Isotopic composition of xenon in petroleum from the shell bullwinkle field

We have measured the abundance and isotopic composition of xenon in petroleum samples from the Shell Bullwinkle Field off the coast of Louisiana. We used an oxidation and purification procedure designed to insure complete extraction and clean up of xenon from the petroleum. The xenon isotopic composition was found to be similar to the atmospheric value for one petroleum sample. While the results of the second sample suggest possible enrichment of the heavier isotopes, the errors associated with these excesses preclude a definitive statement to that effect. No monoisotopic enrichment in¹²⁹Xe was detected in either sample, the presence of which might have allowed us to deduce the petroleum age. Our results represent only the second xenon measurement from petroleum, and the concentrations are within the range of values published in the earlier report.     

气候变暖背景下祁连山区秋季层状云变化特征

利用祁连山区及周边29 个气象观测站近41 年秋季云形状和气温观测资料, 分析了祁连山区秋季层状云出现频率的空间分布与时间变化特征, 探讨了秋季层状云出现频率与气候变暖的关系, 并选用同期NCEP/NCAR全球再分析资料, 对祁连山区秋季层状云的环流特征和水汽输送进行了分析。结果表明:①祁连山区秋季层状云出现频率为8%～26%, 呈西少东多的空间分布。②近41 年来, 祁连山区秋季增温1.2℃, 气温变化的倾向率为0.29℃/10a, 80 年代中期以后发生了增温的突变。③祁连山区秋季层状云的出现频率呈明显的减少趋势, 近41 年来减少约11%, 倾向率为-2.7%/10a, 尤其在20 世纪80 年代中期以后与同期祁连山区显著增温相对应, 层状云出现频率减少更为明显, 层状云出现频率与气温呈明显的反相变化趋势。④在气候变暖的背景下, 祁连山区的层状云出现频率减少, 减少的幅度从西北向东南递增。当祁连山区秋季平均气温在升高1℃ 时, 祁连山区层状云出现频率减少2%～10%, 祁连山西段、中段减少2%～4%, 祁连山东段减少4%～10%。⑤祁连山区秋季层状云偏多与偏少年在欧亚500 hPa 环流场上存在明显的差异, 层状云偏多年, 极涡向亚洲北部伸展, 东亚大槽较偏弱, 乌拉尔山高压脊偏强, 脊前偏北气流引导极地冷空气沿偏西北路径向中国西北地区输送, 中亚地区到高原上不断有低值系统发展东移, 同时南支槽加强, 来自阿拉伯海、南海、东海的暖湿气流向内陆地区的输送明显加强, 与进入高原北部的冷空气交绥, 从而使祁连山区层状云出现频次增多;层状云偏少年, 中亚-中国西北地区暖性高压异常加强, 东亚大槽偏强, 冷空气活动路径偏东, 亚洲大陆至西太平洋冬季风特征明显, 偏北风加强, 不利于东南暖湿气流向西北内陆地区的输送, 冷暖气流在祁连山区交绥次数减少, 从而使祁连山区层状云出现频次减少。⑥印度洋沿孟加拉湾的向北的水汽输送, 副热带西太平洋的偏东气流在南海和中南半岛附近转为向北的水汽输送, 地中海、里海的西风带纬向水汽输送是3支影响祁连山区秋季层状云多寡的水汽输送通道, 进而对祁连山区秋季降水产生影响。     

APPLICATION OF THE MULTIGRID METHOD IN NUMERICAL SIMULATION OF SEDIMENT TRANSPORT

IINTRODUCTIONThemultigridmethod(Brandt,1988)iswidelyusedinmanydisciplinesandengineeringsubjects,especiallyintheareaofComputationalFluidMechanicsbecauseofitshighefficiencyincomputation.Themultigridmethodhasbeenprovenintheorytobeoneofbestnumericalmethodsforsolvinglinearellipticproblemsbecausetheloadofcomplltationisindirectproportiontothenumberofgridnodes;theconvergentspeedofmultigridmethodisirrelevanttothesizeofgird.Soitissuitableforthenumericalsimulationoffullscaleengineeringprojects.The…     

