Decadal variability in tree rings
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The document explores decadal and multidecadal climate variability as observed through tree-ring records, highlighting the impact of severe droughts on tree growth and recovery patterns. It discusses the coherence of tree-ring data across different timescales and the effectiveness of various detrending methods to recover intermediate frequency signals. Additionally, it emphasizes the need for high-resolution proxy data to better understand decadal climate variability due to limitations of the short observational record.
![… THE USE OF
HIGH-RESOLUTION PROXY DATA
SHOULD BE EXPANDED BECAUSE
THE SHORT OBSERVATIONAL RECORD
AND MODEL UNCERTAINTY
ARE UNABLE TO SIMULATE
[DECADAL CLIMATE VARIABILITY]…
“ ”
Mehta et al., 2011
Bulletin of the American Meteorological Society](https://image.slidesharecdn.com/stgeorge-170216061546/85/Decadal-variability-in-tree-rings-39-320.jpg)
Decadal variability in tree rings
- 1. DECADAL VARIABILITY IN TREE-RING RECORDS SCOTT ST. GEORGE | UNIVERSITY OF MINNESOTA
- 2. Source: Laura Anne Heller
- 4. Decadal-To-Multidecadal Variability In The Earth’s Climate Viewed Through The Lens Of Ancient Trees University of Minnesota Johannes Gutenberg-Universität Mainz Helmholtz-Zentrum Geesthacht
- 5. ?WHY DO TREE-RING WIDTHS EXHIBIT SO MUCH VARIANCE ON DECADAL AND MULTIDECADAL TIMESCALES?
- 7. BIOLOGY
- 9. WE FOUND PERVASIVE AND SUBSTANTIAL “LEGACY EFFECTS” OF REDUCED GROWTH AND INCOMPLETE RECOVERY FOR 1 TO 4 YEARS AFTER SEVERE DROUGHT. “ ” Anderegg et al., 2015 Science
- 11. THESE LARGE VALUES OF SERIAL CORRELATION SUGGEST THAT THE NON-RANDOMNESS OF TREE-RING SEQUENCES IS DUE TO THE STORAGE OF FOOD PRODUCTS IN THE TREE RATHER THAN THE YEAR TO YEAR VARIATIONS OF RAINFALL OR SOIL MOISTURE. “ ” Matalas, 1962 International Association of Scientific Hydrology Bulletin
- 12. CLIMATE
- 15. Mean summer (JJA) PDSI LAG-1 AC
- 16. DR. EDWARD COOK DR. DAVID STAHLE
- 17. THE AR MODEL OF THE INSTRUMENTAL PDSI WAS ADDED TO THE PREWHITENED TREE-RING ESTIMATES AND THE RESULTING RECONSTRUCTION EXPLAINS 62% OF THE VARIANCE IN THE OBSERVED PDSI. “ ” Stahle et al., 2011 Geophysical Research Le ers
- 18. CLIMATEBIOLOGY
- 19. DR. DAVID MEKO UNIVERSITY OF ARIZONA
- 20. Source: Meko, Ph.D. dissertation, 1981
- 21. 1Are decadal or multidecadal pa erns spatially coherent across large tree-ring networks?
- 22. MAP COLORADO UPPER COLORADO BASIN
- 23. Source: Nevada Tourism Media Relations COLORADO RIVER
- 24. DR. TOBY AULT CORNELL UNIVERSITY
- 25. HOW DOES BETWEEN-CHRONOLOGY COHERENCE VARY ACROSS TIMESCALES? Source: Meko et al., Geophysical Research Le ers, 2007
- 26. WE USE THE RBAR STATISTIC TO GAUGE THE MEAN CORRELATION BETWEEN A SINGLE TREE- RING RECORD AND ALL OTHERS IN THE NETWORK AT INTERANNUAL (H), DECADAL (M), AND MULTIDECADAL AND CENTENNIAL (L) TIMESCALES.
- 27. INTERANNUAL (H) DECADAL (M), MULTIDECADAL AND CENTENNIAL (L) MOST RECORDS SHOW STRONG COHERENCE AT HIGHER FREQUENCIES, BUT WEAKER AGREEMENT AT LOWER FREQUENCIES.
- 28. Source: Adapted from Ault et al., Journal of Climate, 2013 PALEO-PRECIPITATION RECONSTRUCTIONS FROM TREE RINGS HAVE LESS VARIANCE AT LOW FREQUENCIES THAN THE ORIGINAL TREE-RING CHRONOLOGIES.
- 29. THE MOST OBVIOUS SOURCE OF NONCLIMATIC PERSISTENCE IN TREE-RING DATA IS ERROR IN REMOVAL OF THE GROWTH TREND WHEN CONVERTING ANNUAL RING WIDTHS TO TREE-RING INDICES. “ ” Meko, 1981 Doctoral dissertation, University of Arizona
- 30. 2What detrending methods are best when trying to recover these ‘intermediate’ frequency signals?
- 32. NAM2K PHASE 2 TREE-RING NETWORK
- 34. 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0 0.05 0.1 0.15 0.2 0.25 0.3 Mean squared coherence Frequency (1/f) Signal-free version of the age-dependent spline-detrended chronology Variance-stabilized standard version of the age-dependent spline-detrended chronology Standard version of the age-dependent spline-detrended chronology Variance-stabilized signal-free version of the age-dependent spline-detrended chronology Negative exponential chronology FOR THESE TEMPERATURE-SENSITIVE TREES, SIGNAL-FREE DETRENDING DOES INCREASE THE BETWEEN- CHRONOLOGY COHERENCE AT LOW FREQUENCIES.
- 36. -0.15 -0.1 -0.05 0.05 0.1 0.15 0 20 40 60 80 100 120 Standard chronologies Signal-free chronologies 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0 Number of chronologies Between-tree correlation Difference in RBAR RBAR higher in SigFreeRBAR higher in Std
- 37. 0 0.1 0.2 0.3 0.4 0.5 0.1 0.12 0.14 0.16 0.18 0.2 0.22 0.24 Median coherence between neighboring chronologies Negative-exponential detrended Signal-free detrended MEAN SQUARED COHERENCE BUT FOR MOISTURE-SENSITIVE TREES, SIGNAL-FREE DETRENDING DOES NOT AFFECT THEIR AGREEMENT WITH NEIGHBORING CHRONOLOGIES ONE BIT.
- 39. … THE USE OF HIGH-RESOLUTION PROXY DATA SHOULD BE EXPANDED BECAUSE THE SHORT OBSERVATIONAL RECORD AND MODEL UNCERTAINTY ARE UNABLE TO SIMULATE [DECADAL CLIMATE VARIABILITY]… “ ” Mehta et al., 2011 Bulletin of the American Meteorological Society
- 40. ADVANTAGE DISADVANTAGE Short relative to decadal timescales Firmly grounded in reality Too sensitive to volcanic forcing? Simulations are much longer than the timescale of interest Long records grounded in reality Proxy systems may distort or exaggerate decadal signals THE DECADAL CLIMATE “CONUNDRUM”
- 41. DR. BENOIT MANDELBROT MARCH 2007
- 43. Source: Baillie, Journal of Econometrics, 1996 TREE-RING WIDTHS HAVE OFTEN USED TO ILLUSTRATE LONG-MEMORY BEHAVIOR IN NATURE.