Study on European Beech Annual Tree Ring Widths Time Series, Solar–Climatic Relationships and Solar Dynamo Regime Changes

2021 ◽  
pp. 74-100
Author(s):  
Boris Komitov
Keyword(s):  
Time Series ◽  
Tree Ring ◽  
European Beech ◽  
Solar Dynamo ◽  
Regime Changes

scholarly journals The European Beech Annual Tree Ring Widths Time Series, Solar–Climatic Relationships and Solar Dynamo Regime Changes

Atmosphere ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 829
Author(s):  
Boris Komitov
Keyword(s):  
Time Series ◽  
Tree Ring ◽  
18Th Century ◽  
Sunspot Cycle ◽  
Ring Width ◽  
European Beech ◽  
Regime Changes ◽  
Transition Effects ◽  
The One ◽  
Good Coincidence

In this study, the results from the analysis of annual ring widths (‘Dm’) time series of two “very sensitive” to the climate and solar–climate relationships of long lived European beech (Fagus sylvatica) samples (on age of 209 ± 1 and 245 ± 5 years correspondingly) are discussed. Both series are characterized by very good expressed and relating to the solar magnetic Hale cycle 20–22-year oscillations. A good coincidence between the changes of ‘Dm’ and the growth or fading of the solar magnetic cycle is found. The transition effects at the beginning and ending of the grand Dalton (1793–1833) and Gleissberg minima (1898–1933) are very clearly visible in the annual tree ring width data for the one of beech samples. Some of these effects are also detected in the second sample. The problem for the possible “lost” sunspot cycle at the end of 18th century is also discussed. A prediction for a possible “phase catastrophe” during the future Zurich sunspot cycles 26 and 27 between 2035–2040 AD as well as for general precipitation upward and temperature fall tendencies in Central Bulgaria, more essential after 2030 AD, are brought forth.

scholarly journals Paleo-hydrologic reconstruction of 400 years of past flows at a weekly time step for major rivers of Western Canada

2019 ◽  
Author(s):  
Andrew R. Slaughter ◽  
Saman Razavi
Keyword(s):  
Time Series ◽  
Water Resources ◽  
Tree Ring ◽  
Flow Distribution ◽  
Future Climate Change ◽  
Western Canada ◽  
Tree Ring Chronology ◽  
Time Step ◽  
Water Resources Systems ◽  
Tree Ring Data

Abstract. The assumption of stationarity in water resources no longer holds, particularly within the context of future climate change. Plausible scenarios of flows that fluctuate outside the envelope of variability of the gauging data are required to assess the robustness of water resources systems to future conditions. This study presents a novel method of generating weekly-time-step flows based on tree-ring chronology data. Specifically, this method addresses two long-standing challenges with paleo-reconstruction: (1) the typically limited predictive power of tree-ring data at the annual and sub-annual scale, and (2) the inflated short-term persistence in tree-ring time series and improper use of prewhitening. Unlike the conventional approach, this method establishes relationships between tree-ring chronologies and naturalised flow at a biennial scale to preserve persistence properties and variability of hydrological time series. Biennial flow reconstructions are further disaggregated to weekly, according to the weekly flow distribution of reference two-year instrumental periods, identified as periods with broadly similar tree-ring properties to that of every two-year paleo-period. The Saskatchewan River Basin (SaskRB), a major river in Western Canada, is selected as a study area, and weekly flows in its four major tributaries are extended back to the year 1600. The study shows that the reconstructed flows properly preserve the statistical properties of the reference flows, particularly, short- to long-term persistence and the structure of variability across time scales. An ensemble approach is presented to represent the uncertainty inherent in the statistical relationships and disaggregation method. The ensemble of reconstructed weekly flows are publically available for download from https://doi.org/10.20383/101.0139 (Slaughter and Razavi, 2019).

scholarly journals Different Wood Anatomical and Growth Responses in European Beech (Fagus sylvatica L.) at Three Forest Sites in Slovenia

2021 ◽  
Vol 12 ◽  
Author(s):  
Domen Arnič ◽  
Jožica Gričar ◽  
Jernej Jevšenak ◽  
Gregor Božič ◽  
Georg von Arx ◽  
...  
Keyword(s):  
Tree Ring ◽  
Climatic Factors ◽  
Ring Width ◽  
European Beech ◽  
Growing Season ◽  
Climatic Conditions ◽  
Maximum Temperature ◽  
Tree Ring Width ◽  
Vessel Area ◽  
Temperature And Precipitation

