A Perspective on the Evolution of Atmospheric Blocking Theories: From Eddy-Mean flow Interaction to Nonlinear Multiscale Interaction     

Dehai LUO  Binhe LUO  Wenqi ZHANG 《大气科学进展》2023,40(4):553-569

In this paper, we first review the research advancements in blocking dynamics and highlight the merits and drawbacks of the previous theories of atmospheric blocking. Then, the dynamical mechanisms of atmospheric blocking are presented based on a nonlinear multi-scale interaction(NMI) model. Previous studies suggested that the eddy deformation(e.g., eddy straining, wave breaking, and eddy merging) might lead to the formation and maintenance of atmospheric blocking.However, the results were specu...  相似文献   

Extreme Cold Events in North America and Eurasia in November-December 2022: A Potential Vorticity Gradient Perspective     

Yao YAO  Wenqin ZHUO  Zhaohui GONG  Binhe LUO  Dehai LUO  Fei ZHENG  Linhao ZHONG  Fei HUANG  Shuangmei MA  Congwen ZHU  Tianjun ZHOU 《大气科学进展》2023,40(6):953-962

From 17 November to 27 December 2022, extremely cold snowstorms frequently swept across North America and Eurasia. Diagnostic analysis reveals that these extreme cold events were closely related to the establishment of blocking circulations. Alaska Blocking(AB) and subsequent Ural Blocking(UB) episodes are linked to the phase transition of the North Atlantic Oscillation(NAO) and represent the main atmospheric regimes in the Northern Hemisphere. The downstream dispersion and propagation of Rossby...  相似文献   

从青海共和—贵德盆地地热勘查成果探讨干热岩综合地球物理勘查技术     

赵贵福  尉亮  李百祥  王志林 《甘肃地质》2016,25(2):62-67

青海共和—贵德盆地位于秦岭—昆仑造山带"秦昆岔口",是新生代断陷盆地。盆缘断裂构造、岩浆岩发育,水热活动强烈,温泉密集,超过60℃的温泉6处,最高可达93.5℃(超过当地沸点92℃为沸泉)。盆地内地温场高,据地热钻井揭露见花岗岩的3个钻孔,共和QR1孔深969m孔底温度为70℃;DR1孔深1 455m孔底温度87℃;贵德R2孔深1 709.56m,孔底温度可达97℃。钻孔测温,地温梯度高达6~7℃/100m,是正常地温梯度2倍,地热增温随深度而升高,推测3 000m温度可达150℃~200℃。重力低推断的基底凹陷,与可控源音频大地电磁测深、地震反射波勘探推断基底界面不符,并有磁异常对应,经钻探证实,此重、磁异常为花岗岩引起。花岗岩为燕山—印支期,据区域资料对比,花岗岩铀、钍、钾丰度高、生热率高,上述进入花岗岩钻孔深部有热无水,花岗岩作为盆地热源称其为干热岩。  相似文献   

致密煤层气藏三维全隐式数值模拟   总被引：2，自引：0，他引：2  

同登科  张先敏 《地质学报》2008,82(10):1428-1431

我国煤层普遍存在低渗、低储层压力和低含气饱和度等不利条件,许多研究表明,低渗透多孔介质中的气体运移存在启动压力梯度。为了让数值模拟模型能更加准确地描述致密煤储层中流体的运移特性,基于前人的研究成果,建立了考虑启动压力梯度的致密煤层气藏三维、非平衡吸附、拟稳态条件下气、水两相耦合流动数值模拟模型,并给出了模型的全隐式有限差分格式和数值求解方法。最后利用沁水盆地某生产井的试井资料进行了模拟计算,模拟结果表明,在其他条件相同的情况下,启动压力梯度的存在使得煤层的降压效果变差,且延迟了产气高峰的到来。对比该井的开采资料,模拟结果是合理的,模型能正确反映致密煤层气藏中流体的运移特征。  相似文献   

黄土高原MIS 3时期蜗牛化石记录的温湿气候及其成因机制探讨   总被引：2，自引：1，他引：1       下载免费PDF全文

陈晓云  吴乃琴 《第四纪研究》2008,28(1):154-161

通过对黄土高原西峰和洛川黄土剖面末次冰期较高分辨率的蜗牛化石组合研究发现,深海氧同位素第3期(MIS3)(59～29kaB.P.)黄土高原的气候变化可分为3个阶段:MIS3c时期,气候总体相对温暖湿润,但暖湿程度远不及全新世时期,这一阶段出现两次比较温湿的气候波动,西峰最温湿的时期发生在约48～46kaB.P.,其次在约54kaB.P.,洛川较温湿的时期出现在约57kaB.P.;MIS3b时期,西峰气候比较寒冷,但具有一定的湿度,洛川总体上气候比较冷湿,但较之于西峰无论是温度还是湿度都要高一些;MIS3a时期,西峰的气候从温凉变得冷干,洛川出现频繁的气候波动。研究认为黄土高原MIS3c时期较温湿气候状况可能是受控于这一时期地轴倾角控制的太阳辐射梯度的变化,地轴倾角增大,中纬度夏季太阳辐射强度高于低纬度的辐射强度,使得中低纬度之间夏季太阳辐射梯度增加,低纬度海洋向中纬度大陆传输的热量和湿度增加,夏季风加强,从而改善了黄土高原的温湿度状况,喜暖湿的蜗牛种类得以在冰期的环境中生长发育。蜗牛化石的研究结果显示MIS3时期黄土高原不同地区存在明显的区域性差异,与现今气候格局不同的是这一时期黄土高原存在更大的气候环境梯度。  相似文献   

