Seasonal and Diurnal Ozone Variations: Observations and Modeling

Ozone mixing ratios observed by the Bordeaux microwave radiometer between 1995 and 2002 in an altitude range 25–75 km show diurnal variations in the mesosphere and seasonal variations in terms of annual and semi-annual oscillations (SAO) in the stratosphere and in the mesosphere. The observations with 10–15 km altitude resolution are presented and compared to photochemical and transport model results.Diurnal ozone variations are analyzed by averaging the years 1995–1997 for four representative months and six altitude levels. The photochemical models show a good agreement with the observations for altitudes higher than 50 km. Seasonal ozone variations mainly appear as an annual cycle in the middle and upper stratosphere and a semi-annual cycle in the mesosphere with amplitude and phase depending on altitude. Higher resolution (2 km) HALOE (halogen occultation experiment) ozone observations show a phase reversal of the SAO between 44 and 64 km. In HALOE data, a tendancy for an opposite water vapour cycle can be identified in the altitude range 40–60 km.Generally, the relative variations at all altitudes are well explained by the transport model (up to 54 km) and the photochemical models. Only a newly developed photochemical model (1-D) with improved time-dependent treatment of water vapour profiles and solar flux manages to reproduce fairly well the absolute values.     

Simulation of stratospheric ozone in global forecast model using linear photochemistry parameterization

The two types of ozone, the simulation with interactive (prognostic) ozone using linear photochemistry parameterization (LPP) (INTR) and the simulation with non-interactive ozone using ozone climatology (CLIM), were used in the global forecast model. These two types of ozone were compared with ozone observations from the Aura Microwave Lim Sounder (MLS) and ozonesondes from 16-30 September 2008. The INTR is sensitive to LPP schemes while less sensitive to the time average of initial ozone data. Among three LPP schemes, CARIOLLE, COPCAT, and LINOZ, the COPCAT produces ozone profiles with least differences from MLS and ozonesondes. CLIM overestimates MLS at 200-20 hPa while INTR with COPCAT scheme underestimates MLS ozone above 5 hPa. Over the Antarctic in the lower stratosphere CLIM overestimates MLS and ozonesondes whereas INTR underestimates MLS but overestimates the ozonesonde data. Thus, COPCAT agrees better with ozonesonde data than any other LPP schemes and CLIM. Changing the ozone distribution from CLIM to INTR affects temperature profiles mainly through the modification of differential radiative fluxes. The correlations between ozone, differential radiative fluxes, and temperature are distinguished by altitude (or pressure levels). The correlations are strong or moderate between 3-1000 hPa (lower atmosphere) and weak above 3 hPa (upper atmosphere). This study demonstrates that the simulation of ozone using an appropriate LPP scheme is excellent in overcoming the drawbacks of using climatological ozone profiles that poorly agree with observations in extreme ozone hole events.     

中国中部典型高山气象站风速的均一性检验及其变化特点

采用二相回归方法并结合台站历史沿革信息,在对中国中部典型高山站南岳和庐山1960-2017年平均风速资料进行均一性检验和订正的基础上,分析其变化特征及其与周边低海拔台站的差异,并利用NCEP/NCAR再分析风速资料对其差异进行验证。结果表明：南岳站平均风速序列存在一个由测风仪器变更而导致的非均一点,而庐山站不存在非均一点;南岳和庐山年及四季平均风速均显著高于周边台站,且高山站以春季和夏季风速最大,而低海拔台站各季节风速差异较小;近58 a高山站及周边低海拔台站的年及四季平均风速均呈显著的减小趋势,但高山站的减小速率显著高于低海拔台站;同区域NCEP/NCAR的1000 hPa和850 hPa平均风速变化的差异与高山站和低海拔台站的差异基本一致,说明中低空和地面风速的这种差异在中国中部地区具有一定的普遍性。     

Concentration of trace gases in the lower troposphere,simultaneously recorded at neighboring mountain stations Part II: Ozone

