利用卫星资料分析我国北方东西部臭氧分布差异

利用SAGE Ⅱ和HALOE臭氧垂直分布资料和TOMS臭氧总量资料, 研究我国北方(45°~55°N和35°~45°N范围), 东部(105°~135°E) 和西部(75°~105°E) 大气臭氧总量和垂直分布特征和差异。结果表明:我国北方东部冬季、春季和秋季臭氧总量明显大于西部, 主要表现在平流层臭氧极大值附近及其以下高度臭氧含量东部比西部明显偏大, 这种差异在冬、春季尤为明显; 随着纬度的降低, 冬季和秋季臭氧总量东、西部差异减小, 但春季臭氧总量东、西部差异没有明显改变; 夏季, 在45°~55°N范围, 东、西部臭氧分布没有明显差异, 但在35°~45°N范围, 臭氧分布东、西部差异较明显, 臭氧总量东、西部差异达到20.6 DU, 16 km以下臭氧柱总量东、西部差异达到12.8 DU。该文还对导致我国东、西部臭氧分布差异的原因进行了分析。     

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 ...     

An Empirical Method for Estimating Background Stratospheric Aerosol Extinction Profiles over China

The current paper introduces an empirical method for estimating the vertical distribution of background stratospheric aerosol extinction profiles covering the latitude bands of 50±5°N,40±5°N,30±5°N,and 20±5°N and the longitude range of 75 135°E based on Stratospheric Aerosol and Gas Experiment (SAGE) II aerosol extinction measurements at wavelengths of 1020 nm,525 nm,452 nm,and 386 nm for the volcanically calm years between 1998 2004.With this method,the vertical distribution of stratospheric aerosol extinction coefficients can be estimated according to latitude and wavelength.Comparisons of the empirically calculated aerosol extinction profiles and the SAGE II aerosol measurements show that the empirically calculated aerosol extinction coefficients are consistent with SAGE II values,with relative differences within 10% from 2 km above the tropopause to 33 km,and within 22% from 33 km to 35 km.The empirically calculated aerosol stratospheric optical depths (vertically integrated aerosol extinction coefficient) at the four wavelengths are also consistent with the corresponding SAGE II optical depth measurements,with differences within 2.2% in the altitude range from 2 km above the tropopause to 35 km.     

Ozone in ambient air at a tropical megacity, Delhi: characteristics, trends and cumulative ozone exposure indices

Seven year data of hourly surface ozone concentration is analyzed to study diurnal cycle, trends, excess of ozone levels above threshold value and cumulative ozone exposure indices at a tropical megacity, Delhi. The ozone levels clearly exhibit a diurnal cycle, similar to what has been found in other urban places. A sharp increase in the ozone levels during forenoon and a sharp decrease in the early afternoon can be observed. The average rate of increase in ozone concentration between 09 and 12 h has been observed to be 7.1 ppb h⁻¹. We find that the daily maximum and daytime 8-h (10–17 h) ozone levels are increasing at a rate of about 1.7 (± 0.7) and 1.3 (± 0.56) ppb y⁻¹, respectively. The directives on ozone pollution in ambient air provided by United Nations Economic Commission for Europe and World Health Organization for vegetation (AOT40) and human health protection were used to assess the air quality. The present surface ozone levels in the city are high enough to exceed “Critical Levels” which are considered to be safe for human health, vegetation and forest. The human health threshold was exceeded for up to ~45 days per year. The AOT40 (Accumulated exposure Over a Threshold of 40 ppb) threshold was exceeded significantly during winter (D-J-F) and pre-monsoon (M-A-M) (Rabi crop growing season) season in India. Translating AOT40 exceedances during pre-monsoon into relative yield loss we estimate yield loss of 22.7%, 22.5%, 16.3% and 5.5% for wheat, cotton, soybean and rice, respectively.     

