Variations in tree ring stable isotope records from northern Finland and their possible connection to solar activity

https://doi.org/10.1016/j.jastp.2010.02.020Get rights and content

Abstract

Within a project on climate in Europe during the past few hundred years we have collected a record on stable isotope ratios 13C/12C and 18O/16O in tree ring cellulose from pine trees in northern Finland. The records cover the time interval 1600–2002 AD and have an annual time resolution. The carbon stable isotope record from northernmost Finland correlates quite strongly with local growth period temperature. Statistical analysis of the carbon and oxygen stable isotope records reveals variations in the periods around 100, 11 and 3 years. A century scale connection between the 13C/12C record and solar activity is most evident. These results based on stable isotope records support previous evidences of a centennial solar-climatic link obtained for northern Finland using tree ring data.

Introduction

Global warming, which has a potential impact on many aspects of life, strengthens the need to quantify changes of regional and global climate in the past. For this reason reliable data on a large spatial scale extending as far back in time as possible is required. Since widespread instrumental data are only available for about the past century, we need proxy climate indicators to yield insights into past long-term climate variations (e.g. lake sediments and ice cores). Tree rings is one of the best of several existing natural archives providing annually resolved information on climate for up to thousands of years. Tree ring can be used to measure several proxy indicators e.g. ring width, density, and stable isotope composition. Biological and physical processes determine natural variations of carbon stable isotope 13C/12C ratios in organic matter during photosynthetic uptake of CO2 from the air (Farquhar et al., 1982). The stable isotopes of oxygen 18O/16O, on the other hand, are determined by isotopic composition of source water to the tree, evaporation effects in tree leaf and biochemical steps during cellulose synthesis (Roden et al., 2000; Sternberg et al., 1986). These processes in turn are influenced by local climatic and environmental conditions. Thus records of these isotope ratios in tree rings can serve as climatic proxies. Compared to ring-width stable isotope ratios in tree rings have the advantage that they need not to be age detrended due to growth related non climatic trends and thus they can contain information also in the low frequency domain (Gagen et al., 2008). Stable isotope analysis has been successfully used for investigation of different climatic parameters over various geographical areas in the past (Rafalli-Delerce et al., 2004; Barber et al., 2004; Masson-Delmotte et al., 2005; Szchepanek et al., 2006; Treydte et al., 2006; Reynolds-Henne et al., 2007; Gagen et al., 2007; Kirdyanov et al., 2008; Etien et al., 2008; Tardif et al., 2008).

Four hundred year long annual records of stable isotope ratios of carbon (δ13C) and oxygen (δ18O) in tree rings covering the period (AD 1600–2002) were measured from Scots pine (Pinus sylvestris L.) from sites in northern and eastern Finland (Hilasvuori et al., 2009). The present work is devoted to analysis of the obtained δ13C and δ18O records from northern Finland. These series are of importance because northern Fennoscandia (65–70°N) is a geographic region close to the auroral oval and remote from areas of intensive volcanic activity. Therefore, it is particularly convenient for investigation of a possible relationship between space weather anomalies and climate. Our previous research showed that a solar-climatic link could be detected from tree ring width records from northern Fennoscandia (Ogurtsov et al., 2002a).

Section snippets

Stable isotope δ13C and δ18O records from northern Finland

Records of stable isotope ratios of carbon and oxygen obtained using tree rings from Kessi (northern Finland, 68° 56′ N, 28° 19′ E) are shown in Fig. 1. The isotope ratios were measured from extracted tree ring cellulose and expressed using the conventional δ (delta) notation, where isotope ratios are expressed as relative deviation from the international standards VPDB for carbon and VSMOW for oxygen. A detailed description of the material, the methods used and the reliability of the data

Spectral properties and periodicities of δ13C and δ18O records from northern Finland

In order to analyze the spectral content of the different records and their evolution in time, we used both Fourier and wavelet approaches. The Fourier transform can evaluate only the average power of the data sets at a given frequency, and it is impossible to trace the variation in spectral content through time. The wavelet transform differs from the Fourier one in that the analyzed signal is decomposed not into infinite sinusoidal harmonics but into a number of orthogonal waves of solyton

Conclusions

The carbon stable isotope record from Scots pine in northern Finland reflects summer temperature quite precisely and reliably. Throughout the 20th century it correlates with instrumental July temperature better then reconstructions based on ring width data. This record also contains apparent long-term trends and thus preserves low-frequency variability, which often is suppressed in tree ring width proxies due to standardization procedure. The relation between the oxygen stable isotope record

Acknowledgements

M.G. Ogurtsov is thankful to the program of an exchange between the Russian and Finnish Academies (project no. 16), and the program “Solar activity and physical processes in the Sun–Earth system” of the Presidium of Russian Academy of Sciences, RFBR grants nos. 06-04-48792, 07-02-00379, 09-02-00083 for financial support. The isotope records were obtained within the framework of the EU-project Isonet (EVK2–2002–00147). We thank Professor G. Dreschhoff for valuable discussions.