Summary Long-term ozone recordings at different altitude levels, conducted in remote areas, can make a valuable contribution to an understanding of the background level of ozone, its periodical variations and possible long-term trends.The measuring stations (three high mountain stations between 740 and nearly 3000 m a.s.l. with small horizontal distance) are described together with recording and calibration procedures. Information is provided on the time history of all recordings since 1978, considering not only the annual means but also the monthly and 10-day means as a function of height. An analysis is presented of the annual variations which differ considerably in the respective height levels and—in three-dimensional diagrams—the correlation between daily and annual variation is shown as a function of height. Then follows a careful parameterization: analysis of the frequency distribution of the ozone concentration, correlation with relative humidity, relative sunshine duration, and temperature. It can be seen that the correlations are very different and partly inverse, depending on the altitude level.Many ozone profiles obtained between valley level and nearly 3000 m a.s.l. (cable car O₃ radiosonde) give a picture of the typical ozone profile for different meteorological situations and for the case of stratospheric intrusions of ozone into the troposphere. The stratospheric contribution of ozone to the tropospheric ozone budget is discussed.Since obviously a very high photochemical production rate can be established for ozone in the lowest layer above ground (correlation of O₃ with the daily variation of the sunshine duration) it was examined if this O₃ variation might be caused only by horizontal transport of ozone from remote areas with high anthropogenic activity by the daily quasiperiodical currents near the ground. But this is not the case.The correlation between ozone concentration, other trace gases such as nitrogen-oxygen compounds and hydrocarbons is shown.With 29 Figures     

Lower/middle tropospheric ozone variability in Senegal during pre-monsoon and monsoon periods of summer 2008: observations and model results

During the summer (8 June through 3 September) of 2008, 9 ozone profiles are examined from Dakar, Senegal (14.75°N, 17.49°W) to investigate ozone (O₃) variability in the lower/middle troposphere during the pre-monsoon and monsoon periods. Results during June 2008 (pre-monsoon period) show a reduction in O₃ concentrations, especially in the 850–700 hPa layer with Saharan Air Layer (SAL) events. However, O₃ concentrations are increased in the 950–900 hPa layer where the peak of the inversion is found and presumably the highest dust concentrations. We also use the WRF-CHEM model to gain greater insights for observations of reduced O₃ concentrations during the monsoon periods. In the transition period between 26 June and 2 July in the lower troposphere (925–600 hPa), a significant increase in O₃ concentrations (10–20 ppb) occur which we suggest is caused by enhanced biogenic NO_X emissions from Sahelian soils following rain events on 28 June and 1 July. The results suggest that during the pre-monsoon period ozone concentrations in the lower troposphere are controlled by the SAL, reducing ozone concentrations through heterogeneous chemical processes. At the base of the SAL we also find elevated levels of ozone, which we attribute to biogenic sources of NO_X from Saharan dust that are released in the presence of moist conditions. Once the monsoon period commences, lower ozone concentrations are observed and modeled which we attribute to the dry deposition of ozone and episodes of ozone poor air that is horizontally transported into the Sahel from low latitudes by African Easterly Waves (AEWs).     

北半球100 hPa等压面经向风与臭氧总量年变化

本文用多年平均的北半球100hPa经向风和臭氧总量资料分析了两者的关系,结果发现:臭氧总量的变化与100 hPa经向风密切相关,与100 hPa面上北风相对应的是臭氧高值区,与南风对应的是低值区,前者支配后者.充分说明了臭氧总量变化主要受低层平流层环流影响.     

