高分辨区域输送模式中不同输送格式的对比试验   总被引：3，自引：0，他引：3  

葛孝贞  J.S. Chang  雷孝恩 《大气科学》1996,20(1):37-46

本文对两种输送格式在理论试验的基础上，引入19层高分辨区域输送模式EM3，由中尺度模式（MM4)提供实例输送风场，积分至13、18、30、50、70小时，作分析和对比数值试验。采用的两种格式是:二阶动量矩守恒的Prather格式（以下简称为SOM)及通量订正的Smolar格式。数值试验结果表明，高精度的SOM格式使数值扩散减小一个量级， 使输送物质（SO#-[2])中心浓度比Smolar格式增大3～4倍， 采用SOM格式还明显改进了浓度中心水平平均运动轨迹的模拟精度，选择高精度的平流格式是改进模拟结果的重要途径。  相似文献   

热带太平洋线性海气耦合系统的主模与ENSO   总被引：2，自引：0，他引：2  

谢倩  杨修群 《大气科学》1996,20(5):547-555

本文利用包含海洋表面边界层、线性海洋大气动力学以及完整的关于不均匀气候态线性化SST预报方程的热带太平洋海气耦合模式， 在真实的气候背景态和参数域内，研究了海气耦合系统的特征值问题，确定了线性耦合系统主模的特征周期及其稳定性特征，进而揭示了主模和ENSO的关系。结果表明:准两年振荡是线性海气耦合系统中的最不稳定模态，且只有该模态类似于ENSO水平结构。因此，准两年振荡很可能是海气耦合系统固有的最根本性的振荡过程。本文也对准两年振荡的形成与年循环的关系以及它在ENSO时间尺度形成中的作用进行了讨论。  相似文献   

等离子体发射光谱法分析毒砂单矿物     

曾惠芳 《岩矿测试》1992,11(3):211-216

研究了大孔膦酸树脂对毒砂中主、次和痕量元素的吸附行为及洗脱条件,结合巯基棉和TBP柱分离技术,建立了两个分离流程。在J-A1160型多道直读光谱仪上实现了毒砂单矿物中包括主量元素Fe和As在内的20个元素测定。主量元素As和Fe的相对标准偏差(n为5～10)分别为1.03％和0.9％,其它元素在5％～11％范围。流程经实际试样分析验证,结果与化学法相符。  相似文献   

On the stability of a coupled ocean atmosphere system in the presence of wave-CISK     

Sudha Selvarajan  B. N. Goswami 《Journal of Earth System Science》1992,101(2):153-176

The stability of a simple coupled ocean-atmosphere system similar to the one studied by Hirst with general ocean thermodynamics is investigated in which the atmospheric heating is determined by sea surface temperature anomalies as well as the convergence feedback (low level moisture convergence by the waves themselves). It is shown that the unstable coupled mode found by Hirst (UH mode) is profoundly modified by the convergence feedback. The feedback increases the unstable range of the UH mode and can increase its growth rate several folds. The maximally growing UH mode can become westward propagating for certain strength of convergence feedback. If the convergence feedback strength exceeds a critical value, several new unstable intraseasonal modes are also introduced. These modes are basically ‘advective’ modes. For relatively weak strengths of the convergence feedback the growth rates of these modes are smaller than that of the UH mode. As the atmosphere approaches ‘moist neutral’ state, the growth rates of these modes could become comparable or even larger than that of the UH mode. It is argued that these results explain why the El Nino and Southern Oscillation (ENSO) signal is clear in the eastern Pacific but not so in the western Pacific and they may also explain some of the differences between individual ENSO events. Our results also explain the aperiodic behaviour of some coupled numerical models. Importance of this process in explaining the observed aperiodicity of the ENSO phenomenon is indicated.  相似文献   

中尺度数值模式中湿过程参数化的敏感性试验          下载免费PDF全文

俞小鼎  E. Richar  R. Rosset 《大气科学》1995,19(6):645-653

本文利用一个三维中尺度模式，分别采用两种不同的湿过程处理方案ＦＰＡ和ＮＣＡ模拟同一个洋面冷锋个例，以考察模拟结果对湿过程参数化方案的敏感性。两种方案的区别在于前一种使用了次网格湿对流参数化而后者没有。通过比较分别使用ＦＰＡ和ＮＣＡ方案所进行的模拟ＦＰＳ和ＮＣＳ，发现冷锋结构在两者间出现较大差异。从８５０ hPa等压面|Δθe|等值线图所显示的结构看，ＮＣＳ中冷锋呈现为一长一短两条锋带，而ＦＰＳ中冷锋仅呈现为一条锋带。在相应的冷锋横向垂直剖面中，ＮＣＳ中存在两个相邻的锋面垂直环流，而ＦＰＳ中只有一个。另外，ＮＣＳ中对流不稳定的冷锋区出现垂直运动过分发展的现象，而ＦＰＳ中不存在这个问题。通过与卫星云图比较，我们注意到，ＮＣＳ中尽管出现了垂直运动过分发展的现象，但相对于ＦＰＳ而言，其模拟的冷锋结构与实际较为接近，成功地模拟出云图上显示的双冷锋结构。ＮＣＳ中垂直运动过分发展的一个重要原因是模式中采用的静力平衡近似。ＦＰＳ中次网格对流参数化方案的使用，通过减少甚至消除对流不稳定度，一方面使垂直运动的过分发展倾向受到约束，另一方面也可能使在对流不稳定层结下的锋区环境中本应出现的中尺度结构失去了形成的机会。  相似文献   

