Ozone distribution over India

The spatial and temporal distribution of total ozone over India and its vertical distribution in theatmosphere during 1964–1969 was studied using Dobson spectrophotometer data at a network of six stations in India, Srinagar (34°N), New Delhi (28°N), Varanasi (24°N), Ahmedabad (23°N), Dum Dum (22°N), and Kodaikanal (10°N). The annual and seasonal variations show a clear phase-shift in the occurrence of the ozone maxima and minima as one proceeds from higher to lower latitudes in the tropics. In the northern stations (north of 25°N) the increase in total ozone during the course of the annual variation is caused by the fractional increase in all layers from the ground to 28 km, the main contribution coming from 10–24 km. Above 28 km the concentration changes roughly in accordance with photochemical production.In lower latitudes (south of 25°N) an increase in total ozone amount during the annual cycle is caused by a gradual increase in all the layers from the ground to 36 km above which the variation is negligible.     

Vertical ozone distribution on a global scale

All available data of the vertical ozone distribution measured with chemical sondes have been assembled and combined with one year's results from the BUV satellite to obtain the best possible information on the vertical ozone distribution averaged over longitude as a function of season (month by month). For the southern hemisphere Umkehr data have been used as a guideline in the necessary smoothing procedure. Especially in the northern hemisphere considerable adaptation to the observed latitudinal mean of the total amount was needed because most sounding stations, are situated in upper air trough positions.The results are presented as vertical distributions, as meridional cross sections of partial pressure and of mixing ratio and as partial pressure isolines as a function of latitude and season at different levels. The interaction between photochemical processes and transport resonsible for the observed distribution is briefly discussed.     

Ozone distribution over Mediterranean,central and southeast Europe during the International Quiet Sun Year (1964–1965)

Summary Ozone observations made during 1964 and 1965 at nine Mediterranean, central and southeast European stations (latitudes 38–52°N, longitudes 9–23°E) reveal patterns of seasonal and shorter time-variations in total ozone as well as in vertical ozone distribution. During the winter-spring season, a significant increase (20%) of ozone occurs essentially simultaneously with the spring stratospheric warming, and is noticed at all stations.—Autocorrelation coefficients show that the total ozone on any day is strongly related to the total ozone of the preceding four days in summer or one or two days in winter-spring or autumn. Changes of total ozone in southeast Europe correlate closely with those in Mediterranean Europe, and less closely with those from north central Europe.—Power spectrum analysis detects the dependence of ozone changes on processes with periods longer than 6–8 days, and indicates a significant oscillation with a period of 14–15 days, perhaps a result of the direct influence of lower stratospheric circumhemispheric circulation. — Reliable vertical ozone soundings were not available from all stations. The mean vertical profiles at Arosa, Switzerland (47°N) and Belsk, Poland (51°) are very similar. More than 60% of the variability of the total ozone is contributed by changes in ozone concentration between 10 and 24 km; less than 10% is due to variations above 33 km. Changes in ozone partial pressure at different altitudes, and relationships of those changes to total ozone, indicates that a mean vertical ozone distribution may be described adequately by considering the ozone changes in four layers: a) the troposphere, b) the lower stratosphere up to 24 km, c) a transition layer from 24 km to a variable upper border at 33–37 km, and d) the layer above 33–37 km.Part of this paper was presented at the Ozone Seminar in Potsdam, Germany, 27 September 1966.     

