共查询到19条相似文献，搜索用时 109 毫秒
1.
利用NCEP再分析资料和卫星观测资料,结合耦合了沙尘模块的中尺度模式WRF,通过个例分析研究了青藏高原及附近地区沙尘气溶胶从近地面向对流层上部和平流层下部传输的特征和机制以及青藏高原大地形对平流层与对流层之间物质交换的影响。结果表明,深对流活动可将近地面沙尘气溶胶传输到上对流层—下平流层区域,但是下平流层区域的沙尘气溶胶浓度分布依赖于地面沙尘源的位置和对流的强度,且与对流系统内是否有降水有关。在没有穿透性对流情况下,垂直上升运动不能直接将沙尘输送到下平流层,但上对流层的沙尘可通过扩散作用和小尺度的混合过程经过数小时缓慢地进入下平流层。在没有明显系统性降水的情况下,夏季青藏高原上空旺盛的对流活动和高地形使得高原上空成为气溶胶进入下平流层的主要区域。上对流层区域的沙尘气溶胶浓度还受到平流层空气入侵的影响,在没有强的地面沙尘排放源的情况下,平流层空气的入侵对上对流层区域气溶胶浓度的分布和演变有较大的影响。 相似文献
2.
利用NCEP再分析资料和卫星观测资料,结合耦合了沙尘模块的中尺度模式WRF,通过个例分析研究了青藏高原及附近地区沙尘气溶胶从近地面向对流层上部和平流层下部传输的特征和机制以及青藏高原大地形对平流层与对流层之间物质交换的影响。结果表明,深对流活动可将近地面沙尘气溶胶传输到上对流层—下平流层区域,但是下平流层区域的沙尘气溶胶浓度分布依赖于地面沙尘源的位置和对流的强度,且与对流系统内是否有降水有关。在没有穿透性对流情况下,垂直上升运动不能直接将沙尘输送到下平流层,但上对流层的沙尘可通过扩散作用和小尺度的混合过程经过数小时缓慢地进入下平流层。在没有明显系统性降水的情况下,夏季青藏高原上空旺盛的对流活动和高地形使得高原上空成为气溶胶进入下平流层的主要区域。上对流层区域的沙尘气溶胶浓度还受到平流层空气入侵的影响,在没有强的地面沙尘排放源的情况下,平流层空气的入侵对上对流层区域气溶胶浓度的分布和演变有较大的影响。 相似文献
3.
未来甲烷排放增加对平流层水汽和全球臭氧的影响 总被引：3，自引：0，他引：3
利用一个耦合的大气化学-气候模式(WACCM3)研究了地表甲烷排放增加对平流层水汽和全球臭氧变化的影响.结果表明,如果地表甲烷的排放量在2000年的基础上增加50%(达到政府间气候变化专门委员会A1B排放情景中2050年的值),平流层水汽体积分数将平均增加约0.8×10-6.南半球平流层甲烷转化为水汽的效率比北半球高.在北半球平流层中,1mol甲烷分子可以转化为约1.63mol的水汽分子,而在南半球1mol甲烷分子大概可以转化为约1.82mol的水汽分子.甲烷排放增加50%将使全球中低纬度地区以及北半球高纬度地区的臭氧柱总量增加1%-3%,使南半球高纬度地区臭氧柱总量增加近8%,而秋季(南半球春季)南极地区臭氧柱总量增加幅度可高达20%,南极臭氧的这种显着增加主要是由于甲烷增加造成的化学反馈所致.在北半球中高纬度地区,甲烷增加引起的臭氧变化主要与甲烷氧化导致的水汽增加有关.研究还表明,未来甲烷排放增加对臭氧的恢复作用其实与溴化物排放的减少一样重要. 相似文献
4.
《高原气象》2017,(1)
利用全大气气候通用模式WACCM3对青藏高原夏季臭氧谷(OV)的双心结构进行了模拟。通过模式输出资料和ERA-interim再分析资料、MLS卫星资料的对比分析,对模式模拟性能进行了评估。结果表明:WACCM3能模拟出青藏高原夏季OV的双心结构,尤其对上对流层下平流层区(UTLS)的OV中心位置模拟较好,强度偏强。平流层上部的OV模拟较差,中心偏东,强度偏强。因为WACCM3对夏季高原邻近地区上空UTLS区的环流尤其是南亚高压模拟较好,而UTLS区的臭氧损耗的主要原因是动力输送作用,所以模拟效果好。上部OV模拟较差的原因主要是环流场模拟不佳导致了氯化物和氮氧化物的分布模拟较差。 相似文献
5.
