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171.
The interannual variation of the North Atlantic Oscillation (NAO) and North Pacific Oscillation (NPO) and its relationship
with the climate jump in the Northern Hemisphere in the 1960s, are discussed using the data analyses. It is clearly shown
that the amplitudes of the NAO and NPO were all increased obviously in the 1960s and the main period of the oscillations changed
from 3–4 years before the 1960s to 8–15 years after the 1960s. Therefore, the climate jump in the 1960s is closely related
to the anomalies of the NAO and NPO. 相似文献
172.
High-resolution tomographic images across Japan Trenh-Changhai Mountains-lDong Ujimqinqi are displayed, showing the morphological feature of the subducted slab in the norhwestem Pacific margin and the eharaeter istics of lithosphere stmctures under the Changhai Mountains and the Da Hinggan Mnuntains. The Pacific plate began to penetrate into the deeper mantle after it subducted to the 660 km discontinuity with an underthmsting angle of 26°, but did not continue to mnve furrther westward. In contrast, there appeared a remarkable thermal upwelling zone to the west of the downward plate. In addition, the evidence frnm the subduction time and time lag between the subduetion and eon sequent magmatism indicates that there is no direct genetic correlatiom between the Mesoznic magmatism in eastern China ami subduction of the Pacific plate. In this work. we also emphasize that what the tomographic images reflect is the pre sent structure in the deep earth interior, which should preserve some Mesozoic lithospheric structure characteristics. In summary, we attribute the Mesozoic intense magmatic evolution in north China to the intraplate asthenosphere upwelling zone. 相似文献
173.
东太平洋多金属结核U、Th同位素深度分布特征与生长速率 总被引:2,自引:1,他引:1
研究了东太平洋多金属结核中U、Th同位素的深度分布与生长速率。表明,东太平洋多金属结核中的^234U/^238U)A.R.与海水接近,证实了U的海水来源;234U及238U的活度并不随深度增加而减小,而是在次表层和更深层出现极大值。2367站核中^232Th的活度在次表层有最大值,之后随深度的增加而降低,反映了结核生长过程中成岩作用的影响;1797站南结核中^232Th表层有最大值,其它各层的变化 相似文献
174.
175.
The observed sea surface temperature (SST) data of recent 100 years are analyzed and the existence of the Indian Ocean temperature dipole in the equatorial region is exposed further. It is very clear that the amplitude of the positive phase (higher SST in the west and lower SST in the east than normal) is larger than that of the negative phase (higher SST in the east and lower SST in the west). The dipole is stronger in September-November and weaker in January-April than in other months and it also appears obviously inter-annual and inter-decadal variations. Although the Indian Ocean dipole in the individual year seems to be independent of ENSO in the equatorial Pacific Ocean, in general, the Indian Ocean dipole has obviously negative correlation with the Pacific Ocean dipole (similar to the inverse phase of ENSO mode). The atmospheric zonal (Walker) circulation over the equator is fundamental to relate the two dipoles to each other. 相似文献
176.
An assimilation data set based on the GFDL MOM3 model and the NODC XBT data set is used to examine the circulation in the western tropical Pacific and its seasonal variations. The assimilated and observed velocities and transports of the mean circulation agree well. Transports of the North Equatorial Current (NEC), Mindanao Current (MC), North Equatorial Countercurrent (NECC) west of 140°E and Kuroshio origin estimated with the assimilation data display the seasonal cycles, roughly strong in boreal spring and weak in autumn, with a little phase difference.The NECC transport also has a semi-annual fluctuation resuiting from the phase lag between seasonal cycles of two tropical gyres' recirculations. Strong in summer during the southeast monsoon period, the seasonal cycle of the Indonesian throughfiow (ITF) is somewhat different from those of its upstreams, the MC and New Guinea Coastal Current (NGCC), implying the monsoon's impact on it. 相似文献
177.
对东太平洋结核区6个站点沉积物样品进行细菌培养和数量统计,发现各个站点间的细菌总量变化幅度较大,站点E2003-01的细菌量最多;细菌量纵向分布规律基本是从表层到深层逐渐递减.对所获得的菌株进一步用RFLP和16S rDNA基因序列分析,发现所获得的菌株主要来自变形菌门(Proteobacteria)的α、β、γ亚群和放线菌门(Actinobacteria),厚壁菌门(Firmicutes)等类群.此外还发现了与已知细菌菌种相似性在97%~95%之间的有12株,它们可能是新种;与已知细菌菌种相似性小于或等于95%的有4株,它们可能是新的属种. 相似文献
178.
LU Zunli** LING Hongfei* ZHOU Feng JIANG Shaoyong CHEN Xiaoming ZHOU Huaiyang 《自然科学进展(英文版)》2005,15(6)
Hydrogeneticferromanganesecrusts(Fe Mn crustshereafter),areinorganiccolloidprecipitatesfromseawater,whicharebelievedtohaverecorded theevolutionofelementalandisotopiccompositionsof seawaterovertime[1—7].Studiesontraceelements andisotopeshavebroughtmoreinsightsthanstudies onironandmanganesecontents.TheMn/Feratio hasbeenconsideredtoreflectwaterdepth,deep wa teroxygenation[8,9],andhasalsobeensuggestedasa reliablecriterionfordistinguishingdifferentgenetic typesofferromanganesedeposits[10].Apossi… 相似文献
179.
暖池区1.53 Ma以来上层海水变化的颗石藻证据 总被引:4,自引:0,他引:4
对位于西太平洋暖池区核心的大洋钻探计划(ODP)807站1.53Ma以来深海沉积样品进行了颗石藻化石分析,通过Florisphaeraprofunda数量百分比讨论了营养跃层深度变化的趋势,并计算了初级生产力.结果表明1.53Ma以来暖池核心区海水营养跃层经历了明显变化:从1.53~0.9Ma,营养跃层深度逐渐变浅;自0.9Ma起营养跃层开始变深并保持到0.48Ma;0.48~0.28Ma之间是营养跃层深度明显变浅的一个时期,在这以后营养跃层逐渐变深.根据颗石藻得出的海水营养跃层变化与初级生产力变化基本一致,也与根据浮游有孔虫转换函数得出的温跃层深度变化趋势基本一致.对比ODP807站和南海ODP1143站F.profunda数量百分比和初级生产力变化曲线,两站在0.9Ma以前变化的趋势相反,而0.9Ma以后基本一致.说明0.9Ma以前暖池核心地区与边缘区上层海水的变化有差异,而0.9Ma以后两者则趋同. 相似文献
180.
基于自适应网络模糊推理系统ANFIS,讨论了从实际信号中检测识别系统的主要影响因子,进而滤除其干扰的方法途径,进行了相应的去噪试验;运用模糊推理方法对西太平洋副高异常的近赤道海温影响因子进行了诊断检测分析。 相似文献