北京城区大气混合层内臭氧垂直结构特征的初步分析——基于臭氧探空

本文利用2013年6月至2015年10月北京南苑观象台两年多午后臭氧探空资料,初步分析了北京城区大气混合层内臭氧浓度的垂直分布规律以及典型天气条件下大气边界层臭氧的变化特征.主要结果有：（1）季节平均而言,地表至对流层中部（8 km）的臭氧浓度在夏季最高,冬季最低,相差50~130 μg·m^-3,最大差异在边界层.总体而言,对流层臭氧浓度随高度有比较缓慢的增加,但是边界层内臭氧浓度的垂直结构随季节有比较大的差异：夏季混合层中部存在一个臭氧浓度极大值,这与夏季比较强的光化学生成臭氧有关;而在冬季地面臭氧浓度很低,平均值小于40 μg·m^-3,说明冬季地面是臭氧很强的汇.（2）臭氧浓度季节内变率的季节差异也十分明显,夏季最大、冬季最小.季节内变率在从边界层向自由对流层过渡区域最小（夏季为24 μg·m^-3,冬季仅为10 μg·m^-3）,在边界层内变率较大,夏季可达64 μg·m^-3（冬季为30 μg·m^-3）,这也说明边界层化学过程明显影响臭氧浓度的变化.（3）我们从所有白天样本中严格筛选了部分混合层样本,并把臭氧浓度在由混合层向自由大气过渡时的垂直分布分成了三类,即臭氧浓度随高度增大（Ⅰ型）、减小（Ⅱ型）以及基本稳定不变（Ⅲ型）;臭氧垂直结构类型有明显的季节特征,夏季主要是Ⅱ型,而冬季则以Ⅰ型为主.（4）此外,我们还针对一些典型天气过程（强风、静稳雾天和PM_2.5污染）边界层内臭氧的变化特征进行了分析,结果表明：强风切变产生的机械对流引起的充分混合,有利于高层臭氧向低层输送,使得混合层内臭氧浓度的垂直梯度明显减小,同时混合层高度较高,达3 km以上;在高湿度静稳天气控制下,大气混合层较稳定,对北京上空污染物的垂直扩散十分不利：颗粒物浓度升高,削弱到达近地层的太阳辐射,从而降低臭氧的生成效率,混合层内臭氧浓度与混合层厚度都处于较低水平.     

Fourteen-year series of vertical ozone distribution over Arosa,Switzerland, from Umkehr measurements

Summary Observations of the vertical ozone distribution over Arosa, Switzerland, have been carried out routinely since 1956 (with one two-year gap). Long-term trends of ozone concentration at different levels indicated by this series are discussed in the light of the results obtained from five years of parallel measurements with two Dobson spectrophotometers. Further substantiation of the suggested correlation between ozone concentration in the upper stratosphere and solar activity (with a two- to three-year lag of ozone against sun-spot numbers) is needed because no full agreement was obtained from the two instruments with respect to the secular variation at those top levels.     

Solar response in the vertical structure of ozone and temperature in the tropical stratosphere

The aim of the present paper is to study the solar response in the vertical structure of ozone and temperature over the Indian tropical region and a search for any mutual relationship between their solar coefficients on a decadal scale in the lower stratosphere. For the purpose, the data obtained by ozonesonde and Umkehr methods for the lower stratospheric ozone and that of the total ozone amount from Dobson spectrophotometer during the period 1979–2001 have been analyzed. These data are analyzed using the multi-functional regression model, which takes into account most of the known natural and anthropogenic signals. The NCEP- and MSU-satellite data for the temperature over this region have been used. Results indicate an in-phase correlation of around 0.5 between ozone and solar flux (F10.7) in the vertical structure over the equatorial station, Trivandrum (8.3°N) but no significant correlation over Pune (18.3°N). The solar components of ozone and temperature indicate an in-phase but poor correlation in the lower stratospheric altitudes over both stations. However, when total ozone content data is analyzed, it indicates a very high correlation (⩾0.9) between the solar components of ozone and temperature. The solar trend in the vertical distribution of ozone is found to be of the order of 5–25% per 100 units of F10.7 solar flux for Trivandrum but it is relatively smaller (1.6–15.2%) over Pune. The solar dependence of temperature is found to be quite significant for the entire Indian tropical region with not much latitudinal variation.     

