共查询到18条相似文献，搜索用时 250 毫秒
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平流层微量气体变化趋势的研究 总被引：4，自引：1，他引：3
采用HALOE提供的1992—2005年的资料,分析了平流层几种微量气体（臭氧、HCl,HF,NO,NO2,水汽和甲烷）的混合比在不同高度、不同纬度带的变化趋势, 以期为研究平流层的辐射和化学过程提供一些有用的数据。结果表明,在不同纬度带这些微量气体的变化特征并不相同,在不同高度上他们的变化特征也不大一样。这14年臭氧的变化趋势与其他几种微量气体的变化趋势对比表明,在平流层上层,1990年代中期以后臭氧浓度的恢复比较明显,而且这14年臭氧的变化趋势与HCl、HF和水汽的变化趋势是相反的。在平流层中层臭氧的变化趋势复杂一些,除一些微量成分对它的破坏外,还受到其它因素的影响。但1997—2002年臭氧混合比增大,与HCl、NO,NO2和水汽混合比的减小趋势是相反的,这说明《蒙特利尔条约》及其它环保措施的实施对平流层中层臭氧浓度的恢复也已初见成效。 相似文献
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《地球化学》2020,(3)
利用飞机航测于2018年夏季在东北吉林省用宽范围粒径谱仪对10 nm～10μm大气颗粒物的数浓度谱进行在线监测,分析大气颗粒物的垂直分布廓线和粒径分布特征。结果表明,东北地区近地面颗粒物数浓度为5.8×10~3～9.9×10~(4)cm~(-3),平均值为(2.7±2.2)×10~(4)cm~(-3);垂直方向上颗粒物数浓度随海拔升高整体呈降低趋势,且垂直廓线存在两种类型:一种是在边界层附近存在较明显的分界线,即在边界层下方,大气颗粒物数浓度随高度升高而显著降低,在边界层上方,大气颗粒物数浓度变化随高度变化不明显;第二种是随高度的升高,城市上空的大气颗粒物数浓度降低,且海拔高度与大气颗粒物数浓度呈现近似线性负相关的关系。在观测期间,颗粒物的粒径大多集中在爱根模态,其峰值位于25～30 nm,后向气流轨迹显示,气团来源于蒙古及内蒙古地区。在四平城市上空观测到1例新粒子生成事件,其核模态颗粒物数浓度为当日其他地区的4倍,后向气流轨迹显示其气团来源于中国辽宁省且受局地气团影响。 相似文献
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臭氧是地球大气中最重要的痕量气体之一,在气候变化和生态环境中均扮演着至关重要的角色。对流层臭氧作为光化学烟雾的重要成分之一,其浓度变化与人类活动息息相关。基于卫星遥感技术监测对流层臭氧浓度可以帮助我们更好地发现和定量解释对流层臭氧在不同季节、不同时刻以及不同区域的变化特征,探讨臭氧在对流层中的成因机制。随着卫星遥感技术的全面发展,臭氧遥感产品（例如臭氧总量、廓线等）无论在产品精度或是时空分辨率方面均取得了显著进步,然而,由于受较弱卫星信号与复杂下垫面的影响,对流层臭氧遥感产品精度仍无法满足目前对流层大气成分的精细化科学应用研究。主要围绕对流层臭氧卫星遥感,回顾和分析了臭氧卫星遥感载荷的发展历程和现状,结果表明国内外已基于不同谱段（紫外—可见光、热红外和太赫兹）实现了全球及区域臭氧的时空分布探测;讨论了基于不同技术遥感反演算法（直接与间接反演、多波段联合反演、天底—临边协同反演、基于机器学习技术的创新算法等）的特点及适用性,分析表明算法精度的提升包括从复杂大气背景下的辐射传输模拟、基于地面观测的先验信息优化以及仪器定标与信噪比等多方面的工作;展望了卫星遥感在全球和区域尺度提供可靠对流层臭... 相似文献
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河套干旱地区夏季边界层结构特征观测分析 总被引：2，自引：0，他引：2
利用2013年夏季7月爱尔达K/LLX802J型机动式边界层风廓线雷达获取的三维风场资料和银川站高空气象探测资料,对河套干旱地区夏季边界层日变化特征进行了分析.结果表明:爱尔达K/LLX802J型机动式风廓线雷达能较好的反映并分辨出夏季河套干旱地区边界层内大气湍流和风场的演变过程.夏季7月河套干旱地区边界层高度白天平均为2127.2 m,夜间平均为1760.7 m,白天边界层高度比夜间平均高366.5 m.河套干旱区夏季地表非绝热加热对边界层的影响主要集中在800 m以下,800~2000 m高度边界层则主要受昼夜交替和大尺度天气系统的影响.夏季7月河套干旱地区边界层风速在300 m以下随高度增加而增大,离地500 m以下边界层易在北京时间07:00-11:00和18:00-21:00时段发生风速切变;300 m以下边界层白天盛行西南偏南风、夜间盛行南风,300~2000 m高度边界层白天和夜间均盛行东南风;离地300 m以下边界层易在夜间21:00-23:00时出现风向切变.夏季7月白天河套干旱地区边界层大气垂直速度在300 m高度以下随高度增加而增大,由0.3 m·s-1增大到0.6 m·s-1,夜间边界层大气垂直速度在200 m高度以下随高度增大而增大;300 m高度以上边界层大气垂直速度无论昼夜随高度变化均较小. 相似文献
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利用卫星数据考察平流层传播性行星波活动特征 总被引：2，自引：0，他引：2
中层大气是大气波动盛行的区域。这些波动不仅是这里大气扰动的主要形态,伴随其传播的耗散成为作用在背景流场上的动力强迫和作用于环境物质上的湍流混合,影响到了中层大气的各个方面,尤其对一些典型环流结构的形成起着控制作用。简要地回顾了这个研究领域发展的历史。与此同时,利用美国卫星温度探测数据（SABER/TIMED温度数据）考察了平流层（20~70 km高度范围）传播性行星波活动的整体性质,给出了他们的空间分布和年变化形式。利用温度标准差（T SDEV）代表行星波活动的强度,当前研究显示无论在热带外地区或以赤道为中心的热带地区,全年传播性行星波活动都是相当显著的。结合同期定常行星波活动强度分析结果,通过比较说明在热带外地区,传播性波动和定常波动表现出相近的季节活动性;从T SDEV数值看,在定常波活动达到最强的季节(冬末春初),这两类波动活动的强度达到了相当的程度（TSDEV=12~14 K）。当前结果还显示,在定常波活动受到显著抑制的夏季条件下,传播性波动成为平流层行星波活动的主导成分。在赤道地区的分析结果表明传播性波动是这里的控制性波动,并且其活动强度在全年都处在相当稳定的状态;T SDEV分析结果还给出了一个值得关注的现象,从平流层下部开始（20 km高度）逐渐随高度增大（大于2 K）,但是这种随高度增长的趋势在30 km高度左右突然终止;从30 km开始直到中间层底部,T SDEV几乎不随高度变化,这隐含地说明这里的波动处于一种饱和的状态。 相似文献
