中国科学院机构知识库网格系统: 检索

Multi-centennial climate cycles and their impact on the Tubo Dynasty in the southern Tibetan Plateau 期刊论文 OAI收割
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY, 2021, 卷号: 578, 页码: 11
作者: Li, Hao; Xu, Deke; Shen, Caiming; Cui, Anning; Zuo, Xinxin

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收藏 | 浏览/下载：64/0 | 提交时间：2021/10/21

Uniform discrete wavelet spectrum for detection of hydrologic variability at multiple timescales 期刊论文 OAI收割
JOURNAL OF HYDRO-ENVIRONMENT RESEARCH, 2021, 卷号: 35, 页码: 31-37
作者: Sang, Yan-Fang; Sivakumar, Bellie; Zhu, Yanxin

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收藏 | 浏览/下载：34/0 | 提交时间：2021/06/10

Hydrologic variability Signal detection Discrete wavelet spectrum Periodicities Trend

Uniform discrete wavelet spectrum for detection of hydrologic variability at multiple timescales 期刊论文 OAI收割
JOURNAL OF HYDRO-ENVIRONMENT RESEARCH, 2021, 卷号: 35, 页码: 31-37
作者: Sang, Yan-Fang; Sivakumar, Bellie; Zhu, Yanxin

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收藏 | 浏览/下载：13/0 | 提交时间：2021/06/10

Hydrologic variability Signal detection Discrete wavelet spectrum Periodicities Trend

An underlying clock in the extreme flip-flop state transitions of the black hole transient Swift J1658.2-4242 期刊论文 OAI收割
Astronomy and Astrophysics, 2020, 卷号: 641, 页码: A101
作者: HXMT

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收藏 | 浏览/下载：58/0 | 提交时间：2022/02/08

accretion accretion disks black hole physics X-rays: binaries time Astrophysics - High Energy Astrophysical Phenomena Abstract:
Aims: Flip-flops are top-hat-like X-ray flux variations, which have been observed in some transient accreting black hole binary systems, and feature simultaneous changes in the spectral hardness and the power density spectrum (PDS). They occur at a crucial time in the evolution of these systems, when the accretion disc emission starts to dominate over coronal emission. Flip-flops remain a poorly understood phenomenon, so we aim to thoroughly investigate them in a system featuring several such transitions.
Methods: Within the multitude of observations of Swift J1658.2-4242 during its outburst in early 2018, we detected 15 flip-flops, enabling a detailed analysis of their individual properties and the differences between them. We present observations by XMM-Newton, NuSTAR, Astrosat, Swift, Insight-HXMT, INTEGRAL, and ATCA. We analysed their light curves, searched for periodicities, computed their PDSs, and fitted their X-ray spectra, to investigate the source behaviour during flip-flop transitions and how the interval featuring flip-flops differs from the rest of the outburst.
Results: The flip-flops of Swift J1658.2-4242 are of an extreme variety, exhibiting flux differences of up to 77% within 100 s, which is much larger than what has been seen previously. We observed radical changes in the PDS simultaneous with the sharp flux variations, featuring transitions between the quasi-periodic oscillation types C and A, which have never been observed before. Changes in the PDS are delayed, but more rapid than changes in the light curve. Flip-flops occur in two intervals within the outburst, separated by about two weeks in which these phenomena were not seen. Transitions between the two flip-flop states occurred at random integer multiples of a fundamental period of 2.761 ks in the first interval and 2.61 ks in the second. Spectral analysis reveals the high and low flux flip-flop states to be very similar, but distinct from intervals lacking flip-flops. A change of the inner temperature of the accretion disc is responsible for most of the flux difference in the flip-flops. We also highlight the importance of correcting for the influence of the dust scattering halo on the X-ray spectra.

Trends, periodicities and discontinuities of precipitation in the Huangfuchuan Watershed, Loess Plateau, China 期刊论文 OAI收割
CURRENT SCIENCE, 2016, 卷号: 111, 期号: 4, 页码: 727-733
作者: He, Yi; Mu, Xingmin; Gao, Peng; Zhao, Guangju; Wang, Fei

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收藏 | 浏览/下载：48/0 | 提交时间：2019/09/26

Ensemble empirical mode decomposition periodicities and discontinuities precipitation variability watershed

The 18.6-year periodicity of great earthquakes 期刊论文 OAI收割
CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION, 2011, 卷号: 54, 期号: 9, 页码: 2256-2262
Du PR (Du Pin-Ren); Zhao JM (赵俊猛); Gao XL (Gao Xiang-Lin)

收藏 | 浏览/下载：36/0 | 提交时间：2012/05/09

SOUTHERN-CALIFORNIA SOLAR PERIODICITIES NORTH-AMERICA LUNAR TIDE TEMPERATURE DROUGHT

Variability of Extended Bipolar Regions 期刊论文 OAI收割
Solar Physics, 2009, 卷号: 257, 期号: 1, 页码: 83-90
Song, W. B.; Feng, X. S.; Shen, F.; Zhang, Y. Z.

收藏 | 浏览/下载：46/0 | 提交时间：2014/04/30

Magnetic fields Photosphere north-south asymmetry solar-cycle magnetic-fields evolution periodicities oscillations sunspots flux

Solar activity, global surface air temperature anomaly and pacific decadal oscillation recorded in urban tree rings 期刊论文 OAI收割
ANNALS OF FOREST SCIENCE, 2007, 卷号: 64, 期号: 7, 页码: 743-756
He; XG (He; Xingyuan); Chen; ZJ (Chen; Zhenju); Chen; W (Chen; Wei); Shao XM(邵雪梅); He; H (He; HongS); Sun; Y (Sun; Yu)

收藏 | 浏览/下载：49/0 | 提交时间：2010/05/21

PAST 6 CENTURIES WAVELET ANALYSIS CLIMATE VARIABILITY PERIODICITIES CHRONOLOGIES GROWTH CYCLE RECONSTRUCTION INFERENCES LATITUDES

Solar activity, global surface air temperature anomaly and pacific decadal oscillation recorded in urban tree rings SCI/SSCI论文 OAI收割
2007
He X. G.; Chen Z. J.; Chen W.; Shao X. M.; He H.; Sun Y.

收藏 | 浏览/下载：45/0 | 提交时间：2012/06/08

urban tree rings sunspot number Pacific decadal oscillation global surface air temperature anomaly wavelet analysis past 6 centuries wavelet analysis climate variability periodicities chronologies growth cycle reconstruction inferences latitudes

Solar activity, global surface air temperature anomaly and Pacific Decadal Oscillation signals observed in urban outskirts tree ring records from Shenyang, China SCI/SSCI论文 OAI收割
2006
Chen Z. J.; He X. Y.; Chen W.; Shao X. M.; Sun Y.; Tao D. L.

收藏 | 浏览/下载：48/0 | 提交时间：2012/06/08

urban outskirts tree ring sunspot number Pacific Decadal Oscillation global surface air temperature anomaly wavelet analysis past 1000 years wavelet analysis maunder minimum climate variability reconstruction periodicities chronologies brazil cycle inferences