Mass exchange between stratosphere and trotosphere over the Tibetan Plateau and its surroundings

Using NCEP dataset we calculate the exchange of mass across the thermal tropopause by the Wei's method from 1978 to 1997 over the Tibetan Plateau and its surroundings. We also calculate the annual variation of aerosol and ozone of 100 hPa level with the monthly SAGE dataset from July 1988 to December 1993. Results indicate that ( i ) the mass from troposphere to stratosphere is magistral station in summer over the Tibetan Plateau and its surroundings. The air transport reaches the summit in midsummer with two large value centers, which lie in the north of Bengal Bay and southeastern Tibetan Plateau, respectively. A large value center, which lies over the Tibetan Plateau, is smaller than that aforementioned. In winter, the mass transport is from stratosphere to troposphere, and reaches the minimum in January. ( ii ) As far as the 19-year mean cross-tropopause mass exchange from June to September is concerned, the net mass transport is 14.84x1018 kg from troposphere to stratosphere. So the area from the Tibetan Plateau to the Bengal Bay is a channel through which the mass of lower atmosphere layer gets into upper troposphere and lower stratosphere. (iii) The cross-tropopause mass may take the lower level aerosol to the tropopause. Then, the concentration of aerosol near the tropopause becomes larger, which may cause the content of ozone to reduce.     

穿越东亚不同定义对流层顶质量和臭氧通量的分析

选取动力学和热力学定义的对流层顶作为平流层和对流层之间的分界,并利用等熵坐标下的Wei公式对东亚地区穿越对流层顶的质量和臭氧通量进行了分析,结果发现对流层顶的选择对于研究平流层与对流层交换方面的作用至关重要.东亚地区质量和臭氧通量交换在整体上具有明显的年代际变化特征,1958～2001年近44a的通量交换距平变化可以分为3个比较稳定的时段:即1958～1971,1972～1985和1986～2001年.在这3个时段中,通量交换距平分布表现为"负正负"的变化趋势,说明在东亚地区质量和臭氧净通量交换情况为先增强后减弱.东亚地区平流层和对流层之间质量和臭氧交换正距平区在东北平原和华北平原附近经历了一个逐渐增强的变化过程,表明这些区域在东亚地区平流层和对流层之间的质量和臭氧通量交换中扮演着越来越重要的角色.     

大气对流层顶的臭氧时空分布变化

 利用1958~2001年的臭氧垂直分布和NCEP资料,计算出全球对流层顶的气候场,并对其空间分布、季节、年际和年代际演变进行了分析.结果表明:①对流层顶臭氧质量比呈纬向分布的特征明显,南北半球中纬度和南极为高值区,赤道和北极为低值区,且与对流层顶高度和温度场有对应关系;②从400~70 hPa的温度和臭氧质量比垂直经向剖面中,显现出对流层顶的上层和下层由于具有不同的物理和化学过程导致垂直分布存在差异;③对流层顶臭氧质量比纬向距平场的年代际变率具有不同位相的时空演变尺度,南半球的时空差异比北半球大,南极最不稳定,低纬和赤道地区幅度变化较小,但时间尺度较大;④极地各季节对流层顶的臭氧分布和高度场特征相似,低纬则与温度场分布较一致;⑤对流层顶断裂带中臭氧质量比最大值出现在春季,秋季为最小值,其对应的纬度存在明显的季节空间经向波动,夏季达到最高纬度,冬季到达最低纬度;⑥对流层顶臭氧质量比纬向距平的季节变率表现出准半年变化趋势,且两半球变化趋势相反.     

对流层顶大气臭氧的季节变化研究

 采用季节划分和季节突变的概念、理论及方法,对44a(1958~2001年)的大气臭氧资料及对流层顶气压场资料进行了计算,并分析了对流层顶大气臭氧的季节变化.结果发现对流层顶大气臭氧的季节变化在全球大部分区域中的突变性都比较明显,表明对流层顶大气臭氧的季节变化受到上对流层和下平流层中多种因素的影响.通过分析还发现,利用曾庆存所定义的参数R_W(t)及有关的一些概念和方法确能很好地反映对流层顶大气臭氧的季节变化.     

