Are there multiple scaling regimes in Holocene temperature records?

Nilsen, Tine; Rypdal, Kristoffer; Fredriksen, Hege‐Beate

doi:10.5194/esd-7-419-2016

Cited by 23 publications

(19 citation statements)

References 57 publications

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“…Similar spectral characteristics were obtained for other tree-ring chronolo-595 gies in (Franke et al, 2013;Zhang et al, 2015;Esper et al, 2015;Büntgen et al, 2015). The memory properties in a number of proxy-based temperature reconstructions have been studied in (Østvand et al, 2014;Nilsen et al, 2016) using the power spectrum along with selected other techniques. In these studies, LRM was detected in all records up to centennial/millennial time scales.…”

Section: C1 Analyses Of Proxy Recordsmentioning

confidence: 65%

Spatio-temporal variability of Arctic summer temperatures over the past two millennia: an overview of the last major climate anomalies

Werner

Divine

Ljungqvist

et al. 2017

Preprint

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Abstract.In this article, the first spatially resolved millennium-long summer (June-August) temperature reconstruction over the Arctic and Subarctic domain (north of 60• N) is presented. It is based on a set of 54 annually dated temperature sensitive proxy archives of various types, mainly from the updated and revised PAGES2k database supplemented with 6 new recently published proxy records. As a major novelty, an extension of the Bayesian BARCAST climate field (CF) reconstruction technique provides 5 a means to treat climate archives with dating uncertainties. In total 1400 realisations of the temperature CF were generated, enabling further analyses to be carried out in a probabilistic framework. The new seasonal CF reconstruction for the Arctic region can be shown to be skilful for the majority of the terrestrial nodes. The decrease in the proxy data density back in time however limits the analyses in the spatial domain to the period after 750 CE, while the spatially averaged reconstruction covers the entire time interval of 1-2002 CE. The analysis of basic features of the reconstructed seasonal CF focuses on the regional 10 expression of past major climate anomalies in order to uncover the potential of the new product for studying Common Era temperature variability in the region.The long-term, centennial to millennial, evolution of the reconstructed temperature is in good agreement with a general pattern that was inferred in recent studies for the Arctic and its sub-regions. On the pan-Arctic scale the reconstruction shows a cooling trend which is, however, statistically insignificant and the estimated magnitude of the millennial scale cooling is three

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Section: C1 Analyses Of Proxy Recordsmentioning

confidence: 65%

Spatio-temporal variability of Arctic summer temperatures over the past two millennia: an overview of the last major climate anomalies

Werner

Divine

Ljungqvist

et al. 2017

Preprint

Self Cite

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“…Additionally, the Arctic region is of utmost importance in the context of global climate and global climate change. Reduction in perennial sea ice cover leads to increased heat transport northward (Müller et al, 2012;Smedsrud et al, 2008) as well as changes the Arctic energy balance due to positive albedo feedbacks (Curry et al, 1995;Miller et al, 2010;Perovich et al, 2002Perovich et al, , 2011. Melting of permafrost can release methane (CH 4 ), a more efficient greenhouse gas than carbon dioxide (CO 2 ), and likewise gives a positive feedback that may further amplify the temperature increase (O'Connor et al, 2010;Shakhova et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Spatio-temporal variability of Arctic summer temperatures over the past 2 millennia

