Empirical-Statistical Methodology and Methods for Modeling and Forecasting of Climate Variability of Different Temporal Scales

2001 ◽  
Vol 18 (5) ◽  
pp. 844-863
Author(s):  
Vladimir A. Lobanov
Keyword(s):  
Climate Variability ◽  
Statistical Methodology ◽  
Temporal Scales ◽  
Modeling And Forecasting

scholarly journals What climate signal is contained in decadal- to centennial-scale isotope variations from Antarctic ice cores?

2018 ◽  
Vol 14 (12) ◽  
pp. 2053-2070 ◽  
Author(s):  
Thomas Münch ◽  
Thomas Laepple
Keyword(s):  
Climate Variability ◽  
Ice Cores ◽  
Relative Magnitude ◽  
True Temperature ◽  
Large Set ◽  
Atmospheric Conditions ◽  
Temporal Scales ◽  
Simple Method ◽  
Climate Signal ◽  
Spatial And Temporal Scales

Abstract. Ice-core-based records of isotopic composition are a proxy for past temperatures and can thus provide information on polar climate variability over a large range of timescales. However, individual isotope records are affected by a multitude of processes that may mask the true temperature variability. The relative magnitude of climate and non-climate contributions is expected to vary as a function of timescale, and thus it is crucial to determine those temporal scales on which the actual signal dominates the noise. At present, there are no reliable estimates of this timescale dependence of the signal-to-noise ratio (SNR). Here, we present a simple method that applies spectral analyses to stable-isotope data from multiple cores to estimate the SNR, and the signal and noise variability, as a function of timescale. The method builds on separating the contributions from a common signal and from local variations and includes a correction for the effects of diffusion and time uncertainty. We apply our approach to firn-core arrays from Dronning Maud Land (DML) in East Antarctica and from the West Antarctic Ice Sheet (WAIS). For DML and decadal to multi-centennial timescales, we find an increase in the SNR by nearly 1 order of magnitude (∼0.2 at decadal and ∼1.0 at multi-centennial scales). The estimated spectrum of climate variability also shows increasing variability towards longer timescales, contrary to what is traditionally inferred from single records in this region. In contrast, the inferred variability spectrum for WAIS stays close to constant over decadal to centennial timescales, and the results even suggest a decrease in SNR over this range of timescales. We speculate that these differences between DML and WAIS are related to differences in the spatial and temporal scales of the isotope signal, highlighting the potentially more homogeneous atmospheric conditions on the Antarctic Plateau in contrast to the marine-influenced conditions on WAIS. In general, our approach provides a methodological basis for separating local proxy variability from coherent climate variations, which is applicable to a large set of palaeoclimate records.

scholarly journals What climate signal is contained in decadal to centennial scale isotope variations from Antarctic ice cores?

2018 ◽  
Author(s):  
Thomas Münch ◽  
Thomas Laepple
Keyword(s):  
Climate Variability ◽  
Ice Cores ◽  
Relative Magnitude ◽  
True Temperature ◽  
Large Set ◽  
Atmospheric Conditions ◽  
Temporal Scales ◽  
Simple Method ◽  
Climate Signal ◽  
Spatial And Temporal Scales

Abstract. Ice-core-based records of isotopic composition are a proxy for past temperatures and can thus provide information on polar climate variability over a large range of timescales. However, individual isotope records are affected by a multitude of processes that may mask the true temperature variability. The relative magnitude of climate and non-climate contributions is expected to vary as a function of timescale, and thus it is crucial to determine those temporal scales at which the actual signal dominates the noise. At present, there are no reliable estimates of this timescale dependence of the signal-to-noise ratio (SNR). Here, we present a simple method that applies spectral analyses to stable-isotope data from multiple cores to estimate the SNR, and the signal and noise variability, as a function of timescale. The method builds on separating the contributions from a common signal and from local variations and includes a correction for the effects of diffusion and time uncertainty. We apply our approach to firn-core arrays from Dronning Maud Land (DML) in East Antarctica and from the West Antarctic Ice Sheet (WAIS). For DML and decadal to multicentennial timescales, we find an increase of the SNR by nearly one order of magnitude (~ 0.2 at decadal and ~ 1.0 at multicentennial scales). The estimated spectrum of climate variability also shows increasing variability towards longer timescales, contrary to what is traditionally inferred from single records in this region. In contrast, the inferred variability spectrum for WAIS stays close to constant over decadal to centennial timescales, and the results even suggest a decrease in SNR over this range of timescales. We speculate that these differences between DML and WAIS are related to differences in the spatial and temporal scales of the isotope signal, highlighting the potentially more homogeneous atmospheric conditions on the Antarctic Plateau in contrast to the marine-influenced conditions on WAIS. In general, our approach provides a methodological basis for separating local proxy variability from coherent climate variations which is applicable to a large set of palaeoclimate records.

Roles of forest disturbance and climate variability on streamflow components in snow‐dominated paired watersheds at multiple temporal scales

2021 ◽  
Vol 35 (12) ◽  
Author(s):  
Qiang Li ◽  
Mingfang Zhang ◽  
Xiaohua Wei ◽  
Rita Winkler ◽  
Sheena Spencer ◽  
...  
Keyword(s):  
Climate Variability ◽  
Forest Disturbance ◽  
Temporal Scales ◽  
Paired Watersheds
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