The Madden-Julian oscillation in the Canadian Climate Centre general circulation model     

Jian Sheng 《Climate Dynamics》1995,12(2):125-140

The Madden-Julian oscillation (MJO) simulated by the Canadian Climate Centre general circulation model (CCC GCM) is identified by a principal oscillation pattern (POP) analysis and compared with that observed in the real atmosphere. The results are based upon two integrations of the CCC GCM, one with a parameterization of penetrative cumulus convection (EXP1) and the other with a moist convective adjustment scheme (EXP2). The signal of MJO can be detected in both integrations as the first POP of the 200 hPa velocity potential along the equator. The disturbances show a distinctive wave number one structure with the strongest local amplitude found in the longitudes corresponding to the region of the Asian monsoon. The phase speed of the eastward wave propagation is higher in the eastern Pacific and lower in the monsoon region where the convective activities are strongest. These features are in good agreement with the observations. The energy spectrum of the velocity potential peaks at the frequency corresponding to a period of about 38 days for EXP1, which is somewhat shorter compared to the observed periods of 40–50 days. On the other hand, two spectral peaks can be clearly identified for EXP2, one with a period of 24 days and the other with a much longer period, somewhere near 112 days. Both peaks appear statistically significant at 95% level. Long term data of the observed atmosphere show little indication of such spectral separation. The horizontal patterns identified by the POP analysis resemble to some extent the baroclinic response of tropical flow to a heat source travelling with the speed of MJO. At the upper level, Rossby wave energy propagates westward with winds generally following the height contours, whereas Kelvin wave energy propagates to the east from the heat source with strong cross-contour flow near the equator. At the lower level, the patterns are essentially reversed. The model-generated precipitation and diabatic heating are examined by compositing against the moving MJO. It is found in EXP2 that the composite heating distribution is coherent with the flow pattern only in a certain sector of the equator, depending on whether the fast or slow mode is used to determine the reference point. The composite vertical heating profile of a slower mode tends to have a maximum found at a lower level. The sensitivity of simulated MJO to the cumulus convection scheme in the model is discussed. Received: 19 December 1994 / Accepted: 11 July 1995  相似文献   

PRESENT　STATUS　OF　EXPERIMENTAL　STUDY　ON　HEAVY　METAL　POLLUTANT　ADSORPTION－DESORPTION　BY　SEDIMENT　IN　CHINA   总被引：1，自引：0，他引：1  

HUANG Suiliang  WAN Zhaohui 《国际泥沙研究》1995,(3)

ＰＲＥＳＥＮＴＳＴＡＴＵＳＯＦＥＸＰＥＲＩＭＥＮＴＡＬＳＴＵＤＹＯＮＨＥＡＶＹＭＥＴＡＬＰＯＬＬＵＴＡＮＴＡＤＳＯＲＰＴＩＯＮ－ＤＥＳＯＲＰＴＩＯＮＢＹＳＥＤＩＭＥＮＴＩＮＣＨＩＮＡＨＵＡＮＧＳｕｉｌｉａｎｇａｎｄＷＡＮＺｈａｏｈｕｉ（Ｐｏｓｔｄｏｃ...  相似文献   

Tomographic determination of 3-D crustal structure — Joint inversion of explosion and earthquake data     

Xian-Kang Zhang  Zhuo-Xin Yang  Yu-Chun Yang  Jian Yang  Jian-Li Song  Ping Zhao 《地震学报(英文版)》1995,8(4):519-529

In this paper, the theory and method, obtaining the tomographic determination of three-dimensional velocity structure of the crust by use of the joint inversion of explosion and earthquake data, are given. The velocity distribution of the crust is regarded as a continuous function of the spatial coordinates without parametrization of the velocity model ahead, so that the inversion solution would not be influenced by different parametrization procedures. The expressions of integration kernels, which relates the two kinds of data sets, are also given. The authors have processed the observed data in Tangshan earthquake region by the method proposed in this paper, and obtained the tomographic results of the middle and upper crust structures in this region. The comparison of these results with the result obtained only by the explosion data, has also been made.  相似文献   

大气重力波触发的Rayleigh－Taylor不稳定性的时空演变          下载免费PDF全文

黄朝松  李钧 《地球物理学报》1995,(3)

对大气重力波触发的赤道电离层Ｒａｙｌｅｉｇｈ－Ｔａｙｌｏｒ不稳定性的时空演变进行了数值模拟．结果表明，重力波能在Ｆ区底部触发Ｒａｙｌｅｉｇｈ－Ｔａｙｌｏｒ不稳定性，这种等离子体不稳定扰动穿过Ｆ峰，到达Ｆ区顶部，形成等离子体泡结构．等离子体泡出现向西倾斜和分岔等特征．当夜Ｆ区较高时，产生等离子体泡的时间仅１９００ｓ．数值模拟结果证实了重力波触发．Ｒａｙｌｅｉｇｈ－Ｔａｙｌｏｒ不稳定性的理论，解释了大量电离层观测现象．  相似文献   