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古尔班通古特沙漠是中国唯一冬季存在长期积雪的沙漠,在此特殊地理环境下,沙漠及周边区域冬季雪深和边界层高度的时空变化特征和相互关系尚未明确。本文利用1980—2019年SMMR（Scanning Multichannel Microwave Radiometer）、SSM/I（Special Sensor Microwave/Imager）、SSMI/S（Special Sensor Microwave Imager/Sounder）被动微波遥感雪深数据、古尔班通古特沙漠腹地雪深观测数据和ERA5再分析资料（the Fifth Generation ECMWF Reanalysis）边界层高度数据,分析了沙漠及周边区域冬季雪深和边界层高度的时空变化特征与相互关系。结果表明：古尔班通古特沙漠及周边区域冬季雪深年均值为8.45 cm,整体呈现东北部和南部积雪较深,其他区域积雪较浅并呈现出由沙漠中心区域向四周逐渐减少的特点,雪深在古尔班通古特沙漠及其东北、南边的邻近区域呈升高趋势,剩余地区呈下降趋势。古尔班通古特沙漠及周边区域冬季边界层高度年均值为105.54 m,呈现东南部和西北部高,中心沙漠区域、东北部、西南部较低的特点,边界层高度在沙漠及周边区域升高而其他区域降低。古尔班通古特沙漠的冬季雪深和大气边界层高度时空变化整体呈负相关,其中93.17%以上的沙漠区域呈负相关,平均相关系数为-0.32,最大相关系数绝对值为-0.58,空间相关系数为-0.42（P<0.05）。 相似文献
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平流层爆发性增温中平流层环流及化学成分变化过程研究 总被引：3，自引：1，他引：2
利用欧洲中期天气预报中心（ECMWF）气象分析场、欧洲空间局ENVISAT/MIPAS卫星观测资料以及平/对流层大气化学输送模式MOZART 3综合分析了2003—2004年冬季北半球爆发性增温事件对于平流层大气环流、物质输送以及对流层顶附近臭氧通量等多方面的影响。结果表明：①本次增温过程持续时间长、强度大,平流层极涡从高层向下逐层分裂,增温效应作用到大气较低层,当纬向东风形成并维持后极涡又自上向下逐层恢复;②SSW过程前后行星波活动频繁,有长时间多次的上传,且以1波作用为主,2波对其进行补充;③在θ PVLAT坐标中分析发现SSW扰动过程中平流层中存在一对向极、向下的传播模态,相应的对流层中有一向赤道的传播模态,不同符号的纬向风、温度异常信号沿这两个模态传播,且上、下层传播模态在时间上存在着一定的联系;④增温过程中行星波活动引起的向极输送以及极区垂直运动的变化,共同影响了平流层的物质输送过程,从而导致北半球平流层N2O、O3、CH4、H2O等微量气体成分的垂直、水平分布发生显著变化;⑤增温过程中活跃的行星波可以造成平流层Brewer Dobson环流增强,同时导致高纬度地区（60~90°N）穿越对流层顶的臭氧通量（Cross Tropopause Ozone Flux, CTOF）显著增强,与行星波相联系的等熵物质运动引起“middleworld”区域内向赤道的臭氧通量也有所增强。 相似文献
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B. H. Subbaraya K. S. Appu K. P. Chatterjee A. F. Chizhov V. D. Grinchinkov A. Jayaraman G. A. Khokin V. A. Kononkov I. S. Moshnikov V. Narayanan S. P. Perov O. V. Shtrikov Y. V. Somayajulu C. R. Sreedharan K. S. Zalpuri 《Journal of Earth System Science》1987,96(1):25-40
A total of seventeen vertical profiles of ozone were obtained during an Indo-USSR collaborative experiment on ozonesonde intercomparison conducted at Thumba during March 1983. The vertical distribution of ozone was measured using rocket-borne, balloon-borne as well as ground-based instruments. Four different rocket ozonesondes from India and USSR and the balloon ozonesonde were used to makein situ observations of ozone concentrations in addition to the Dobson spectrophotometric observations of total ozone and Umkehr. The rocket and the balloon launchings were effected in three salvos and measurements were made at different times of the day as well as during night. The results of all these measurements are used to obtain a mean ozone vertical distribution over Thumba foT the spring equinoxial period. The mean profile shows the maximum ozone concentration at 27 km with a value of (3.86±0-52)×1012 molecules per cc. Comparison of this mean profile with available satellite data for the equatorial regions shows that, in general, the Thumba values are lower by 10–15% at altitudes below 40 km and larger at altitudes above 50 km compared to the satellite results. The data also show evidence for a day-to-day variability and a possible day-to-night variability in the ozone vertical distribution with the night-time values higher than the daytime values at all altitudes above 35 km and the difference is found to increase with the increasing altitude. 相似文献
