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91.
应用正交偶极子测井资料测量EDA地层的横波各向异性 总被引:17,自引:4,他引:13
采用3种分析EDA地层横波各向异性的技术处理了从WyomingPowder河谷用正交偶极子测井取得的数据资料。这些处理技术基于挠曲波在各向异性介质中发生分裂的现象而模拟VSP中的横波数据处理。四组分的正交偶极子测井数据是用Schlumberger公司的测井仪从井深3550m的一段长为56m的垂向裂缝发育的地层中采集的。根据对各发射-接收器组记录数据处理结果的一致性与方差来看,非正交旋转法效果最好。但线性变换法的结果也是可以接受的。线性变换法的优点是节省机时。从这组数据处理的结果来看,极化能谱法计算量相对较大并且对噪音的影响较敏感。 相似文献
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94.
We compute the power radiated per unit solid angle of a moving magnetic dipole moment, and its instantaneous radiated power, both non-relativistically and relativistically. This is then applied to various interesting situations: solar neutrons, electron synchrotrons and cosmological Dirac neutrinos. Concerning the latter, we show that hypothesized early-universe Big Bang conditions allow for neutrino radiation cooling and provide an energy loss-mechanism for subsequent neutrino condensation. 相似文献
95.
印度洋地区异常海温的偶极振荡与中国降水及温度的关系 总被引:42,自引:15,他引:42
利用1951-1997年近47年的印度洋海温距平场资料以及相应中国160站降水资料,通过相关普查得出,印度洋地区东西海温的偶极振荡与中国6-8月汛期的降水有较好的相关关系,特别是前期3-5月份的印度洋地区东西海温的偶极指数与中国6-8月降水的相关较好。分析1958-1995年NCEP 500hPa北半球高度场资料发现,印度洋偶极指数与欧亚中高纬度地区的高度场异常有密切的联系,其中印度洋偶极指数IODI负位相年有明显的PJ波列存在,印度洋偶极海湿异常很可能是通过PJ波列来影响中国的降水。同时,对印度洋地区海温偶极指数和中国地区温度的相关分析表明,印度洋地区海温偶极指数与冬季中国南部地区的温度也有较好的相关关系。 相似文献
96.
热带太平洋与印度洋相互作用的年代际变化 总被引:1,自引:0,他引:1
利用全球海表海温资料(GISST)和NCEP/NCAR再分析资料,研究了热带太平洋与印度洋之间的相互作用及其在不同年代二者作用关系的变化。结果表明:热带印度洋偶板子指数超前热带太平洋Nin03指数2月时相关最大,印度洋单板子指数滞后Nin03指数3~4月时相关最大。印度洋偶板子在一定程度上影响E1 Nino事件的发生,而E1 Nino事件的发生、发展会影响印度洋单板子事件的发生。热带印度洋偶板子事件与热带太平洋ENSO事件的相互作用在1961年发生了明显跃变,其原因可能是1961年之前热带印度洋偶板子对热带太平洋上空的纬向风影响很小,而1961年以后其影响明显加强。热带印度洋单板子事件与热带太平洋ENSO事件的相关一直显著,没有明显跃变。 相似文献
97.
Two modes of dipole events in tropical Indian Ocean 总被引:1,自引:0,他引:1
By analyzing the distributions of subsurface temperature and the surface wind stress anomalies in the tropical Pacific and
Indian Oceans during the Indian Ocean Dipole (IOD) events, two major modes of the IOD and their formation mechanisms are revealed.
