Retrieval of Tropospheric CO Profiles Using Correlation Radiometer.Ⅱ: Effects of Other Gases and the Retrieval in Cloudy Atmosphere

l.Intr0ducti0nAschemeforretrievingCOprofilesinthetroPOspherehasbeendiscussedinthepreviousPartI(WuandGille,partI)foragascorrelationradiometerMeasurementsofPollutionintheTroPOsphere(M0PITT)workingatthe4.6pmwaveband.Thebasicequationshavebeendiscussed.TheuseofthewidebandsignalforprovidingthesurfacetemPeratureandanaddi-tionalchannelforthecolumnarC0amounttoimprovetheretrievalinthenearsurfacelayerhasbeentested.Itisfoundthaterrorsinthetemperatureprofilemayincreaseerrorsinthere-trievedprofiles…     

北京大气中主要温室气体近10年变化趋势

对1993～2002年10年间北京市大气中三种主要温室气体的监测数据进行分析,研究二氧化碳、甲烷和氧化亚氮这三种温室气体浓度的变化趋势,并初步探讨了造成这种变化的原因.分析结果表明:北京市大气二氧化碳浓度总体是上升趋势,且后5年增长较快;大气甲烷浓度前5年缓慢上升,后5年转为下降,总体已是下降趋势;与大气二氧化碳变化趋势相似,大气氧化亚氮总体也是上升趋势,后5年增长较快.     