Kinetic Study of the Reactions of Ozone with Polycyclic Aromatic Hydrocarbons Adsorbed on Atmospheric Model Particles

In this experimental study, rate constants were measured for the reactions of ozone with 13 polycyclic aromatic hydrocarbons (PAHs) adsorbed on different types of particles. Graphite and silica were chosen to model, respectively, carbonaceous and mineral atmospheric particles. The pseudo-first order rate constants were obtained from the fit of the experimental decay of particulate PAH concentrations versus time. Second order rate constants were calculated considering the ozone gaseous concentration. At room temperature, rate constants varied, in the case of graphite particles, between (1.5 ± 0.5) × 10⁻¹⁷ and (1.3 ± 0.7) × 10⁻¹⁶ cm³ molecule⁻¹ s⁻¹ for chrysene and dibenzo[a,l]pyrene, respectively, and, in the case of silica particles, between (1.5 ± 0.3) × 10⁻¹⁷ and (1.4 ± 0.3) × 10⁻¹⁶ cm³ molecule⁻¹ s⁻¹ for fluoranthene and benzo[a]pyrene, respectively. Different granulometric parameters (particle size, pore size) and different PAH concentrations were tested in the case of silica particles. Heterogeneous reactions of ozone with particulate PAHs are shown to be more rapid than those occurring in the gas-phase, and may be competitive with atmospheric photodegradation.     

关于确定东亚夏季风强度指数的探讨

文中利用作者曾定义的东亚夏季风在中国东北地区 (12 2 .5°E ,4 0°N)的建立标准 ,根据相同的方法 ,分别计算了沿 112 .5 ,117.5 ,和 12 2 .5°E上 ,2 0°N及以北每隔 5个纬度东亚夏季风建立、持续和撤退时间 (候 ) ,将某年持续和多年平均持续候数相比的标准化值 ,定义为一种沿某一经圈上某一纬度的东亚夏季风强度指数ISMΦ,还分析了该指数与中国夏季降水量场和 5 0 0hPa高度场的相关。结果表明 :(1)沿 117.5°E经度上 ,东亚夏季风在 2 0 ,2 5 ,30 ,35 ,和 4 0°N建立的平均日期分别为 2 7.2 6 ,2 8.5 4 ,34.4 3,37.12和 37.6 5 (候 ) ,撤退平均日期分别为 5 4 .4 4 ,5 3.6 9,5 1.85 ,4 8和 4 6 .76 (候 ) ,其中 117.5°E ,2 0°N代表南海的中北部 ,文中确定的该区夏季风建立、撤退日期分别为 2 7.2 6 (候 )和 5 4 .4 4 (候 ) ,与国内学者公认的 5月 4候 (2 8候 )和 10月 1候 (5 5候 )相当吻合 ;(2 )沿 112 .5°E、117.5°E和12 2 .5°E的同一纬度上 ,东亚夏季风建立的平均日期并不相同 ,西边先于东边建立 ,每隔 5个经度 ,相差约 1～ 2候 ,而撤退的平均日期 (30°N及以北 )分布则相反 ,东边先撤退 ;(3)沿 117.5°E ,30°N和 35°N的ISMΦ和沿 12 2 .5°E ,4 0°N的ISMΦ均与中国华北和东北地区大部 7～     

Measurements of surface ozone at semi-arid site Anantapur (14.62°N, 77.65°E, 331 m asl) in India

In the present study, an attempt has been made to examine the governing photochemical processes of surface ozone (O₃) formation in rural site. For this purpose, measurements of surface ozone and selected meteorological parameters have been made at Anantapur (14.62°N, 77.65°E, 331 m asl), a semi-arid zone in India from January 2002 to December 2003. The annual average diurnal variation of O₃ shows maximum concentration 46 ppbv at noon and minimum 25 ppbv in the morning with 1σ standard deviation. The average seasonal variation of ozone mixing ratios are observed to be maximum (about 60 ppbv) during summer and minimum (about 22 ppbv) in the monsoon period. The monthly daytime and nighttime average surface ozone concentration shows a maximum (55 ± 7 ppbv; 37 ± 7.3 ppbv) in March and minimum (28 ± 3.4 ppbv; 22 ± 2.3 ppbv) in August during the study period. The monthly average high (low) O₃ 48.9 ± 7.7 ppbv (26.2 ± 3.5 ppbv) observed at noon in March (August) is due to the possible increase in precursor gas concentration by anthropogenic activity and the influence of meteorological parameters. The rate of increase of surface ozone is high (1.52 ppbv/h) in March and lower (0.40 ppbv/h) in July. The average rate of increase of O₃ from midnight to midday is 1 ppbv/h. Surface temperature is highest (43–44°C) during March and April months leading to higher photochemical production. On the other hand, relative humidity, which is higher during the rainy season, shows negative correlation with temperature and ozone mixing ratio. It can be seen that among the two parameters are measured, correlation of surface ozone with wind speed is better (R ²=0.84) in compare with relative humidity (R ²=0.66).     