海南岛博鳌港沉积物的沿岸输送

分析了博港沿岸沉积牧粒度参数的沿岸变化，并应用沉积物粒径趋势分析模型（GSTA模型）对沉积物运动趋势进行了分析。GSTA模型结果表明，博鳌港沿岸的泥沙在横向上表现为：万泉河口以北岸段为由海向岸运动，近期处于淤积状态；万泉河口以南岸段即玉带滩大致以NNE走向到NE走向的转折点为界，北部主要是由岸向海运动，是侵蚀岸段，而南部则主要为由海向岸运动，有少量的淤积，博鳌港沿岸泥沙输送在纵向上表现为：万泉河口以北由南向北运动，万泉河口以南，北部是由北向南运动，南部是由南向北运动，其次还运用了经验公式对GSTA结果进行了验证，得到了通过万泉河口南部（玉带滩）3个断面的沿岸漂沙量，其沿岸漂沙方向主要为南北向，以上两种分析方法得出的结果和当地的许多地貌证据基本符合，而GSTA模型在玉带滩北部泥沙纵向输运方向与经验公式计算结果所表现出的一些差异，主要是由于研究时间尺度和所用的资料特征的差异性造成的。     

南海北部陆坡深水区沉积物输送模式探讨

南海北部陆坡深水区沉积物输送模式复杂多样,研究发现主要有碎屑流、浊流、砂质碎屑流、碳酸盐岩重力流、块体搬运、河流搬运、深水水道搬运7种类型,它们共同影响着南海北部陆坡沉积物类型和储层分布。其中(砂质)碎屑流沉积、块体搬运沉积、河流供给、深水水道砂是南海北部深水储层的主要成因,而纯粹的浊积岩在该地区发育不广泛。珠江口盆地的深水储层受到河流的供给和后期流体改造的影响,并且存在碳酸盐岩重力流沉积物薄层,证明该地区水动力条件较强;琼东南盆地深水储层分布受到了碎屑流控制和深水水道的影响,相对浅水区来看可能存在分选较好、干净的砂体储层,具有良好的勘探潜力。     

天山南坡暖季暴雨过程的水汽来源及输送特征

利用1981—2020年5—9月天山南坡16个气象站逐日降水资料和NCEP/NCAR GDAS再分析资料,分析天山南坡暖季暴雨过程的环流形势,并采用HYSPLIT模式,模拟追踪水汽源地及输送特征。结果表明:天山南坡暖季暴雨主要发生在南亚高压双体型、500 hPa以上西南急流(气流)、700 hPa切变辐合以及天山地形辐合抬升的重叠区域。水汽主要源自中亚、大西洋及其沿岸、地中海和黑海及其附近,经TKAP(塔吉克斯坦、吉尔吉斯坦、阿富汗东北部、巴基斯坦北部和印度西北部)、南疆、北疆关键区,分别从偏西、偏南、偏北通道输入暴雨区,700 hPa以上偏西通道、以下偏北通道占主导地位,且贡献最大的是南疆关键区。源自中亚的水汽主要输送至暴雨区700 hPa及以下,对暴雨的贡献较大,且沿途损失较大;源自大西洋及其沿岸、地中海和黑海及其附近的水汽主要输送至暴雨区700 hPa以上,对暴雨的贡献较小。另外,中低层还存在源自北疆、南疆、北美洲东部、蒙古的水汽。基于上述特征,建立了天山南坡暖季暴雨过程水汽三维精细化结构模型。     

