Identifying the Origin of Anomalous High Tropospheric Ozone in the Ozonesonde Data at Uccle by Comparison with Nearby De Bilt

Abstract

The ozonesonde stations at Uccle (Belgium) and De Bilt (Netherlands), separated by only 175?km, offer a unique opportunity to test the influence of different ozonesonde types and different correction strategies, as well as to detect the presence of inhomogeneities in the ozonesonde time series resulting from changes in sounding equipment (solution, radiosonde, ozonesonde, interface, sounding software, etc.). In particular, we highlight a 2.5 year period (beginning of 2007 to mid-2009) of anomalous high tropospheric ozone values measured by ozonesondes at Uccle and compare these with the observations from De Bilt. Because the ozone deviations are only observed in the free troposphere where ozone concentrations are relatively low, and not in the boundary layer or the stratosphere, this issue is directly related to the sensitivity of ozonesondes. Therefore, the effect of every instrumental change, even though small, during this 2.5 year anomalous period is analyzed considering a change in the radiosounding equipment, different ozonesonde batches, operational differences at the stations, differences on ascent and descent during the anomalous period; an environmental cause is also examined. Unfortunately, one single, specific cause for the observed high tropospheric ozone values at Uccle could not be identified. There are two explanations consistent with the observations and not ruled out by the analysis here: 1) the majority of the ozonesondes used at Uccle between March 2007 and August 2009 needed longer conditioning of their sensors and, therefore, behaved more accurately at low ozone concentrations during their descent or when used a second time, and 2) an environmental origin arising from a local difference in the air mass between Uccle and De Bilt and between the ascent and descent.     

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。     

A Study of Ozone Laminae Using Diabatic Trajectories, Contour Advection and Photochemical Trajectory Model Simulations.

In this paper, we show that the rate of ozone loss in both polar and mid-latitudes, derived from ozonesonde and satellite data, has almost the same vertical distribution (although opposite sense) to that of ozone laminae abundance. Ozone laminae appear in the lower stratosphere soon after the polar vortex is established in autumn, increase in number throughout the winter and reach a maximum abundance in late winter or spring. We indicate a possible coupling between mid-winter, sudden stratospheric warmings (when the vortex is weakened or disrupted) and the abundance of ozone laminae using a 23-year record of ozonesonde data from the World Ozone Data Center in Canada combined with monthly-mean January polar temperatures at 30 hPa.Results are presented from an experiment conducted during the winter of 1994/95, in phase II of the Second European Stratospheric And Mid-latitude Experiment (SESAME), in which 93 ozone-enhanced laminae of polar origin observed by ozonesondes at different time and locations are linked by diabatic trajectories, enabling them to be probed twice or more. It is shown that, in general, ozone concentrations inside laminae fall progressively with time, mixing irreversibly with mid-latitude air on time-scales of a few weeks. A particular set of laminae which advected across Europe during mid February 1995 are examined in detail. These laminae were observed almost simultaneously at seven ozonesonde stations, providing information on their spatial scales. The development of these laminae has been modelled using the Contour Advection algorithm of Norton (1994), adding support to the concept that many laminae are extrusions of vortex air. Finally, a photochemical trajectory model is used to show that, if the air in the laminae is chemically activated, it will impact on mid-latitude ozone concentrations. An estimate is made of the potential number of ozone molecules lost each winter via this mechanism.     

The 1991 WMO International ozonesonde intercomparison at Vanscoy,Canada

Abstract

An intercomparison of ozonesondes was held at Vanscoy, Saskatchewan, from 13 to 24 May 1991. The intercomparison, which was sponsored by the WMO and hosted by the Atmospheric Environment Service (AES) of Canada, was attended by scientists from six countries: Canada, Finland Germany, India, Japan and the United States. Four different makes of ozonesondes were used: the ECC sonde, the Brewer‐Mast sonde, the Indian ozonesonde and the Japanese RSH‐KC79 ozonesonde. These represent most of the sonde types that are in routine operation in the Global Ozone Observing System.

A balloon payload and telemetry system was developed to accommodate up to eight ozonesondes that could operate independently and transmit data simultaneously to a ground receiver. Ten flights were launched, each carrying 7 or 8 sondes, and a total of 65 successful profile measurements were made. The payloads were carried to altitudes between 35 and 40 km. The measured profiles are used to determine statistically meaningful evaluations of the different sonde types. The results compared with those from previous intercomparisons indicate that there has been a general improvement in performance for most of the types. In addition there appears to have been changes with time in the relative sensitivity to tropospheric ozone for different sonde types. This result should be considered when drawing conclusions regarding trends in tropospheric ozone.     