国产ECC型O3探空仪性能测试及室外比对观测

该文介绍了中国科学院大气物理研究所（简称IAP）研制的电化学浓度电池（ECC）型臭氧（O₃）探空仪基本性能测试和2013年上半年室外比对观测结果。结果表明:ECC的背景电流（I_bg）在0.1 μA以下或更低;测量O₃的响应时间为21~26 s;NO₂（SO₂）使O₃测值偏高（低）;抽气泵低压泵效系数（C_ef）在100 hPa高度以下为1.0左右,在该高度以上上升,10 hPa达到1.17±0.10,5 hPa达到1.28±0.16,性能略低于同类进口产品（1.055以下）。国产和进口仪器在气象探空或抽气泵等部件上具有良好兼容性;两者所测O₃垂直分布廓线总体一致。IAP O₃探空仪O₃总量与Brewer光谱仪测值比值为0.9~1.1;C_ef和I_bg订正有效降低了IAP O₃探空仪在平流层低层与进口仪器测值的差别,这一订正对O₃柱浓度在平流层和对流层的贡献分别为约15 DU和4~6 DU;在对流层,IAP O₃探空仪测值与进口仪器间的绝对差别稳定且低于0.5 mPa;而平流层受泵效影响较明显。因此,建议IAP O₃探空仪提高其C_ef的稳定性,参与国际比对测试,国产气象探空平台数据接收处理增加必要的滤波技术以降低平流层探测数据（包括O₃）的振荡。     

Depletion of Column Ozone in the Arctic During the Winters of 1993-94 and 1994-95

The total ozone reduction in the Arctic during the winters of 1993/94 and 1994/95 has been evaluated using the ground-based total ozone measurements of five SAOZ spectrometers distributed in the Arctic and from number density profiles of a balloon-borne version of the instrument. The ozone change resulting from transport has been removed using a 3D Chemistry Transport Model (CTM) run without chemistry. A cumulative total ozone depletion at the end of winter in March of 18% ± 4% in 1994 and of 32% ± 4% in 1995 was observed within the polar vortex, and of 15% ± 4% in both years outside the vortex. This evaluation is not sensitive to the vertical transport in the model. The periods, locations and altitudes at which ozone loss occurred were tightly connected to temperatures lower than NAT condensation temperature. The maximum loss was observed at 50 hPa in 1994 and lower, 60-80 hPa, in 1995. Half of the depletion in 1994 and three quarters in 1995 occurred during the early winter, showing that a late final warming is not a prerequisite for large ozone destruction in the northern hemisphere. The timing, the geographical location and the altitude of the ozone losses are well captured by the 3D CTM photochemical model using current chemistry, but its amplitude at low sun during the early winter, is underestimated. The model simulations also capture the early season reductions observed outside the vortex. This suggests that the losses occurred in situ in the early winter, when low temperatures are frequent, and not later in March, when ozone is most reduced inside the vortex, which would be the case if leakage from the vortex was the cause of the depletion.     

青藏高原对流层顶高度与臭氧总量及上升运动的耦合关系

根据1979-2008年青藏高原地区14个探空站对流层项气压资料以及同期各标准等压面上的温度资料,分析了不同季节高原上空两类对流层顶高度与高空各层温度之间的关系;在此基础上,结合同期的NCEP／NCAR月平均再分析资料以及NASA提供的TOMS／SBUV月平均臭氧总量资料,分别讨论了高原上升运动以及高原臭氧总量与对流层顸高度的耦合关系。结果表明：高原第一（二）对流层顶高度全年处在300～200hPa（100hPa附近）高度,在季节变化、年际变化以及长期变化趋势上,两类对流层顸高度与各自对应高度层上的温度存在着密切的反相变化关系,当对流层顶高度偏高（低）时,相应高度上的温度偏低（高）。上升运动有助于两类对流层顶高度的抬升,尤其是当高空200（100）hPa附近有上升运动时,有利于第一（二）对流层项高度抬升。各季节高原臭氧总量与第二对流层顶高度均呈显著的负相关关系,当臭氧含量减少（增加）时,该对流层顶高度将偏高（偏低）,近年来伴随着高原臭氧总量的减少,高原第二对流层顸高度出现了明显的抬升。     

Dynamical and Chemical Features of a Cutoff Low over Northeast China in July 2007: Results from Satellite Measurements and Reanalysis

