicted that climate change will have strong impacts on the coffee crop, although no information on the effective impact of elevated CO₂ on this plant exists. Here, we aim at providing a first glimpse on the effect of the combined impact of enhanced [CO₂] and high temperature on the leaf mineral content and balance on this important tropical crop. Potted plants from two genotypes of Coffea arabica (cv. Icatu and IPR 108) and one from C. canephora (cv. Conilon Clone 153) were grown under 380 or 700 μL CO₂ L^?1 air, for 1 year, after which were exposed to an stepwise increase in temperature from 25/20 °C (day/night) up to 42/34 °C, over 8 weeks. Leaf macro???(N, P, K, Ca, Mg, S) and micronutrients (B, Cu, Fe, Mn, Zn) concentrations were analyzed at 25/20 °C (control), 31/25 °C, 37/30 °C and 42/34 °C. At the control temperature, the 700 μL L^?1 grown plants showed a moderate dilution effect (between 7 % and 25 %) in CL 153 (for N, Mg, Ca, Fe) and Icatu (for N, K and Fe), but not in IPR 108 (except for Fe) when compared to the 380 μL L^?1 plants. For temperatures higher than control most nutrients tended to increase, frequently presenting maximal contents at 42/34 °C (or 37/30 °C), although the relation between [CO₂] treatments did not appreciably change. Such increases offset the few dilution effects observed under high growth [CO₂] at 25/20 °C. No clear species responses were found considering [CO₂] and temperature impacts, although IPR 108 seemed less sensitive to [CO₂]. Despite the changes promoted by [CO₂] and heat, the large majority of mineral ratios were kept within a range considered adequate, suggesting that this plant can maintain mineral balances in a context of climate changes and global warming.     

Interactive effects of elevated [CO2] and temperature on growth and development of a short- and long-season peanut cultivar

Temperature and CO₂ are two of the main environmental factors associated with climate change. It is generally expected that elevated [CO₂] will increase crop production. However, other environmental factors such as temperature along with management practices could further modify a crop’s response to CO₂. The goal of this study was to determine the interactive effects of elevated [CO₂] and above-optimum temperature on growth, development and yield of two peanut (Arachis hypogaea L.) cultivars, e.g., Pronto and Georgia Green. One of the objectives was to determine if there was any variation in response between these two cultivars with respect to possible adaptation to climate change. Peanut plants were grown in controlled environment chambers in the University of Georgia Envirotron under conditions of non-limiting water and nutrient supply. Plants were exposed to day/night air temperatures of 33/21°C (T _A), 35.5/23.5°C (T _A + 2.5°C), and 38/26°C (T _A + 5°C) along with CO₂ treatments of 400 and 700 μmol CO₂ mol^???1 air. The selected range of temperatures was based on the temperatures that are common for southwest Georgia during the summer months. The results showed that LAI of both cultivars responded positively, e.g., 28.3% for Pronto and 49.3% for Georgia Green to elevated [CO₂]. Overall, elevated [CO₂] alone resulted in a significant increase in total biomass at final harvest across all temperatures (P?< 0.0001), but decreased final seed yield (P?< 0.0005), except for Georgia Green at (T _A + 5°C). The higher temperatures compared to T _A reduced the relative response of total biomass to CO₂ for both cultivars. It can be concluded that final seed yield response to CO₂ depends on the sensitivity of individual cultivars to temperature, especially during the reproductive development stage.