Comparison of model predicted cloud parameters and surface radiative fluxes with observations on the 100 km scale

Summary Cloud parameters and surface radiative fluxes predicted by regional atmospheric models are directly compared with observations for a 10-day period in late summer 1995 characterized by predominantly large-scale synoptic conditions. Observations of total cloud cover and vertical cloud structure are inferred from measurements with a ground-based network of Lidar ceilometers and IR-radiometers and from satellite observations on a 100 kilometer scale. Ground-based observations show that at altitudes below 3 km, implying liquid water clouds, there is a considerable portion of optically non-opaque clouds. Vertical distributions of cloud temperatures simultaneously inferred from the ground-based infrared radiometer network and from satellite can only be reconciled if the occurrence of optically thin cloud structures at mid- and high tropospheric levels is assumed to be frequent. Results of three regional atmospheric models, i.e. the GKSS-REMO, SMHI-HIRLAM, and KNMI-RACMO, are quantitatively compared with the observations. The main finding is that all models predict too much cloud amount at low altitude below 900 hPa, which is then compensated by an underestimation of cloud amount around 800 hPa. This is likely to be related with the finding that all models tend to underestimate the planetary boundary layer height. All models overpredict the high-level cloud amount albeit it is difficult to quantify to what extent due to the frequent presence of optically thin clouds. Whereas reasonably alike in cloud parameters, the models differ considerably in radiative fluxes. One model links a well matching incoming solar radiation to a radiatively transparent atmosphere over a too cool surface, another model underpredicts incoming solar radiation at the surface due to a too strong cloud feedback to radiation, the last model represents all surface radiative fluxes quite well on average, but underestimates the sensitivity of atmospheric transmissivity to cloud amount. Received August 31, 2000 Revised March 15, 2001     

辐射参数化的变化对模式中期和月预报的影响

在T106中期数值预报模式和T63气候模式中进行了两种辐射过程参数化的对比试验。目前在这两个模式中用作对照积分的辐射方案(OPE)是ECMWF的早期业务方案，而新的辐射方案(NEW)是ECMWF 1989年5月2日成为业务的版本。试验结果表明，OPE高估了短波水的吸收，导致太大的短波大气吸收和地表太小的向下短波辐射；OPE还低估了长波辐射冷却和大气顶的向外长波辐射(OLR)；NEW增加了地表有效辐射能量和对流层总的冷却，产生了较大的湍流热通量，对流活动加强，降水量明显增加；NEW还使平流层温度偏暖得到矫正。业务平行试验的统计检验表明，NEW对4～7天中期预报有较显著的改进。     

Evaluating the Ozone Valley over the Tibetan Plateau in CMIP6 Models

Total column ozone (TCO) over the Tibetan Plateau (TP) is lower than that over other regions at the same latitude, particularly in summer. This feature is known as the “TP ozone valley”. This study evaluates long-term changes in TCO and the ozone valley over the TP from 1984 to 2100 using Coupled Model Intercomparison Project Phase 6 (CMIP6). The TP ozone valley consists of two low centers, one is located in the upper troposphere and lower stratosphere (UTLS), and the other is in the middle and upper stratosphere. Overall, the CMIP6 models simulate the low ozone center in the UTLS well and capture the spatial characteristics and seasonal cycle of the TP ozone valley, with spatial correlation coefficients between the modeled TCO and the Multi Sensor Reanalysis version 2 (MSR2) TCO observations greater than 0.8 for all CMIP6 models. Further analysis reveals that models which use fully coupled and online stratospheric chemistry schemes simulate the anticorrelation between the 150 hPa geopotential height and zonal anomaly of TCO over the TP better than models without interactive chemistry schemes. This suggests that coupled chemical-radiative-dynamical processes play a key role in the simulation of the TP ozone valley. Most CMIP6 models underestimate the low center in the middle and upper stratosphere when compared with the Microwave Limb Sounder (MLS) observations. However, the bias in the middle and upper stratospheric ozone simulations has a marginal effect on the simulation of the TP ozone valley. Most CMIP6 models predict the TP ozone valley in summer will deepen in the future.     

