Ozone measurements from the Balloon Intercomparison Campaign

Measurements of the Balloon Intercomparison Campaign (BIC), conducted during fall, 1982 (BIC-1) and summer, 1983 (BIC-2), are reported. Results of five remote and two in situ techniques agree (with a few exceptions) within 95% confidence level uncertainties and generally within 15% above 20 km. Weighted mean profiles, which best represent conditions during the capaign, are used as a comparison standard. Accuracies of experiments indicated by BIC generally confirm estimated uncertainites for ECC sondes, UV photometry, and microwave emission experiments, are somewhat better for far IR emission and IR absorption experiments, and are somewhat worse for IR emission and solar UV absorption experiments. The large collection of BIC measurements confirms a problem reported earlier with current theoretical modeling of ozone near 40 km where transport is negligible and the chemistry is believed to be simpler.     

Stratospheric methane concentration profiles measured during the Balloon Intercomparison Campaigns

Following the Balloon Intercomparison Campaigns carried out from the NSBF, Palestine, Texas, in the fall of 1982 (BIC1) and spring of 1983 (BIC2), three instruments have reported infrared measurements (one in emission and two in absorption) from which results on the concentration of methane between 20 and 40 km altitude have been deduced. While the absorption-retrieved concentration profiles are in excellent agreement, the results from the emission measurements are significantly lower. Recent methane profiles obtained by satellite and from Spacelab 1 are in satisfactory agreement with the absorption data reported here.     

Intercomparison of stratospheric water vapor profiles obtained during the Balloon Intercomparison Campaign

The Balloon Intercomparison Campaign (BIC) was set up to intercompare remote sensing measurements of a number of compounds other than water vapor; however, water vapor has strong absorption features throughout the infrared and mm wave regions of the spectrum. Therefore many of the investigators involved in BIC have absorption or emission features due to water vapor in the data they obtained during the balloon flights made under the campaign. These features have been used by the investigators to determine the stratospheric water vapor profiles which are compared in this paper. The profiles allow comparison of a wide range of remote sensing techniques involving both emission and absorption in the mid-infrared and emission techniques in the far infrared.     

Balloon Intercomparison Campaigns: Results of remote sensing measurements of HCl

All of the techniques used to measure stratospheric HCl during the two BIC campaigns involved high resolution infrared spectroscopy. The balloon-borne instruments included five different spectrometers, three operating in the solar absorption mode and two in emission (at distinctly different wavelengths). Ground-based and aircraft correlative measurements were made close to the balloon locations, again by near-infrared spectroscopy.Within this set of results, comparisons between different techniques (absorption vs emission) viewing the same airmass (i.e., on the same gondola) were possible, as were comparisons between the same technique used on different gondolas spaced closely in time and location. The final results yield a mean profile of concentration of HC1 between 18 and 40 km altitude; an envelope of ±15% centered on this profile encompasses all of the results within one standard deviation of their individual mean values. The absolute accuracy of the final profile is estimated to be no worse than 10%. It is concluded also that the measurement techniques for HCl have reached a level of performance where a precision of 10% to 15% can be confidently expected.     

Intercomparison of remote measurements of stratospheric NO and NO2

During the 1982 and 1983 Balloon Intercomparison Campaigns, the vertical profile of stratospheric NO₂ was measured remotely by nine instruments and that of NO by two. Total overhead columns were measured by two more instruments. Between 30 and 35km, where measurements overlapped, agreement between NO profiles was within ±30%, which is better than the accuracies claimed by the experimenters. Between 35 and 40km there was similarly good agreement between NO₂ profiles, but below 30km, differences of greater than a factor three were found. In the second Campaign, NO₂ values from most instruments agreed within their quoted errors, except that the Oxford radiometer gave much lower values; but the first Campaign and the column measurements show a more uniform spread of results.These differences below 30km could not be resolved, but new laboratory measurements are planned which should do so.     