References (38)

  • I. Daubechis

    Recent results in wavelet applications

    Journal of Electronic Imaging

    (1998)
  • N. Etien et al.

    A bi-proxy reconstruction of Fontainebleau (France) growing season temperature from A.D. 1596 to 2000

    Climate of the Past

    (2008)
  • G.D. Farquhar et al.

    On the relationship between carbon isotope discrimination and the intercellular carbon dioxide concentration in leaves

    Australian Journal of Plant Physiology

    (1982)
  • E. Friis-Christensen et al.

    Length of solar cycle: an indicator of solar activity closely associated with climate

    Science

    (1991)
  • M. Gagen et al.

    Exorcising the ‘segment length curse’: summer temperature reconstruction since AD 1640 using non-detrended stable carbon isotope ratios from pine trees in northern Finland

    The Holocene

    (2007)
  • D.H. Hathaway et al.

    Group sunspot numbers: sunspot cycle characteristics

    Solar Physics

    (2002)
  • S. Helama et al.

    Multicentennial ring-width chronologies of Scots pine along a north–south gradient across Finland

    Tree-Ring Research

    (2005)
  • Hilasvuori, E., Berninger, F., Sonninen, E., Tuomenvirta, H., Jungner, H., 2009. Stability of climate signal in carbon...
  • S. Mallat

    A Wavelet Tour of Signal Processing

    (1999)
  • Cited by (12)

    • Assessing the signals of the Hale solar cycle in temperature proxy records from Northern Fennoscandia

      2020, Advances in Space Research
      Citation Excerpt :

      Correlations between the unfiltered Northern Fennoscandia summer temperature (NFST) and solar forcing data since CE 1715 have been found by Ogurtsov et al. (2017). A significant century-scale (55–140 years) correlation between solar activity and NFST was demonstrated by Ogurtsov et al. (2001, 2011, 2013) to persist over the last 1000 years. Regarding much longer time scales, Helama et al. (2010) showed millennial- and bimillennial-scale correlations between the solar activity records and those of reconstructed summer temperature in the same region over the mid and late Holocene, i.e. since 5500 BCE.

    • Decadal and multidecadal natural variability in European temperature

      2020, Journal of Atmospheric and Solar-Terrestrial Physics
    • Solar signal on regional scale: A study of possible solar impact upon Romania's climate

      2018, Journal of Atmospheric and Solar-Terrestrial Physics
    • North Atlantic sea surface temperature, solar activity and the climate of Northern Fennoscandia

      2017, Advances in Space Research
      Citation Excerpt :

      In addition century-scale (55–140 year) cyclicity, likely of solar origin, has been reported in reconstructed summer temperatures over Lapland (68–70°N, 20–29°E) and Northern Fennoscandia (67–70° N, 19–33°E) during the last millennium (Ogurtsov et al., 2001, 2002, 2013). These tree ring based evidence for century-scale relationship between solar activity (SA) and the climate of Fennoscandia has further been confirmed by an analysis of the 13C record obtained from Kessi area in North Finland (68.56°N, 28.19°E) (Ogurtsov et al., 2011). Kobashi et al. (2011)revealed 210 yr and 87 yr solar cycles in Greenland surface temperature over the past 4000 years.

    • Temporal instability of isotopes-climate statistical relationships - A study of black spruce trees in northeastern Canada

      2015, Dendrochronologia
      Citation Excerpt :

      In order to evaluate the stability of the climate/tree-ring isotopic ratio over time, a few studies followed the evolution of the correlation between climatic parameters (temperature, relative humidity or precipitation) and isotopic series (δ13C and/or δ18O) over the periods when reliable measured data are available. Attempts were made to assess the relationship between isotope ratios and climatic parameters with the centred moving average method (Aykroyd et al., 2001; Etien et al., 2008; Haupt et al., 2011; Ogurtsov et al., 2011; Reynolds-Henne et al., 2007; Seftigen et al., 2011). These studies have found losses of correlation through time, which vary depending on the isotopes used and the various climatic parameters selected.

    • Dendroclimatic reconstruction of autumn-winter mean minimum temperature in the eastern Tibetan Plateau since 1600 AD

      2015, Dendrochronologia
      Citation Excerpt :

      The power spectrum analysis reveals that the major periodicities are concentrated on 5, 11, and 102–103a cycles at the 99% confidence level. The 102–103a cycle is close to the quasi-70–100a cycle (Gleissberg cycle) (Eddy, 1977) of solar activity, which has been found in extensive geological records (Gou et al., 2010; Ogurtsov et al., 2011). The quasi-200a and quasi-100a cycles are notable in research on global temperature of the last millennium.

    View all citing articles on Scopus
    View full text