Summertime diurnal variations of atmospheric peroxides and formaldehyde in Sweden     

Howard B. Ross  Christer Johansson  Claes de Serves  John Lind 《Journal of Atmospheric Chemistry》1992,14(1-4):411-423

Atmospheric peroxides and formaldehyde were measured at two sites in Sweden; inside a Scots pine stand (Jädraås) and on top of Mt. Åreskutan (1250 msl). Peroxide levels at Jädraås were highest during the day and lowest during the night. Mid-day concentrations of H₂O₂ varied between 0.05 and 2 ppbv. Isentropic trajectories together with local O₃ measurements indicated the importance of long range transport on surface H₂O₂ lévels. Large diurnal variations and vertical profiles showed the importance of turbulent mixing processes and dry deposition. A comparison of H₂O₂ and O₃ diurnal variations indicated a more rapid dry deposition of H₂O₂ to the forest. It would appear that terpenes emitted from the forest play a minor role in controlling the H₂O₂ levels. Formaldehyde at Jädraås had a different diurnal variation than peroxides; highest levels were observed in the early evening indicating chemical production of CH₂O. Diurnal variations of peroxides on Mt Åreskutan were opposite to those at Jädraås, highest concentrations were observed during the night. This result is to be expected if during the day air from inside the valley, with lower peroxide levels relative to the free troposphere, rises to the mountain top. In the evening, subsidence brings free tropospheric air with higher peroxides levels to the mountain.  相似文献   

北半球大气臭氧和气温的关系   总被引：2，自引：0，他引：2  

吴统文  郑光  瞿章  惠小英 《高原气象》1992,(2)

本文根据北半球21个臭氧站1979年7月1—31日逐日日平均臭氧总量与日平均10—200hPa气温资料,分析了逐日臭氧变化与气温变化的相互联系和影响。结果发现,臭氧总量变化落后于50—200hPa层气温变化,超前于5—50hPa层气温变化。  相似文献   

The potential impact of the reaction OH+ClO→HCl+O2 on polar ozone photochemistry     

D. J. Lary  M. P. Chipperfield  R. Toumi 《Journal of Atmospheric Chemistry》1995,21(1):61-79

We call attention to the likely importance of the potential reaction OH+ClOHCl+O₂. It may only be a minor channel for the reaction of OH with ClO, which is often ignored in models, but if it occurs it considerably increases the rate of recovery of HCl after an air parcel has encountered a polar stratospheric cloud (PSC). The net effect of this reaction on the ozone concentration depends on the relative HCl concentration and whether the air parcel is in a PSC. When an air parcel is in a PSC and the HCl concentration is less than the sum of the HOCl and ClONO₂ concentrations, heterogeneous ClO _x production is rate limited by the production of HCl. Under these conditions the reaction allows HCl to be reprocessed more rapidly by the heterogeneous reactions of HCl with HOCl and ClONO₂. This allows high ClO _x concentration to be maintained for longer, and at a slightly higher level, than would otherwise be possible which in turn leads to more ozone depletion. When there are PSCs but HCl is in excess, or outside of the PSC regions (i.e. during the recovery phase), the reaction will always reduce the ClO/HCl ratio and hence slightly reduce the ozone loss.  相似文献   

Transformation of Irradiance Measurements into Spectral Actinic Flux for Photolysis Rates Determination     

HÉLÈNE COTTE  CLAUDE DEVAUX  PATRICK CARLIER 《Journal of Atmospheric Chemistry》1997,26(1):1-28

The actinic flux is the only radiometric quantity suitable for photolysisfrequency determination. It is derived from solar spectral irradiancemeasurements performed by a portable spectroradiometer in the 300–850nm wavelength range. The spectral irradiance is first divided into a directpart and a diffuse part, according to the atmospheric conditions, and thenconverted into the corresponding actinic flux quantity. As an intermediary,the ratio of diffuse actinic flux to diffuseirradiance is calculated by the spherical harmonics radiative code withrespect to wavelength, solar zenith angle, surface albedo, and aerosolproperties.The results of extensive sensitivity studies of asa function of the main atmospheric parameters are discussed and lead to theconclusion that aerosol optical depth is the major critical value for aprecise determination. The global algorithm totransform spectral irradiance into actinic flux is finally applied forphotodissociation rate calculations by convolution of the obtained actinicflux spectra with the absorption cross-sections and quantum yields of themolecule studied. Photolysis rates of different atmospheric photooxidants havebeen measured with this spectroradiometric method during the summers of 1993and 1994 in Brittany and in Portugal. The ozone and nitrogen dioxidephotodissociation rates obtained present a good agreement with thej(O₃) and j(NO₂) actinometerresults, for the same experimental conditions in Brittany.  相似文献   

未来百年夏季青藏高原臭氧变化趋势及可能机制   总被引：1，自引：0，他引：1       下载免费PDF全文

苏昱丞  郭栋  郭胜利  施春华  刘仁强  刘煜  宋刘明  徐建军 《大气科学学报》2016,39(3):309-317

利用全大气气候通用模式(WACCM3)对政府间气候变化专门委员会排放情景特别报告中2001年到2099年A1B、A2、B1三种排放情景进行了模拟,分析了三种排放情景下青藏高原地区未来百年臭氧总量在夏季(6—8月)的变化趋势及引起该变化的可能机制。结果表明:在三种排放情景下未来百年夏季高原区臭氧总量均呈现增长趋势,其中A2情景下臭氧增长最快,B1情景下增长最慢,但相对于同纬度其他地区,高原区的臭氧总量增长较慢,即高原区臭氧谷加深。高原区高空污染物的减少以及局域Hadley环流的减弱是未来高原区臭氧总量增加的原因;而南亚高压的增强,以及与之相对应的辐散增强则可能是高原区臭氧谷继续加深的原因。  相似文献   

