质地对土壤热扩散率的影响   总被引：1，自引：0，他引：1  

刘经星  李春桃  梁玉祥  张春来 《中国沙漠》2010,30(3):577-581

土壤热性质的研究是分析地表能量平衡的重要途径之一,土壤热扩散率是表征土壤热性质的重要参数。根据非稳态一维热传导方程的差分解计算了不同质地土壤的热扩散率。结果表明,风干土热扩散率小于1.4×10-3 cm2·s-1,并随着时间的推移逐渐减小;土壤质地越轻土墒条件越好热量传输速度越慢。  相似文献   

The effect of diapycnal mixing on the ventilation and CFC-11 uptake in the Southern Ocean     

Yongqi GAO  Helge DRANGE 《大气科学进展》2004,21(5):755-766

1. Introduction Ocean General Circulation Models (OGCMs) arekey tools in the assessment of the future ocean up-take of atmospheric greenhouse gases and heat. Fur-thermore, whereas nature experiences one realisationof the climate state, climate models can be used as alaboratory to produce a multitude of climate realisa-tions, and by that contribute to the understanding ofthe variability and stability properties of the system.It is, in this respect, crucial to evaluate the climatemodels ag…  相似文献   

棉田土壤热通量的计算   总被引：9，自引：1，他引：8  

申双和  崔兆韵 《气象科学》1999,19(3):276-281

本文在两年棉花田间试验观测的基础上,利用土壤中热传导方程模拟5cm层土壤温度的时间变化,进而推算出其它层次的土壤温度,与实测值相比,模拟均方误最大为0．14,最大温度绝对误差为0．7℃．通过对温度方程求深度上的偏导数获得土壤热通量的计算公式,计算值与实测值比较,均方误最大为0．006,效果较好。本文还通过2cm层土壤热通量与棉花冠层净辐射之间的关系,结果表明土壤热通量与冠层净辐射有着很好的相关性。  相似文献   

Mixing in Shallow Waters： Measurements, Processing, and Applications     

Iossif Lozovatsky  Elena Roget  H.J.S.Fernado 《中国海洋大学学报(英文版)》2005,4(4):293-305

Microstructure profiling measurements taken on a shallow Black Sea shelf and in Lake Banyoles and Boadella reservoir (Both in Spain) are analyzed to investigate the influence of boundary-layer-induced turbulence of various sources on mixing in the water interior. The state of turbulence in shallow waters is examined and details of microstructure data processing and error analysis are discussed. The dependence between averaged activity parameter AG and buoyancy Reynolds number Reb for the shelf turbulence indicates that for Reb < 1 the state of turbulence can be described by the fossil turbulence model, which postulates AG-Reb1/2. For Reb> 1, however, the influence of Reb on AG is weak, signifying that the buoyancy Reynolds number can no longer serve as the governing parameter for active turbulent mixing. The generation of turbulence by a one-minute long wind bursts (the Boadella reservoir) increases the averaged dissipation rate (e) of the surface mixed layer by more than 5 times (up to 3×10-6 W kg-1). The influence of the wind bursts was also traced below the ther-mocline, where turbulent patches with  相似文献   

Extended precise integration method for axisymmetric thermo‐elastic problem in transversely isotropic material          下载免费PDF全文

Zhi Yong Ai  Quan Long Wu  Lu Jun Wang 《国际地质力学数值与分析法杂志》2016,40(2):297-312

This paper presents a numerical solution for the analysis of the axisymmetric thermo‐elastic problem in transversely isotropic material due to a buried heat source by means of extended precise integral method. By virtue of the Laplace–Hankel transform applied into the basic governing equations, an ordinary differential matrix equation is achieved, which describes the relationship between the generalized stresses and displacements in transformed domain. An extended precise integration method is introduced to solve the aforementioned matrix equation, and the actual solution in the physical domain is acquired by inverting the Laplace–Hankel transform. Numerical examples are carried out to demonstrate the accuracy of the proposed method and elucidate the influence of the character of transverse isotropy, the anisotropy of linear expansion coefficient, the anisotropy of thermal diffusivity, and medium's stratification on the thermo‐elastic response. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

关于黄土包气带水份运移参数计算问题     

李喜荣 《地球科学与环境学报》1991,(1)