天山乌鲁木齐河源1号冰川物质平衡高度变化特征及其对径流的影响

利用天山乌鲁木齐河源1号冰川1980-2010年的物质平衡、水文气象实测资料, 分析了1号冰川1980-2010年的各高度带物质平衡特征, 进而分析了1984-2010年纯积累和纯消融的变化特点及其与气象要素、冰川融水径流变化的关系. 结果表明: 1号冰川物质平衡处于持续的负平衡, 纯积累量与年降水的相关系数为-0.16, 纯消融量与年均温的相关系数为0.61, 与夏季(6-8月)气温的相关系数为0.78. 2010年1号冰川为有观测记录以来的最强消融年(b_n=-1 327 mm), 整个冰川处于消融区(平衡线高度大于海拔4 484 m, 积累区面积为0), 同时东、西支冰川各高度区间的物质平衡变化也与往年度显著不同, 说明2010年是1号冰川物质平衡变化的特殊年份, 也有可能1号冰川的物质平衡变化进入了一个新的亏损变化阶段. 对其径流数据的分析还表明, 温度对径流的影响大于降水对径流的影响.     

热害矿井巷道温度场分布规律研究

为解决深部开采带来的热害问题，基于地质学和热力学理论，建立了热害矿井巷道温度场的数学模型，研究了巷道内部温度场随埋深和通风热速的变化规律。计算结果表明，巷道温度场对埋深的敏感度要高于风速、温度随埋深的增加而呈阶段性递增。控制入口温度是解决矿井热害的关键。以上结论为矿井热害的综合治理提供了重要依据。     

Evidence of Self‐Organized Criticality in riverbank mass failures: a matter of perspective?

A growing body of field, theoretical and numerical modelling studies suggests that predicting river response to even major changes in input variables is difficult. Rivers are seen to adjust rapidly and variably through time and space as well as changing independently of major driving variables. Concepts such as Self‐Organized Criticality (SOC) are considered to better reflect the complex interactions and adjustments occurring in systems than traditional approaches of cause and effect. This study tests the hypothesis that riverbank mass failures which occurred both prior to, and during, an extreme flood event in southeast Queensland (SEQ) in 2011 are a manifestation of SOC. Each wet‐flow failure is somewhat analogous to the ‘avalanche’ described in the initial sand‐pile experiments of Bak et al. (Physical Review Letters, 1987, 59(4), 381–384) and, due to the use of multitemporal LiDAR, the time period of instability can be effectively constrained to that surrounding the flood event. The data is examined with respect to the key factors thought to be significant in evaluating the existence of SOC including; non‐linear temporal dynamics in the occurrence of disturbance events within the system; an inverse power‐law relation between the magnitude and frequency of the events; the existence of a critical state to which the system readjusts after a disturbance; the existence of a cascading processes mechanism by which the same process can initiate both low‐magnitude and high‐magnitude events. While there was a significant change in the frequency of mass failures pre‐ and post‐flood, suggesting non‐linear temporal dynamics in the occurrence of disturbance events, the data did not fit an inverse power‐law within acceptable probability and other models were found to fit the data better. Likewise, determining a single ‘critical’ state is problematic when a variety of feedbacks and multiple modes of adjustment are likely to have operated throughout this high magnitude event. Overall, the extent to which the data supports a self‐organized critical state is variable and highly dependent upon inferential arguments. Investigating the existence of SOC, however, provided results and insights that are useful to the management and future prediction of these features. Copyright © 2014 John Wiley & Sons, Ltd.     

Laboratory simulation of geogas microbubble flow

Preliminary laboratory tests provided first data on the behavior of gas microbubbles through porous media in the framework of the geogas theory. Under experimented conditions with laboratory equipment arranged for pressure controlled gas-tracer injection and sampling, gas microbubbles moved up to ten times faster than singlephase flow in dry media under the same injection pressure. Microbubbles were determined to be very sensitive to changes in injection pressure and their terminal velocity seems to be described with good approximation by the Stokes formula. The capability of microbubbles to pick up and transport upward for short distances solid ultra-small particles (metallic and radionuclide compounds) has been proved. Results are consistent with a time-dependent process linked to the transport properties of microbubbles (e.g., flotation), such as that reported by some authors.