Effect of increased nitrogen fixation on stratospheric ozone

Nitrogen compounds are produced by biological reactions and by industrial processes from the abundant nitrogen gas (N₂) in the atmosphere. The formation of compounds from atmospheric nitrogen is called fixation. In nature, nitrogen compounds undergo many conversions, but under aerobic conditions, characterized by the presence of oxygen, they tend to be converted to the nitrate (NO ₃ ^- ) form. Under anaerobic conditions, characterized by the absence of oxygen, the nitrate is denitrified, and the nitrogen contained therein is converted into nitrogen gas (N₂) and nitrous oxide (N₂O), which escape into the atmosphere. The nitrous oxide diffuses into the stratosphere, where it decomposes to yield nitrogen gas and small amounts of nitric oxide (NO) and nitrogen dioxide (NO₂), which react with ozone (O₃) to convert it to oxygen (O₂). The ozone in the stratosphere is produced by the reaction of light with oxygen and is destroyed primarily by reactions with the nitrogen oxides.As long as the production and destruction are equal, the ozone in the stratosphere is maintained at a constant concentration. Increased nitrogen fixation will lead to increased denitrification, increased amount of nitrous oxide moving into the stratosphere, and a reduction in ozone concentration.Ozone in the stratosphere attenuates the ultraviolet light received from the sun. As the ozone concentration decreases, more ultraviolet light will reach the surface of the earth. The fear is that this additional radiation will have detrimental effects on living organisms and possibly on the climate.Because the global use of fixed nitrogen in fertilizers has increased greatly in recent years and in 1974 amounted to almost 40 million metric tons, the eventual generation of nitrous oxide from the fertilizer nitrogen after application to the soil has been cited as a potential environmental hazard. In response to this concern, this document estimates nitrogen fixation, nitrous oxide production, and ozone reduction based on two methods of calculation and on various increases in nitrogen fixation. Uncertainties and information gaps in the nitrogen cycle are pointed out.This document does not review either the projected biological effects of ozone depletion or the stratospheric chemistry of ozone. These topics are dealt with at length in other studies.World fixation of nitrogen in 1974, expressed in millions of metric tons per year (MT/yr), was estimated to be as follows.Most of the estimates given are based on inadequate data; consequently, actual amounts may be significantly different from those shown. The study of nitrogen fixed in the oceans has not progressed far enough to permit reliable estimates. However, estimates of the amount of nitrogen fixed for fertilizer and other industrial uses in 1974 are considered reliable. The trend of industrial fixation of nitrogen offers some indication of the trend in total amount of nitrogen fixed. It is estimated that 174 MT of nitrogen were fixed by all processes in 1950. Total fixation in 1850 could have been 150 MT of nitrogen.Nitrous oxide-nitrogen production on land is estimated as 5 to 10 MT/yr; published estimates of production in the ocean, however, range from less than 1 to 100 MT/yr. The higher value was based on reported supersaturation of ocean waters with nitrous oxide.Two methods of estimating the decrease in ozone concentration in the stratosphere were used. Method I is based on nitrogen fixation. It involves the assumptions that the relative increase in production of nitrous oxide is proportional to the relative increase in total nitrogen fixation and that sufficient time has elapsed for the rate of denitrification to come to equilibrium with fixation; i.e., the lag time between increased fixation and increased denitrification has passed. This method, using fixation estimated for 1950 as a base, suggests that the reduction in ozone would be 5.8 and 11.5% as a consequence of increased fixation of 50 and 100 MT of nitrogen per year, respectively.Method II is based on nitrous oxide evolution. It involves the assumption that the global rate of production of nitrous oxide is 100 MT/yr (based on supersaturation of this gas in the ocean and on changes in measured concentrations of nitrous oxide in the atmosphere). Method II leads to estimates of ozone reduction much lower than those from Method I. For example, on the assumption that global production of nitrous oxide-nitrogen is 100 MT/yr and that 5% of the nitrogen denitrified is released as nitrous oxide, the estimated ozone reduction is 1% with an increase of 100 MT/yr in nitrogen fixation. This method is forced to assume an unknown source of nitrous oxide in the ocean and an unknown sink for nitrous oxide in the troposphere.There are great uncertainties in many of the estimates that have been made for nitrogen fixation and for nitrous oxide production, and there are many information gaps that need to be filled before the question of the effects of increased nitrogen fixation on the ozone layer can be answered. Perhaps the biggest information needs are in the areas of nitrogen transformations and the quantities of nitrous oxide produced in the ocean. Other needs deal with the complexities of the nitrogen cycle on land. The lag time between fixation by various processes and denitrification must be known as a basis for estimating how soon predicted effects based on equilibrium conditions can be expected. Concentrations of nitrous oxide and their fluctuations in the troposphere (lower atmosphere) need to be monitored to provide an index to variations and increases in production. Improved models are needed to relate the ozone concentration in the stratosphere to nitrogen fixation and nitrous oxide production on earth.In spite of the uncertainties in the predictions of the effects of increased fixation of nitrogen on stratospheric ozone, the potential hazard is sufficiently serious that, in addition to research on the various phases of the global nitrogen cycle that impinge upon the nitrous oxide-ozone question, research on the efficiency of use of all fixed forms of nitrogen should be worthwhile. Editor's Note: Although the data for sources, sinks, reservoirs, and rate processes in this article are undergoing rapid revision presently, it, nonetheless, is one of the clearest statements of the physics, chemistry, and biology of the fertilizer/ozone problem available to date.This report was developed by eleven scientists (see Appendix 1 for names and affiliations) representing the subject matter areas of atmospheric chemistry, chemical engineering, environmental science and chemistry, microbiology, oceanography, plant genetics, soil biochemistry, soil physics, and soil chemistry. This task force of scientists chaired by Parker F. Pratt, met under the auspices of the Council for Agricultural Science and Technology (CAST), whose headquarters office is at the Department of Agronomy, Iowa State University, Ames, Iowa 50011, U.S.A. The task force met in Denver, Colorado from October 23 to 25, 1975, to prepare a first draft of the report. The chairman then prepared a revised version and returned it to members of the task force for review and comment. A second revision was then prepared and returned for further comment. Finally, the report was edited and reproduced for transmittal through the U.S. Congressional Committees concerned with the matter of ozone depletion. It was originally issued as a CAST Report Number 53, January, 1976, but had not been formally published heretofore.     

Simulations of Hydrological Cycle Changes Between the LGM and the Present Day over China

Based on the International Satellite Cloud Climatology Project (ISCCP) data in 1983–2006,it is found that there is a high value center of high cloud amount over the Tibetan Plateau (TP),while there is a high value center of middle cloud amount over the Sichuan Basin extending to the coastal area of southeastern China along the same latitude,and a low one over the TP.The present day (PD) and Last Glacial Maximum (LGM) climates are simulated by using the NCAR Community Climate Model (CCM3) nested with a regio...     