氟利昂R12及其替代物的分子构型和特征光谱研究     

李静  刘玉柱  程启源  陈飞  林华  秦朝朝 《南京气象学院学报》2016,8(4):327-332

采用密度泛函理论对氟利昂R12及其替代物R134a在B3LYP/6-311G++（d,p）基组水平上进行结构优化和特征光谱计算.首次在该高精度基组下优化得到了R12和R134a的键长、键角和二面角等分子构型参数,且通过进一步的计算,得到了这两种分子的红外光谱和拉曼光谱.其中R12红外光谱的计算结果与美国国家标准局数据库（NIST）提供的实验结果基本吻合,说明了计算结果的准确性.另外通过从头算CIS方法对能量进行计算,得到了R12和R134a的紫外可见吸收光谱.计算结果可为进一步保护大气臭氧提供有用的数据参考.  相似文献   

对流层臭氧影响植被研究进展:观测、参数化方案及应用     

周智敏  李芳  曾晓东  倪长健 《气候与环境研究》2017,22(5):613-622

对流层臭氧(O_3)作为最重要的大气污染物之一,对植物的形态特征和生理生化指标有着重要影响;并通过作用于陆面植被间接改变全球和区域的碳循环以及气候和环境。本文系统地回顾了对流层臭氧影响陆面植被的观测事实,主要包括其对光合作用、气孔导度、叶面积、生物量、产量等方面的影响;归纳和分析了常用的O_3暴露指数(ozone exposure index)和O_3影响植被的参数化方案的优缺点;并介绍这些参数化方案应用于生态模式和地球系统模式,模拟O_3通过作用于陆面植被对碳、水、能量通量和状态的影响。最后探讨了O_3影响植被在观测、参数化方案及其模拟应用方面亟需解决的问题以及未来发展方向。  相似文献   

臭氧处理海水生成氧化物对扁藻生长的影响海水养殖     

郑波  马甡  王成刚  谷向伟 《中国海洋大学学报(自然科学版)》2002,32(2):212-218

研究了臭氧处理海水生成氧化物对扁藻(Tetraselmis chuii)生长的影响.臭氧生成氧化物浓度在0.736mg/L以下不产生毒害作用,在1.113mg/L 以上观察到了毒害作用,并且浓度越高毒性越强.实验发现扁藻对臭氧生成氧化物的毒害有抵抗能力.  相似文献   

2008年以来青藏高原春季大气温度逆转趋势及其与臭氧总量变化之间的可能联系     

王晴  黄富祥  夏学齐 《气候变化研究进展》2019,15(4):385-394

利用ERA-Interim和MERRA-2再分析资料,考察1980—2017年青藏高原大气温度变化趋势和规律,年、季、月不同时间尺度分析结果均揭示2008年以来青藏高原春季大气温度变化呈现逆转趋势：高原上空平流层下部150~50 hPa呈现明显的增温趋势（1.0~2.7℃/10a),对流层上部300~175 hPa呈现明显的降温趋势（-3.1~-1.0℃/10a),这与此前的大气温度变化趋势完全相反。利用TOMS和OMI卫星臭氧遥感资料,考察同期青藏高原臭氧总量变化特征,表明2008年以来青藏高原臭氧总量也表现出逆转的增加趋势,与大气温度逆转趋势吻合,从冬末至春季各月均有显著增加趋势,尤以5月臭氧总量增加速率最大,达13.7 DU/10a。青藏高原春季大气温度变化趋势与同期臭氧总量变化特征紧密相关,2008年后臭氧总量的快速恢复可能是引起大气温度逆转趋势的一个重要影响因素。  相似文献   

Trends of Lower-to Mid-Stratospheric Water Vapor Simulated in Chemistry-Climate Models          下载免费PDF全文

HU Ding-Zhu  HAN Yuan-Yuan  SANG Wen-Jun  XIE Fei 《大气和海洋科学快报》2015,8(1):57-62

Using the outputs from 16 chemistry-climate models(CCMs), the trends of lower- to mid-stratospheric water vapor(WV) during the period 1980–2005 were studied. Comparisons were made between the CCM results and European Centre for Medium-Range Weather Forecasts(ECMWF) Interim Reanalysis(ERA-Interim).The results of most of the CCMs, and those based on ERA-Interim, showed the trends of lower- to mid-stratospheric WV during the period 1980–2005 to be positive, with the extent of the trend increasing with altitude. The trend of lower- to mid-stratospheric WV in the ensemble mean of the CCMs was 0.03 ppmv per decade,which was about twice as large as that based on ERA-Interim. The authors also used a state-of-the-art general circulation model to evaluate the impacts of greenhouse gas(GHG) concentration increases and ozone depletion on stratospheric WV. The simulation results showed that the increases of lower- to mid-stratospheric WV affected by the combined effects of GHG and ozone changes happened mainly via warming of the tropopause and enhancement of the Brewer-Dobson circulation(BDC), with the former being the greater contributor.GHG increase led to a higher and warmer tropopause with stronger BDC, which in turn led to more WV entering the stratosphere; while ozone depletion led to a higher and cooler tropopause, which caused the decreases of lowerto mid-stratospheric WV, despite also causing stronger BDC.  相似文献