多层模式中臭氧加热率的计算及其对大气温度场的影响

本文介绍一个简单、经济的适用于各种多层大气环流模式中计算臭氧加热率的参数化方案,利用这一方案,可根据臭氧总量气候观测值及其垂直分布资料计算臭氧加热率,也可以在模式中加入臭氧方程,用预报的臭氧含量计算臭氧加热率.用此方案对单站气候资料试算,结果指出,随着高度的增加,臭氧吸收太阳辐射对大气太阳加热率的贡献逐渐接近、达到并在平流层50hPa附近明显超过其它物质如水汽的贡献.此方案用于九层大气环流模式时,对其辐射加热率的计算有较理想的改进,并使模拟的大气温度垂直分布更符合观测事实.     

Influences of Two Convective Schemes on the Radiative Energy Budget in GAMIL1.0

The Grid-point Atmospheric Model of IAP LASG version 1.0 (GAMIL1.0) is used to investigate the impacts of different convective schemes on the radiative energy budget.The two convective schemes are Zhang and McFarlance (1995)/Hack (1994) (ZM) and Tiedtke (1989)/Nordeng (1994) (TN).Two simulations are performed:one with the ZM scheme (EX_ZM) and the other with the TN scheme (EX_TN).The results indicate that during the convective process,more water vapor consumption and temperature increment are found in the EX_ZM,especially in the lower model layer,its environment is therefore very dry.In contrast,there is a moister atmosphere in the EX_TN,which favors low cloud formation and large-scale condensation,and hence more low cloud fraction,higher cloud water mixing ratio,and deeper cloud extinction optical depth are simulated,reflecting more solar radiative flux in the EX_TN.This explains why the TN scheme underestimates the net shortwave radiative flux at the top of the atmosphere and at surface.In addition,convection influences longwave radiation,surface sensible and latent heat fluxes through changes in cloud emissivity and precipitation.     

GPSO3和Vaisala臭氧探空仪平行施放比对结果的初步分析

为促进中国大气臭氧高空探测业务化进程，中国科学院大气物理研究所和中国气象局监测网络司联合组织了对国产GPS数字化大气臭氧探空仪（GPSO3）和芬兰Vaisala 公司产大气臭氧探空仪(Vaisala)主要技术性能的比对。现场平行施放比对于2002年1月在北京进行，共施放了7对臭氧探空仪。对两类大气臭氧探空仪现场平行施放比对试验结果的分析表明，两种臭氧探空仪所获得的大气中臭氧浓度随高度的变化特征之间有很好的一致性。在12～27 km高度范围内，两种探空仪臭氧测值之间的相对误差平均在10％以内，而在10 km以下和27 km以上，GPSO3探空仪的臭氧测值偏高。本文介绍了比对方法，分析了两类探空仪对臭氧廓线某些特征值的比对结果并讨论了平行施放比对时气球升速的差异可能对臭氧测值带来的影响。     

Measurements of stratospheric ozone at a mid-latitude observing station Valentia, Ireland (51.94° N, 10.25° W), using ground-based and ozonesonde observations from 1994 to 2009

Sixteen years (1994 – 2009) of ozone profiling by ozonesondes at Valentia Meteorological and Geophysical Observatory, Ireland (51.94^° N, 10.23^° W) along with a co-located MkIV Brewer spectrophotometer for the period 1993–2009 are analyzed. Simple and multiple linear regression methods are used to infer the recent trend, if any, in stratospheric column ozone over the station. The decadal trend from 1994 to 2010 is also calculated from the monthly mean data of Brewer and column ozone data derived from satellite observations. Both of these show a 1.5 % increase per decade during this period with an uncertainty of about ±0.25 %. Monthly mean data for March show a much stronger trend of?~?4.8 % increase per decade for both ozonesonde and Brewer data. The ozone profile is divided between three vertical slots of 0–15 km, 15–26 km, and 26 km to the top of the atmosphere and a 11-year running average is calculated. Ozone values for the month of March only are observed to increase at each level with a maximum change of +9.2?±?3.2 % per decade (between years 1994 and 2009) being observed in the vertical region from 15 to 26 km. In the tropospheric region from 0 to 15 km, the trend is positive but with a poor statistical significance. However, for the top level of above 26 km the trend is significantly positive at about 4 % per decade. The March integrated ozonesonde column ozone during this period is found to increase at a rate of ~6.6 % per decade compared with the Brewer and satellite positive trends of ~5 % per decade.     