Evaluation of surface ozone measurements during 2000–2005 at a rural area in the upper Spanish plateau

This paper presents the main experimental results of surface ozone concentrations measured at a rural area in Northern Spain from February 2000 to December 2005. Daily and seasonal variation of ozone has been analysed. The peak concentration levels are obtained in the afternoon, mean value around 88 μg m⁻³, with extreme average values of 59 μg m⁻³ in January and 113 μg m⁻³ in July. Small differences are found in the mean and median of the ozone levels from April to August, when spring and summer maxima are observed. Despite the great inter-annual ozone variability obtained, most air quality indicators showed a positive trend. Further analysis of the monthly mean ozone concentrations of the main percentiles have also been performed using a harmonic model. The upward trend was 6.2 ± 1.7 μg m⁻³ for the 98th percentile. To interpret the main features of the annual cycle and describe the ozone peaks, the influence of meteorological factors is studied. In summer, ozone production is governed by local processes, air temperature being the major controlling factor. However, the origin of the spring maximum is not so well identified.     

根据Dobson和TOMS资料分析北京和昆明大气臭氧总量变化特征

用约２０年 Ｄｏｂｓｏｎ和ＴＯＭＳ资料来分析北京（３９.９３°Ｎ，１１６.４０°Ｅ）和昆明 （２５.０２°Ｎ，１０２．６８°）两地大气臭氧总量的变化特征，结果表明：（１）在１９７９－２０００年间北京大气臭氧长期变化趋势是－０．６４２ ＤＵ／年，而昆明在１９８０－２０００年间的趋势是－０.００９ ＤＵ／年；（２）北京和昆明两地大气臭氧都有很强的季节内变化（尤其冬季更强），与季节性变化强度相当；（３）在北京和昆明，由记录较短的大气臭氧资料分析得到的长期变化趋势，与较长记录得到的结果有显著差异；（４）在北京（中纬度）和昆明（低纬度）大气臭氧都有显著的准两年振荡信号；（５）两个站点大气臭氧的年际变化主要由长期趋势项和准两年振荡信号组成；（６）Ｄｏｂｓｏｎ仪测量得到的臭氧总量与ＴＯＭＳ资料非常一致。     

The Northward Shift of Climatic Belts in China During the Last 50 Years and the Corresponding Seasonal Responses

Along the meridian of 105°E, the Chinese region are divided into two parts, east and west. The results show that in the east part of China the temperate extratropical belt, the warm extratropical belt,and the northern subtropical belt shift northward significantly, whereas the middle subtropical belt and the southern subtropical belt have less or no change. As for the northern subtropical belt, the maximal northward shift can reach 3.7 degrees of latitude. As for the warm extratropical belt, along the meridian of 120°-125°E, the maximal northward shift can reach 3-4 degrees. In the west part of China, each climatic belt changes little. Only in the Xinjiang area are the significant northward shifts. Correspondingly, it is found that in the last 50 years the traditional seasons have changed. For Beijing, Hailar, and Lanzhou, in general, summer becomes longer and winter shorter over the last 50 years. Summer begins early and ends late with respect to early 1950s. Contrary to the summer, winter begins la     

Tropospheric ozone and oxides of nitrogen over the north-western Pacific in summer

In summer, atmospheric ozone was measured from an aircraft platform simultaneously with nitric oxide (NO), oxides of nitrogen (NO _y ), and water vapor over the Pacific Ocean in east Asia from 34° N to 19° N along the longitude of 138±3°E. NO _y was measured with the aid of a ferrous sulfate converter. The altitude covered was from 0.5 to 5 km. A good correlation in the smoothed meridional distributions between ozone and NO _y was seen. In particular, north of 25° N, ozone and NO _y mixing ratios were considerably higher than those observed in tropical marine air south of 25° N. NO _y and O₃ reached a minimum of 50 pptv and 4 ppbv respectively in the boundary layer at a latitude of 20° N. The NO concentration between 2 and 5 km at the same latitude was 30 pptv. The profiles of ozone and water vapor mixing ratios were highly anti-correlated between 25° N and 20° N. In contrast, it was much poorer at the latitude of 33° N, suggesting a net photochemical production of ozone there.     