Long-term changes (1980–2003) in total ozone time series over Northern Hemisphere midlatitudes

Long-term changes in total ozone time series for Arosa, Belsk, Boulder and Sapporo stations are examined. For each station we analyze time series of the following statistical characteristics of the distribution of daily ozone data: seasonal mean, standard deviation, maximum and minimum of total daily ozone values for all seasons. The iterative statistical model is proposed to estimate trends and long-term changes in the statistical distribution of the daily total ozone data. The trends are calculated for the period 1980–2003. We observe lessening of negative trends in the seasonal means as compared to those calculated by WMO for 1980–2000. We discuss a possibility of a change of the distribution shape of ozone daily data using the Kolmogorov-Smirnov test and comparing trend values in the seasonal mean, standard deviation, maximum and minimum time series for the selected stations and seasons. The distribution shift toward lower values without a change in the distribution shape is suggested with the following exceptions: the spreading of the distribution toward lower values for Belsk during winter and no decisive result for Sapporo and Boulder in summer.     

The Nimbus-4 Backscatter Ultraviolet (BUV) atmospheric ozone experiment — tow years' operation

Summary In April 1970 the Backscatter Ultraviolet (BUV) experiment was placed into orbit aboard the Nimbus-4 satellite. This double monochromator experiment measures ultraviolet terrestrial radiance at twelve discrete wavelengths between 2550 Å and 3400 Å. Approximately 100 scans covering a 230 km square are made between terminator crossings on the daylight side of the earth. A colinear photometer channel with the same field of view is used to derive the Lambert reflectivity of the lower boundary of the scattering atmosphere. The extraterrestrial solar irradiance is measured at the northern terminator. The instrument has currently produced almost three years of nearly continuous data which are being used to infer the high-level ozone distribution and total ozone on a global basis. The high-level ozone data have been verified by independent coincident rocket ozone soundings, and the total ozone values show good agreement with Dobson spectrophotometer determinations as well as those made with the Infrared Interferometer Spectrometer also on Nimbus-4. An increase has been observed in equatorial radiance at 2550 Å relative to 2900 Å, which seems to indicate that the amount of ozone in the upper stratosphere is related to the eleven-year solar cycle.     

Studies of variations in the vertical ozone profiles over India

The latitudinal and temporal variations in the vertical profiles of ozone over the Indian subcontinent are discussed. In the equatorial atmosphere represented by Trivandrum (8°N) and Poona (18°N), while tropospheric ozone shows marked seasonal variations, the basic pattern of the vertical distribution of ozone in the stratosphere remains practically unchanged throughout the year, with a maximum at about 28 to 26 km and a minimum just below the tropopause. The maximum total ozone occurs over Trivandrum in the summer monsoon season and the latitudinal anomaly observed over the Indian monsoon area at this time is explained as arising from the horizontal transport of ozone-rich stratospheric air from over the thermal equator to the southern regions.In the higher latitudes represented by New Delhi (28°N), the maximum occurs at 23 km. Delhi, which lies in the temperate regime in winter, shows marked day-to-day variations in association with western disturbances and the strong westerly jet stream that lies over north and central India at this time.Although the basic pattern of the vertical distribution of ozone in the equatorial atmosphere is generally the same in all seasons, significant though small changes occur in the lower stratosphere and in the troposphere. There are small perturbations in the ozone and temperature structures, distinct ozone maxima being always associated with temperature inversions. There are also large perturbances not related to temperature, ozone-depleted regions normally reflecting a stratification of either destructive processes or materials such as dust layers or clouds at these levels. Particularly interesting are the upper tropospheric levels just below the tropopause where the ozone concentration is consistently the smallest, in all seasons and at all places where soundings have been made in India.     