江汉平原不同稻作模式下温室气体排放特征

采用静态箱-气相色谱法在江汉平原开展早稻、晚稻、中稻、虾稻和再生稻5种稻作类型温室气体排放监测试验,研究不同稻作模式下稻田CH₄和N₂O排放特征、总增温潜势及温室气体排放强度,为准确评估稻田生态系统温室气体排放提供参考依据。结果表明:CH₄排放集中在水稻前期淹水阶段,排放峰值最高为虾稻（85.7 mg·m-2·h-1）,较其他稻作模式高71.7%~191.5%。N₂O排放峰值主要出现于中期晒田和施肥阶段,排放峰值最高为再生稻（1100.7 μg·m-2·h-1）,较其他稻作模式高16.8%~654.9%。CH₄累积排放量从大到小依次为虾稻、再生稻、早稻、晚稻、中稻;N₂O累积排放量从大到小依次为再生稻、早稻、晚稻、中稻、虾稻;总增温潜势从大到小依次为虾稻、再生稻、早稻、晚稻、中稻;温室气体排放强度从大到小依次为虾稻、早稻、再生稻、晚稻、中稻。CH₄排放占比为82.9%~99.0%,稻虾田高排放主要原因为持续淹水时间长、秸秆还田和饲料投入,探究该模式CH₄减排举措最为关键;中稻由于水旱轮作,稻田温室气体排放最低,可作为低碳减排的主要稻作类型。     

DEVELOPMENT OF THE 2-D COUPLED STRATOSPHERICTROPOSPHERIC DYNAMICAL-RADIATIVE-CHEMICAL MODEL—PART Ⅱ:THE RESULTS AND DISCUSSION OF SENSITIVITY EXPERIMENTS

By using the 2-D stratospheric-tropospheric dynamic-radiative-chemical coupled model,somesensitivity experiments have been done,which are interactions among ozone,radiation andtemperature,vapor effects,as well as effects of source and sink.The result of temperatureexperiment shows that feedback interaction among ozone,radiation and temperature,mainlyoccurs in the upper and middle stratosphere,the maximum of ozone concentration decrease is 1ppm,the maximum of temperature change is 6 K,and the maximum of total ozone change is 20DU.From the experiment of water vapor,we can see that the area of the middle and high latitudesof the Northern Hemisphere is sensitive to vapor change.When the maximum difference betweenboth surface sources is in the Antarctic,the maximum of ozone change is also there.Because thecharacter of surface varies with latitude,dry deposition is different in different latitudes.Thechange of dry deposition makes ozone in boundary layer quite obvious,especially in both poles.The maximum change of total volume ozone in experiments of vapor,source and sink is more than12 DU.     

DEVELOPMENT OF THE 2-D COUPLED STRATOSPHERICTROPOSPHERIC DYNAMICAL-RADIATIVE-CHEMICAL MODEL—PART Ⅱ: THE RESULTS AND DISCUSSION OF SENSITIVITY EXPERIMENTS

By using the 2-D stratospheric-tropospheric dynamic-radiative-chemical coupled model,some sensitivity experiments have been done,which are interactions among ozone,radiation and temperature,vapor effects,as well as effects of source and sink.The result of temperature experiment shows that feedback interaction among ozone,radiation and temperature,mainly occurs in the upper and middle stratosphere,the maximum of ozone concentration decrease is 1ppm,the maximum of temperature change is 6 K,and the maximum of total ozone change is 20 DU.From the experiment of water vapor,we can see that the area of the middle and high latitudes of the Northern Hemisphere is sensitive to vapor change.When the maximum difference between both surface sources is in the Antarctic,the maximum of ozone change is also there.Because the character of surface varies with latitude,dry deposition is different in different latitudes.The change of dry deposition makes ozone in boundary layer quite obvious,especially in both poles.The maximum change of total volume ozone in experiments of vapor,source and sink is more than 12 DU.     

A simplified interpretation of the radiances from the SSM/T-2

Summary A microwave radiometer with channels near the 18 GHz water vapor line and in nearby windows, the Special Sensor Microwave/Temperature-2 (SSM/T-2) was launched on a Defense Meteorological Satellite Program (DMSP) satellite in November of 1991. The instrument is intended to provide data for the retrieval of atmospheric water vapor profiles. Because the relationship between the radiances observed by the instrument and the water vapor profile are both non-linear and non-local and because of the influence of clouds, the interpretation of the radiances is inherently complex. Here we develop a simplified, albeit approximate, algorithm for the profile retrievals and test it with simulation studies. Specifically it is shown that for each channel of the instrument near the 183 GHz line there is a nearly constant overburden of water vapor above the height at which the atmospheric temperature equals the observed brightness temperature. This relationship, in turn, provides the basis for a simple analytic algorithm for the relative humidity immediately above that height.The simplified algorithm is useful as a first guess for iterative solutions to the non-linear equations and for a variety of analyses such as estimating the impact of uncertainty in the radiances or the temperature profile on the retrieved water vapor profile. It is also useful as a conceptual tool to aid in the understanding of the more complex algorithms.With 7 Figures     

