Ground-Based UV Measurements of BrO and OClO over Ny-Ålesund during Winter 1996 and 1997 and Andøya during Winter 1998/99

Presented here are measurements of BrO and OClO performed by ground-based UV-visible zenith-sky viewing spectrometers developed by the Norwegian Institute for Air Research (NILU). Measurements were taken at Ny-Ålesund, Spitsbergen (79° N, 11° E), in winter and spring1996 and 1997 and at Andøya (69.3° N, 16° E) from summer 1998 until summer 1999. AM and PM differential slant column densities (DSCDs) at 90°SZA of BrO and OClO reached their maxima during polar vortex conditions in the winter months and were anti-correlated to temperature andNO₂. Comparison of BrO with a 3-D chemical transport model showed good agreement for seasonal trends and non-vortex conditions. BrO AM/PM ratios were underestimated by the model for vortex conditions, indicating the need for better quantification of BrO source and sink reaction rates. The detection of OClO above 200 K at the 475 K isentropic level indicates the possible activation of chlorine on sulphate particles. Several episodes of boundary layer ozone depletion due to marine-derived BrO were evident in our zenith-skyspectra during April 1997 in Ny-Ålesund.     

冷浸-氟硅酸钾法测定矿石中的二氧化硅

以氢氟酸、硝酸、过氧化氢混合溶剂冷浸过夜的方式分解样品 ,然后在 3mol/ L硝酸溶液加入氯化钾生成氟硅酸钾沉淀 ,经过滤、洗涤后以沸水水解 ,所生成的氢氟酸用氢氧化钠标准溶液滴定 ,来测定二氧化硅的含量。方法操作简便 ,易于掌握。经标样验证 ,结果吻合     

论大气二氧化碳温室效应的饱和度

利用最新版本的大气分子吸收光谱资料HITRAN2000，用精确的逐线积分算法，计算了大气CO₂浓度变化后产生的辐射强迫。在此基础上，研究了CO₂温室效应的饱和度以及影响CO₂辐射强迫的各种因子。主要结论如下：地面温度愈高，一般辐射强迫也愈大，但辐射强迫并不完全取决于地面温度，它还受大气温度廓线的强烈影响；研究的 6种模式大气中，吸收带重叠对热带大气的CO₂辐射强迫影响最大，对亚极冬季大气的影响最小；与长波辐射强迫相比，短波辐射强迫的贡献很小；CO₂的温室效应在15μm带中心等波段确实已经达到饱和，但在其它（15μm带两翼，10μm，5.2μm带等）波段远未达到饱和，在最近的将来也不会达到饱和。     

The carbon isotopic ratio of atmospheric carbon dioxide at Tsukuba,Japan

To find out the secular and seasonal trends of the ¹³C value and CO₂ concentration in the surface air and the determination of the ¹³C in the atmospheric CO₂ collected at Tsukuba Science City was carried out during the period from July 1981 to October 1983. The monthly average of the ¹³C value of CO₂ in the surface air collected at 1400 LMT ranged from -7.52 to \s-8.45 with an average of -7.96±0.25 and the CO₂ concentration in the air varied from 334.5 l 1^-1 to 359 l 1^-1 with an average of 347.2±6.3 l 1^-1. The ¹³C value is high in summer and low in winter and is negatively correlated with the CO₂ concentration. In general, the relationship between the ¹³C and the CO₂ concentration is explainable by a simple mixing model of two different constant carbon isotopic species but the relationship does not always follow the model. The correlation between the ¹³C value and the CO₂ concentration is low during the plant growth season and high at other times. The observed negative deviation of the ¹³C value from the simple mixing model in the plant growth season is partly due to the isotopic fractionation process which takes place in the land biota.     

The oxidation of S(IV) during riming by cloud droplets

Experiments have been performed to investigate whether the process of freezing during riming in clouds may induce oxidation of dissolved SO₂ to SO ₄ ^2– . The experiments were conducted in a cold room at varying temperatures between –6 and –15 °C. Solutions containing dissolved SO₂ and NH₄OH in various proportions, in the range of concentrations between 3×10^–5 and 10^–3 M, were sprayed. Rime was collected on a rotating cylinder and analyzed. Absorption of oxygen from laboratory air was prevented, except in the spray, to avoid spurious oxidation. Blank experiments were made at +3 to +6 °C. The results indicate clearly that, as the dominant cation becomes NH ₄ ⁺ rather than H⁺, substantial oxidation of S(IV) occurs during riming. This is consistent with redox reactions taking place as a result of charge separation at the ice-water interface during freezing.     