华南地区地磁场长期变化特征

使用华南地区5个国家基准地磁台2008—2018年地磁观测数据,通过对磁偏角D、磁倾角I、总强度F、北向分量X、东向分量Y、水平分量H、垂直分量Z月均值及年变率的分析,研究该区地磁场长期变化特征。结果表明,华南地区5个地磁台近10年来七要素月均值及年变率均呈缓慢变化趋势,且变化量相当,反映了该区域地磁场长期变化的特征。     

測量大气臭氧垂直分布的逆轉方法<C>——对逆轉方法<A><B>的改进

本文给出了1个新的测量大气臭氧垂直分布的逆转方法,该方法将臭氧层分为6层,各层的臭氧含量,前后两次用图解法由联立方程定量的解出。使用这个方法,我们对在北京观测的10条逆转曲线作了计算,并将这些计算结果作了讨论及初步的误差估计。     

The average tropospheric ozone content and its variation with season and latitude as a result of the global ozone circulation

Evaluations of radiosonde soundings over North America and Europe, measurements aboard commercial airlines, and permanent ozone registrations at nineteen ground-based stations between Tromsö, Norway, and Hermanus, South Africa, yield three belts of higher ozone intrusion from the stratosphera and maximum values of the annual means at about 30°N, at between 40°–45°N and at about 60°N. A marked decrease of the annual mean values of the tropospheric ozone is detected towards the equator and the pole, respectively.In the northen hemisphere the maximum of the annual cycle of the tropospheric ozone concentration occurs in spring at high latitudes and in summer at mid-latitudes.For the tropical region from 30°S to 30°N a strong asymmetry of the northern and southern hemisphere occurs. This fact is discussed in detail. The higher troposphere of the tropics seems to be a wellmixed reservoir and mainly supplied with ozone from the tropopause gap region in the northern hemisphere. The ozone distribution in the lower troposphere of the whole tropics seems to be controlled by the up and down movements of the Hadley cell. The features of large-scale and seasonal variation of tropospheric ozone are discussed in connection with the ozone circulation in the stratosphere, the dynamic processes near the tropopause and the destruction rate at the earth's surface.     

Ozone concentration studies and ozone flux measurements near the ground at Poona

Using a modified Brewer bubbler ozone sensor, continuous measurements of the ozone concentration near the ground were made at Poona (18°N, 73°E) for one year 1969–1970. The surface ozone concentration shows a pronounced seasonal variation, with a minimum during the monsoon months and a maximum during the pre-monsoon summer months. There is also a marked diurnal variation in surface ozone concentration which clearly follows the diurnal variation of temperature and is again a maximum during the summer months and a minimum during the monsoon. A secondary maximum in ozone concentration occurs in the forenoon during the winter months, associated with the temperature inversions that occur near the ground in this season.Both ozone and radioactive tracers, such as Cs-137 both in air and in precipitation show variations indicating that they have identical source regions and sinks. The latitudinal anomaly of surface ozone and Cs-137 observed in the low latitudes over India is explained as arising from the reduction in the rate of transfer of these tracers from the stratosphere to the troposphere, as a result of the reversed circulation at the upper levels in this season.From continuous measurements of surface ozone made with three electrochemical sensors exposed at three levels, 0, 15 and 35 m above the ground, the ozone flux has been directly calculated for the first time in the tropics. The ozone flux was calculated using both the rate of decay method used by Kroening and Ney and Regener's profile method. The profile method gives values of the order of 1.71 to 7.04×10¹¹ mol/cm²/sec and that obtained by the rate of decay method is found to be 4.2 to 5.6×10¹¹ mol/cm²/sec and are in good agreement with the flux values reported by other investigators.     

Statistical characteristics of the vertical ozone distribution in mid-latitudes

Summary The correlation matrix for the vertical ozone distribution and the temperature-ozone cross-correlation matrix, which was calculated from ozone soundings made over Berlin between 1967 and 1970, the statistical structure of the vertical ozone profile (correlation coefficients, average profiles, average standard deviation, relative variability) was derived for the three ozone seasons. The partial ozone pressure does not at all heights follow a normal distribution (e. g. at tropopause level). Generally, the correlation between tropospheric and stratospheric ozone is rather poor. In some layers the highest correlation coefficients, i.e. –0.3 and +0.4, occur in autumn (October to December) and in winter and spring (January to April). The correlation between the ozone amounts of various stratospheric layers is distinct in autumn, less distinct in summer (May to September) and entirely missing from January to April. Conspicuous cross-correlations between temperature and ozone have been found for all three seasons. a) With a negative correlation between tropospheric temperature and middle tropospheric to middle stratospheric ozone (maximum up to –0.8); b) with a rather strong positive correlation between the ozone amount and the temperature in the lower stratosphere (maximum up to +0.84); c) with a positive correlation between the ozone amount of the middle stratosphere and the temperature of the middle stratosphere (maximum up to +0.8). The highest correlation coefficients occur in autumn.     