Cloud Base Height and Effective Cloud Emissivity Retrieval with Ground-Based Infrared Interferometer

Based on ground-based Atmospheric Emitted Radiance Interferometer (AERI) observations in Shouxian, Anhui province, China, the authors retrieve the cloud base height (CBH) and effective cloud emissivity by using the minimum root-mean-square difference method. This method was originally developed for satellite remote sensing. The high-temporal-resolution retrieval results can depict the trivial variations of the zenith clouds continu-ously. The retrieval results are evaluated by comparing them with observations by the cloud radar. The comparison shows that the retrieval bias is smaller for the middle and low cloud, especially for the opaque cloud. When two layers of clouds exist, the retrieval results reflect the weighting radiative contribution of the multi-layer cloud. The retrieval accuracy is affected by uncertainties of the AERI radiances and sounding profiles, in which the role of uncertainty in the temperature profile is dominant.     

长波辐射对大气变化的敏感性和在WRF模式中的应用检验

用RRTM长波辐射 (LWR)参数化方案测试了LWR对大气变化的敏感性。结果表明 :高云对向外长波辐射(OLR)、30 0和 5 0 0hPa净LWR通量的减弱作用较中、低云大 ;低云对 85 0hPa和地表净LWR通量的减弱作用较中、高云大。在云层中 ,LWR冷却率受云影响最大 ;在云层下方 ,云对LWR的影响迅速减小 ;而在云层上方 ,冷却率几乎不受云的影响。当水汽含量减少或增加时 ,地表向下LWR受到相应减弱或增强 ,而净LWR则在一定程度上受到相应增强或减弱 ,并且越接近地面 ,受到水汽变化的影响就越大。O3 对LWR的影响相对云和水汽来说是比较小的。文中介绍了在WRF模式中应用RRTM方案预报LWR不同季节的 2个个例 ,给出了应用NCEP/AVN分析资料预报和验证中国范围 2d之内LWR通量的模拟结果。试验表明 ,OLR和 5 0 0hPa净LWR通量与高度形势场有较好的对应关系 ,而地表净LWR很大程度上还受到地形的影响。     

Simulation of the Effect of Water-vapor Increase on Temperature in the Stratosphere

To analyze the mechanism by which water vapor increase leads to cooling in the stratosphere, the effects of water-vapor increases on temperature in the stratosphere were simulated using the two-dimensional, interactive chemical dynamical radiative model (SOCRATES) of NCAR. The results indicate that increases in stratospheric water vapor lead to stratospheric cooling, with the extent of cooling increasing with height, and that cooling in the middle stratosphere is stronger in Arctic regions. Analysis of the radiation process showed that infrared radiative cooling by water vapor is a pivotal factor in middle-lower stratospheric cooling. However, in the upper stratosphere (above 45 km), infrared radiation is not a factor in cooling; there, cooling is caused by the decreased solar radiative heating rate resulting from ozone decrease due to increased stratospheric water vapor. Dynamical cooling is important in the middle-upper stratosphere, and dynamical feedback to temperature change is more distinct in the Northern Hemisphere middle-high latitudes than in other regions and signiffcantly affects temperature and ozone in winter over Arctic regions. Increasing stratospheric water vapor will strengthen ozone depletion through the chemical process. However, ozone will increase in the middle stratosphere. The change in ozone due to increasing water vapor has an important effect on the stratospheric temperature change.     

