Primary Study of Surface-Wave Magnitude Determined by Chinese Stations

Using the data set of 20±2 sec and(A/T)max of surface waves recorded by Type-763 and Type-SK seismographs from five stations in Beijing and elsewhere,the mean square deviations u and relative mean deviations D of Ms values determined by five calibration functions(a,a763,a300 aN and from Msz(NEIS)are compared and analyzed.Results show that a and a763 are rather good between 20° and 160°;and a763 are rather good between 10 and 30 for 20 sec; a300 is relatively good between 160 and 179.     

Therm odynamics of Diagenetic Fluid and Fluid／Mineral Reactions in the Eogene Xingouzui Formation,Oil Field T,Jianghan Basin

This study focuses on the thermodynamics of diagenetic fluid from the Eogene Xingouzui Formation which represents the most important reservoir in Field Oil T in the Jianghan Basin. The measured homogenization temperatures (110–139 °C) of fluid inclusions in diagenetic minerals fell within the range of 67 –155 °C at the middle diagenetic stage. The pressure of diagenetic fluid is estimated at 10.2 –56 MPa. The activity of ions in the fluid shows a tendency of Ca²⁺ > Mg²⁺ > Na⁺ > K⁺ > Fe³⁺ > Fe²⁺ for cations, and HCO ₃ ⁻ > SO ₄ ²⁻ > F⁻ > Cl⁻ > CO ₃ ²⁻ for anions. For the gaseous facies, there is a tendency of CO₂> CO> H₂S> CH₄> H₂. According to the thermodynamic calculations, the pH and Eh of the fluid are 5.86–6.47 and −0.73–−0.64V, respectively. As a result of the interaction between such a diagenetic fluid and minerals in the sediments, feldspars were dissolved or alterated by other minerals. The clay mineral kaolinite was instable and hence was replaced by illite and chloritoid. This project was jointly funded by the National Natural Science Foundation of China (49133080) and the Open Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences.     

The effect of topographic forcing on the formation and maintenance of blocking

A barotropic channel model in β-plane is used to study the effect of topographic forcing on the formation and maintenance of blocking. The approximate analytical solution of potential vorticity equation can show the main property of the whole process of blocking. It is indicated that the topographic forcing is one of the main factors caus-ing the blocking process. The results suggest that the nonlinear interaction plays a very important role in the stable “Ω” situation of blocking. The atmospheric circulation with periodic and low-frequency oscillation, perhaps, is partly caused by topographic forcing.     

A numerical study of the mechanism for the effect of northern winter arctic ice cover on the global short-range climate evolution

By using a nine-layer global spectral model involving fuller parameterization of physical processes, with a rhomboidal truncation at wavenumber 15, experiments are performed in terms of two numerical schemes, one with long-term mean coverage of Arctic ice (Exp.1), the other without the ice (Exp.2). Results indicate that the Arctic re-gion is a heat source in Exp.2 relative to the case in Exp.1. Under the influence of the polar heat source simulated, there still exist stationary wavetrains that produce WA-EUP and weak PNA patterns in Northern winter. That either the Arctic or the tropical heat source can cause identical climatic effects is due to the fact that the anomaly of the Arc-tic ice cover will directly induce a south-propagating wavetrain, and bring about the redistribution of the tropical heat source/ sink. The redistribution is responsible for new wavetrains that will exert impact on the global climate. The simulation results bear out further that the polar region in Exp.2 as a heat source, can produce, by local forcing, a pair of positive and negative difference centers, which circle the Arctic moving eastwards. Observed in the Northern Hemisphere extratropics is a 40-50 day oscillation in relation to the moving pair, both having the same period.     

A NUMERICAL STUDY FOR THE EFFECT OF TROPICAL 40-50 DAY OSCILLATION ON ASIAN SUMMER MONSOON

By using a five-layer primitive equation model with P-sigma coordinates,the effect of convective heating source with the oscillation of a dipole pattern over the tropical Indian Ocean-Western Pacific on Asian summer monsoon is investigated.The results from simulations show that the oscillatary heating source may cause oscillations in east-west zonal circulation at the equator,in cross-equatorial flow,in meridional monsoon circulation and in the phase of high-low level circulation over Asia,with period same as that of the oscillating heat source.Furthermore,the influence mechanism of the tropical heating source associated with oscillations on Asian summer monsoon circulation is also studicd.It is clearly shown that the westward propagation of thermally-forced Rossy waves to the west of the oscillatary heating source and the northward propagation of disturbances can give rise to oscillations of the equatorial east-west zonal circulation and monsoonal meridional circulation.Finally,the oscillation of all the Asian summer monsoon circulation is formed.     