The European Centre for Medium-Range Weather Forecasts Re-Analysis Interim (ERA-Interim) meteorology and measurements from the Microwave Limb Sounder, High Resolution Dynamics Limb Sounder, and Ozone Monitoring Instrument onboard the Earth Observing System Aura satellite were applied to analyze the dynamical and chemical features of a cutoff low (COL) event over northeast China in early July 2007. The results showed the polar stratospheric origin of an upper-level warm-core cyclone at 100--300 hPa, associated with a funnel-shaped tropopause intruding into the mid-troposphere just above the COL center. The impacts of the stratospheric intrusion on both column ozone and ozone profiles were investigated using satellite measurements. When the intensity of the COL peaked on 10 July 2007, the total column ozone (TCO) increase reached a maximum (40--70 DU). This could be dynamically attributed to both the descent of the tropopause (～75%) and the downward transport of stratospheric ozone across the tropopause (～25%). Analysis of the tropospheric ozone profiles provided evidence for irreversible transport/mixing of ozone-rich stratospheric air across the tropopause near the upper-level front region ahead of the COL center. This ozone intrusion underwent downstream transport by the upper tropospheric winds, leading to further increase in TCO by 12--16 DU over broad regions extending from east China toward the northern Japan Sea via South Korea. Meteorological analysis also showed the precedence of the stratospheric intrusion ahead of the development of cyclones in the middle and lower troposphere.     

青藏高原上空气溶胶含量的分布特征及其与臭氧的关系

采用1991年10月—2005年11月的HALOE资料,分析了青藏高原(27°~40°N,75°~105°E)上空气溶胶数密度、体积密度、面积密度的分布和变化特征,探讨了它们与臭氧的关系,并且与同纬度带中国东部地区(107°~122°E,27°~40°N)、北太平洋(170°E~170°W,27°~40°N)上空进行了对比。结果表明:高原上空气溶胶的体积密度、面积密度受Pinatubo火山喷发的影响主要发生在1991—1995年,然而气溶胶数密度受火山影响则不如前二者明显;高原上空气溶胶在对流层顶附近存在一个极大值区,在夏季该极大值区位于对流层顶下方(约120 hPa),而其他季节则位于对流层顶上方(约100hPa);青藏高原、中国东部地区、北太平洋三地上空气溶胶数密度的差异主要出现在60 hPa以下的气层,夏季差异最突出,高原上120 hPa附近的气溶胶数密度约为平原上的1.8倍,约为海洋上的5.5倍;在高原上空对流层顶附近以及平流层低层,气溶胶数密度与臭氧体积混合比呈很好的负相关关系,而在20 hPa以上则有明显的正相关关系;对比三地上空气溶胶与臭氧的关系,得到在对流层顶附近及平流层低层气溶胶在高原和平原上空与臭氧的变化呈很好的负相关,其中以高原上空的负相关关系更好,但是在海洋上空气溶胶和臭氧的相关不明显。而在20 hPa以上气层中,三地上空的气溶胶与臭氧的变化都具有很好的正相关关系。     

The mid-latitude horizontal and vertical structure of the zonally asymmetric intraseasonal and interannual ozone variability in boreal winters

 A singular value decomposition (SVD) is used to calculate SVD-selected fields of ozone and geopotential, which exhibit maximum covariance, from the observed zonally asymmetric total ozone field and that of the three-dimensional geopotential field thus leaving almost purely dynamical induced variations in the remaining ozone field. This procedure was applied to Total Ozone Mapping Spectrometer data (TOMS) and to geopotential values from the National Centers for Environmental Prediction in the boreal mid-latitudes in the winter months of 1979–1992. Intraseasonal variability (December–February) and trend-eliminated interannual winter mean variability of total ozone and geopotential are analyzed. The first four modes of SVD analysis explain more than 70% of the covariance for the intraseasonal variability and more than 80% of that for the interannual variability. The vertical structure of geopotential regression maps reveals a clear wave-1 pattern for modes one and two and a wave-2 pattern for modes three and four. These patterns show differently but generally westward tilted phases and are more complex at heights below 70 hPa. Further a linear transport model of a conservative tracer was applied to each individual geopotential mode found by the SVD analysis in connection with an observed height and latitude dependent zonal mean ozone distribution. The model results of total ozone reproduce the spatial patterns of the SVD-selected total ozone field quite well whereas their magnitudes are variously underestimated. This method allows us to assess the vertical distribution of the contribution of single modes to the total ozone variability. Maximum contributions are found between 150 and 70 hPa. Smaller amplitude maxima are found around 10 hPa, which result from contributions of horizontal advection of ozone alone. These results reflect an expected dynamical link between the variability of the zonally asymmetric parts of geopotential and ozone. Received: 7 November 1997 / Accepted: 10 June 1998     