国际大气环流模式比较计划（AMIP）进展

介绍了国际大气环流模式比较计划（AMIP）的概况，它的分析子计划及执行情况、科学进展、相关计划及未来发展等情况，以便国内学者了解并积极参与该研究计划。     

Large Aperture Scintillometer Intercomparison Study

Two field studies with six large aperture scintillometers (LASs) were performed using horizontal and slant paths. The accuracy of this novel and increasingly popular technique for measuring sensible heat fluxes was quantified by comparing measurements from different instruments over nearly identical transects. Random errors in LAS measurements were small, since correlation coefficients between adjacent measurements were greater than 0.995. However, for an ideal set-up differences in linear regression slopes of up to 21% were observed with typical inter-instrument differences of 6%. Differences of 10% are typical in more realistic measurement scenarios over homogeneous natural vegetation and different transect heights and locations. Inaccuracies in the optics, which affect the effective aperture diameter, are the most likely explanation for the observed differences.     

国产GPS探空仪国际比对试验结果

通过2010年7月12日—8月1日第8届世界气象组织阳江国际探空比对,采取同球比对施放方式,选择芬兰Vaisala探空仪作为比对标准,对中国参加国际比对的长峰探空仪与华云探空仪,使用共29次同球比对数据,从典型个例分析与统计分析两方面开展系统性评估。初步评估结果表明:对于温度探测,中国长峰探空仪整体系统偏差在0.4℃之内,标准偏差在0.7℃之内,中国华云探空仪在30 km高度以下性能与长峰探空仪相当,但是30 km高度以上偏差明显增大;对于气压与风的探测,两者系统偏差与标准偏差均较小,表明GPS定位以及气压与风的算法准确;对于湿度探测,与芬兰Vaisala探空仪相比,还存在一定差距,特别是低温性能需要提高。     

多种土壤湿度资料在中国地区的对比分析

利用1992—2012年中国区域土壤湿度观测资料对目前使用较为广泛的5套土壤湿度资料(ERA-Interim、NCEP再分析资料、GLDAS同化资料、CPC模式资料和AMSR-E卫星反演资料)的适用性进行检验,分析5套资料对中国区域土壤湿度的时空分布特征和变化趋势的描述能力。结果表明:5套资料都能大体反映暖季中国区域土壤湿度东南湿、西北干,自东南向西北递减的分布格局以及西北干旱区和半干旱区变湿、长江流域部分地方变干的变化趋势,其中CPC资料最接近观测事实,并能较好地表现局地特征;在描述土壤湿度的季节变化和年际变化方面,GLDAS和NCEP资料与观测数据的相关性较好,能较好反映土壤湿度的时间演变特征。进一步利用检验效果较好的GLDAS、NCEP和CPC资料分别对中国区域土壤湿度时间和空间的长期变化趋势分析发现:中国区域标准化年平均土壤湿度在1948—1996年处在相对湿润期,而1996—2012年处在相对干旱期;中国区域年平均土壤湿度的空间变化特征是东部变干、西部变湿,自东北、华北至西南呈现一个干旱化带。     

气球施放安全与风险评估方法初探

根据有关法律、法规,阐述了气球施放安全与风险评估的必要性,并结合工作实际,介绍气球施放安全与风险评估应包括的主要内容和具体的操作流程。研究结果认为,适当而足够的风险评估方法应包括6个方面的内容：一是识别所有的危险源;二是评估事故出现的机会和几率;三是对事故可能引发的后果进行分析、分级;四是判断风险是否可以被容忍,辨别事关重大的风险;五是如果风险或潜在后果不可以被容忍的话,辨别出必须做些什么,如何落实防范风险措施;六是为制定在一段相当的时期内保持有效的控制方法提供依据,对不能通过控制活动降低事故发生几率的,依法对气球施放申请作出不批准的决定。     

亚洲区域气候模式比较计划的进展

区域气候变化的信息是气候变化影响评估的基础。在发展全球气候模式的同时 ,发展高分辨的区域气候模式是获取区域气候变化信息的重要途径之一。作者介绍了由中国科学院大气物理研究所START全球变化东亚区域研究中心发起和主持 ,有中、美、韩、日和澳大利亚 1 0个研究组参加的亚洲区域气候模式比较计划的目的、意义、工作任务和试验设计等主要内容 ,给出了该国际比较计划第 1阶段 (连续 1 8个月积分 )和第 2阶段( 1 988～ 1 998年连续 1 0年积分 )的初步结果 ,讨论了区域气候模式在亚洲应用中的一些共性问题以及进一步研究的方向。     