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2008-2012年拉萨地基与卫星臭氧总量观测比较 总被引：1，自引：0，他引：1
通过比较2008-2012年拉萨站地基观测臭氧总量与三种卫星反演产品, 评估地基和卫星观测臭氧总量数据的质量信息. 结果表明: 地基与卫星臭氧总量绝对差为-10~15 DU, 相对差为-4%~4%, 日尺度相对差呈随机分布特征; TOSOMI算法反演的SCIAMACHY臭氧总量更接近地基观测结果, DOAS算法反演OMI臭氧总量与地基观测结果差异最大. 地基与卫星臭氧总量标准差存在季节性变化, 夏季最大, 冬季最小; 云的影响会加剧地基与卫星臭氧总量差异, 以SCIAMACHY产品最为显著. 相似文献
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Nandita D. Ganguly 《Journal of Earth System Science》2008,117(1):79-82
The Indian reserve of coking coal is mainly located in the Jharia coal field in Jharkhand. Although air pollution due to oxides
and dioxides of carbon, nitrogen and sulphur is reported to have increased in this area due to large-scale opencast mining
and coal fires, no significant study on the possible impact of coal fires on the stratospheric ozone concentration has been
reported so far. The possible impact of coal fires, which have been burning for more than 90 years on the current stratospheric
ozone concentration has been investigated using satellite based data obtained from Upper Atmospheric Research Satellite (UARS
MLS), Earth Observing System Microwave Limb Sounder (EOS MLS) and Ozone Monitoring Instrument (OMI) in this paper. The stratospheric
ozone values for the years 1992–2007, in the 28–36 km altitude range near Jharia and places to its north are found to be consistently
lower than those of places lying to its south (up to a radius of 1000 km around Jharia) by 4.0–20%. This low stratospheric
ozone level around Jharia is being observed and reported for the first time. However, due to lack of systematic ground-based
measurements of tropospheric ozone and vertical ozone profiles at Jharia and other far off places in different directions,
it is difficult to conclude strongly on the existence of a relationship between pollution from coal fires and stratospheric
ozone depletion. 相似文献
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Characterization of the atmospheric boundary layer from radiosonde observations along eastern end of monsoon trough of India 总被引：1，自引：0，他引：1
In this paper, a comparison of two methods for the calculation of the height of atmospheric boundary layer (ABL), using balloon-borne GPS radiosonde data is presented. ABL has been characterized using vertical profiles of meteorological parameter. The gradient of virtual potential temperature (?? v ) profile for the determination of mixed layer heights (MLH) and the mean value of turbulent flow depth (TFD) obtained from the vertical profile of Bulk Richardson Number (R i B ) have been used in this study. One-year data have been used for the study. There is large seasonal variability in MLH with a peak in the summer and winter whereas the TFD remained steady throughout the year. Results from the present study indicate that the magnitudes of TFD are often larger than the MLH. 相似文献