水平气压梯度力差分格式误差的定量分析          下载免费PDF全文

曾西平  任阵海 《大气科学》1995,19(6):722-732

通过分析发现地形坐标系中气压梯度力差分格式的计算误差应分为二类，其中，第二类误差在水平坐标面倾斜时出现。这种误差可理解为将水平坐标面上的气压(或位势高度)插回到等高面(或等压面)上的插值误差。 构造气压梯度力差分格式的目的正是为了减小这种第二类误差，而不是其他误差。 误差分析表明静力扣除法和Corby 格式的第二类误差都很小，比一般方法的误差小约一个量级。分析还表明第二类误差产生的主要原因是由于气压随高度非线性变化。依据这一分析思路，本文改进了#As(z)#a坐标系中的静力扣除法。 改进后的方法比改进前的误差小约一个量级。  相似文献   

2D Coupled 3D:A New Numerical Model for Dual - Structured - Aquifer System     

Chen Chongxi  Fang Shuzhen  Lin Min 《中国地质大学学报(英文版)》1995,(1)

２Ｄ　Ｃｏｕｐｌｅｄ　３Ｄ：Ａ　Ｎｅｗ　Ｎｕｍｅｒｉｃａｌ　Ｍｏｄｅｌ　ｆｏｒＤｕａｌ－Ｓｔｒｕｃｔｕｒｅｄ－Ａｑｕｉｆｅｒ　Ｓｙｓｔｅｍ￥ＣｈｅｎＣｈｏｎｇｘｉ；ＦａｎｇＳｈｕｚｈｅｎ；ＬｉｎＭｉｎ（ＦａｃｕｌｔｙｏｆＥｎｖｉｒｏｎｍｅｎｔａｌＳｃ...  相似文献   

The Coupled Re—Os and Pt—Os Systematics：A Theoretical Consideration     

熊永良  翟裕生 《中国地球化学学报》1995,14(1):52-59

The ^190Pt-^186Os system should be a unique tracer for mantle processes be-cause both Pt and Os are concentrated in the mantle.The ^190Pt-^186Os system will also be a good supplement to the ^187Re-^187Os system for dating and tracing mantle pro-cesses because the ^190Pt-^186Os system is not so easily contaminated by crustal materials as the ^187Re-^187Os system.In turn,the application of the ^187Re-^187Os system to Pt-enriched materials uncontaminated by crustal materials will indirectly refine the half life of ^190Pt.The ^190Pt is refined.In the coupled ^187Re-^187Os and ^190Pt-^186Os sys-tematics,an ^186Os*/^190Pt-^187Os*/^187Re Concordia diagram similar to the ^206Pb*/^238U-^208Pb*/^232Th Concordia can be constructed.In such a Concordia diagram,a date will be obtained so long as the ^190Pt-^186Os system remains closed even if the ^187Re-^187Os sys -tem is contaminated by crustal materials.In addition ,for the coupled ^190Pt-^186Os and ^187Re-^187Os systematics,the mantle processes and the interactions between the mantle and the crust will be described by two ratios:^186Os/^188Os and ^187Os/^188Os .The coupled ^187Re-^187Os and ^190Pt-^186Os systematics will be a powerful tool in the investigation of the geodynamic history of the Earth because the ^187Re-^187Os system is sensitive to the interactions between the mantle and the crust,while the ^190Pt-^186Os system is a good tracer for mantle processes.  相似文献   

An experiment on reservoir representation schemes to improve hydrologic prediction: coupling the national water model with the HEC-ResSim     

Jungho Kim  Laura Read  Lynn E. Johnson  David Gochis  Rob Cifelli  Heechan Han 《水文科学杂志》2020,65(10):1652-1666

ABSTRACT

This study experiments with reservoir representation schemes to improve the ability to model active water management in the National Water Model (NWM). For this purpose, we developed an integrated water management model, NWM-ResSim, by coupling the NWM with HEC-ResSim, and two reservoir representation schemes are tested: simulation of reservoir operations and retrieval of scheduled operations. The experiments focus on a pilot reservoir domain in the Russian River basin – Lake Mendocino, California – and its contributing watershed. The evaluation results suggest that the NWM-ResSim improves the simulation performance of reservoir outflow from this managed reservoir over the NWM default level pool routing scheme. The degree of this improvement depends on the suitability of the operation guidance; the reservoir operations simulation scheme could have acceptable errors for the purposes of water resources management, but not for flood operations. Results of the retrieval scheme of scheduled operations demonstrated better performance for sub-daily flood operations.  相似文献   

Analyses of trace elements on quartz surfaces in sulfidic mine tailings from Kristineberg (Sweden) a few years after remediation     

B.?MüllerEmail author  M.?D.?Axelsson  B.??hlander 《Environmental Geology》2003,45(1):98-105

Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has been applied to determine the elemental composition of the surface layer, as well as of the first interior layer, of quartz grains from the mine tailings from Kristineberg (northern Sweden) in order to determine concentration gradients between these two layers. The quartz grains were collected from the oxidized and unoxidized zones within the tailings. The aim of this study is to assess the role of quartz surfaces as sites for the attenuation of solutes from the mine-tailings porewater. Concentrations of Cu, Ag, Sb, Pb and Bi are highest near the surface of each grain and decrease towards the interior. The surface concentration of Cu, Zn and Pb is more pronounced within the unoxidized than within the oxidized zone of the tailings. Cu exhibits a distinct concentration peak at the surface of the quartz grains below the pre-remediation oxidation front. For Zn and Ce the trend of high surface concentration is less pronounced than for Cu or Pb. Silver, Bi and As are preferably adsorbed within the uppermost layers of the oxidized zone where the pH is as high as 6.2. The conversion of intensity signals of the elements to concentration values in ppm was done by using external standards (NIST silicate glass).  相似文献