Simulation of Tropospheric Ozone with MOZART-2： An Evaluation Study over East Asia

Climate changes induced by human activities have attracted a great amount of attention. With this, a coupling system of an atmospheric chemistry model and a climate model is greatly needed in China for better understanding the interaction between atmospheric chemical components and the climate. As the first step to realize this coupling goal, the three-dimensional global atmospheric chemistry transport model MOZART-2 (the global Model of Ozone and Related Chemical Tracers, version 2) coupled with CAM2 (the Community Atmosphere Model, version 2) is set up and the model results are compared against observations obtained in East Asia in order to evaluate the model performance. Comparison of simulated ozone mixing ratios with ground level observations at Minamitorishima and Ryori and with ozonesonde data at Naha and Tateno in Japan shows that the observed ozone concentrations can be reproduced reasonably well at Minamitorishima but they tend to be slightly overestimated in winter and autumn while underestimated a little in summer at Ryori. The model also captures the general features of surface CO seasonal variations quite well, while it underestimates CO levels at both Minamitorishima and Ryori. The underestimation is primarily associated with the emission inventory adopted in this study. Compared with the ozonesonde data, the simulated vertical gradient and magnitude of ozone can be reasonably well simulated with a little overestimation in winter, especially in the upper troposphere. The model also generally captures the seasonal, latitudinal and altitudinal variations in ozone concentration. Analysis indicates that the underestimation of tropopause height in February contributes to the overestimation of winter ozone in the upper and middle troposphere at Tateno.     

A Comparison of Match Ozonesonde-Derived and 3D Model Ozone Loss Rates in the Arctic Polar Vortex during the Winters of 1994/95 and 1995/96

Ozone loss rates from ozonesonde data reported in the Match experiments of winters 1994/95 and 1995/96 inside the Arctic polar vortex are compared with simulations of the same winters performed using the SLIMCAT 3D chemistry and transport model. For 1994/95 SLIMCAT reproduces the location and timing of the diagnosed ozone destruction, reaching 10 ppbv/sunlit hour in late January as observed. SLIMCAT underestimates the loss rates observed in February and March by 1–3 ppbv/sunlit hour. By the end of March, SLIMCAT ozone exceeds the observations by 25–35%. In January 1995 the ozonesonde-derived loss rates at levels above 525 K are not chemical in origin but due to poor conservation of air parcels. Correcting temperature biases in the model forcing data significantly improved the agreement between the model and observed ozone at the end of winter 1994/95, increasing ozone destruction in SLIMCAT in February and March. The SLIMCAT simulation of winter 1995/96 does not reproduce the maximum ozone loss rates diagnosed by Match of 13 ppbv/sunlit hour. Comparing the data for the two winters reveals that the SLIMCAT photochemistry is least able to reproduce observed losses at low temperatures or when low temperatures coincide with high solar zenith angles (SZA). When cold (T = 192 K), high SZA (90°)matches are excluded from the 1995/96 analysis, agreement between the diagnoses and SLIMCAT is better with ozone loss rates of up to 6 ppbv/sunlit hour. For the rest of the winter SLIMCAT consistently underestimates the Match rates of ozone loss by 1–3 ppbv/sunlit hour. In March 1996 the monthly mean SLIMCAT ozone is 50% greater than observations at 430–540 K. In both winters, ozone destruction rates peaked more rapidly and declined more slowly in the Match observations than in the SLIMCAT simulations. The differences between the observed and modelled cumulative ozone losses demonstrate that the total ozone destruction by the end of the winter is sensitive to errors in the instantaneous ozone loss rates of 1–3 ppbv/sunlit hour.     

北京地区对流层顶变化及其对上对流层/下平流层区域臭氧变化的影响

根据2001～2003年期间获得的大气臭氧探空资料,揭示了北京地区上空对流层顶高度的某些变化特征及其对上对流层(UT)和下平流层(LS)区域内大气臭氧含量变化的影响.结果显示:北京地区上空对流层顶高度的平均值约11.1 km,其变化范围为7.7～14.4 km,臭氧层顶始终处在对流层顶下方约0.9 km高度处.对流层顶高度变化与臭氧总量变化之间的关系相对较弱.通常情况下,LS中的臭氧积分量明显高于UT中的相应值,并且二者呈相反的季节变化特征.北京地区上空仲夏和初秋季节第一对流层顶出现的频数明显减少,在第一对流层顶消失的情况下,LS中的臭氧积分量明显减少,而UT中的臭氧积分量明显增加,臭氧量减少最多发生在200～100 hPa层次中,而臭氧量增幅最大的层次是400～250 hPa.     