利用建立的球面分层大气散射模式，研究了Ｂｒｅｗｅｒ仪器工作波长进行Ｕｍｋｅｈｒ短法反演所包含的信息量，给出Ｂｒｅｗｅｒ仪器探测大气臭氧垂直廓线的方法。同时，用气溶胶光学厚度计算得到气溶胶订正系数，建立了Ｕｍｋｅｈｒ反演的程序，用此程序对ＴａｂｌｅＭｏｕｎｔａｉｎ资料进行气溶胶修正，得到了较好的结果。对北京测站１９９１年１─３月资料进行由气溶胶造成的臭氧反演廓线的误差计算，结果表明，用常规反演方法得到的各层臭氧含量的误差与平流层气溶胶光学厚度有一近似线性的关系；进行气溶胶修正后，与国外的臭氧反演廓线的误差修正工作￣［１］比较，结果较一致。研究提出的气溶胶订正反演方法为更好地对平流层臭氧变化趋势进行研究提供了可能性和可靠的基础。 相似文献
6.
地球系统模式是研究全球气候与生态环境变化问题的重要工具，气溶胶与大气化学模式负责为其中的大气环流模式提供与气候效应有关的气态化学物质和气溶胶成分。本文在全球嵌套网格空气质量预报模式系统的基础上发展了一个适用于中国科学院地球系统模式（CAS-ESM）耦合计算的气溶胶与大气化学分量模式（IAP-AACM），采用简化的气相化学机制，不仅考虑了人为气溶胶，同时考虑了海盐、沙尘和二甲基硫等自然气溶胶及其前体物的在线排放。评估结果表明，IAP-AACM氧化剂插值计算可靠，采用简化机制和碳键机制（CBM-Z）模拟的差异较小。和观测的对比表明，得益于CAS-ESM的气溶胶双向反馈作用，简化版能够较好地抓住气溶胶及其前体物的空间分布，为IAP-AGCM提供可靠的气溶胶模拟。另外，简化版能大幅提升计算效率，满足CAS-ESM耦合长期积分的需求。为了在全球气候变化的研究中提供更完善的气溶胶模拟，未来考虑在IAP-AACM中增加氮化学和臭氧平流层化学机制。 相似文献
7.
通过WACCM-3模式中气溶胶光学厚度与卫星资料的对比发现,模式可以很好地再现全球气溶胶的主要分布特征,但在一些区域还存在数值上的差异。利用数值试验研究对流层气溶胶的直接气候效应对平流层气候的影响,结果表明:对流层气溶胶对平流层气候有明显影响,平流层化学过程在这一影响中起重要作用,而对流层气溶胶对平流层辐射的影响不是其直接气候效应对平流层影响的主要原因。其机制可能是对流层气溶胶改变对流层的辐射平衡,影响对流层的温度和大气环流,进而影响行星波的上传,使得平流层气候发生变化;影响区域主要位于高纬度和极地地区,南半球的变化比北半球大,温度变化最大达10 K,纬向风变化最大可达12 m/s,臭氧体积分数最多减少0.8×10-6。 相似文献
8.
大城市气溶胶对光化辐射通量及臭氧的影响研究(Ⅱ)——数值试验分析 总被引：8，自引：8，他引：8
城市化已引起大量痕量气态污染物、气溶胶以及臭氧前体物的人为排放,从而引起区域大气化学循环的扰动变化。在分析国内外研究现状与观测实例的基础上,进一步用辐射模式与化学模式研究了气溶胶对到达地面的光化辐射通量以及臭氧形成的影响,表明气溶胶可显著减小到达地面的光化学辐射通量,减缓光化学反应进程,并进一步抑制臭氧的形成;在目前广州等大城市的污染过程中,高浓度的气溶胶可造成光化学辐射通量衰减高达70%~80%,紫外线的衰减比可见光更明显,在可见光波段随波长增大衰减幅度减小,气溶胶层的存在对短波长激发的光化学过程的影响更加显著。分析说明城市污染大气中光化学反应的生成物与反应物之间存在自抑制过程,在目前的城市群复合污染情况下,气溶胶与臭氧之间的非线性相互作用值得关注。 相似文献
9.
