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91.
当大西洋上的天气系统受到具有急流分支(一支通过英国北部,另一支通过英国南部)为特征的阻塞型式阻挡其正常发展时,联合王国经常出现极端的天气.夏季,这种形势可导致持续一段时期的晴好天气(如1976年);冬季,一般会伴随出现严冬(如1986年2月).月时间尺度天气的可预报性很可能主要依赖于维持并稳定这种阻塞型式的物理机制.因此,最近在阻塞动力学方面的研究已进行了重大努力,提出了一些新理论.本文对这些新发展进行了检验. 相似文献
92.
从西藏南部的定日、嘎拉至青海铜铁山的天然地震探测剖面,实际路线长约2000km,布设了约110台便携地震仪,记录了数百次远震和近震事件,采用多种方法进行了资料处理与解释.依据SKS,PKS,ps等横波分裂特征计算的青藏高原中部上地幔的地震各向异性表明:研究区各构造单元内的地震各向异性有明显变化,发现上地幔各向异性快速波的偏振方向与造山带的走向不完全一致.在雅江缝合线、崩错-嘉黎、唐古拉山口、昆仑山口几条断裂带处南、北各向异性出现显著的差异,而金沙江缝合线和班公-怒江缝合线的南、北则没有明显的各向异性变化.由P波走时残差,利用层析技术反演了400km深度内的速度图像,可以看出近地表100km范围内速度的不均匀变化与地表划分的构造单元很吻合,进一步佐证了青藏高原是由不同时期的微板块拼合而成的认识.在青藏高原中部150km深度以下发现了多处低速区.在金沙江缝合带下方约200km深度处有一长250km以上、延伸150km的低速体,推测可能是一地幔柱.利用PS转换波划分的界面,显示出青藏高原北部具有低速层和高速层交替出现的地壳结构. 相似文献
93.
通过对北大西洋深海钻探计划(DSDP)钻孔的地层和有机地球化学资料的复查校正,证明在点105、107、367、386、398、549和551处存在有CTBSH层(CTBSH为Cenomanian-Turonian Black Shale Horizon之缩写,即西诺曼期—土伦期黑色页岩层)。这套沉积物通常含黄铁矿或磷酸盐,或者两者都含,其层厚为1毫米或小于1毫米的纹层。它的总有机炭含量(TOC—Total Organic Carbon之缩写,即总有机炭)大于2%,平均值一般为10%,最大值可达30%,所含有机质主要是海相成因的。 相似文献
94.
The Boao coastal system along the eastern coast of Hainan Island is a dynamic delta-tidal inlet-barrier formed during the late Holocene. The delta developed inside a shallow lagoon barred by a sandy barrier with a narrow, shallow tidal inlet opening. Two major distributary channels separated by small islands characterize the delta. The lagoon is silting up receiving and trapping sediments from both the river and, in minor measure during storms, through the tidal inlet opening and barrier washovers. The barrier at the tidal inlet is highly dynamic and changes its form, accreting (migrating spit) against the inlet during fair-weather conditions and being eroded during storms and river floods.The delta has almost completely filled the lagoon and major concerns exist on the effect that ongoing large development plans may have on the environment. These concerns include the effect on floods and rate of siltation once banks of the islands have been stabilized and floodwater and sediment load are impeded from spreading over the lowlands, and the effect of increasing pollutant loads from the new facilities on the ecosystems of the increasingly restricting lagoon water and on the seashores. 相似文献
95.
PAULJ.GEMPERLINE 《地理学报(英文版)》1989,(3)
One of the major application areas of factor analysis, multivariate calibration and quantitation, is coveredin this review. The algorithms, methodologies and applications covered include principal componentregression, target transformation factor analysis, singular value decomposition and rank annihilationfactor analysis. Many important areas of research having relevance to multivariate calibration andquantitation problems are also covered in this review, including background correction, measurementerror, rank determination, cross-validation, figures of merit, detection of invalid samples, experimentaldesign, sample selection, statistical inference and wavelength selection. 相似文献
96.
97.
Qin YANG Puyu GUO Elena Y.ABIDUEVA Elena V.LAVRENTYEVA Irina M.LISEVICH Ilya A.OSTERMAN Petr V.SERGIEV Shaowei LIU Chunmei XUE Chenghang SUN 《海洋湖沼学报(英文)》2023,(4):1307-1320
To explore pharmaceutical actinobacteria from salty environments in Siberia, 8 soil samples were collected from different depths of Gudzhirganskoe saline lake, the Republic of Buryatia, Russia.Totally, 635 actinobacterial strains affiliated with 21 genera in 12 families of 7 orders were obtained by culture-dependent approaches. The predominant genus was Streptomyces(74.5%), followed by Microbacterium(4.9%), Agromyces(3.5%), Nocardiopsis(3.0%), and Kitasatospora(2.5%). Seven strains showed relati... 相似文献
98.
Ronan Connolly Willie Soon Michael Connolly Sallie Baliunas Johan Berglund C. J. Butler Rodolfo Gustavo Cionco Ana G. Elias Valery M. Fedorov Hermann Harde Gregory W. Henry Douglas V. Hoyt Ole Humlum David R. Legates Nicola Scafetta Jan-Erik Solheim László Szarka Víctor M. Velasco Herrera Hong Yan Weijia Zhang 《天文和天体物理学研究(英文版)》2023,(10):369-388
Since 2007, the Intergovernmental Panel on Climate Change(IPCC) has heavily relied on the comparison between global climate model hindcasts and global surface temperature(ST) estimates for concluding that post-1950s global warming is mostly human-caused. In Connolly et al., we cautioned that this approach to the detection and attribution of climate change was highly dependent on the choice of Total Solar Irradiance(TSI) and ST data sets.We compiled 16 TSI and five ST data sets and found by alter... 相似文献
99.
For high-precision pulsar timing analysis and low-frequency gravitational wave detection, it is essential to accurately determine pulsar pulse times of arrival(ToAs) and associated uncertainties. To measure the ToAs and their uncertainties, various cross-correlation-based techniques can be employed. We develop methodologies to investigate the impact of the template-matching method, profile shape, signal-to-noise ratio of both template and observation on ToA uncertainties. These methodologies are... 相似文献
100.
The extremely accurate estimates of stellar variability and radial velocity in the Gaia Data Release 3(Gaia DR3)have enabled us to examine the close binarity and radial velocity(RV) of central stars(CSs) of planetary nebulae(PNe). This study is twofold:(1) searching for new close binary CS candidates to better understand how binarity affects the formation and evolution of PNe; and(2) extending the sample size of known RVs of PNe in order to understand their kinematics and the dynamics of the Mil... 相似文献