نتایج جستجو برای: abrupt change

تعداد نتایج: 601788  

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2000
D Peteet

Rapid climate change characterizes numerous terrestrial sediment records during and since the last glaciation. Vegetational response is best expressed in terrestrial records near ecotones, where sensitivity to climate change is greatest, and response times are as short as decades.

2008
Amy C. Clement Larry C. Peterson

[1] More than a decade ago, ice core records from Greenland revealed that the last glacial period was characterized by abrupt climate changes that recurred on millennial time scales. Since their discovery, there has been a large effort to determine whether these climate events were a global phenomenon or were just confined to the North Atlantic region and also to reveal the mechanisms that were...

2008
Richard W. Turner

Ice core records suggest that the Earth’s climate has undergone rapid, catastrophic shifts on multiple occasions in geologically recent times. The multiplicity of steady states found in fluid convection models has led many to speculate that the changes may have been caused by transitions between different stable modes of ocean current patterns. This paper reviews analytical and numerical modeli...

2003
Stefan Rahmstorf

[1] Many paleoclimatic data reveal a 1,500 year cyclicity of unknown origin. A crucial question is how stable and regular this cycle is. An analysis of the GISP2 ice core record from Greenland reveals that abrupt climate events appear to be paced by a 1,470-year cycle with a period that is probably stable to within a few percent; with 95% confidence the period is maintained to better than 12% o...

2012
Jinho Ahn Edward J. Brook Andreas Schmittner Karl Kreutz

[1] During the last glacial period atmospheric carbon dioxide and temperature in Antarctica varied in a similar fashion on millennial time scales, but previous work indicates that these changes were gradual. In a detailed analysis of one event we now find that approximately half of the CO2 increase that occurred during the 1500-year cold period between Dansgaard-Oeschger (DO) events 8 and 9 hap...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2015
Sarah E Moffitt Tessa M Hill Peter D Roopnarine James P Kennett

Anthropogenic climate change is predicted to decrease oceanic oxygen (O2) concentrations, with potentially significant effects on marine ecosystems. Geologically recent episodes of abrupt climatic warming provide opportunities to assess the effects of changing oxygenation on marine communities. Thus far, this knowledge has been largely restricted to investigations using Foraminifera, with littl...

2009
Sang Hyun Kim

In this paper, a fast motion compensation algorithm is proposed that improves coding efficiency for video sequences with brightness variations. We also propose a cross entropy measure between histograms of two frames to detect brightness variations. The framewise brightness variation parameters, a multiplier and an offset field for image intensity, are estimated and compensated. Simulation resu...

2008
W. P. He G. L. Feng Q. Wu S. Q. Wan J. F. Chou

Based on Detrended Fluctuation Analysis (DFA), we propose a new method – Moving Detrended Fluctuation Analysis (MDFA) – to detect abrupt change in dynamic structures. Application of this technique shows that this method may be of use in detecting time-instants of abrupt change in dynamic structures and we even find that the MDFA results almost do not depend on length of subseries, and are less ...

2015
Emma Wiik Helen Bennion Carl D. Sayer Thomas A. Davidson Stewart J. Clarke Suzanne McGowan Stephen Prentice Gavin L. Simpson Laura Stone

Citation: Wiik E, Bennion H, Sayer CD, Davidson TA, Clarke SJ, McGowan S, Prentice S, Simpson GL and Stone L (2015) The coming and going of a marl lake: multi-indicator palaeolimnology reveals abrupt ecological change and alternative views of reference conditions. Front. Ecol. Evol. 3:82. doi: 10.3389/fevo.2015.00082 The coming and going of a marl lake: multi-indicator palaeolimnology reveals a...

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