Intercomparison of measurements of stratospheric hydrogen fluoride

Observations of the vertical profile of hydrogen fluoride (HF) vapor in the stratosphere and of the vertical column amounts of HF above certain altitudes were made using a variety of spectroscopic instruments in the 1982 and 1983 Balloon Intercomparison Campaigns. Both emission instruments working in the far infrared spectral region and absorption instruments using solar occultation in the 2.5m region were employed. No systematic differences were seen in results from the two spectral regions. A mean profile from 20–45 km is presented, with uncertainties ranging from 20% to 50%. Total columns measured from ground and from 12 km are consistent with the profile if the mixing ratio for HF is small in the tropophere and low stratosphere.     

NCEP再分析资料和中国站点观测资料的分析与比较

美国国家环境预报中心(NCEP)和国家大气中心(NCAR)的全球再分析资料,在很多气候模拟和预测研究中都被作为区域气候模式的驱动场和初始场资料,并用来检验模拟结果的.作者通过对NCEP的2种再分析资料NCEPI和NCEPⅡ与中国台站观测资料的月平均温度和月降水总量进行相互插值,分析和比较了NCEPⅠ、NCEPⅡ再分析值与中国区域内观测值之间的差异以及2种再分析资料之间的差异.从结果可以看到,NCEP再分析资料的月平均温度较观测值普遍偏低,而月降水总量较观测值则偏高;就季节变化而言,NCEP再分析值在夏季和年平均模拟的较好,冬季较差.同时可以看到,在温度和降水方面NCEPⅡ较NCEPⅠ都有所改进,尤其在中国东部地区,改进较为明显.     

Intercomparison of Formaldehyde Measurements in Clean and Polluted Atmospheres

Three different techniques used tomeasure atmospheric formaldehyde were compared duringa field campaign carried out at a clean maritime siteon the West coast of Ireland. Two spectroscopictechniques Differential Optical AbsorptionSpectroscopy (DOAS) and Tunable Diode Laser AbsorptionSpectroscopy (TDLAS), together with a glass coil/Hantzschreaction/fluorescence technique, wereemployed for measurements of atmospheric formaldehydeof the order of a few hundred pptv. The betteragreement was observed between the fluorescence andDOAS instruments.Two DOAS instruments were compared to the glasscoil/Hantzsch reaction/fluorescence technique at asemi-polluted site on the North Norfolk coast, U.K.,where concentrations of formaldehyde were observed atlevels up to 4 ppbv. A very good agreement wasobserved between the two instruments.The glass coil/Hantzsch reaction/fluorescence and theTDLAS instruments were also deployed simultaneously inorder to measure indoor air inside a mobile laboratorylocated at the Imperial College Silwood Park site nearAscot, U.K. The doors of the mobile laboratory wereleft open in order to obtain the backgroundformaldehyde concentrations. Closing them afterwardsallowed us to observe the increase in concentrationsas a result of indoor emissions. The agreement betweenthe two instruments was outstanding (correlationcoefficient was 99%).The results from this study showed that of the fourinstruments included in this intercomparison the glasscoil/Hantzsch reaction/fluorescence technique provedthe most suitable for continuous measurements offormaldehyde in the background atmosphere.     

中国GTS1-2型电子探空仪阳江国际比对结果分析

根据世界气象组织阳江第八届国际探空比对资料,对中国GTS1-2型探空仪系统开展了系统性评估。初步评估结果表明：GTS1-2型探空仪温度传感器系统偏差在0.2℃之内（高度在33 km以下）,标准偏差在1℃之内;气压传感器系统偏差在0.7 hPa之内,标准偏差在1 hPa之内;位势高度系统偏差在40 gpm之内,标准偏差在320 gpm之内;温度、气压、位势高度一致性较好,但是还需进一步改善高空辐射误差修正软件;湿度测量结果与其他国家有一定的差距,具体表现温度在-30℃～-50℃,时间常数明显增大,变化幅度变小,反应滞后;风向风速与GPS导航卫星定位测风的结果比较接近。     

Intercomparison of Two Hydroxyl Radical Measurement Techniques at the Atmosphere Simulation Chamber SAPHIR