西宁夏季对流层臭氧垂直分布变化与气象要素的关系

根据臭氧、气象探空观测数据,分析了1996年7月5日至8月3日西宁（36°44’N,101°45＇E,海拔高度2296m）上空对流层臭氧垂直分布变化与气象要素之间的关系。对流层臭氧浓度的增加（减少）总伴随着干、冷（暖、湿）气流的输送变化,而这又与大气垂直方向的运动是紧密联系在一起的。分析表明天气动力输送过程对对流层臭氧垂直分布变化有重要作用。     

INTERCOMPARISON OF OZONE VERTICAL PROFILES BETWEEN ECC OZONESONDE AND BREWER UMKEHR MADE OVER QINGHAI PLATEAU OF CHINA*

From October 1995 to August 1996.a total of 50 ECC(electrochemical concentration cell) ozonesoundings were made in Xining(36.43°N,101.45°E,2296 m ASL)to study the distribution and seasonal characteristics of ozone profile,and intercompare the Brewer Umkehr ozone profiles obtained at Waliguan Baseline Station over the Qinghai Plateau.It was demonstrated that(1) Umkehr produced estimates of the ozone comparing with ECC profiles were accurate to better than 25% in the 20-38 km altitude range,and where 23-33 km region was the most accurate,within about 15% of the ECC ozonesonde:(2)higher differences between Brewer Umkehr and ECC ozonesonde occurred in the troposphere and lower stratosphere;and ozone amounts were overestimated in Umkehr layers 1,2 and 3,and were underestimated in Umkehr layers 6 and 7 by Brewer Umkehr method.     

Influences of Physical Processes and Parameters on Simulations of TOA Radiance at UV Wavelengths: Implications for Satellite UV Instrument Validation

Numerous factors can influence the radiative transfer simulation of hyper-spectral ultraviolet satellite observation,including the radiative transfer scheme, gaseous absorption coefficients, Rayleigh scattering scheme, surface reflectance, aerosol scattering, band center wavelength shifts of sensor, and accuracy of input profiles. In this study, a Unified Linearized Vector Radiative Transfer Model(UNL-VRTM) is used to understand the influences of various factors on the top of atmosphere(TOA) normalized radiance in the ultraviolet(UV) region. A benchmark test for Rayleigh scattering is first performed to verify the UNL-VRTM accuracy, showing that the model performances agree well with earlier peer-reviewed results. Sensitivity experiments show that a scalar radiative transfer approximation considering only ozone and a constant surface reflectance within the UV region may cause significant errors to the TOA normalized radiance. A comparison of the Ozone Mapping and Profiler Suite(OMPS) radiances between simulations and observations shows that the surface reflectance strongly influences the accuracy for the wavelengths larger than 340 nm. Thus, using the surface reflectivity at 331 nm as a proxy for simulating the whole OMPS hyperspectral ultraviolet radiances is problematic. The impact of rotational Raman scattering on TOA radiance can be simulated through using SCIATRAN, which can also reduce the difference between measurements and simulations to some extent. Overall, the differences between OMPS simulations and observations can be less than 3% for the entire wavelengths. The bias is nearly constant across the cross-track direction.     

An empirical model for estimating stratospheric ozone vertical distributions over China

Based on the Stratospheric Aerosol and Gas Experiment (SAGE) II and the Halogen Occultation Experiment (HALOE) ozone profiles and the Total Ozone Mapping Spectrometer (TOMS) total ozone data sets, an empirical model for estimating the vertical distribution of stratospheric ozone over China is proposed. By using this model, the vertical distribution of stratospheric (16–50 km) ozone can be estimated according to latitude, month and total ozone. Comparisons are made between the modeled ozone profiles and the ...     

A Method for Retrieving Vertical Ozone Profiles from Limb Scattered Measurements

A two-step method is employed in this study to retrieve vertical ozone profiles using scattered measure- ments from the limb of the atmosphere. The combination of the Differential Optical Absorption Spectroscopy (DOAS) and the Multiplicative Algebraic Reconstruction Technique (MART) is proposed. First, the limb radiance, measured over a range of tangent heights, is processed using the DOAS technique to recover the effective column densities of atmospheric ozone. Second, these effective column densities along the lines of sight (LOSs) are inverted using the MART coupled with a forward model SCIATRAN (radiative transfer model for SCIAMACHY) to derive the ozone profiles. This method is applied to Optical Spectrograph and Infra Red Imager System (OSIRIS) radiance, using the wavelength windows 571-617 nm. Vertical ozone profiles between 10 and 48 km are derived with a vertical resolution of 1 km. The results illustrate a good agreement with the cloud-free coincident SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) ozone measurements, with deviations less than ± 10% ( ± 5% for altitudes from 17 to 47 km). Furthermore, sensitivities of retrieved ozone to aerosol, cloud parameters and NO 2 concentration are also investigated.