青藏高原平流层臭氧和气溶胶的变化趋势研究 总被引：2，自引：1，他引：2
通过分析SAGEⅡ资料,发现青藏高原平流层臭氧存在递减趋势,15—50 km臭氧的变化对臭氧总量变化贡献最大,其中25—50 km和15—25 km两层的贡献大致相当。通过青藏高原和中国东部地区平流层臭氧变化的对比,清楚地看出:两地臭氧总量变化的差异主要是由于在15—25 km臭氧变化不同所致。5—7月臭氧变化趋势的情况与年平均的变化类似,两地臭氧变化的差异主要在平流层低层,即15—25 km。青藏高原平流层气溶胶面密度的时间变化序列显示:大的火山喷发对青藏高原平流层气溶胶具有重要影响,其影响可持续6年左右。从1997年至今,青藏高原18—25 km气溶胶面密度增加,最大的增长出现在23 km,每年大约增长4%—5%。而在16—17 km气溶胶的面密度出现减少趋势。与此同时,在37 km以下,青藏高原的温度出现递减的趋势,而且其递减速度比中国东部地区快;在37—50 km,温度出现增加的趋势,青藏高原的增温也比中国东部地区快。青藏高原平流层低层气溶胶的增加和温度的降低都将增强该区域非均相反应的作用。 相似文献
10.
11.
The impact of sulfate aerosol, ClOx and NOx perturbations for two different magnitudes of CH4 sources on lower stratospheric ozone is studied by using a heterogeneous chemical system that consists of 19 species belonging to 5 chemical families （oxygen, hydrogen, nitrogen, chlorine and carbon）. The results show that the present modeled photochemical system can present several different solutions, for instance, periodic states and multi-equilibrium states appearing in turn under certain parameter domains, through chlorine chemistry and nitrogen chemistry together with sulfate aerosol as well as the increasing magnitude of CH4 sources. The existence of catastrophic transitions could produce a dramatic reduction in the ozone concentration with the increase of external sources. 相似文献
12.
The impact of sulfate aerosol, ClO2 and NOx perturbations for two different magnitudes of CH4 sources on lower stratospheric ozone is studied by using a heterogeneous chemical system that consists of 19 species belonging to 5 chemical families (oxygen, hydrogen, nitrogen, chlorine and carbon). The results show that the present modeled photochemical system can present several different solutions, for instance, periodic states and multi-equilibrium states appearing in turn under certain parameter domains, through chlorine chemistry and nitrogen chemistry together with sulfate aerosol as well as the increasing magnitude of CH4 sources. The existence of catastrophic transitions could produce a dramatic reduction in the ozone concentration with the increase of external sources. 相似文献
13.
In this paper the bromine family and radiative effects are considered in an updated box model under the framework of ozone-temperature feedback,in order to further analyze the possible behavior of atmospheric ozone in the lower mid-latitude stratosphere.Results show that this updated photochemical system can present several different solutions,within a certain domain of parameters,with fixed-point and periodic states appearing in turn.The temperature feedback effect introduced in this box model has not changed the topology of the ozone system.This result presents nonlinear characteristics of the ozone system,and possible trends in the stratospheric atmosphere between complex chemistry and radiation processes. 相似文献
14.
R.K.R. Vupputuri 《大气与海洋》2013,51(4):359-374
Abstract A coupled 1‐D radiative‐convective and photochemical diffusion model is used to study the influence of ozone photochemistry on changes in the vertical temperature structure and surface climate resulting from the doubling of atmospheric CO2, N2O, CH4 and increased stratospheric aerosols owing to the El Chichón volcanic eruption. It is found when CO2 alone is doubled, that the total ozone column increases by nearly 6% and the resulting increase in the solar heating contributes a smaller temperature decrease in the stratosphere (up to 4 K near the stratopause level). When the concentration of CO2, N2O and CH4 are simultaneously doubled, the total ozone column amount increases by only 2.5% resulting in a reduced temperature recovery in the stratosphere. Additional results concerning the effect of the interaction of ozone photochemistry with the stratospheric aerosol cloud produced by the El Chichón eruption show that it leads to a reduction in stratospheric ozone, which in turn has the effect of increasing the cooling at the surface and above the cloud centre while causing a slight warming below in the lower stratosphere. 相似文献
15.
Venkat NR. Mukku 《大气科学进展》1990,7(2):192-196
Recently, the depletion in ozone and aerosol extinctions inside Antarctic Spring westerly vortex and condensa-tion nuclei enhancement events in the mid latitudes stratosphere were related to downward transport of aerosols by subsidence and sedimentation. However, the problems associated with such hypothesis would keep a constraint on photochemical theories on ozone hole and stratospheric condensation nuclei (CN) events. Alternately, the gross fea-tures of aerosol hole are better explicable assuming a reversed residual circulation. This opens a path for combined operation on ozone by both photochemistry and dynamics in the same space domain.Independently, we relate the CN events to the growth and transport of negative ion complexes above the Peak of Junge Layer (PJL) without invoking photochemistry in order to be consistant with the observed interhemispheric dif-ferences in the planetary wave activity and CN concentration. 相似文献
16.
