Atmospheric and Coupled Model Intercomparison in Terms of Amplitude Phase Characteristics of Surface Air Temperature Annual Cycle

A model intercomparison in terms of surface air temperature annual cycle ampitude-phase characteristics(SAT AC APC)is performed. The models included in the intercomparison belong to two groups:five atmospheric models with prescribed sea surface temperature and sea ice cover and four coupled models forced by the atmospheric abundances of anthropogenic consituents (in total six coupled model simulations). Over land, the models, simulating higher than observed time averaged SAT,also tend to simulate smaller than observed amplitude of its annual and semiannual harmonics and (outside the Tropics laterthan-observed spring and autumn moments. The models with larger(smaller) time averaged amplitudes of annual and semiannual harmonics also tend to simulate larger(smaller)interannual standard deviations. Over the oceans, the coupled models with larger interannual standard deviations of annual mean SAT tend to simulate larger interannual standard deviations of both annual and semiannual SAT harmonics amplitudes. Most model errors are located in the belts 60°-70°N and 60°-70°S and over Antarctica. These errors are larger for those coupled models which do not employ dynamical modules for sea ice.No systematic differences are found in the simulated time averaged fields of the surface air temperature annual cycle characteristics for atmospheric models on one hand and for the coupled models on the other. But the coupled models generally simulate interannual variability of SAT AC APC better than the atmospheric models (which tend to underestimate it). For the coupled models, the results are not very sensitive to the choice of the particular scenario of anthropogenic forcing.There is a strong linear positive relationship between the model simulated time averaged semiannual SAT harmonics amplitude and interannual standard deviation of annual mean SAT.It is stronger over the tropical oceans and is weaker in the extratropics. In the tropical oceanic areas, it is stronger for the coupled than for the atmospheric models.     

Changes in low and high flows in the Vistula and the Odra basins: Model projections in the European‐scale context

A number of extensive droughts and destructive floods have occurred in Poland in the last 25 years; hence, projections of low and high river flows are of considerable interest and importance. In the first part of this paper, projections of low and high flows in the rivers of the Vistula and the Odra basins (VOB region), for two future time horizons, are presented. Projections are based on the Soil and Water Assessment Tool (SWAT) hydrological model simulations driven by results of the EURO‐CORDEX experiment under Representative Concentration Pathways 4.5 and 8.5. The VOB region covers most of Poland and parts of five neighboring countries, giving this study an international relevance. In the second part of the paper, a review of projections of low and high flows in rivers in Central and Eastern Europe is presented. Despite a substantial spread of flow projections, the main message of the modelling part is that increases of both low and high flows are dominating. The magnitude of increase of low flow is considerably higher than that of high flow. In other words, future streamflow droughts are projected to be less severe, whereas, in contrast, river floods are projected to increase, which is a challenge for flood risk reduction, water management, and climate change adaptation. There is an overall agreement of our findings for the VOB region with projections of hydrological extremes from large‐scale models forced by EURO‐CORDEX results in the European‐scale studies.     

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。     

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。     

近20年来气候模式的发展与模式比较计划

20世纪80年代以来，全球气候观测系统的不断完善、国际大型外场观测试验的成功实施以及高性能计算机的飞速发展，为气候模式的迅猛发展提供了基础和条件。近20年来气候模式的复杂程度和模拟能力得到了显著的提高，目前已成为研究全球和区域气候的形成及变异、气候系统各圈层之间的相互作用以及全球变化等的有力工具。对气候模式（包括大气环流模式、陆面过程模式、海洋环流模式以及区域气候模式）的主要发展进行综合评述，并简要介绍了目前世界上一些主要的模式比较研究计划。     

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。     

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.     

