Frequency Analysis of an Annually Resolved, 700 Year Paleoclimate Record from the GISP2 Ice Core

Author(s):  
James W. C. White ◽  
David Gorodetzky ◽  
Edward R. Cook ◽  
Lisa K. Barlow
Keyword(s):  
Tellus B ◽  
2005 ◽  
Vol 57 (4) ◽  
pp. 351-355 ◽  
Author(s):  
THOMAS B. van HOOF ◽  
KARSTEN A. KASPERS ◽  
FRIEDERIKE WAGNER ◽  
RODERIK S. W. van de WAL ◽  
WOLFRAM M. KURSCHNER ◽  
...  

Tellus B ◽  
2005 ◽  
Vol 57 (4) ◽  
pp. 351-355 ◽  
Author(s):  
Thomas B. Van Hoof ◽  
Karsten A. Kaspers ◽  
Freiderike Wagner ◽  
Roderik S.W. Van De Wal ◽  
Wolfram M. Kürschner ◽  
...  

2014 ◽  
Vol 10 (5) ◽  
pp. 1659-1672
Author(s):  
M. Gay ◽  
M. De Angelis ◽  
J.-L. Lacoume

Abstract. Ice core dating is a key parameter for the interpretation of the ice archives. However, the relationship between ice depth and ice age generally cannot be easily established and requires the combination of numerous investigations and/or modelling efforts. This paper presents a new approach to ice core dating based on time–frequency analysis of chemical profiles at a site where seasonal patterns may be significantly distorted by sporadic events of regional importance, specifically at the summit area of Nevado Illimani (6350 m a.s.l.), located in the eastern Bolivian Andes (16°37' S, 67°46' W). We used ion concentration depth profiles collected along a 100 m deep ice core. The results of Fourier time–frequency and wavelet transforms were first compared. Both methods were applied to a nitrate concentration depth profile. The resulting chronologies were checked by comparison with the multi-proxy year-by-year dating published by de Angelis et al. (2003) and with volcanic tie points. With this first experiment, we demonstrated the efficiency of Fourier time–frequency analysis when tracking the nitrate natural variability. In addition, we were able to show spectrum aliasing due to under-sampling below 70 m. In this article, we propose a method of de-aliasing which significantly improves the core dating in comparison with annual layer manual counting. Fourier time–frequency analysis was applied to concentration depth profiles of seven other ions, providing information on the suitability of each of them for the dating of tropical Andean ice cores.


Author(s):  
Migdat Hodzic ◽  
Ivan Kennedy

The Vostok ice core data cover 420,000 years indicating the natural regularity of Earth’s surface temperature and climate. Here, we consider four major cycles of similar duration, ranging from 86,000 to 128,000 years, comprising 15% of periods for the warming interglacials compared to some 85% of cooling periods. Globally, we are near the peak of a rapid warming period. We perform a detailed frequency analysis of temperature and CO2 cycles, as a primary stage in building a logical Climate Prediction Engine (CPE), illustrated with specific harmonics. This analysis can be repeated for all harmonics and various cycle combinations. Our time correlation estimates the CO2 time lag for temperature at 400–2300 years, depending on the cycle, longer on average than previously concluded. We also perform Fast-Fourier transform analysis, identifying a full harmonic spectrum for each cycle, plus an energy analysis to identify each harmonic amplitude − to achieve further prediction analysis using a Kalman filter harmonic bank. For Vostok data we can use combinations of different cycles compared to the most recent for learning and then the current ongoing cycle for testing. Assuming causal time regularity, more cycles can be employed in training, hence reducing the prediction error for the next cycle. This results in prediction of climate data with both naturally occurring as well as human forced CO2 values. We perform this detailed time and frequency analysis as a basis for improving the quality of our climate prediction methodologies, with particular attention to testing alternative hypotheses of the possible causes of climate change. These include the effect on albedo of suspended dust and increasing water vapor with temperature in initiating interglacial warming, the effect of temperature and pH values of surface water on ambient level of CO2 in the atmosphere and finding a larger latent heat capacity in the atmosphere required to sustain its circulatory motions, leading to friction and turbulent release of heat in boundary layer. All these potentials can be examined in an effective CPE.


2019 ◽  
Vol 7 (2) ◽  
pp. 907
Author(s):  
Migdat Hodzic ◽  
Ivan Kennedy

2002 ◽  
Vol 12 (3) ◽  
pp. 165-168
Author(s):  
S. Withington ◽  
P. Kittara ◽  
G. Yassin

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