基于特征向量法的地基红外高光谱反演大气温湿廓线附加影响因子分析

在地基高光谱遥感中,特征向量法获取的温湿廓线以初值的方式对物理反演进行约束,其反演精度对物理反演结果有着重要的影响。利用AERI的观测辐射资料和同站点的探空数据,基于特征向量法分析了温度廓线与湿度廓线反演的异同点;研究了主成分个数的选择问题,综合考虑反演精度和特征向量中包含的信息将反演温度廓线和湿度廓线的最优主成分个数定为7。为提高反演精度,引入地面温度、湿度、气压作为影响因子,试验结果表明,考虑反演精度和稳定性,地面气压的引入相比于其他2种单一气象要素以及3种气象要素组成的因子集表现更好,尤其是对边界层中下部的温湿廓线有着明显的提升,并随着高度的降低提升作用更明显,温度廓线RMSE降低最高达到1.5K,湿度廓线RMSE降低最高达到0.42g/kg。同时,分析了对数反演形式对湿度廓线的影响,结果表明,以水汽混合比的形式反演时取自然对数对反演精度的影响较小;将反演得到的水汽混合比转化为相对湿度后,取自然对数对反演精度有12%以上的提升。     

云对云中大气臭氧影响因子的分析

应用一个较详细的气相光化学和液相化学耦合的箱体模式, 研究了云层对云中大气臭氧的影响过程。这一过程可分解为三个因子来考虑： 因子Ａ （云的辐射效应）, 由于云的存在改变太阳光辐射通量, 使得对流层光化学反应减弱或增强, 从而降低或增加臭氧浓度; 因子Ｂ（云的吸收效应）, 云层中液态水对大气臭氧及其前体物 （ＮＯｘ、ＮＭＨＣ、自由基等） 的直接吸收作用; 因子Ｃ（云的液相化学效应）, 吸收进入云中的物质发生液相化学反应从而改变大气臭氧浓度。数值研究结果表明： 上述三因子对云中臭氧浓度影响的程度差别很大, 并且与云层的物理结构有密切关系。讨论了云的吸收及液相化学效应影响臭氧浓度的主要原因     

Nonlinear Retrieval of Atmospheric Ozone Profile from Solar Backscatter Ultraviolet Measurements:Theory and Simulation

ＮｏｎｌｉｎｅａｒＲｅｔｒｉｅｖａｌｏｆＡｔｍｏｓｐｈｅｒｉｃＯｚｏｎｅＰｒｏｆｉｌｅｆｒｏｍＳｏｌａｒＢａｃｋｓｃａｔｅｒＵｌｔｒａｖｉｏｌｅｔＭｅａｓｕｒｅｍｅｎｔｓ：ＴｈｅｏｒｙａｎｄＳｉｍｕｌａｔｉｏｎ①ＬｉＪｕｎ（李俊）ａｎｄＬｕＤａｒｅｎ...     

极轨气象卫星TOVS资料微机处理系统简介

极轨气象卫星大气垂直探测（ＴＯＶＳ）资料微机处理系统可实时接收处理ＴＯＶＳ／ＨＲＰＴ资料，生成空间分辨率约７５（或５０）ｋｍ的大气温度和湿度廓线、位势高度、热成风、大气中水汽总含量、射出长波辐射（ＯＬＲ）、臭氧总含量等大气参数以及ＴＯＶＳ水汽图象等产品。其中，大气温度的平均相对误差为２．５Ｋ，大气湿度的平均相对误差为２５％。由于气象卫星覆盖范围广，观测频次多，因此，ＴＯＶＳ产品可弥补海洋、高原、沙漠等地区常规探测资料之不足。     

Comparative estimates of influence of changes in carbon dioxide,methane, nitrous oxide,and water vapor concentrations on radiation-equilibrium temperature of Earth’s surface

This paper deals with direct calculations of the radiation-equilibrium temperature profile in the Earth’s atmosphere from experimental spectroscopic data. The calculations are made for its present composition and for the modified ones, when concentration of a gas, namely, one of carbon dioxide CO₂, methane CH₄, nitrous oxide N₂O or water vapor H₂O is changed. Calculations were carried out with one-dimensional (horizontally homogeneous) radiation model proceeding from the values of absorption coefficients of atmospheric layers estimated from actual data. Calculations are carried out for small disturbances of the said gases’concentrations. Approximate estimates of large disturbance were made for the cases of total withdrawal of concrete gas from the atmosphere or, on the contrary, of large increase in its concentration.     

