Trace gas exchange at the air/water interface: Measurements of mass accommodation coefficients     

W. Kirchner  F. Welter  A. Bongartz  J. Kames  S. Schweighoefer  U. Schurath 《Journal of Atmospheric Chemistry》1990,10(4):427-449

A liquid jet of 90 m diameter and variable length has been utilized to determine absorption rates and, hence, mass accommodation coefficients , of atmospheric trace gases. The compounds investigated are HCl (0.01), HNO₃ (0.01), N₂O₅ (0.005), peroxyacetyl nitrate (>0.001), and HONO (0.005). It is concluded that the absorption of these trace gases by liquid atmospheric water is not significantly retarded by interfacial mass transport. The strengths and limitations of the liquid jet technique for measuring mass accommodation coefficients are explored.  相似文献   

Spectral Simulation and Conditioning to Local Continuity Trends in Geologic Modeling     

Tingting Yao  Craig Calvert  Tom Jones  Glen Bishop  Yuan Ma  Lincoln Foreman 《Mathematical Geology》2006,38(1):51-62

Spectral simulation has gained application in building geologic models due to the advantage of better honoring the spatial continuity of petrophysical properties, such as reservoir porosity and shale volume. Distinct from sequential simulation methods, spectral simulation is a global algorithm in the sense that a global density spectrum is calculated once and the inverse Fourier transform is performed on the Fourier coefficient also only once to generate a simulation realization. The generated realizations honor the spatial continuity structure globally over the whole field instead of only within a search neighborhood, as with sequential simulation algorithms. However, the disadvantage of global spectral simulation is that it traditionally cannot account for the local information such as the local continuity trends, which are often observed in reservoirs and hence are important to be accounted for in geologic models. This disadvantage has limited wider application of spectral simulation in building geologic models. In this paper, we present ways of conditioning geologic models to the relevant local information. To account for the local continuity trends, we first scale different frequency components of the original model with local-amplitude spectrum ratios that are specific to the local trend. The sum of these scaled frequency components renders a new model that displays the desired local continuity trend. The implementation details of this new method are discussed and examples are provided to illustrate the algorithm.  相似文献   

利用LPAC图分析北半球夏半年环流季节转换及异常     

蔡新玲王盘兴  杜继稳刘子臣 《南京气象学院学报》2005,28(5):710-716

用NCEP／NCAR再分析月平均风、压场资料得到1958—1997年5—10月月际场的局地型相似系数（LPAC）。多年平均LPAC表明了对流层和平流层低层印度夏季风环流的建立、东亚夏季风环流的北进和南亚高压上高原的过程，这些区域LPAC值较同纬度非季风区明显偏低。在平流层中层，夏季型环流表现出纬向对称性和由高纬向低纬的传播特征。对东亚LPAC气候变率时空剖面及3个涝年LPAC异常的分析反映出环流型季节转变异常及其与东亚月降水异常的关系。  相似文献   

粗差发现和定位能力与相关系数的关系   总被引：2，自引：0，他引：2  

顾利亚  岑敏仪  李志林 《武汉大学学报(信息科学版)》2005,30(7):621-624

根据粗差判断方程中的判断矩阵和两个统计检验量之间相关系数的函数式,论证了两种不同的研究方法所确定的粗差不能定位的数学模型实际上是相等的。通过算例,不仅说明两种研究方法对观测量不能定位粗差的判断是一致的,而且使用判断矩阵研究观测量的粗差发现和定位能力会更加方便简单。  相似文献   

超级计算机上矩阵乘的并行计算与实现   总被引：3，自引：0，他引：3       下载免费PDF全文

伍湘君  黄丽萍 《应用气象学报》2005,16(1):121-128

数值预报系统中经常要用到矩阵乘运算。在分布式超级计算机 (如IBM-SP) 上, 矩阵乘的并行计算需要较多的数据移动, 有效的数据传输对矩阵乘的实现至关重要。该文讨论了两种矩阵乘的并行算法, 一种是基于矩阵的列-行划分方式, 一种是基于矩阵的网格划分方式。在IBM-SP计算机上的实验结果表明, 网格划分的矩阵乘并行算法通讯开销更小, 并行效率更高, 其并行加速比较列-行并行算法改善约10 %。  相似文献   