本文利用陕西省礼泉县西庄头村实验场竖井不同深度5个土样(黑垆土—0.5m;马兰黄土—2.5m;古土壤—8.4m;离石黄土—12m)的实验数据,计算了其水份运移参数D(θ)和C(θ);并借助相关分析法,建立了这5种土样水份运移参数的经验公式,最后,用比较计算含水率和实测含水率的办法,证明了经验公式的可靠性。  相似文献   

The Baroclinic, Variable Eddy Viscosity Ekman Layer     

Bradford W. Berger  Branko Grisogono 《Boundary-Layer Meteorology》1998,87(3):363-380

The WKB method is used in conjunction with the variation of parameters technique to find an approximate analytical solution for Ekman layers with eddy viscosity and horizontal pressure gradient that are each variable with height from the surface. Behaviour of the solution is illustrated by comparing model output when several eddy viscosity and horizontal pressure gradient profiles are used. Cases where the pressure gradient decreases with height accentuate the super-geostrophic peak in the wind velocity profile, with decreasing eddy viscosity with height further enhancing this effect. Increasing pressure gradient with height reduces or eliminates the peak. The model output when using an eddy viscosity that has a low-level peak fits marine boundary-layer data taken during ASTEX better than the classic solution - the model giving greater low-level mixing which is seen in ASTEX data as well as in data from ERICA.  相似文献   

南海北部中深层细结构混合研究   总被引：1，自引：0，他引：1  

卢著敏  陈桂英  尚晓东 《热带海洋学报》2009,28(3):21-28

基于2007年8月获得的ADCP（声学多普勒流速剖面仪）海流资料和CTD（温盐深剖面仪）水文资料，应用Gregg模型对南海中深层内波尺度的混合进行估计，同时应用Thorpe尺度对中深层存在的垂向翻转及由此引起的混合进一步分析。两种方法均显示，吕宋海峡附近上层400m的耗散率及混合率均强于18&#176;N断面，中深层两个区域的混合率并没有显著区别。这表明吕宋海峡上层400m，可能存在更活跃的内波活动，从而产生更强的内波混合和垂向水团翻转。Gregg模型估计的耗散率和混合率量级分别为10^-9W&#183;kg^-1和10^-6m^2&#183;s^-1。大部分CTD站位在中深层均存在垂向翻转，而且保持较高的发生率，翻转所对应的混合率并不随深度增加而减小。以上南海北部的细结构混合特征增强对南海中深层混合的认识。  相似文献   

盐浴法红宝石离子扩散优化处理研究     

杨如增  葛梦雅  李敏捷 《上海国土资源》2010,(1):64-66

采用盐浴法,对红宝石进行离子热扩散处理,应用XL-30 ESEM型扫描电镜与phoenix能谱仪,对样品进行了形貌和元素测试,分析了盐浴法红宝石离子扩散处理的机理,为红宝石热扩散处理提供一种更好的方法。  相似文献   

南海中南部上层的盐指与湍流混合过程     

鲁远征  周生启  岑显荣  郭双喜  尚晓东 《海洋与湖沼》2014,45(6):1158-1167

基于2012年8月12日至9月5日中国南海海洋湍流微结构剖面仪(Turbo Map)观测资料和温盐深剖面仪(CTD)资料,对南海中南部海域上层500m以浅的混合过程进行了分析。南海次表层高温高盐的水团和中层低温低盐的水团构成的垂向温盐环境,利于在该深度范围内盐指的发育。通过盐指与湍流相关参数的计算,评估了盐指在南海上层跨越等密面混合的作用。结果表明南海中部(18°N)相对于南海南部呈现高的温度耗散率(χ)、高的混合效率(Γ)、低湍动能耗散率(ε)及低浮性雷诺数(Rε)等特征,即中部盐指信号明显强于南部。但整体海域仍然呈现出"低Γ;高Rε"的湍流特征,表明盐指对混合的贡献较小,南海中南部的上层混合还是以湍流混合为主导。另外,南海南部的混合强于中部,且呈现出整体水柱均具有较强混合的特征,其原因可能和内潮与南部相对较浅而复杂的地形相互作用有关。  相似文献