Retrieval of the single scattering albedo of Asian dust mixed with pollutants using lidar observations

The vertical distribution of single scattering albedos （SSAs） of Asian dust mixed with pollutants was derived using the multi-wavelength Raman lidar observation system at Gwangju （35.10°N,126.53°E）.Vertical profiles of both backscatter and extinction coefficients for dust and non-dust aerosols were extracted from a mixed Asian dust plume using the depolarization ratio from lidar observations.Vertical profiles of backscatter and extinction coefficients of non-dust particles were input into an inversion algorithm to retrieve the SSAs of non-dust aerosols.Atmospheric aerosol layers at different heights had different light-absorbing characteristics.The SSAs of non-dust particles at each height varied with aerosol type,which was either urban/industrial pollutants from China transported over long distances at high altitude,or regional/local pollutants from the Korean peninsula.Taking advantage of independent profiles of SSAs of non-dust particles,vertical profiles of SSAs of Asian dust mixed with pollutants were estimated for the first time,with a new approach suggested in this study using an empirical determination of the SSA of pure dust.The SSAs of the Asian dust-pollutants mixture within the planetary boundary layer （PBL） were in the range 0.88-0.91,while the values above the PBL were in the range 0.76-0.87,with a very low mean value of 0.76 ± 0.05.The total mixed dust plume SSAs in each aerosol layer were integrated over height for comparison with results from the Aerosol Robotics Network （AERONET） measurements.Values of SSA retrieved from lidar observations of 0.92 ± 0.01 were in good agreement with the results from AERONET measurements.     

北半球30 hPa环流春季转变过程的诊断研究

利用1965—1986年30 hPa逐日高度、温度资料和月平均臭氧资料，对环流的春季转变过程进行了诊断研究。结果表明:50°N以北极冠地区高度场涡动方差E指数小于4×104（dagpm）2的初日可以作为30 hPa自然天气季节进入春节的近拟度量；冬末至早春环流在压、温和经、纬向风场方面均有显著变化；定常和瞬变涡旋动量、热量通量和通量辐散（合）的时-空变化特征明显；春季转变早、迟两类情况下极区平流层热源——臭氧在经向、纬向和垂直分布方面呈现异常。     

Concentration of Stratospheric Ozone Derived from Lidar,Satellite, and Surface Observations

Data of stratospheric ozone measurements with the AK-3 lidar over Obninsk in 2012–2015 are compared with Aura/MLS and Aura/OMI satellite data and parallel surface observations of total ozone (TO) with the Brewer spectrophotometer. The maximum difference in mean ozone concentration between the lidar and Aura/MLS data in the altitude range of 13 to 32 km does not exceed 0.2 x 10¹² mol./cm³ (or the maximum of 9% at the altitude of 13 km). At the same time, Aura/OMI data have a positive bias of about 20% relative to lidar data in the range of 13 to 20 km that is associated with OMI measurement errors according to literature data. Total ozone values calculated from lidar measurements jointly with the known climatology data are compared with those measured with the Brewer spectrophotometer. It is demonstrated that the correlation between the results of measurements obtained by two methods is close to linear, and the mean relative difference in the overall measurement range does not exceed 5%.     