(1) The subsurface temperature anomaly (STA) in the tropical Indian Ocean during the IOD events can be described as a “<”
-shaped and west-east-oriented dipole pattern; in the east side of the “<” pattern, a notable tongue-like STA extends westward
along the equator in the tropical eastern Indian Ocean; while in the west side of the “<” pattern, the STA has opposite sign
with two centers (the southern one is stronger than the northern one in intensity) being of rough symmetry about the equator
in the tropical mid-western Indian Ocean. (2) The IOD events are composed of two modes, which have similar spatial pattern
but different temporal variabilities due to the large scale air-sea interactions within two independent systems. The first
mode of the IOD event originates from the air-sea interaction on a scale of the tropical Pacific-Indian Ocean and coexists
with ENSO. The second mode originates from the air-sea interaction on a scale of the tropical Indian Ocean and is closely
associated with changes in the position and intensity of the Mascarene high pressure. The strong IOD event occurs when the
two modes are in phase, and the IOD event weakens or disappears when the two modes are out of phase. Besides, the IOD events
are normally strong when either of the two modes is strong. (3) The IOD event is caused by the abnormal wind stress forcing
over the tropical Indian Ocean, which results in vertical transports, leading to the upwelling and pileup of seawater. This
is the main dynamic processes resulting in the STA. When the anomalous easterly exists over the equatorial Indian Ocean, the
cold waters upwell in the tropical eastern Indian Ocean while the warm waters pileup in the tropical western Indian Ocean,
hence the thermocline in the tropical Indian Ocean is shallowed in the east and deepened in the west. The off-equator component
due to the Coriolis force in the equatorial area causes the upwelling of cold waters and the shallowing of the equatorial
India Ocean thermocline. On the other hand, the anomalous anticyclonic circulations and their curl fields located on both
sides of the equator, cause the pileup of warm waters in the central area of their curl fields and the deepening of the equatorial
Indian Ocean thermocline off the equator. The above three factors lead to the occurrence of positive phase IOD events. When
anomalous westerly dominates over the tropical Indian Ocean, the dynamic processes are reversed, and the negative-phase IOD
event occurs.
Supported by National Natural Science Foundation of China (Grant No. 40776013), National Basic Research Program of China (Grant
No. 2006CB403601) and the Knowledge Innovation Project of Chinese Academy of Sciences (Grant No. KZCX-SW-222) 相似文献
98.
The relationship between the orientation of the interplanetary magnetic field (IMF), represented by the clock angle which is the angle defined by IMF-By and -Bz components, and the AL and AU indices is examined at various dipole tilt angles for the period of 1978-1988. We use the IMF data obtained from the IMP 8 satellite, AL and AU indices with corrected seasonal variations, and the dipole tilt angle, which is the dipole magnetic latitude of the subsolar point calculated as a function of the day of year and universal time. For both positive (dipole tilted to the Sun) and negative dipole tilt angles, the values of |AL| and AU decrease as the IMF clock angle moves away from 180°, becoming more northward. The indices also tend to become smaller for larger dipole tilt angle, either toward or away from the Sun. This dependence on dipole tilt angle enhances the semiannual variation of geomagnetic activity. 相似文献
99.
Based on the data of 1950 – 1999 monthly global SST from Hadley Center, NCAR/NCEP
reanalysis data and rainfall over 160 weather stations in China, investigation is conducted into the
difference of summer rainfall in China (hereafter referred to as the “CS rainfall”) between the years with
the Indian Ocean Dipole (IOD) occurring independently and those with IOD occurring along with ENSO so
as to study the effects of El Ni?o - Southern Oscillation (ENSO) on the relationship between IOD and the
CS rainfall. It is shown that CS rainfall will be more than normal in South China (centered in Hunan
province) in the years of positive IOD occurring independently; the CS rainfall will be less (more) than
normal in North China (Southeast China) in the years of positive IOD occurring together with ENSO. The
effect of ENSO is offsetting (enhancing) the relationship between IOD and summer rainfall in Southwest
China, the region joining the Yangtze River basin with the Huaihe River basin (hereafter referred to as the
“Yangtze-Huaihe basin”) and North China (Southeast China). The circulation field is also examined for
preliminary causes of such an influence. 相似文献
100.
本文收集了1226个来自Cluster、Geotail、GOES、IMP8、Interball、LANL、Polar、TC1、THEMIS和Wind卫星磁层顶穿越事例,并主要利用时间推移使上游行星际磁场clock angle或等离子体变化特征与磁鞘中的相吻合方法为这些数据配对上来自ACE或Wind卫星5 min平均值太阳风数据.通过对这些数据以及网上公布的1482个Hawkeye卫星磁层顶穿越点数据分析研究,发现:(1)高纬磁层顶在极隙区存在内凹结构,其内凹范围比较大;(2)磁层顶内凹位置明显受地磁偶极倾角控制,最内凹点所对应的天顶角和地磁偶极倾角大致呈线性关系,这种关系在南北半球大致呈反对称;(3)磁层顶内凹深度、内凹范围以及内凹中心不变纬度基本不受地磁偶极倾角影响. 相似文献