Biases in AMIP model simulations of the east China monsoon system

 AMIP model simulations of the east China (5–50°N; 105–122°E) monsoon system are analyzed to study coherent relationships between rainfall and wind annual cycle biases. A comparison with observed interannual variability patterns is carried out to identify the physical processes that explain the biases. The analyses show that poleward displacement of the simulated east Asian jet stream causes the ascending branch of the jet-induced transverse circulation to move north and, as a consequence, produces negative (positive) rainfall biases occur in central (northeast) China. The model simulations show decreased southwesterly flow and ITCZ rainfall over the South China Sea when weaker (versus observations) summer Hadley and Walker circulations are present. This results from diminished model tropical disturbance activity, and highlights the importance of air-sea interactions. In addition, during October–January, intensified model low-level easterlies enhance moisture transport and produce positive local rainfall biases over central and northeast China. Biases in the east China monsoon system are concurrently reflected in the planetary circulation. Enhanced northeast China rainfall results from increased surface pressure over the North Pacific and an amplified zonal pressure gradient along the east China coast. This bias pattern is associated with differences in model representations of topography. On the other hand, the South China Sea experiences an extensive elongated meridional rainfall bias dipole structure that straddles the equator. This is accompanied by a baroclinic vertical pattern over the tropics as well as a barotropic wave train that extends from Australia to the Antarctic, where the teleconnection is likely a direct atmospheric response to tropical convective heating. Received: 20 June 2000 / Accepted: 17 September 2000     

IMPACT OF CONVECTION OVER THE SOUTH CHINA SEA ON TROPICAL CYCLONE MOTION OVER THE WESTERN NORTH PACIFIC DURING SUMMER MONSOON

The intraseasonal oscillation(ISO) of the South China Sea(SCS, 105-120°E, 5-20°N) convection and its influences on the genesis and track of the western North Pacific(WNP) tropical cyclones(TCs) were explored, based on the daily average of NCEP/NCAR reanalysis data, the OLR data and the western North Pacific tropical cyclone best-track data from 1979 to 2008. The mechanism of the influences of ISO on TC movement and the corresponding large-scale circulation were discussed by a trajectory model. It was found as follows.(1) During the SCS summer monsoon, the SCS convection exhibits the ISO features with active phases alternating with inactive phases. The monsoon circulation patterns are significantly different during these two phases. When the SCS convection is active(inactive), the SCS-WNP monsoon trough stretches eastward(retreats westward) due to the activity(inactivity) of SCS monsoon, and the WNP subtropical high retreats eastward(stretches westward), which enhances(suppresses) the monsoon circulation.(2) The amount of TC genesis in the active phase is much more than that in the inactive phase. A majority of TCs form west of 135 °E during the active phases but east of 135 °E in the inactive phases.(3) The TCs entering the area west of 135 °E and south of 25 °N would move straight into the SCS in the active phase, or recurve northward in the inactive phase.(4) Simulation results show that the steering flow associated with the active(inactive)phases is in favor of straight-moving(recurving) TCs. Meanwhile, the impacts of the locations of TC genesis on the characteristics of TC track cannot be ignored. TCs that occurred father westward are more likely to move straight into the SCS region.     

海陆分布对于大气环流的地形与热力的影响

关於海陆分布对大气环流的影响,有两派意见.一派著重於热力的影响,另一派则着重於动力的影响.对海洋而言,在冬季大陆可以看作冷源,在夏季则好似一热源.由於海洋上与大陆上受热不同的结果,冬季在西伯利亚可长期维持着一强大高压.关於冬夏季风的产生,一般也都认为是由於海陆受热不同的效果.     