TOVS 水汽反演的误差分析及其订正

该文利用同步物理反演法以6小时数值预报场为背景场对1992年1月份NOAA-12卫星垂直探测（TOVS）资料进行了大气参数反演，并对水汽反演误差进行了检验和分析。以常规观测作为检验的标准，检验结果按3条轨道统计，发现反演的相对湿度平均误差与背景场的误差密切相关，均为负值；在高层和高纬度，误差绝对值随高度的增加而增加，随纬度的升高而增加；误差的日际变化在高层比较稳定，低层振动较大。对反演误差进行订正后的结果表明，在500 hPa以上反演均比背景质量要好，尤其轨道A所有层次上订正后的反演比背景场好。     

利用探空资料验证GOME卫星臭氧数据

利用1996年3月-2003年6月部分时段拉萨、西宁、北京3个站的臭氧探空资料验证了GOME（Global Ozone Monitoring Experiment）卫星臭氧廓线及对流层臭氧柱总量。对比结果表明:在对流层中下层,拉萨和西宁两地GOME与探空的平均偏差小于5%,北京地区平均偏差小于10%;在对流层上层/平流层下层,拉萨和西宁平均偏差小于10%,北京小于20%;在平流层中上层3个站的平均偏差均小于5%。在对流层上层/平流层下层区域,GOME与臭氧探空的平均偏差在北京明显高于拉萨和西宁。3个地区对流层柱总量的平均偏差都在10%以内,表明该资料可用于研究我国对流层臭氧总量的变化规律。同时段的GOME最低层（0~2.5km）月平均臭氧浓度对比结果显示,GOME结果同地面臭氧观测值有很好的相关性,GOME臭氧浓度反映了拉萨、瓦里关、临安地面臭氧浓度的主要变化特征。     

Three-Year Observations of Ozone Columns over Polar Vortex Edge Area above West Antarctica

Ozone vertical column densities (VCDs) were retrieved by Zenith Scattered Light-Differential Optical Absorption Spectroscopy (ZSL-DOAS) from January 2017 to February 2020 over Fildes Peninsula, West Antarctica (62.22°S, 58.96°W). Each year, ozone VCDs started to decline around July with a comparable gradient around 1.4 Dobson Units (DU) per day, then dropped to their lowest levels in September and October, when ozone holes appeared (less than 220 DU). Daily mean values of retrieved ozone VCDs were compared with Ozone Monitoring Instrument (OMI) and Global Ozone Monitoring Experiment 2 (GOME-2) satellite observations and the Modern-Era Retrospective analysis for Research and Applications Version 2 (MERRA-2) reanalysis dataset, with correlation coefficients (R2) of 0.86, 0.94, and 0.90, respectively. To better understand the causes of ozone depletion, the retrieved ozone VCDs, temperature, and potential vorticity (PV) at certain altitudes were analyzed. The profiles of ozone and PV were positively correlated during their fluctuations, which indicates that the polar vortex has a strong influence on stratospheric ozone depletion during Antarctic spring. Located at the edge of polar vortex, the observed data will provide a basis for further analysis and prediction of the inter-annual variations of stratospheric ozone in the future.     

北极臭氧垂直分布和天气尺度变化的观测研究

北极地区臭氧对北极气候和环境系统起着重要作用。研究其分布和变化有助于了解北极的气候和环境及其对全球气候系统的影响,有助于气候和环境变化的数值预报。中国北极科学探测1999在北冰洋楚可奇海域成功的进行了大气臭氧观测。通过在中国“雪龙”号破冰船甲板上（于1999年8月18-24日在75°N,160°W附近处）释放大气臭氧探空仪获得了高分辨率的大气垂直结构和臭氧分布资料,可以进行大气尺度的大气臭氧变化研究。分析大气监测资料、TOMS臭氧总量资料和NCEP大气环流资料表明,大气臭氧总量随着对流层顶的低一高一低变化呈高一低一高的变化过程。研究还表明,大气柱的臭氧总量与13公里以下的大气臭氧含量关系密切,而在约20公里处的大气臭氧浓度最大值的变化与整个气柱臭氧的关系不大。500 hPa天气形势图上一个弱一强一弱的西南天气型造成的弱臭氧平流可能是这次臭氧变化的主要原因。