Representativeness of total ozone trends as derived from satellite BUV and ground-based measurements

The information content of the 7-year BUV data set has been reexamined by a comparison with a fairly large set of ground Dobson and M-83 instruments. The satellite-ground intercomparison of total ozone was done under different types of ground observation techniques (observation code) and different instrument exposure (exposure code) and for various distances of the subsatellite point from the station. Because of the existing latitudinal gradient in total ozone, at a given station the bias ground-BUV tends to be smaller when the subsatellite point is at a latitude higher than the station's latitude. Knowing the total ozone gradient at a given station, the BUV total ozone has been corrected to account for the ozone gradient and the correlation was calculated with the corresponding ground observations. These correlations seem to offer no improvement when compared with the correlations between the ground ozone and the actual BUV ozone at distances of the subsatellite point from the station within 200 km from the station used in previous studies. The seasonal variation of the BUV-ground correlation reveals information on the noise level of the measurements and the geographical distribution of the percentage mean bias: (Ground-BUV)×100/(Ground) is discussed. Both on short and on longer time scales it appears that the BUV derived recommended total ozone data set is reasonably good and possible instrumental drifts are not large. The analysis includes an extension through April 1977 of the BUV and contour-derived total ozone trends byLondon andLing (1980). Over the northern hemisphere both data sets (contour and BUV) show comparable trends over middle and high latitudes which range from –3 D.U./year to –5 D.U./year during the 7-year period April 1970–April 1977. In the southern hemisphere, however, long-term variation in total ozone cannot be determined from ground observations alone. It is concluded that for unknown reasons during the 7-year period of study, total ozone has been decreasing over most of the globe. The negative growth rates at high latitudes of the northern hemisphere are highly significant.     

Meridional distribution of tropospheric ozone from measurements aboard commercial airliners

Aboard commercial airliners twenty registrations of the ozone concentration of the upper troposphere were carried out within a period of 14 months between Europe and South Africa. Nearly each of these meridional ozone profiles shows an approximately constant ozone content between 25°S and 25°N with a pronounced seasonal variation. Most of these profiles show two marked peaks of the ozone concentration at about 30°N and between 40° and 45°N. Though the number of these registrations is not sufficient for statistical computations, the first results confirm the meridional ozone distribution, which was expected from studies with ozone-radiosonde soundings. Moreover a strong asymmetry of the northern and southern hemisphere is confirmed by these ozone measurements.     

对流层-平流层之间过渡层中臭氧含量及其加热率的变化研究

利用1958~2001年共44年的ECMWF资料及参数化方法,计算了对流层顶上、下3 km气层间的臭氧含量及其吸收太阳辐射加热率的时空分布.结果表明: (1) 臭氧分布的空间梯度从赤道指向两极,而加热率则是分别由高纬和低纬指向副热带,这样的经向梯度可能是驱动对流层顶结构变化的一种重要因素;两者空间分布的季节变化显著,但其对应关系并不完全一致,1月和4月的空间结构与7月和10月的相反,随季节调整具有突变现象;东亚及青藏高原是季节变化相对稳定的区域.(2) 在热带对流层顶控制区加热率与臭氧含量呈正相关,而极地对流层顶控制区各季节有所不同,还与太阳赤纬变化相关联;各纬度间加热率季节变化的位相和变率都存在差异,但南半球相对较为一致,最大距平为±2×10^-4 K·d^-1,北半球则较复杂,最大正距平为4×1010^-4 K·d^-1;两半球的季节周期位相趋于相反.(3) 除赤道外,臭氧距平的季节变化位相超前于加热率距平2~3月,并且发生在季节变化的调整期;最大距平出现在南极的8月大于0.4 DU,3~4月则小于-0.2 DU,而北极为±0.2 DU.(4) 臭氧含量和加热率的年际与年代际演变关系对应一致,并具有多尺度的结构特征;但两半球及赤道的时空演变差异明显,30° S~30° N间副热带控制区的加热率变幅剧烈,最大距平为±2.5×10^-4 K·d^-1,高纬和两极的变幅在不同演变期各不相同;臭氧的变幅结构与之相反,北极的最大距平分别大于0.25 DU和小于-0.35 DU.(5) 20世纪70年代以前及70年代中期,两半球的正负距平具有相反的演变结构,而90年代是负距平演变最剧烈的时期.     