Relationship of Late-Winter Temperatures in Europeto North Atlantic Surface Winds: A Correlation Analysis

Summary  The relationship between European surface temperature and winds over the eastern North Atlantic are investigated for the years 1988 to 1997. Daily Special Sensor Microwave Imager SSM/I observations are used to evaluate a monthly surface wind index that quantifies the influence of southwesterly flow. Our wind index and the monthly-mean surface-air temperatures in late winter and early spring over France and northern-latitude Europe are highly correlated. In February, the year-to-year increases/decreases match every year for France (correlation of 0.82 with the Index); and every year with just one exception for Europe (correlation with the Index of 0.76 for a longitudinal strip through Europe 45–50° N, and 0.73 for the 50–60° N strip). In March, the increases/decreases of the wind Index and of the temperatures for France also match, but the correlation with the Index is lower, 0.65. The high correlation between our Index and the large interannual fluctuations in the monthly temperature in late winter and early spring indicate that the onset of the spring conditions in Europe is significantly influenced by the wind patterns over the eastern North Atlantic. Coinciding with the fluctuations from warm-Europe/high-Index winter to the opposite conditions, we observe “seesaw” effects, fluctuations over the North Atlantic, in opposite directions in the east (25–5° W), and the west (65–45° W). In the low-Index years we find that: (a) the surface-air temperatures in the west are appreciably higher than in the east (but slightly lower in the high-Index year), and (b) the difference between the 500 mb meridional wind in the west and that in the east is positive and large, exceeding 10 m s⁻¹ (but it becomes negative and small in the high-Index years). The “seesaw” effects suggest that a positive feedback exits between these cross-Atlantic temperature differences and the surface winds. Received August 7, 1998 Revised April 23, 1999     

近百年东亚冬季气温及其大气环流变化型态

利用最新20世纪近百年再分析气象资料,研究近百年东亚冬季气温变化型及其相关的大气环流型态.结果表明近百年内东亚冬季气温主要有两种变化型:第一是东亚西南与东北相反气温变化型,表现在40°N以南及105°E以西地区(西南地区)气温变化与40°N以北及105°E以东地区(东北地区)变化相反;第二是40°N以南气温一致变化型.与第一种气温变化型耦合的大气模态是500hPa欧亚型遥相关、西伯利亚高压及北大西洋涛动.当欧亚型遥相关负位相,北大西洋涛动正位相及西伯利亚高压减弱时,有利于蒙古和我国105° E以东的区域增温而我国西南地区和青藏高原降温,反之亦然.第二种气温变化型耦合大气模态是500hPa西太平洋型遥相关,北太平洋涛动.当西太平洋型遥相关及北太平洋涛动处于正位相时(北太平洋北负南正),东亚40°N以南地区增温,东亚40°N以北地区降温.耦合的大气模态的型态差异,影响各阶段气温的年际变化.近一百年中,欧亚型遥相关和北大西洋涛动在1984～2010期间的型态最显著,是20世纪80年代东亚显著增暖的原因之一.研究还发现20世纪中期后东亚气温的年际变化与极地环流的变化联系紧密,表现在西伯利亚高压范围东扩并与极地环流联系,也是近百年气温趋势上升的一个原因.     

