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121.
MEASUREMENTS AND MODEL SIMULATIONS OF SURFACE OZONE VARIATIONS AT DIFFERENT BACKGROUND CONCENTRATIONS OF THE PRECURSORS 总被引:1,自引:0,他引:1
Ozone photochemical production and loss in very different environments at Waliguan baselinestation and Lin'an background station were simulated by using the measurement data and photo-chemical box model.The results show that net ozone photochemical production rate is negative,about 0.5 ppb/d,at Waliguan baseline sation,because of very low precursor concentrations.Butat Lin'an background station,the net photochemical ozone production is positive,about 2—3 ppb/h.which is very closed with the measurement at Lin'an.That means ozone production was con-trolled by photochemical reactions at Lin'an background station,because of the higher precursorconcentrations.The net destruction rate,at Waliguan Mt.,is not large,so that future increase inanthropogenic emission of reactive nitrogen will lead to larger production rates of steady-state O_3concentration. 相似文献
122.
单波高精度测距系统的研究 总被引:12,自引:0,他引:12
本文介绍了测距精度优于10^-6的自动高精度测距系统的构成、原理及春应用。 相似文献
123.
124.
大气臭氧与气溶胶垂直分布的高空气球探测 总被引:17,自引:2,他引:17
本文给出了1993年9月12日利用高空科学气球在河北省香河地区探测到的大气臭氧和气溶胶的垂直分布。结果发现:(1) 大气臭氧的数密度在整个对流层较低(~10[12]mol/cm3),并从地面到对流层顶略有下降;对流层顶以上开始快速增加,极值层高度在~24 km,其值为4.78×10[12]mol/cm3;臭氧分压有类似的分布特征,极值146×10[-4]Pa,位于同一高度;(2) 在平流层低层,臭氧分压有一个次极值62×10[-4]Pa,位于15~16 km;(3) 0~30 km大气气溶胶数密度呈现出三个峰值:143,8和1.1 个/cm[3],分别位于近地面、5 km和21 km;(4)气溶胶的数密度谱在对流层为双模态;在平流层,次峰消失。同时,我们还与其他观测结果作了比较分析。 相似文献
125.
126.
Loreto Donoso Rodrigo Romero Alberto Rondón Emmanuel Fernandez Pedro Oyola Eugenio Sanhueza 《Journal of Atmospheric Chemistry》1996,25(2):201-214
The levels of low molecular weight hydrocarbons were measured at pristine sites and rural locations affected by hydrocarbon emissions from oil and gas producing fields in Venezuela. At the clean sites, lower concentrations of C2 to C6 alkanes were observed, whereas, in comparison with remotes sites, very much higher levels were measured at the polluted sites. Alkenes present relatively high concentrations, with isoprene being the most abundant, all over the study region. The main sources of alkenes are likely to be natural, mainly from vegetation. The levels of alkanes recorded at the clean sites and the alkene levels found everywhere in the region are in agreement with the values reported for other clean sites in the tropics. The increase of ozone production capacity due to the anthropogenic emissions of alkanes from oil and gas fields was estimated. Due to the presence in the atmosphere of important amounts of naturally emitted isoprene, ethene and propene, which makes a substantial contribution to the reactivity of the hydrocarbon mixture, a small increase (<5%) was estimated to occur in the capacity of the ozone production at a regional scale during the rainy season. 相似文献
127.
S. J. Reid G. Vaughan A. R. W. Marsh H. G. J. Smit 《Journal of Atmospheric Chemistry》1996,25(2):215-226
Measurements of atmospheric ozone at concentrations typical of the free troposphere have been compared for ECC sondes and a UV-absorption photometer, using a Bendix chemiluminescent analyser as a transfer standard. Comparisons were conducted in the laboratory and in the tropospheric part of the atmosphere. It was found that the measurements agreed to within 4% provided that the background current for the ECC sonde was measured before exposure to ozone in the preparation procedure, and was assumed to be constant throughout the sonde flight. These results confirm those of earlier experiments and mean that the methods currently used to correct for the background current in the troposphere need to be revised. 相似文献
128.
Anomalies found in the isotope ratios of ozone are traceable to the ozone formation process. Metastable electronic states may be responsible for the preferred production of the heavy molecules. While laboratory isotope data and first tropospheric results agree well in the magnitude of isotope enrichments, stratospheric measurements show often higher values. Only through the collection of ozone samples can sufficiently large amounts of gas be obtained to analyze the three isotopes 48O3, 49O3, and 50O3. Collector systems have been developed and successfully operated in the troposphere and in the stratosphere. They will play in the future an important role in atmospheric oxygen isotope studies. 相似文献
129.
Sverre Solberg Norbert Schmidbauer Arne Semb Frode Stordal Øystein Hov 《Journal of Atmospheric Chemistry》1996,23(3):301-332
Several years of measurements of ozone, hydrocarbons, sulphate and meteorological parameters from Spitsbergen in the Norwegian Arctic are presented. Most of the measurements were taken on the Zeppelin Mountain at an altitude of 474 m a.s.l. The focus is the episodes of ozone depletion in the lower troposphere in spring, which are studied in a climatological way. Episodes of very low ozone concentrations are a common feature on the Zeppelin Mountain in spring. The low ozone episodes were observed from late March to the beginning of June. When the effect of transport direction was subtracted, the frequenty of the low ozone episodes was found to peak in the beginning of May, possibly reflecting the seasonal cycle in the actual depletion process. Analyses based on trajectory calculations show that most of the episodes occurred when the air masses were transported from W-N. Ozone soundings show that the ozone depletion may extend from the surface and up to 3–4 km altitude. The episodes were associated with a cold boundary layer beneath a thermally stable layer, suppressing mixing with the free troposphere. The concentration of several individual hydrocarbons was much lower during episodes of low ozone than for the average conditions. The change in concentration ratio between the hydrocarbons was in qualitative agreement with oxidation of hydrocarbons by Br and Cl atoms rather than by OH radicals. 相似文献
130.
Ground-based visible differential absorption spectrometry during twilight has been used for NO2 total column observations at the Antarctica Peninsula, Marambio Base (64S, 56W), during the austral spring of 1989 (9 September to 25 November).Results show moderate NO2 vertical column levels of 1.5 to 2.5×1015 molec cm-2 in the morning and 2 to 3×1015 molec cm-2 in the evening until middle October, highly modulated by planetary wave activity. From that date until the end of the period, a steady increase occurs which is associated with the rising of lower stratosphere temperature as the vortex weakens, reaching values of 5×1015 molec cm-2 in late November, with small a.m.-p.m. differences. NO2 is found to be positively correlated to both total ozone and 50 hPa temperature during the entire spring. However, when analyzing the departures from linear trends, a highly negative correlation has been observed from day 301 onwards. 相似文献