南平石(Nanpingite)——一种新的铯矿物

南平石是一种新的铯矿物,它产于福建南平31号白云母—钠长石—锂辉石型伟晶岩中,以细脉形式发育在伟晶岩中部铯沸石集合体附近的石英—羟磷铝锂石组石带内。形态酷似白云母,比重为3.11(实测)和3.19(计算)。二轴晶,负光性,折光率,Ng=1.588,Nm=1.584,Np=1.551,b=Ng。结晶化学式:(Cs_(0.83)K_(0.06)Rb_(0.01))_(0.95)(Al_(1.64)Mg_(0.22)Fe_(0.17)Li_(0.15))_(2.18)[(Si_(3.16)Al_(0.84)_4O_(10)][(OH)_(1.78)F_(0.21]_2。南平石属单斜晶系,2M_1多型,空间群为C2/c,晶胞参数:a=5.362(3),b=8.86(1),c=21.42(1),β=95.72(2)°,V=1012.3~3,Z=4。热谱分析表明,吸热谷仅有920℃一处,失重约3.3％。红外吸收谱带波数(cm~(-1))是3634、3429、1625、1083、1018、911、823、788、741、663、515、467、420、350。     

安庐石英正长岩带的地质和地球化学特征及成因探讨

安庐石英正长岩带由黄梅尖、城山、大龙山三个多阶段复式岩体组成,其形成与郯庐断裂带在中生代末发展演化成陆内裂谷的事件有关。岩带的成岩物质来源较深,是地幔分熔产生的安粗岩浆,在其上升侵位过程中经受上部地壳物质混染,为幔壳混源成因,其中地幔组分约占60.2—53.8％,地壳组分约占39.8—46.2％。岩带中的岩石偏碱性、贫水和非造山等一系列地质地球化学特征可与A型花岗岩相类比。     

北部湾涠洲岛橄榄岩中熔体包裹体——大陆岩石圈地幔交代作用的新证据

根据北部湾涠洲岛晚更新世火山岩中尖晶石二辉橄榄岩的矿物化学和形成条件推测,它们是来自地下约40km-50km的大陆岩石圈地幔样品。涠洲岛地幔橄榄岩中同时出现高硅（64％～68％）和低硅（49％～57％）两种熔体成分,它们普遍富碱、Al2O3和H2O、CO2等挥发组分（2％-5％）。研究认为,两种熔体存在不同的成因机制。高硅熔体可能与软流圈上升的玄武质岩浆和斜方辉石反应或下地壳物质循环进入地幔后的部分熔融有关。低硅熔体直接提供了富硅熔体与橄榄石发生交代作用的证据。这可以用富SiO2熔体＋Ol→贫SiO2熔体＋Opx反应解释,其结果是消耗橄榄石生成斜方辉石。涠洲岛橄榄岩中两种熔体的发现,进一步提供了发生在大陆岩石圈地幔流（熔）体与橄榄岩交代作用的普遍性、复杂性,以及地幔熔体多样性的新证据。     

Historical and potential changes of precipitation and temperature of Alberta subjected to climate change impact: 1900–2100

We investigated changes to precipitation and temperature of Alberta for historical and future periods. First, the Mann-Kendall test and Sen’s slope were used to test for historical trends and trend magnitudes from the climate data of Alberta, respectively. Second, the Special Report on Emissions Scenarios (SRES) (A1B, A2, and B1) of CMIP3 (Phase 3 of Coupled Model Intercomparison Project), projected by seven general circulation models (GCM) of the Intergovernmental Panel on Climate Change (IPCC) for three 30 years periods (2020s, 2050s, and 2080s), were used to evaluate the potential impact of climate change on precipitation and temperature of Alberta. Third, trends of projected precipitation and temperature were investigated, and differences between historical versus projected trends were estimated. Using the 50-km resolution dataset from CANGRD (Canadian Grid Climate Data), we found that Alberta had become warmer and somewhat drier for the past 112 years (1900–2011), especially in central and southern Alberta. For observed precipitation, upward trends mainly occurred in northern Alberta and at the leeward side of Canadian Rocky Mountains. However, only about 13 to 22 % of observed precipitation showed statistically significant increasing trends at 5 % significant level. Most observed temperature showed significant increasing trends, up to 0.05 °C/year in DJF (December, January, and February) in northern Alberta. GCMs’ SRES projections indicated that seasonal precipitation of Alberta could change from ?25 to 36 %, while the temperature would increase from 2020s to 2080s, with the largest increase (6.8 °C) in DJF. In all 21 GCM-SRES cases considered, precipitation in both DJF and MAM (March, April, and May) is projected to increase, while temperature is consistently projected to increase in all seasons, which generally agree with the trends of historical precipitation and temperature. The SRES A1B scenario of CCSM3 might project more realistic future climate for Alberta, where its water resources can become more critical in the future as its streamflow is projected to decrease continually in the future.     

Vertical profiles of aeolian sand mass flux

Vertical profiles of the horizontal mass flux of blown sand are investigated experimentally using a passive vertical array in a wind tunnel. Considering lower sampling efficiency of the sand trap in the near-bed region, this investigation is complemented by the measurements of the longitudinal profiles of mass flux made using a horizontal sand trap. The experiments were conducted with two test sands and five different stream velocities.In the upper part of the vertical profile, the measured data exhibit an exponential decay distribution with a positive deviation occurring in the near-bed region. The measured longitudinal profiles are similar to the measured vertical profiles. Linking both profiles and the modes of sand transport, it is possible that saltating sand grains give rise to the well-known exponential decay distribution of mass flux, and that creeping and reptating grains force a deviation from it. A simple equation applicable for both the vertical and the longitudinal sand mass flux variations is introduced and the parameters are estimated from experimental data.