Xue Xi Tie Guy Brasseur Xing Lin Pierre Friedlingstein Claire Granier Philip Rasch 《Journal of Atmospheric Chemistry》1994,18(2):103-128
The paper discusses the potential effects on the ozone layer of gases released by the engines of proposed high altitude supersonic aircraft. The major problem arises from the emissions of nitrogen oxides which have the potential to destroy significant quantities of ozone in the stratosphere. The magnitude of the perturbation is highly dependent on the cruise altitude of the aircraft. Furthermore, the depletion of ozone is substantially reduced when heterogeneous conversion of nitrogen oxides into nitric acid on sulfate aerosol particles is taken into account in the calculation. The sensitivity of the aerosol load on stratospheric ozone is investigated. First, the model indicates that the aerosol load induced by the SO2 released by aircraft is increased by about 10–20% above the background aerosols at mid-high latitude of the Northern Hemisphere at 15 km for the NASA emission scenario A (the NASA emission scenarios are explained in Tables I to III). This increase in aerosol has small effects on stratospheric ozone. Second, when the aerosol load is increased following a volcanic eruption similar to the eruption of El Chichon (Mexico, April 1982), the ozone column in spring increases by as much as 9% in response to the injection of NO
x
from the aircraft with the NASA emission scenario A. Finally, the modeled suggests that significant ozone depletion could result from the formation of additional polar stratospheric clouds produced by the injection of H2O and HNO3 by the aircraft engines. 相似文献
17.
In late December 2012 a blocking anticyclone followed by the event of minor stratospheric warming, set in the troposphere over West Siberia and, after that, over the European part of Russia. As a result of the deformation of a polar stratospheric vortex, the temperature in the lower stratosphere over Obninsk dropped below the threshold of the formation of polar stratospheric clouds. The lidar measurements of temperature, ozone values, and aerosol characteristics in the middle atmosphere were carried out at the lidar station during this atmospheric event. In three cases, polar stratospheric clouds (PSCs) referred to NAT Ia type according to the sounding results, were registered at the height of about 20 km. No considerable decrease in the ozone concentration in the area of PSC formation was revealed in these measurements. 相似文献
18.
The global zonally averaged atmospheric chemistry model is developed in this paper.Theformation mechanism of the Antarctic ozone hole is numerically simulated using the model to checkthe viewpoints on the formation mechanism.The results show that:(1)The Antarctic ozone hole is a special phenomenon resulting from the heterogeneousreactions on the surface of the polar stratospheric cloud particles,under the special conditions oftemperature and circulation in Antarctic spring.The heterogeneous reactions reduce the NO_2concentration,resulting in the decrease of ozone production rate.The ozone content decreaseswhen its production is less than its destruction.This is the direct cause for the formation of theAntarctic ozone hole.(2)The impact of the polar vortex on the transport of trace species is not the determinativefactor in the formation of the Antarctic ozone hole.but makes the intensity of the ozone holechanged.(3)The solar cycles have negligible influence on the intensity of the Antarctic ozone holethrough photochemical reactions. 相似文献
19.
A photochemical box model including a detailed heterogeneous chemistrymodule has been used to analyze in detail the effects of temperature andaerosol surface area on odd oxygen production/depletion in the lowerstratosphere at 30° S. Results show that for background aerosolloading, the hydrolysis of BrONO2 and N2O5are most important atall temperatures studied except when the temperature falls below about205 K, when ClONO2 hydrolysis becomes most important. Thisprocessing leads to removal of active nitrogen to form nitric acid andenhancement of HOx, BrOx, ClOx levels. Detailed O3 budgets asa function of temperature are presented showing how ozone loss andproduction terms vary with changes in stratospheric sulfate aerosol loadingfor the individual families. For (most) aerosol loading levels, thelargest ozone losses occurred at warmer temperatures due to the strongtemperature dependence of the NOx ozone-destroying reactions. Theexception to this occurred for the conditions representative of volcanicloading, which showed a strong increase in ozone destruction due toincreases in destruction from the ClOx and HOx families.The ozoneproduction term k[NO][HO2] did not show a strong dependence oneithertemperature or aerosol loading, due to the offsetting effect of reducedNOxand increased HOx concentrations. 相似文献