Detection of stratospheric ozone intrusions by windprofiler radars

Stratospheric ozone attenuates harmful ultraviolet radiation and protects the Earth's biosphere. Ozone is also of fundamental importance for the chemistry of the lowermost part of the atmosphere, the troposphere. At ground level, ozone is an important by-product of anthropogenic pollution, damaging forests and crops, and negatively affecting human health. Ozone is critical to the chemical and thermal balance of the troposphere because, via the formation of hydroxyl radicals, it controls the capacity of tropospheric air to oxidize and remove other pollutants. Moreover, ozone is an important greenhouse gas, particularly in the upper troposphere. Although photochemistry in the lower troposphere is the major source of tropospheric ozone, the stratosphere-troposphere transport of ozone is important to the overall climatology, budget and long-term trends of tropospheric ozone. Stratospheric intrusion events, however, are still poorly understood. Here we introduce the use of modern windprofiler radars to assist in such transport investigations. By hourly monitoring the radar-derived tropopause height in combination with a series of frequent ozonesonde balloon launches, we find numerous intrusions of ozone from the stratosphere into the troposphere in southeastern Canada. On some occasions, ozone is dispersed at altitudes of two to four kilometres, but on other occasions it reaches the ground, where it can dominate the ozone density variability. We observe rapid changes in radar tropopause height immediately preceding these intrusion events. Such changes therefore serve as a valuable diagnostic for the occurrence of ozone intrusion events. Our studies emphasize the impact that stratospheric ozone can have on tropospheric ozone, and show that windprofiler data can be used to infer the possibility of ozone intrusions, as well as better represent tropopause motions in association with stratosphere-troposphere transport.     

中国西南上空大气臭氧垂直分布的结构特征

 用球载电化学臭氧探空仪于2001年春季在中国西南昆明上空测得臭氧垂直分布的精细结构,结果表明臭氧垂直廓线具有多层次特征.在21～30km高度之间是臭氧分压多峰值的极大值层,极大值平均为15.13mPa,臭氧混合比极大值平均高度在30.2km.对流层顶附近臭氧分压存在极小值,且有南风分量的极大风层对应.对流层上层和平流层低层出现臭氧峰值时,其峰值层附近具有显著的冷平流特征.在5km以下观测到了不稳定的对流层臭氧高浓度峰值层.     

Seasonal variation of global stratosphere-troposphere mass exchange

By Wei formula in pressure coordinate, the stratosphere-troposphere mass exchange (STME) is diagnosed globally for 44 years from 1958 to 2001 using the European Center for Medium-Range Weather Forecasts (ECMWF) reanalysis datasets. Regions of mass flux into the stratosphere are found over Indonesia, bay of Bangladesh and the mid-west coast of South Africa. Compensating mass outflow from the stratosphere appears mainly over mid-latitudes near large-scale troughs. Upward and downward transport of mass at the middle and high latitudes accompany with each other. Mass flux into troposphere is stronger in autumn and winter than in spring and summer. Strong downward mass flux into the troposphere occurs in eastern Asia the whole year with nearly stable sites. Although the area of eastern Asia accounts for only 5.6% of that of the northern hemisphere (NH), its net mass exchange reaches 15.83% of that of the NH, which means that research on STME of eastern Asia is greatly important to that of the NH and even the global areas. Air across the tropopause enters more from stratosphere to troposphere than that from troposphere to stratosphere, which is possibly related with systematic bias of the assimilated datasets and with persistent rise of the tropopause height. Contributions of the mass exchange and the mass flux exchange in the NH and southern hemisphere (SH) on their latitudes increase from equator to pole, with larger contributions in the NH. Mass exchange and mass flux exchange per areas at high latitudes are larger than that at low latitudes, which means greater mass exchange efficiency at high latitudes.     

Seasonal variation of global stratosphere-troposphere mass exchange

By Wei formula in pressure coordinate, the stratosphere-troposphere mass exchange (STME) is diagnosed globally for 44 years from 1958 to 2001 using the European Center for Medium-Range Weather Forecasts (ECMWF) reanalysis datasets. Regions of mass flux into the stratosphere are found over Indonesia, bay of Bangladesh and the mid-west coast of South Africa. Compensating mass outflow from the stratosphere appears mainly over mid-latitudes near large-scale troughs. Upward and downward transport of mass at the middle and high latitudes accompany with each other. Mass flux into troposphere is stronger in autumn and winter than in spring and summer. Strong downward mass flux into the troposphere occurs in eastern Asia the whole year with nearly stable sites. Although the area of eastern Asia accounts for only 5.6% of that of the northern hemisphere (NH), its net mass exchange reaches 15.83% of that of the NH, which means that research on STME of eastern Asia is greatly important to that of the NH and even the global areas. Air across the tropopause enters more from stratosphere to troposphere than that from troposphere to stratosphere, which is possibly related with systematic bias of the assimilated datasets and with persistent rise of the tropopause height. Contributions of the mass exchange and the mass flux exchange in the NH and southern hemisphere (SH) on their latitudes increase from equator to pole, with larger contributions in the NH. Mass exchange and mass flux exchange per areas at high latitudes are larger than that at low latitudes, which means greater mass exchange efficiency at high latitudes.     