基于GOCE梯度的地球引力场恢复(英文)     

SHEN Wenbin LI Jin LI Jiancheng WANG Zhengtao NING Jinsheng CHAO Dingbo  Dept. of Geophysics  School of Geodesy  Geomatics  Wuhan University  Luoyu Road  Wuhan  China  The Key Laboratory of Geospace Environment  Geodesy  Wuhan University  Luoyu Road  Wuhan  China. 《地球空间信息科学学报》2008,(4)

Given the second radial derivative Vr r ( P ) |S of the Earth’s gravitational potential V ( P ) on the surface S corresponding to the satellite altitude, by using the fictitious compress recovery method, a fictitious regular harmonic field rrVr r( P )* and a fictitious second radial gradient field Vr *r ( P) in the domain outside an inner sphere K i can be determined, which coincides with the real field Vr r( P ) in the domain outside the Earth. Vr *r ( P)could be further expressed as a uniformly convergent expansion series in the domain outside the inner sphere, because rrVr r( P )* could be expressed as a uniformly convergent spherical harmonic expansion series due to its regularity and harmony in that domain. In another aspect, the fictitious field V * ( P) defined in the domain outside the inner sphere, which coincides with the real field V ( P ) in the domain outside the Earth, could be also expressed as a spherical harmonic expansion series. Then, the harmonic coefficients contained in the series expressing V * ( P) can be determined, and consequently the real field V ( P ) is recovered. Preliminary simulation calculations show that the second radial gradient field Vr r( P ) could be recovered based only on the second radial derivative Vr r ( P )| S given on the satellite boundary. Concerning the final recovery of the potential field V ( P ) based only on the boundary value Vr r ( P )|S, the simulation tests are still in process.  相似文献   

Heat flow in the Altai-Sayan Area: new data     

L.S. Sokolova  A.D. Duchkov 《Russian Geology and Geophysics》2008,49(12):940-950

Eleven new estimates of heat flow (q) from the southern Altai-Sayan Folded Area (ASFA) have provided update to the heat flow map of Gorny Altai. Measured heat flow in the area varies from 33 to 90 mW/m², with abnormal values of >70 mW/m^q at four sites. The anomalies may have a deep source only at the Aryskan site in the East Sayan (q = 77 mW/m²) while high heat flows of 75–90 mW/m² obtained for the Mesozoic Belokurikha and Kalguty plutons appear rather to result from high radiogenic heat production in granite, which adds a 25–30 W/m² radiogenic component to a deep component of 50–60 mW/m². The latter value is consistent with heat flow estimates derived from helium isotope ratios (54 mW/m² in both plutons). Heat flow variations at other sites are in the range from 33 to 60 mW/m². The new data support the earlier inferences of a generally low heat flow over most of ASFA (average of 45–50 mW/m²) and of a “cold” Cenozoic orogeny in the area (except for southeastern ASFA), possibly driven by shear stresses associated with India indentation into Eurasia.  相似文献   

物探方法在西藏驱龙铜(钼)矿区中的综合应用     

Zhang Yingwen    Wang Liang 《中国煤炭地质》2008,(12)

驱龙铜(钼)多金属矿区,位于西藏自治区拉萨市墨竹工卡县境内,区内井下测井主要采用三侧向电阻率法、电阻率电位法、激发极化法、自然电位法、自然伽马法、简易井温法等方法,地面物探工作主要有联合剖面测量和放射性γ参数测量2种方法。根据该区覆盖层、花岗岩、含矿段、矿化段、溶蚀裂隙发育段等不同地质条件下的电阻率、极化率、自然伽马、自然电位等不同物性变化特征及规律,能够确定其地下地质体的空间分布形态。特别是对区内不规则的热液型多金属矿体,能起到透视作用,以发现隐伏矿体。实例还表明综合物探方法在西藏高原区还能有效划分含水层、确定冻土带、区分地温带、提取环保参数等。  相似文献   

山东省东明地热田地球物理化学特征分析     

王奎峰 《华北地质》2008,31(4)

山东省东明地热田内蕴藏着丰富的地热资源。通过已有地质资料及近年的勘查项目研究成果,对东明地热田的地热资源的地质背景、热储特征、地球物理化学特征等进行了研究分析,认为东明地热田属于层控型低温地热田,热储层主要为新近纪明化镇组下部、馆陶组、古近纪东营组地层,该区的地温梯度主要受构造控制,断裂导热是形成该地温场的一个重要因素,地下热水水平方向水化学组分变化甚微,具有明显的垂直分带性,地热水水源主要为渗入的溶滤水。  相似文献   

Computation of waves scattered by inhomogeneous velocity gradient using generalized Born approximation     

LIU Bo  SUN Jianguo  MENG Xiangyu 《世界地质(英文版)》2020,(1):24-31

The generalized Born approximation is an approximation method that represents the scattering term by the error between the exact Green's function and the approximate Green's function,mainly for the gradient scattering problem.However,so far,the research on the generalized Born approximation has only stayed in theory,and its implementation techniques are rarely reported.In order to fill this gap,the basic theory of generalized Born approximation is reviewed,and the implementation method of generalized Born approximation is discussed in this paper.In particular,the problem of calculating boundary effect elimination is discussed in detail.Finally,through model trial calculation,the calculation of gradient scattering,by comparing Born approximation and finite difference method,shows that using the generalized Born approximation to calculate gradient scattering achieves higher computational accuracy.  相似文献