北太平洋上空臭氧总量长期变化趋势及其影响因素分析

本文基于1979—2014年臭氧总量的卫星遥感数据,利用多元线性回归模型对臭氧总量数据序列进行模拟计算,考察了北太平洋上空臭氧总量长期变化趋势及其影响因素的作用.结果表明,北太平洋地区大气臭氧总量长期变化呈现减少趋势,但是减少速率随季节和纬度带表现出差异性,在各纬度带臭氧峰值季节臭氧下降趋势最为显著.在0°—15°N地区臭氧高值出现在夏秋季节并在8月达到峰值,峰值月份臭氧年均下降率约为0.2DU/a;15°—30°N亚热带地区臭氧高值出现在春夏季并在5月达到峰值,峰值月份臭氧年均下降速率约为0.22DU/a;而在30°—45°N中纬度地区臭氧高值出现在冬春季并在2月达到峰值,峰值月份臭氧年均下降率0.75DU/a.在臭氧分布年平均态基础上,影响臭氧总量分布变化的因素主要有臭氧损耗物质(EESC)、太阳辐射周期(Solar)、准两年振荡(QBO)和厄尔尼诺-南方涛动(ENSO)等.其中,EESC导致臭氧损耗效应随着纬度升高而增大,在从低到高的三个纬度带损耗最大值分别为11DU、16DU和66DU;Solar增强导致臭氧增加,在三个纬度带的增加效应最大值分别为16DU、17DU和19DU;QBO@10hPa和QBO@30hPa对臭氧影响幅度基本在±10DU内波动,只有QBO@10hPa对30°—45°N区域的影响作用达到14DU,值得注意的是QBO影响作用随着纬度变化存在相位差异,在0°—15°N区域臭氧变化与QBO呈现相同相位,而在15°—30°N和30°—45°N区域臭氧变化与QBO呈现相反相位;ENSO对各个纬度带臭氧影响幅度也在±10DU内,ENSO影响作用在不同纬度带也存在相位差异,臭氧总量变化在0°—15°N、15°—30°N区域与ENSO相位相反,在30°—45°N区域与ENSO相位一致.     

Remote sensing of the global distribution of total ozone and the inferred upper-tropospheric circulation from Nimbus IRIS experiments

The global distribution of total ozone is derived for the period April, May, June and July of 1969 from Nimbus-3 Infrared Interferometer Spectrometer (IRIS) experiment. Preliminary estimates of ozone amounts from Nimbus-4 IRIS for the same period of 1970 show similar results. The standard error of estimation of total ozone from both IRIS experiments is 6% with respect to Dobson Spectrophotometer measurements. A systematic variation in the ozone distribution from April to July in the tropical, middle and polar latitudes is observed indicating the changes in the lower stratospheric circulation.The total ozone measurements show a strong correlation with the upper tropospheric geopotential height in the extratropical latitudes. From this relationship total ozone is used as a quasi-stream function to deduce geostrophic winds at the 200 mb level over extratropical regions of the northern and southern hemispheres. These winds reveal the subtropical and polar jet streams over the globe.Allied research associates.