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东南极中山站-昆仑站断面最高和最低气温变化特征 总被引：1，自引：1，他引：0
利用中山站-昆仑站断面自动气象站2 m气温和同期再分析资料分析了南极沿海到内陆高原的最高和最低气温的变化特征, 并通过个例讨论了气温出现极端过程的天气背景. 结果表明: 南极中山站-昆仑站断面最高和最低气温季节变化趋势基本相似, 年际变化不明显. 最高气温标准偏差大于最低气温, 冬季气温标准偏差明显大于夏季, 且夏季气温变化幅度远小于冬季. 随海拔的增加, 最高气温年较差逐渐增大, 最低气温年变化的无芯率(气温没有明显的最小值程度)呈增大趋势, 夏季气温变化幅度逐渐增大, 冬季气温变化幅度的区域性差异不明显; 2005年7月25-31日的极端降温过程主要受到极涡、地面冷高压及下降风的共同影响. 相似文献
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The seasonal cycle of temperature—salinity variations in the Bab el Mandab region (southern Red Sea) is described using CTD
data collected during four cruises spread over the period May 1995—August 1997. A two layer system exists during early summer,
winter and spring while a three layer system exists during summer. During summer, a large amount of the Gulf of Aden water
intrudes into the Bab el Mandab region; up to the northern limit (14.5‡N). The quantity of Red Sea water that flows into the
Gulf of Aden is maximum during the winter and minimum during the summer 相似文献
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S. Suresh Babu S. K. Satheesh K. Krishna Moorthy C. B. S. Dutt Vijayakumar S. Nair Denny P. Alappattu P. K. Kunhikrishnan 《Journal of Earth System Science》2008,117(1):263-271
During the Integrated Campaign for Aerosols, gases and Radiation Budget (ICARB) over India, high-resolution airborne measurements of the altitude profiles of the mass concentrations (MB) of aerosol black carbon (BC) were made off Bhubaneswar (BBR, 85.82°E, 20.25°N), over northwest Bay of Bengal, in the altitude region upto 3 km. Such high-resolution measurements of altitude profiles of aerosols are done for the first time over India. The profiles showed a near-steady vertical distribution of MB modulated with two small peaks, one at 800m and the other at ～2000m. High resolution GPS (Global Positioning System) sonde (Vaisala) measurements around the same region onboard the research vessel Sagar Kanya (around the same time of the aircraft sortie) revealed two convectively well mixed layers, one from ground to ～700m with an inversion at the top and the other extends from 1200m to ～2000m with a second inversion at ～2200m and a convectively stable region in the altitude range 700–1200m. The observed peaks in the MB profile are found to be associated with these temperature inversions. In addition, long-range transport from the Indo-Gangetic Plain (IGP) and deserts lying further to the west also influence the vertical profile of BC. Latitudinal variation of MB showed a remarkable land ocean contrast at the 500m altitude (within the well mixed region) with remarkably lower values over oceans, suggesting the impact of strong sources over the mainland. However, above the ABL (at 1500m), the latitudinal variations were quite weak, and this appears to be resulting from the impact of long-range transport. Comparison of the altitude profiles of MB over BoB off BBR with those obtained during the earlier occasion over the inland stations of Hyderabad and Kanpur showed similarities above ～500m, with MB remaining around a steady value of ～1 μg m?3. However, large differences are seen within the ABL. Even though the observed MB values are not unusually high, their near constancy in the vertical column will have important implications to radiative forcing. 相似文献
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C. V. Srinivas R. Venkatesan K. M. Somayaji A. Bagavath Singh 《Journal of Earth System Science》2006,115(5):557-574
A simulation study of the sea breeze circulation and thermal internal boundary layer (TIBL) characteristics has been carried
out at the tropical site Kalpakkam on the east coast of India, for operational atmospheric dispersion prediction. The community
based PSU/NCAR MM5 Meso-scale meteorological model is used for the study. Three cases on typical days in summer (24 May 2003),
southwest (SW) monsoon (1 July 2001) winter season (2 February 2003) with different large-scale flow pattern are studied.
The MM5 model is used with 3 nested domains with horizontal grid resolutions 18 km, 6 km and 2 km and 26 vertical levels.
The model is integrated for 24 hours in the above cases with initial and boundary conditions taken from NCEP-FNL analyses
data. Observations of 10 meteorological stations and coastal boundary layer experiments conducted at Kalpakkam are used for
comparison and validation of the simulation. The characteristics of simulated sea breeze and TIBL at Kalpakkam are seen to
vary in the above cases according to the prevailing large-scale winds and surface fluxes. The sea breeze circulation is seen
to develop early with larger strength and inland propagation in the summer case under the influence of moderate synoptic wind
and strong heating conditions than in the SW monsoon and winter cases. The horizontal and vertical extents of TIBL are found
to be larger in the summer case than in other cases. Although model parameters agree in general with observations, all the
fine features are not clearly captured and some slowness in model sea breeze development is also seen. The results indicate
the need to improve i) the initial conditions by assimilation of available surface/upper air observations to reduce model
bias and ii) surface net radiation parameterisation. The model could predict the essential features of the local circulation
and further improvement is expected with better initial condition data and incorporation of more realistic surface data. 相似文献