硫酸钡的氧硫同位素分析方法及有关数据的地质应用实例

碳粉在高温条件下可还原硫酸钡，使其氧转入ＣＯ２及ＣＯ气体中。此ＣＯ气体在高温镍金属的催化作用下，可转化为ＣＯ２气体。两种ＣＯ２合并后，可用质谱计分析其氧同位素组成。此组成便是硫酸钡的δ（１８）Ｏ值。水体硫酸根的氧、硫同位素值在水环境研究中大有用处。例如，三山岛金矿矿井水中硫酸根的氧、硫同位素数据表明，此水是地下水及海水的混合产物。这就为矿井排水工程的设计提供出某种信息。     

龙滩水电站坝址区平洞地垢量的估算

龙滩水电站坝址区大部分平洞均存在结垢现象，且从洞口往里，碳酸钙厚度逐渐变薄。从土壤CO2对岩溶作用的驱动、土壤与外界CO2浓度的差异对碳酸钙结垢的影响出发，结合降雨资料及左岸岩体渗透张量的特征，粗略估算了强、弱微风化带内每平方米洞壁的结垢量，估算的结果与 洞壁的 实际情况相符。     

Carbon dioxide and methane in the Arctic atmosphere

Fifty flask air samples were taken during April 1986 from a NOAA WP-3D Orion aircraft which flew missions across a broad region of the Arctic as part of the second Arctic Gas and Aerosol Sampling Program (AGASP II). The samples were subsequently analyzed for both carbon dioxide (CO₂) and methane (CH₄). The samples were taken in well-defined layers of Arctic haze, in the background troposphere where no haze was detected, and from near the surface to the lower stratosphere. Vertical profiles were specifically measured in the vicinity of Barrow, Alaska to enable comparisons with routine surface measurements made at the NOAA/GMCC observatory. Elevated levels of both methane and carbon dioxide were found in haze layers. For samples taken in the background troposphere we found negative vertical gradients (lower concentrations aloft) for both gases. For the entire data set (including samples collected in the haze layers) we found a strong positive correlation between the methane and carbon dioxide concentrations, with a linear regression slope of 17.5 ppb CH₄/ppm CO₂, a standard error of 0.6, and a correlation coefficient (r²) of 0.95. This correlation between the two gases seen in the aircraft samples was corroborated by in situ surface measurements of these gases made at the Barrow observatory during March and April 1986. We also find a similar relationship between methane and carbon dioxide measured concurrenty for a short period in the moderately polluted urban atmosphere of Boulder, Colorado. We suggest that the strong correlation between methane and carbon dioxide concentrations reflects a common source region for both, with subsequent long-range transport of the polluted air to the Arctic.     

Low-level atmospheric sulfur dioxide measurement using HPLC/fluorescence detection

An automated technique for measuring SO₂ in ambient air has been developed. Air is passed through a gas/liquid exchange coil with an aqueous absorber solution containing 10 µM formaldehyde and 0.84 mM Na₂EDTA. The SO₂ rapidly equilibrates with bisulfite (HSO ₃ ^– ) and sulfite (SO ₃ ^2– ) in the aqueous solution. The aqueous S(IV) is subsequently reacted with o-phthaladehyde in the presence of excess ethanolamine to form a fluorescent isoindole in a continuous flow stream. This derivative is then separated using reversed phase HPLC and detected via fluorescence with excitation and emission wavelengths at 330 and 380 nm, respectively. The lower limit of detection is 7 pptv (S/N=3), with a measurement period of eight minutes per sample. The instrument response is linear over several orders of magnitude.     

Grab sampling for the determination of sulfur dioxide and dimethyl sulfide in air by isotope dilution gas chromatography/mass spectrometry

Developments allowing the direct determination of sulfur dioxide and dimethyl sulfide in grab samples by gas chromatography/mass spectrometry with isotopically labeled standards (GC/MS/ILS) are reported. Isotopomers of DMS and SO₂ are used as internal standards. Spiked air samples are dried to a dew point of <–60 °C and trapped cryogenically in loops of Teflon tubing. Sealed samples are transported to the laboratory under liquid nitrogen and later subjected to GC/MS analysis. Holding times of up to one month do not result in significant sample loss. For samples collected in a clean marine environment, concentrations of SO₂ and DMS greater than 5 and 8 pptv, respectively, are significantly different from blanks at the 95% confidence level. Average measurement precision derived from a propagation of errors are 9% for SO₂ and 42% for DMS at concentrations from 5–15 pptv.Improvements are outlined which should provide sensitivity and precision comparable to that of on-site GC/MS. The technique will allow increased flexibility for the determination of trace sulfur species in the field under conditions where deployment of a mass spectrometer is not possible.