et al. 2018

Self Cite

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Abstract. In this article, the first spatially resolved and millennium-length summer (June–August) temperature reconstruction over the Arctic and sub-Arctic domain (north of 60° N) is presented. It is based on a set of 44 annually dated temperature-sensitive proxy archives of various types from the revised PAGES2k database supplemented with six new recently updated proxy records. As a major advance, an extension of the Bayesian BARCAST climate field (CF) reconstruction technique provides a means to treat climate archives with dating uncertainties. This results not only in a more precise reconstruction but additionally enables joint probabilistic constraints to be imposed on the chronologies of the used archives. The new seasonal CF reconstruction for the Arctic region can be shown to be skilful for the majority of the terrestrial nodes. The decrease in the proxy data density back in time, however, limits the analyses in the spatial domain to the period after 750 CE, while the spatially averaged reconstruction covers the entire time interval of 1–2002 CE.The centennial to millennial evolution of the reconstructed temperature is in good agreement with a general pattern that was inferred in recent studies for the Arctic and its subregions. In particular, the reconstruction shows a pronounced Medieval Climate Anomaly (MCA; here ca. 920–1060 CE), which was characterised by a sequence of extremely warm decades over the whole domain. The medieval warming was followed by a gradual cooling into the Little Ice Age (LIA), with 1766–1865 CE as the longest centennial-scale cold period, culminating around 1811–1820 CE for most of the target region.In total over 600 independent realisations of the temperature CF were generated. As showcased for local and regional trends and temperature anomalies, operating in a probabilistic framework directly results in comprehensive uncertainty estimates, even for complex analyses. For the presented multi-scale trend analysis, for example, the spread in different paths across the reconstruction ensemble prevents a robust analysis of features at timescales shorter than ca. 30 years. For the spatial reconstruction, the benefit of using the spatially resolved reconstruction ensemble is demonstrated by focusing on the regional expression of the recent warming and the MCA. While our analysis shows that the peak MCA summer temperatures were as high as in the late 20th and early 21st centuries, the spatial coherence of extreme years over the last decades of the reconstruction (1980s onwards) seems unprecedented at least back until 750 CE. However, statistical testing could not provide conclusive support of the contemporary warming to exceed the peak of the MCA in terms of the pan-Arctic mean summer temperatures: the reconstruction cannot be extended reliably past 2002 CE due to lack of proxy data and thus the most recent warming is not captured.

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“…DO events) would have synchronously changed the Southern Hemisphere atmospheric circulation and wind belts (Buizert et al, 2018;Markle et al, 2017). This could again have quickly changed the source or transport conditions but would again have resulted in a sawtooth-shaped peak, either by steady regrowth of vegetation in the dust source areas or as climate condi-tions in the north Atlantic gradually return to stadial (Pedro et al, 2018).…”

Section: Discussionmentioning

confidence: 99%

Spiky fluctuations and scaling in high-resolution EPICA ice core dust fluxes

Lovejoy¹,

Lambert²

2019

Clim. Past

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Abstract. Atmospheric variability as a function of scale has been divided in various dynamical regimes with alternating increasing and decreasing fluctuations: weather, macroweather, climate, macroclimate, and megaclimate. Although a vast amount of data are available at small scales, the larger picture is not well constrained due to the scarcity and low resolution of long paleoclimatic time series. Using statistical techniques originally developed for the study of turbulence, we analyse the fluctuations of a centimetric-resolution dust flux time series from the EPICA Dome C ice core in Antarctica that spans the past 800 000 years. The temporal resolution ranges from annual at the top of the core to 25 years at the bottom, enabling the detailed statistical analysis and comparison of eight glaciation cycles and the subdivision of each cycle into eight consecutive phases. The unique span and resolution of the dataset allows us to analyse the macroweather and climate scales in detail. We find that the interglacial and glacial maximum phases of each cycle showed particularly large macroweather to climate transition scale τc (around 2 kyr), whereas mid-glacial phases feature centennial transition scales (average of 300 years). This suggests that interglacials and glacial maxima are exceptionally stable when compared with the rest of a glacial cycle. The Holocene (with τc≈7.9 kyr) had a particularly large τc, but it was not an outlier when compared with the phases 1 and 2 of other cycles. We hypothesize that dust variability at larger (climate) scales appears to be predominantly driven by slow changes in glaciers and vegetation cover, whereas at small (macroweather) scales atmospheric processes and changes in the hydrological cycles are the main drivers. For each phase, we quantified the drift, intermittency, amplitude, and extremeness of the variability. Phases close to the interglacials (1, 2, 8) show low drift, moderate intermittency, and strong extremes, while the “glacial” middle phases 3–7 display strong drift, weak intermittency, and weaker extremes. In other words, our results suggest that glacial maxima, interglacials, and glacial inceptions were characterized by relatively stable atmospheric conditions but punctuated by frequent and severe droughts, whereas the mid-glacial climate was inherently more unstable.

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Are there multiple scaling regimes in Holocene temperature records?

Cited by 23 publications

References 57 publications

Spatio-temporal variability of Arctic summer temperatures over the past two millennia: an overview of the last major climate anomalies

Spatio-temporal variability of Arctic summer temperatures over the past two millennia: an overview of the last major climate anomalies

Spatio-temporal variability of Arctic summer temperatures over the past 2 millennia

Spiky fluctuations and scaling in high-resolution EPICA ice core dust fluxes

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