Laboratory Studies Of Wind Stress Over Surface Waves   总被引：4，自引：0，他引：4  

B. Mete Uz  Mark A. Donelan  Tetsu Hara  Erik J. Bock 《Boundary-Layer Meteorology》2002,102(2):301-331

Simultaneous laboratory observations of wind speed, wind stress, and surfacewind-wave spectra are made under a variety of wind forcing patterns using cleanwater as well as water containing an artificial surfactant. Under typical experimentalconditions, more than half of the total stress is supported by the wave-induced stressrather than by the surface viscous stress. When the surfactant reduces the shortwind-wave spectra, the wind stress also decreases by as much as 20–30% at agiven wind speed. When the wind forcing is modulated in time, the wind stresstends to be higher under decreasing wind than under increasing wind at a givenwind speed, mainly because the response of short wind-wave spectra to varyingwind forcing is delayed in time. These examples clearly demonstrate that therelationship between the wind speed and the wind stress can be significantlymodified if the surface wave field is not in equilibrium with the wind forcing.Next, we examine whether the wind stress is estimated accurately if the wave-inducedstress by all surface wave components is explicitly evaluated by linear superpositionand is added to the surface viscous stress. It is assumed that the surface viscous stressis uniquely related to the wind speed, and that the wind input rate is determined by thelocal, reduced turbulent stress rather than the total stress. Our wind stress estimatesincluding the wave contributions agree well with observed wind stress values, evenif the surface wave field is away from its equilibrium with the wind in the presenceof surface films and/or under time-transient wind forcing. These observations stronglysuggest that the wind stress is accurately evaluated as a sum of the wave-induced stressand the surface viscous stress. At very high winds, our stress estimates tend to be lowerthan the observations. We suspect that this is because of the enhancement of wind stressover very steep (or breaking) short wind-waves.  相似文献   

Application of Linear Thermodynamics to the Atmospheric System. Part Ⅰ: Linear Phenomenological Relations and Thermodynamic Property of the Atmospheric System   总被引：1，自引：0，他引：1  

Hu Yinqiao 《大气科学进展》2002,19(3):448-458

从一般的热力学原理或其它自然原理对唯象关系所强加的限制，能够演绎出大气系统的一系列热力学性质。利用非平衡态线性热力学导出了湍流K闭合理论中湍流交换系数同唯象系数的关系，从理论上证明大气系统热量湍流输送同水泡之间存在交叉耦合，还导出了湍流强度同速度和位温梯度的关系，从而证明速度和位温空间分布的非均匀性是湍流之源。并证明湍流强度定理，不可压缩气体和各向同性湍流大气中，湍流强度正比于速度与位温梯度的标积。进而证明大气涡旋定理，位温的切变将导致涡旋运动或各种环流运动，速度涡度等于速度同位温相对梯度的矢积。展现了线性热力学在大气系统的应用前景。  相似文献   

因子计量图的新思路   总被引：3，自引：0，他引：3  

朴寿成  翟玉峰等 《地质与勘探》2002,38(2):68-70

R型因子分析中，因子计量从所有原始变量中将某一特定因子的有关信息集中起来，可被用来解释某一特定地质作用形成的样品在不同空间的分布等问题，由已知典型地质体的元素含量等地球化学指标计算出来的因子计量系数矩阵作为模型，用这个模型可以计算未知地质体的因子计量，这种方法，不仅可以节省每次加入新样品或舍去部分样品时所有因子计量图都需要重新做的繁重的工作量，而且更重要的是这种图的地球化学意义明确，使我们能够用已知的典型地质现象去预测未知地质观象提供了一条新的途径。  相似文献