European beech (Fagus sylvatica L.) adapts to local growing conditions to enhance its performance. In response to variations in climatic conditions, beech trees adjust leaf phenology, cambial phenology, and wood formation patterns, which result in different tree-ring widths (TRWs) and wood anatomy. Chronologies of tree ring width and vessel features [i.e., mean vessel area (MVA), vessel density (VD), and relative conductive area (RCTA)] were produced for the 1960–2016 period for three sites that differ in climatic regimes and spring leaf phenology (two early- and one late-flushing populations). These data were used to investigate long-term relationships between climatic conditions and anatomical features of four quarters of tree-rings at annual and intra-annual scales. In addition, we investigated how TRW and vessel features adjust in response to extreme weather events (i.e., summer drought). We found significant differences in TRW, VD, and RCTA among the selected sites. Precipitation and maximum temperature before and during the growing season were the most important climatic factors affecting TRW and vessel characteristics. We confirmed differences in climate-growth relationships between the selected sites, late flushing beech population at Idrija showing the least pronounced response to climate. MVA was the only vessel trait that showed no relationship with TRW or other vessel features. The relationship between MVA and climatic factors evaluated at intra-annual scale indicated that vessel area in the first quarter of tree-ring were mainly influenced by climatic conditions in the previous growing season, while vessel area in the second to fourth quarters of tree ring width was mainly influenced by maximum temperature and precipitation in the current growing season. When comparing wet and dry years, beech from all sites showed a similar response, with reduced TRW and changes in intra-annual variation in vessel area. Our findings suggest that changes in temperature and precipitation regimes as predicted by most climate change scenarios will affect tree-ring increments and wood structure in beech, yet the response between sites or populations may differ.

scholarly journals Climate sensitivity and resistance under pure- and mixed-stand scenarios in Lower Austria evaluated with distributed lag models and penalized regression splines for tree-ring time series

2019 ◽  
Vol 139 (2) ◽  
pp. 189-211 ◽  
Author(s):  
Arne Nothdurft ◽  
Markus Engel
Keyword(s):  
Tree Ring ◽  
Climate Sensitivity ◽  
European Beech ◽  
Penalized Regression ◽  
Mixed Stand ◽  
Regression Splines ◽  
Mixed Stands ◽  
Distributed Lag ◽  
Distributed Lag Models ◽  
Penalized Regression Splines

Abstract Penalized regression splines and distributed lag models were used to evaluate the effects of species mixing on productivity and climate-related resistance via tree-ring width measurements from sample cores. Data were collected in Lower Austria from sample plots arranged in a triplet design. Triplets were established for sessile oak [Quercus petraea (Matt.) Liebl.] and Scots pine (Pinus sylvestris L.), European beech (Fagus sylvatica L.) and Norway spruce [Picea abies (L.) H. Karst.], and European beech and European larch (Larix decidua Mill.). Mixing shortened the temporal range of time-lagged climate effects for beech, spruce, and larch, but only slightly changed the effects for oak and pine. Beech and spruce as well as beech and larch exhibited contrasting climate responses, which were consequently reversed by mixing. Single-tree productivity was reduced by between − 15% and − 28% in both the mixed oak–pine and beech–spruce stands but only slightly reduced in the mixed beech–larch stands. Measures of climate sensitivity and resistance were derived by model predictions of conditional expectations for simulated climate sequences. The relative climate sensitivity was, respectively, reduced by between − 16 and − 39 percentage points in both the beech–spruce and beech–larch mixed stands. The relative climate sensitivity of pine increased through mixing, but remained unaffected for oak. Mixing increased the resistance in both the beech–larch and the beech–spruce mixed stand. In the mixed oak–pine stand, resistance of pine was decreased and remained unchanged for oak.

scholarly journals Dendroecological reconstructions of forest disturbance history using time-series analysis with intervention detection

2005 ◽  
Vol 35 (4) ◽  
pp. 868-876 ◽  
Author(s):  
Daniel L Druckenbrod
Keyword(s):  
Time Series ◽  
Time Series Analysis ◽  
Tree Ring ◽  
Forest Disturbance ◽  
Ring Width ◽  
Fagus Grandifolia ◽  
Disturbance History ◽  
Series Analysis ◽  
Growth Increments ◽  
Width Measurements

The detection of release events in the annual growth increments of trees has become a central and widely applied method for reconstructing the disturbance history of forests. While numerous approaches have been developed for identifying release events, the preponderance of these methods relies on running means that compare the percent change in growth rates. These methods do not explicitly account for the autocorrelation present within tree-ring width measurements and may introduce spurious events. This paper utilizes autoregressive integrated moving-average (ARIMA) processes to model tree-ring time series and incorporates intervention detection to identify pulse and step outliers as well as changes in trends indicative of a deterministic exogenous influence on past growth. This approach is evaluated by applying it to three chronologies from the Forest Responses to Anthropogenic Stress (FORAST) project that were impacted by prior disturbance events. The examples include a hemlock (Tsuga canadensis (L.) Carrière) chronology from New Hampshire, a white pine (Pinus strobus L.) chronology from Pennsylvania, and an American beech (Fagus grandifolia Ehrh.) chronology from Virginia. All three chronologies exhibit a clustering of step, pulse, and trend interventions subsequent to a known or likely disturbance event. Time-series analysis offers an alternative approach for identifying prior forest disturbances via tree rings based on statistical methods applicable across species and disturbance regimes.

separating groundwater response to climate and anthropogenic changes using long-term groundwater head time series in the Netherlands