利用探空资料对对流层-平流层热力结构的分析

利用16个探空站近6年的高分辨率探空资料,采用经验正交函数和数值积分等方法,分析了对流层、对流层顶和平流层下层的温度层结特征,主要得出以下结论:①对流层顶温度年变幅最小,对流层上层和平流层下层(包括对流层顶)与对流层中低层具有相反的温度变化趋势.②不同地区对流层顶高度表现为随纬度升高而降低的规律,平均每升高1°对流层顶高度下降44 m,同纬度高原地区对流层顶高度高于平原地区.③各站对流层平均温度总体表现为单峰型结构,与地面温度的季节变化特征相同,只是年较差小于地面.④对流层顶高度与对流层平均温度具有显著的正相关关系,对流层增温时对流层顶高度升高,对流层顶高度主要取决于对流层热力状况.     

臭氧氧化法处理模拟染料废水影响因素及降解动力学研究

采用臭氧氧化法对酸性红B模拟染料废水进行处理,通过正交试验和单因素试验研究了反应时间、臭氧通量和初始反应pH值等因素对废水处理效果的影响。实验结果表明,在酸性红B质量浓度为250mg/L、反应时间为10min、臭氧通量为10.53mg/min和初始反应pH值为10.0的条件下,酸性红B去除率可达到99.31%,TOC去除率达到44.91%。采用紫外-可见吸收光谱分析表明臭氧可有效破坏酸性红B分子中的共轭体系,达到脱色的目的。臭氧氧化降解酸性红B近似符合一级动力学方程ln(c0/ct)=0.167 7t+1.624 7。     

全球对流层顶温度场演变的气候学特征分析

 利用经验正交函数分解(EOF)方法对57 a(1948~2004年)NCEP/NCAR全球对流层顶月平均温度场进行分析,并讨论了57 a的主要特征向量空间分布及其对应的时间系数的演变,结果分析表明:第1模态的时空分布特征能够较好地反映对流层顶温度场结构的分布状况,且具有明显的季节变化;南北半球的温度场的空间分布结构不太一致,南半球纬向分布较为平稳,而北半球经向和纬向活动都比较强,且有明显的温度槽脊结构;南北半球的极地对流层顶温度结构在不同的季节有不同的变化趋势;南北半球热带对流层的第1模态温度场全年具有整体一致型分布;温度场各个季节的时间系数变化具有明显的多时间尺度特征.     

基于OMI数据分析青藏高原周边对流层低层臭氧的分布特征

提出一种利用地形海拔落差以及臭氧总量差来估算对流层低层大气臭氧浓度的方法.根据搭载于美国宇航局Aura卫星上的臭氧监测仪(OMI)提供的臭氧总量日观测数据,利用该方法计算出青藏高原与其周边地区四川盆地及印度北部的地形海拔落差及臭氧总量差,进一步分析了该地区低层大气臭氧的分布特征.结果表明:青藏高原周边地区对流层低层大气臭氧分布呈明显的季节变化,且低层大气臭氧分布有南北差异,南部臭氧含量高于北部.     

利用天顶散射光观测反演大气臭氧柱浓度

利用天顶散射光-差分光学吸收光谱法反演了2006年12月至2007年12月上海地区(31.3°N,121.5°E)上空的臭氧柱浓度.在反演过程中,考虑了O3,NO2,O4,H2O的吸收以及大气Ring效应对测量光谱的贡献.利用经验函数对反演结果进行筛选,将Langley plot方法与O4,H2O的拟合结果相结合,确定参考光谱中的臭氧含量.数据分析表明,2007年上海上空臭氧柱总量高值出现在4月至6月,低值出现在10月至1月,月均值的变化幅度约为50DU.实验测量误差在6%～7%左右.将地基臭氧柱总量观测结果与美国TOMS臭氧观测资料进行对比,二者的变化趋势基本一致,相关系数为0.81,地基观测结果普遍低于TOMS臭氧观测值.最后对二者产生差别的原因进行分析和讨论.     