半透明云风矢量高度算法中云下背景辐射的估计

半透明云风矢量高度指定是卫星风矢量算法的重要部分,需要来自半透明云体的辐射和云下背景辐射两个变量。云下背景辐射发生在云层下面,未被卫星直接观测到,为了在半透明云风矢量高度指定算法中更精确地获得云下背景辐射,使用风矢量附近无云区的红外/水汽散点图,估计云下背景辐射。分析表明:在追踪区域里存在无云区的情况下,追踪区的最高红外亮温可代表红外通道的背景辐射;而水汽通道的背景辐射,却在红外亮温高值区段内水汽亮温相对较低区段。追踪区内找不到无云区时应扩大搜索范围,找到无云区后可估计云下背景辐射。在半透明云风矢量高度指定算法中使用云下背景辐射估计的改进算法前后,计算FY-2气象卫星进行风矢量,并将结果与欧洲中期天气预报中心（ECMWF）分析场进行对比表明,在半透明风矢量高度指定算法中使用云下背景辐射估计,FY-2气象卫星风矢量误差明显降低。     

基于观测约束的地基犌犘犁三维水汽层析技术研究

全球定位系统(GPS)卫星信号穿过大气层时发生的偏折和延迟,可以用来反演信号传播路径上的大气水汽总量。为获取区域高精度的大气水汽三维分布,借助分布密集的地基GPS观测网及其斜路径水汽观测,建立新的观测约束层析模型,提出以高斯函数为水平约束,区域逐月多年探空观测为垂直约束,即以平均量为先验值,以标准偏差为权重矩阵的新方法;并在层析算法中引入地面观测,以提高整体尤其是低层反演精度。三维水汽层析网格模型基于长江中游鄂东区域的22站地基GPS加密网搭建,实时解算系统可逐时输出三维水汽产品。三维湿折射度和水汽密度可以分别由斜路径的湿延迟总量和水汽总量观测反演获得。以2010年开展的汛期联合加密探空观测为参照,对三维层析的总体反演精度、低层反演精度、层析区域中心与边缘反演精度进行了对比和分析。结果显示:整体样本检验三维水汽密度平均偏差为-0.63 g/m~3,标准偏差为1.22 g/m~3,与探空相关系数为0.98;水汽密度与探空资料的相关比湿折射度与探空资料的相关好;对于不同层析区域,中心区域观测元数量较为丰富,使得位于中心的层析精度好于整体和边缘;加入低层观测的层析结果与探空的相关比未加低层观测时的好,低层观测的加入提高了层析与探空的相关,减小了低层层析标准差、区域中心和2 km以上层析的均差,有效提高了反演精度;低层观测的加入对整体标准差的影响,可能与加剧观测方程中长度矩阵元素间的量级差异有关。     

Comparative Analysis of the Mechanisms of Intensified Summer Warming over Europe-West Asia and Northeast Asia since the Mid-1990s through a Process-based Decomposition Method

Previous studies have found amplified warming over Europe-West Asia and Northeast Asia in summer since the mid-1990s relative to elsewhere on the Eurasian continent, but the cause of the amplification in these two regions remains unclear. In this study, we compared the individual contributions of influential factors for amplified warming over these two regions through a quantitative diagnostic analysis based on CFRAM (climate feedback-response analysis method). The changes in surface air temperature are decomposed into the partial changes due to radiative processes (including CO2concentration, incident solar radiation at the top of the atmosphere, surface albedo, water vapor content, ozone concentration, and clouds) and non-radiative processes (including surface sensible heat flux, surface latent heat flux, and dynamical processes). Our results suggest that the enhanced warming over these two regions is primarily attributable to changes in the radiative processes, which contributed 0.62 and 0.98 K to the region-averaged warming over Europe-West Asia (1.00 K) and Northeast Asia (1.02 K), respectively. Among the radiative processes, the main drivers were clouds, CO2concentration, and water vapor content. The cloud term alone contributed to the mean amplitude of warming by 0.40 and0.85 K in Europe-West Asia and Northeast Asia, respectively. In comparison, the non-radiative processes made a much weaker contribution due to the combined impact of surface sensible heat flux, surface latent heat flux, and dynamical processes, accounting for only 0.38 K for the warming in Europe-West Asia and 0.05 K for the warming in Northeast Asia.The resemblance between the influential factors for the amplified warming in these two separate regions implies a common dynamical origin. Thus, this validates the possibility that they originate from the Silk Road pattern.