2020 ◽  
Author(s):  
Willem Zaadnoordijk
Keyword(s):  
Time Series ◽  
The Netherlands ◽  
Land Use Changes ◽  
The Other ◽  
Regime Changes ◽  
Base Level ◽  
Groundwater Head ◽  
Groundwater Response ◽  
Groundwater Regime

<div>A set of time series has been investigated which spans more than 50 years of groundwater head measurements throughout the Netherlands.<br>The relation between the groundwater head and precipitation and evaporation has been established using linear transfer noise modeling. This has been done for each entire series and for parts. The latter to detect base level changes and other groundwater regime changes.</div><div>In addition, trends in the other components of the groundwater heads have been investigated as well as possible non linearities in the groundwater response.</div><div>The link is explored between the trends and regime changes from the time series models on one hand and anthropogenic (land use) changes and climate change on the other hand.</div><div> </div>

scholarly journals Wavelet analysis of low-frequency variability in oak tree-ring chronologies from east Central Europe

2016 ◽  
Vol 8 (1) ◽  
Author(s):  
Asok K. Sen ◽  
Zoltán Kern
Keyword(s):  
Time Series ◽  
Wavelet Analysis ◽  
Central Europe ◽  
Tree Ring ◽  
Low Frequency ◽  
Wavelet Coherence ◽  
Time Interval ◽  
East Central Europe ◽  
East Central ◽  
Oak Tree

AbstractThis study investigates the low-frequency (interannual and longer period) variability in three hydroclimatic records from east Central Europe. Two of these records consist of climate proxies derived from oak-tree rings in Bakta forest, and Balaton Highlands in Hungary, for the time interval 1783-2003. The third record consists of homogenized instrumental precipitation data from Budapest, Hungary, from 1842 to 2003. Using wavelet analysis, the three time series are analyzed and compared with one another. It is found that all three time series exhibit strong interannual variability at the 2-4 years timescales, and these variations occur intermittently throughout the length of each record. Significant variability is also observed in all the records at decadal timescales, but these variations persist for only two to three cycles. Wavelet coherence among the various time series is used to explore their time-varying correlation. The results reveal significant coherence at the 2-4 years band. At these timescales, the climatic variations are correlated to the tree-ring signal over different time intervals with changing phase. Increased (decreased) contribution of large-scale stratiform precipitation offers a potential explanation for enhanced (faded) coherence at the interannual timescale. Strong coherence was also observed occasionally at decadal timescales, however these coherences did not appear uniformly. These results reinforce the earlier assertion that neither the strength nor the rank of the similarity of the local hydroclimate signals is stable throughout the past two centuries.

scholarly journals Bayesian Non-Parametric Mixtures of GARCH(1,1) Models

2012 ◽  
Vol 2012 ◽  
pp. 1-16
Author(s):  
John W. Lau ◽  
Ed Cripps
Keyword(s):  
Time Series ◽  
Dirichlet Process ◽  
Time Series Data ◽  
Monte Carlo Algorithm ◽  
Series Data ◽  
Garch Models ◽  
Nonparametric Models ◽  
Regime Changes ◽  
Standard And Poor's ◽  
Financial Index

Traditional GARCH models describe volatility levels that evolve smoothly over time, generated by a single GARCH regime. However, nonstationary time series data may exhibit abrupt changes in volatility, suggesting changes in the underlying GARCH regimes. Further, the number and times of regime changes are not always obvious. This article outlines a nonparametric mixture of GARCH models that is able to estimate the number and time of volatility regime changes by mixing over the Poisson-Kingman process. The process is a generalisation of the Dirichlet process typically used in nonparametric models for time-dependent data provides a richer clustering structure, and its application to time series data is novel. Inference is Bayesian, and a Markov chain Monte Carlo algorithm to explore the posterior distribution is described. The methodology is illustrated on the Standard and Poor's 500 financial index.

Reconstruction of the Annual Variation in Solar Radio Flux and the Catania Sunspot Area from Tree Ring-index Time Series

1994 ◽  
Vol 11 (2) ◽  
pp. 164-169
Author(s):  
J. O. Murphy ◽  
H. Sampson ◽  
T. T. Veblen ◽  
R. Villalba
Keyword(s):  
Time Series ◽  
Tree Ring ◽  
Solar Radio ◽  
Annual Variation ◽  
Sunspot Area ◽  
Radio Flux ◽  
Proxy Data ◽  
Solar Radio Flux ◽  
Index Site ◽  
Index Time Series

AbstractFour tree ring-index site chronologies, representing standardised annual growth rates for spruce trees growing at high altitude sites in Colorado, have been employed as proxy data in a regression model for the annual variation of solar radio flux at 2800 MHz (F10·7) and the Catania sunspot area (Ac). These dendrochronological time series all exhibit significant power spectrum peaks at about 11 years and separately correlate with the annual values of Rz, F10·7 and Ac, as solar activity indicators. The two models constructed give the cyclic variation of F10·7 and Ac back to AD1673.

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