润湿性对岩石电阻率影响的模型估算   总被引：17，自引：1，他引：17       下载免费PDF全文

黄隆基 《地球物理学报》1995,38(3):405-41

模型和实验研究证明，岩石润湿性对原油和地层水在孔隙系统中的分布有重大影响，因而能改变岩石电阻率、电阻增大系数和饱和度指数与含水饱和度的关系．在含水饱和度和地层、水电阻率相同的条件下，油湿和水湿岩石的电阻率相差很大，这对电测井定量解释有很大影响  相似文献   

冬季平流层波动模型的分岔特性          下载免费PDF全文

胡雄  张训械  黄信榆 《地球物理学报》1995,(4)

从描述波流相互作用的Ｈｏｌｔｏｎ－Ｄｕｎｋｅｒｔｏｎ简称Ｈ－Ｄ）模型出发，应用延拓方法求解常微分方程的分岔问题，研究冬季平流层波动模型的分岔特性．给出了大气行星波２与流相互作用的底部边界强迫波、底部边界平均纬向风场、风切变等参数的分岔特性，同时给出了波１与流相互作用的底部边界强迫波的分岔特性的结果．  相似文献   

1911年红海湾6级地震前珠江三角洲及其邻区的区域构造应力场          下载免费PDF全文

孙荀英  黄新辉 《地球物理学报》1995,38(5):618-626

本文包括：（１）通过拟合区内断层错动方式确定区域边界上作用的远场构造应力；（２）根据发震前震中所在断层段要进入塑性状态，确定１９１１年红海湾地震前区内构造应力场．两个应力场均采用正交设计法与弹塑性有限元方法快捷地得到．结果表明：该区远场最大主压应力σ３的方向为Ｎ６８°Ｗ，σ３＝－２００ＭＰａ，最小主压应力σ１＝－８０ＭＰａ；算得的红海湾地震前区内应力场的特点是除滨海断裂的红海湾段已进入屈服状态外，其余断裂均处于弹性状态．  相似文献   

义县留龙沟金矿含金矿物特征     

孔庆瑞  左建 《华东地质学院学报》1987,(1)

本文对留龙沟金矿的矿物成分、共生关系、矿物生成顺序,成矿温度进行了一些研究,为探讨矿床成因提供一些资料。  相似文献   

西藏高原那曲至亚东测线地壳、上地幔的大地电磁研究   总被引：3，自引：1，他引：3       下载免费PDF全文

任爱华  石应骏  李宗舜  李红征  杨仲武  黄伯民  陈光明 《地球物理学报》1982,25(5):457-463

我们用自制仪器于1977年首次在西藏高原进行了大地电磁测量。本文给出了那曲、曲水、江孜、帕里、亚东5个测点的测量和反演结果。 5个测点均反映为五层地电模型。得到如下结果: 1.那曲、曲水、江孜、帕里及亚东前四层总厚度分别为:66、65、62、57、50公里; 2.各测点电性特征相似,均属低-高-低型; 3.各测点的地壳中均存在一低阻层,其埋深约为10-20公里; 4.以雅鲁藏布江为界,南北两地区电性层厚度变化程度有显著差异,北部平缓,南部较剧; 5.表面沉积层厚度在4公里左右。  相似文献   

Carbon Storage in Terrestrial Ecosystems of China: Estimates at Different Spatial Resolutions and Their Responses to Climate Change   总被引：20，自引：1，他引：19  

Jian Ni 《Climatic change》2001,49(3):339-358

The carbon storage of terrestrial ecosystems in China was estimated using acommon carbon density method for vegetation and soils relating to thevegetation types. Usingmedian density estimates, carbon storage of 35.23 Gt (1 Gt = 10¹⁵g) in biomass and119.76 Gt in soils with total of 154.99 Gt were calculated based on thebaseline distribution of37 vegetation types. Total carbon storage of the median estimates at differentspatial resolutionswas 153.43, 158.08 and 158.54 Gt, respectively, for the fine (10),median (20) and coarse (30)latitude × longitude grids. There were differences of –1.56, +3.09and +3.55 Gt carbon storagebetween baseline vegetation and those at different spatial resolutions. Changein mappingresolution would change area estimates and hence carbon storage estimates. Thefiner the spatialresolution in mapping vegetation, the closer the carbon storage to thebaseline estimation. Carbonstorage in vegetation and soils for baseline vegetation is quite similar tothat of biomes predictedby BIOME3 for the present climate and CO₂ concentration of 340ppmv. Climate changealone as well as climate change with elevated CO₂ concentrationwill produce an increasein carbon stored by vegetation and soils, especially a larger increase in thesoils. Total mediancarbon storage of terrestrial ecosystems in China will increase by 5.09 Gt and15.91 Gt for theclimate scenario at CO₂ concentration of 340 ppmv and 500 ppmv,respectively. This ismainly due to changes in vegetation areas and the effects of changes inclimate and CO₂concentration.  相似文献