Recalibration of the hohenpeissenberg dobson spectrophotometer 104 presuming ‘effective absorption coefficients’

The well calibrated Brewer spectrophotometer 17 (Sci-Tec Instruments Inc., Canada) stayed at the Meteorological Observatory Hohenpeissenberg (MOHP) from August 27 until September 1, 1984, in order to check and recalibrate Brewer 10, which had some stability problems. Brewer 17 was initially calibrated in July 1983, the validity of this calibration was repeatedly verified before and after the stay at the MOHP (Kerr et al., 1985; Kerr, 1984). The instrument proved itself to be very stable and appropriate as travellings standard instrument.As Dobson 104 didn't seem to be well calibrated at that time, the occasion was taken to perform also a Dobson recalibration. The methods normally used were not satisfactory, but a different method, presuming Effective Absorption Coefficients (EAC), presented by Kerr et al. at the Quadrennial Ozone Symposium 1984 in Greece, yielded encouraging results. Before recalibration Dobson 104 showed a difference of 2–3% in comparison to Brewer 10-, Brewer 17- and TOMS- (on satellite Nimbus 7) measurements, whereas the agreement with the Brewers after EAC-calibration was good (X _rel < 1%). The different Dobson calibration methods are compared and the results of the Dobson 104 and Brewer 10 recalibrations are presented.

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Zusammenfassung Vom 27. August bis 1. September 1984 befand sich das Brewer Standard Spektrophotometer 17 (Sci-Tec Instruments Inc., Canada) am Meteorologischen Observatorium Hohenpeißenberg (MOHP), um den nicht sehr stabilen Brewer 10 zu überprüfen und neu zu kalibrieren. Der Brewer 17 wurde erstmals im Juli 1983 kalibriert, die Gültigkeit dieser Eichung wurde mehrfach vor und einmal nach dem Aufenthalt am MOHP bestätigt (Kerr et al., 1985; Kerr, 1984). Das Instrument erwies sich als sehr stabil und geeignet als transportables Standardinstrument.Da der Dobson 104 zum damaligen Zeipunkt ebenfalls nicht gut kalibriert schien, wurde die Gelegenheit einer Dobson-Neukalibrierung wahrgenommen. Die normalerweise benutzten Methoden waren nicht zufriedenstellend im Gegensatz zu einer Methode, die von Effektiven Absorption Coeffizienten (EAC) ausgeht. Diese von Kerr et al. auf dem Quadrennial Ozon Symposium 1984 in Griechenland vorgestellte Methode lieferte hier ermutigende Ergebnisse. Vor der Neueichung zeigte der Dobson 104 eine Differenz von etwa 2–3% im Vergleich mit Brewer 10-, Brewer 17- und TOMS- (auf dem Nimbus-7-Satelliten) Messungen, während die Übereinstimmung mit den Brewer-Geräten nach der EAC-Kalibrierung gut war (X _rel < 1%). Die verschiedenen Dobson-Kalibrierungsmethoden werden verglichen und Ergebnisse der Dobson 104- und Brewer 10-Neukalibrierungen werden vorgestellt.

     

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.     

秒级探空数据随机误差评估

利用2007年6月和2008年6—7月国内GPS探空仪同步比对试验数据及2010年中国阳江国际探空系统比对试验数据,基于现有的探空仪随机误差的间接计算方法,深入分析不同的探空原始数据平滑处理程度对随机误差评估的影响。分析表明:现有的探空仪随机误差评估方法不能完全适用于秒级探空数据,特别是对风、平流层温度和对流层相对湿度这3个要素的随机误差的评估。在同步比对施放中,如果对探空原始数据的平滑处理程度一致,可以利用现有的随机误差评估方法,不会产生明显偏差;反之,如果平滑处理程度差异较大,则间接计算得出的随机误差会明显偏大。在比对施放方案中,为了更好地获取某种型号探空仪的随机误差,建议将多个同型号探空仪同球施放进行比对观测,避免作为参考仪器的其他型号探空仪自身的误差参与计算,影响待测探空仪随机误差的评估。同型号探空仪同球施放的探空仪越多,获取的有效统计数据越多,随机误差的分析越准确。