At the atmosphere simulation chamber SAPHIR in Jülich both Laser-Induced Fluorescence Spectroscopy (LIF) and Long-Path Differential Optical Laser Absorption Spectroscopy (DOAS) are operational for the detection of OH radicals at tropospheric levels. The two different spectroscopic techniques were compared within the controlled environment of SAPHIR based on all simultaneous measurements acquired in 2003 (13 days). Hydroxyl radicals were scavenged by added CO during four of these days in order to experimentally check the calculated precisions at the detection limit. LIF measurements have a higher precision (σ= 0.88×10⁶ cm^–3) and better time resolution (Δt = 60 s), but the DOAS method (σ= 1.24×10⁶ cm^–3, Δt = 135 s) is regarded as primary standard for comparisons because of its good accuracy. A high correlation coefficient of r = 0.95 was found for the whole data set highlighting the advantage of using a simulation chamber. The data set consists of two groups. The first one includes 3 days, where the LIF measurements yield (1 – 2) ×10⁶ cm^–3 higher OH concentrations than observed by the DOAS instrument. The experimental conditions during these days are characterized by increased NO_x concentration and a small dynamic range in OH. Excellent agreement is found within the other group of 6 days. The regression to the combined data of this large group yields unity slope without a significant offset.     

Intercomparison of Two Box Models of the Chemical Evolution in Biomass-Burning Smoke Plumes

Results from two independently developed biomass-burning smoke plume models are compared. Model results were obtained for the temporal evolution of two nascent smoke plumes originating from significantly different fire environments (an Alaskan boreal forest and an African savanna). The two smoke plume models differed by 1%–10% for [O₃], with similar differences for NO _x and formaldehyde (relative percent differences). Smaller intermodel differences were observed for the African savanna smoke plume as compared to the plume from the Alaskan boreal fire. Mechanistic differences between the models are heightened for the Alaskan smoke plume due to the higher VOC emission ratios as compared to the African savanna fire. The largest deviations result from the differences in oxidative photochemical mechanisms, with a smaller contribution attributable to the calculation of photolysis frequencies. The differences between the two smoke plume models are significantly smaller than the uncertainties of available photokinetic data or field measurements. Model accuracy depends most significantly on having the fullest possible VOC data, a requirement that is constrained by currently available instrumentation.     

Intercomparison of NO column measurements during MAP/GLOBUS 1985

Column measurements of nitric oxide were made using several techniques during the MAP/GLOBUS campaign in France in September 1985. The data sets are nearly co-located and simultaneous, therefore allowing a valid intercomparison of the various measurement methods. The range of altitudes sampled differs from instrument to instrument. This complicates the comparison because the data sets are to some extent complementary. The NO distributions apparently vary significantly from day to day, and possibly over shorter timescales. Changes in dynamics may be responsible for these variations. The results from the instruments which measure in the infrared and the ultraviolet are self-consistent, and show good agreement with photochemical predictions. On 19 September, when the intercomparison was made, the profile measured by the in-situ chemiluminescent instrument differed significantly from the predicted profile, and the measured columns were generally higher.     

中国土壤湿度的分布与变化 I. 多种资料间的比较

土壤湿度是影响气候的重要因子之一, 但观测资料的欠缺制约着该领域研究工作的开展。本文汇总了目前国际上运用较为广泛的四套土壤湿度资料: ERA40和NCEP/NCAR再分析资料、全球土壤湿度计划资料(GSWP2)、以及NCAR最近完成的利用观测资料强迫“通用陆面模式”CLM所产生的土壤湿度资料。在此基础上, 利用中国区域观测的19年 (1981～1999年) 的土壤湿度和13年 (1992～2004年) 的土壤相对湿度资料, 对四套资料在中国区域的可靠性进行了分析和比较, 主要结论如下: 四套资料基本揭示出土壤湿度的空间分布, GSWP2揭示了四套资料最多的共性, 即东北、 华南湿, 华北、 西北干, 土壤湿度基本由西北向东北和东南呈梯度增加的特征; GSWP2较好地描述了土壤湿度的季节循环; ERA40土壤湿度的年际变化与观测相关最好; 观测资料和四套资料都表明前期降水会增加土壤湿度, 但土壤湿度异常对后期降水的影响则不显著; 气温与土壤湿度的关系较复杂, 不同的区域有不同的特征。