地基与星载仪器观测大气臭氧总量分析

本文选取多个臭氧总量观测站点,采用"三重制约法"分别对下列3组仪器观测臭氧总量数据进行统计分析,解算出不同观测资料的误差标准差,进而对比研究各种仪器的精度特征:1)1996~2003年期间地基WOUDC(World Ozone and Ultraviolet Radiation Data Centre)观测网络仪器(包括Brewer、Dobson和Filter臭氧测量仪)与星载TOMS(Total Ozone Mapping Spectrometer)和GOME(The Global Ozone Monitoring Experiment)仪器;2)2004~2013年期间WOUDC与星载OMI(ozone monitoring instrument)和SCIAMACHY(scanning imaging absorption spectrometer for atmospheric chartography)仪器;3)2004~2013年期间地基SAOZ(Système D’Analyse par Observations Zénithales)与星载OMI和SCIAMACHY仪器。结果表明,1996~2003年期间TOMS V8和GOME观测精度相当,分别为7.6±2.8 DU/46(其中,7.6±2.8 DU为所分析站点观测资料的平均精度及其标准差,46为站点数目)和7.6±1.5 DU/46。TOMS V8观测精度优于TOMS V7(8.5±3.0 DU/46),验证了前者对后者有所改进。2004~2013年期间OMI和SCIAMACHY在WOUDC地基站点观测精度接近,分别为6.6±1.4 DU/21和6.0±1.6 DU/21。SAOZ地基仪器精度为8.4±3.6 DU/8。对于3类WOUDC地基仪器,Brewer站点观测资料的平均精度最优(7.9±3.3 DU/12),Dobson次之(8.7±2.3 DU/19),Filter最差(14.7±4.0 DU/15)。相比于卫星,3种地面仪器观测平均精度较差(10.5±4.3 DU/46),这主要是由于Filter精度较差引起。中国境内的瓦里关(Brewer)、香河(Dobson)和昆明(Dobson)3个地基站点仪器观测精度均较优,分别为7.8 DU、6.7 DU和6.6 DU。尽管不同站点之间存在一定差异,但整体来说,地基与卫星仪器在中国境内3个站点观测臭氧总量吻合较好。     

近十五年全球臭氧变化

利用卫星观测臭氧总含量ＴＯＭＳ（第７版）资料,在剔除季节变化后对全球６０°Ｓ－６０°Ｎ范围首先进行了沿纬度分布的线性趋势和周期分析。结果表明：自本世纪７０年代末,各纬带上的臭氧总量都呈下降趋势,强度随纬度升高而加剧,并发现总体上北半球臭氧的下降趋势较南半球更加明显;同时证实了准两年振荡是臭氧变化中除年周期外最显著的周期。并对臭氧变化中的准两年振荡作了遥相关分析;发现准两年振荡在强度和位相上基本呈纬向分布并主要表现出赤道对称的特征。１３５～１７０°Ｅ地区臭氧总量变化所表现出的不同于其它地区的原因可能是这一地区常年频繁出现的对流活动;而臭氧总量下降趋势表现出的北半球同纬度地区均大于南半球的南北半球差异可能是由两半球人类活动的差异引起     

中国近30a臭氧气候场特征

利用1979—2005年TOMS（total ozone mapping spectrometer）和2006—2007年OMI（ozone mo-nitoring instrument）的卫星观测资料,分析中国地区对流层臭氧含量（tropospheric ozone residue,TOR）、整层臭氧含量（total ozone,TO）的空间分布和季节变化特征,利用二项式加权平均法、Mann-Kendall突变检验法以及小波分析法分析南方典型地区广州臭氧序列的趋势、突变以及周期特征。结果表明,中国地区多年平均对流层臭氧柱含量为35.89DU,东中部地区高于西部,四川东部和重庆西部存在极高值区,青藏高原为极低值区;对流层臭氧夏季平均值最高,冬季最低,春季高于秋季。中国地区多年平均臭氧总量为298.61DU。臭氧总量随着纬度增大而增大,成带状分布,青藏高原为极低值区;臭氧总量春季平均值最大,秋季为最低。南方广州地区的对流层臭氧在1979—2007年之间存在明显的上升趋势,时间变率为0.38DU/（10a）;TOR时间序列在1997年发生突变,存在显著的1a及2a的周期。臭氧总量在1979—2007年之间存在明显的下降趋势,变化率为-2.1DU/（10a）;TO在1993年发生突变,存在显著的2a周期     

土壤湿度和地表反射率变化对中国北方气候影响的数值研究

本文利用ＯＳＵ两层大气环流模式来考察土壤湿度和地表反射率变化对中国北方气候的影响。在（３０—４６°Ｎ，９０—１２０°Ｅ）的区域上进行了３个试验，结果表明干土壤对我国东部季风区和西部非季风区有不同的影响特征。高反射率造成降水减少。并指出地表过程的作用可能是经常发生在华北的春夏连旱现象的重要原因之一。