Ozone mini-hole occurring over the Tibetan Plateau in December 2003

Since the Antarctic ozone-hole was discovered[1], the ozone depletion in stratosphere and its effect on climate and environment have become the global focus[2-6]. In China, since Zhou et al.[7] in 1994 and later Zou[8] dis- covered the total ozone valley …     

全球对流层顶气压场和温度场的时空演变结构特征

 利用1948~2004年共57年的对流层顶气压场和温度场资料,对全球对流层顶平均温压场的空间分布结构、年际和年代际变化以及季节变化进行了分析.结果表明:①热带对流层顶和极地对流层顶的平均气压场的空间位置和热状况大致吻合,并存在空间波动性,两半球对流层顶的温压场具有显著的非对称性;②对流层顶的纬向气压与温度距平场都具有不同尺度的年际和年代际变化,两极地区对流层顶的温压场最不稳定,两半球中纬度地区的时间演变尺度存在明显差异.对流层顶断裂带及其对应温度的时空波动存在反位相关系,20世纪70年代末温度出现突变现象,此时对流层顶断裂带迅速向南部空间移动;③不同季节对流层顶的温压场都将进行空间结构的调整,两者之间存在着季节变化的协调性,但北半球较南半球的演变过程复杂;④对流层顶温压场纬向距平的季节变率可划分为5个位相不同的时空波动区域,构成了气压场和温度场的经向型相关结构.北极地区气压场变化有超前于温度场变化的趋势,对流层顶断裂带的温度季节变化存在着双峰波动结构.冬半年断裂区的地理位置较夏半年稳定,气压场和温度场的最大季节变程均发生在南极.     

大气臭氧对太阳自转活动的响应．

采用交叉谱分析方法，通过年全球平均的大气臭氧总量和１０．７ｃｍ大阳通量两时间序列的对比分析发现，大气臭氧的短期变化和大阳自转活动之间有着极为密切的相关关系：大气臭氧准２７天周期变化和太阳１０．７ｃｍ辐射通量之间存在约１４０°的位相差，落后时间为１０．２天．／／关键词     

大气臭氧耗损的修复

评述了修复大气臭氧耗损的化学法和物理法，某些化学法如在南极旋涡中注入烃类可能由于生成另外的活性氯原子而不能有效地抑制大气臭氧耗损，某些物理法如利用大气电子电荷修复大气臭氧耗损，这是令人感兴趣的方法，它没有其他的化合物生成，但是会遇到技术和光电子材料的难题。在此，提出了另一类修复大气臭氧耗损的新方法，观测到卤代烃在细颗粒物渗溶冰晶表面的低温粘着系数比在冰晶上的粘着系数大2个数量级。因此有可能利用细颗粒物特性和低温非均相反应消除平流层的卤代烃及氯氟烃等达到阻断大气臭氧耗损的链反应。     

通过反常计算dilaton-axion黑洞的霍金辐射

利用Rob inson和W iczek提出的方法,我们从反常的角度研究了带电的d ilaton-axion黑洞的霍金辐射,为了得到规范不变量和广义规范不变量,引入了规范流和能动张量流,最后通过去除反常得到了在事件视界处的霍金温度,所得的结果与来自于普朗克分布的辐射谱的结果相一致.     

一次短历时特大暴雨系统的高分辨率卫星图像

利用水平分辨率为1.25km的FY2-C地球同步卫星的可见光云图,对2005年8月14日发生在北京北部山区一次百年一遇的短历时特大暴雨进行了云图分析,发现高分辨率的可见光云图可以在一个多小时前就识别出水平尺度只有几公里的初始对流,并可利用它在地面上的阴影判别其垂直发展的强度。暴雨发生前水平尺度发展到数十公里,其云顶上的暗影表明强烈的对流已突破对流层顶。     

Development and improvement of mass flux convection parameterization scheme and its applications in the seasonal climate predication model

The features of Gregory cumulus parameterization scheme, which is used in British Weather Office, are researched and then this scheme is developed and improved according to the characteristics of area precipitation over China. Firstly, the influence of the large-scale convergence in lower tropopause upon cumulus convection is directly taken into account in a “bulk“ cloud model. The organized entrainment and detrainment is considered in the model. Secondly, the initial mass flux is revised. Thirdly, the effects of subcooling water upon saturation vapour pressure are considered. Eventually, the drown-draft air is regulated. For several years, the numerical forecast of seasonal precipitation in China has been carried out by using the modified Gregory scheme. The result shows that the model with improved Gregory scheme well simulates the precipitation over China and the prediction result is good.