scholarly journals Climate Change Detection and Attribution using observed and simulated Tree-Ring Width

2021 ◽  
Author(s):  
Jörg Franke ◽  
Michael Neil Evans ◽  
Andrew Schurer ◽  
Gabriele Clarissa Hegerl
Keyword(s):  
Tree Ring ◽  
Radiative Forcing ◽  
Ring Width ◽  
Volcanic Eruptions ◽  
Temperature Sensitive ◽  
Tree Ring Width ◽  
Spatially Resolved ◽  
Detection And Attribution ◽  
Climate Simulations ◽  
First Time

Abstract. The detection and attribution (D&A) of paleoclimatic change to external radiative forcing relies on regression of statistical reconstructions on simulations. However, this procedure may be biased by assumptions of stationarity and univariate linear response of the underlying paleoclimatic observations. Here we perform a D&A study via regression of tree ring width (TRW) observations on TRW simulations which are forward modeled from climate simulations. Temperature and moisture-sensitive TRW simulations show distinct patterns in time and space. Temperature-sensitive TRW observations and simulations are significantly correlated for northern hemisphere averages, and their variation is attributed most closely to volcanically forced simulations. In decadally smoothed temporal fingerprints, we find the observed responses to be significantly larger and/or more persistent than the simulated responses. The pattern of simulated TRW of moisture-limited trees is consistent with the observed anomalies in the two years following major volcanic eruptions. We can for the first time attribute this spatiotemporal fingerprint in moisture limited tree-ring records to volcanic forcing. These results suggest that use of nonlinear and multivariate proxy system models in paleoclimatic detection and attribution studies may permit more realistic, spatially resolved and multivariate fingerprint detection studies, and evaluation of the climate sensitivity to external radiative forcing, than has previously been possible.

Temperature-sensitive tree-ring width chronologies of pink pine (Halocarpus biformis) from Stewart Island, New Zealand

1996 ◽  
Vol 119 (3-4) ◽  
pp. 293-300 ◽  
Author(s):  
Rosanne D. D'Arrigo ◽  
Brendan M. Buckley ◽  
Edward R. Cook ◽  
Wendy S. Wagner
Keyword(s):  
New Zealand ◽  
Tree Ring ◽  
Ring Width ◽  
Temperature Sensitive ◽  
Tree Ring Width

scholarly journals Effects of Memory Biases on Variability of Temperature Reconstructions

2019 ◽  
Vol 32 (24) ◽  
pp. 8713-8731 ◽  
Author(s):  
Lucie J. Lücke ◽  
Gabriele C. Hegerl ◽  
Andrew P. Schurer ◽  
Rob Wilson
Keyword(s):  
Tree Ring ◽  
Climate Models ◽  
Climate Model ◽  
Ring Width ◽  
Volcanic Eruptions ◽  
Ice Age ◽  
Detection And Attribution ◽  
Reconstructed Temperature ◽  
Tree Ring Data ◽  
The Difference

Abstract Quantifying past climate variation and attributing its causes improves our understanding of the natural variability of the climate system. Tree-ring-based proxies have provided skillful and highly resolved reconstructions of temperature and hydroclimate of the last millennium. However, like all proxies, they are subject to uncertainties arising from varying data quality, coverage, and reconstruction methodology. Previous studies have suggested that biological-based memory processes could cause spectral biases in climate reconstructions. This study determines the effects of such biases on reconstructed temperature variability and the resultant implications for detection and attribution studies. We find that introducing persistent memory, reflecting the spectral properties of tree-ring data, can change the variability of pseudoproxy reconstructions compared to the surrogate climate and resolve certain model–proxy discrepancies. This is especially the case for proxies based on ring-width data. Such memory inflates the difference between the Medieval Climate Anomaly and the Little Ice Age and suppresses and extends the cooling in response to volcanic eruptions. When accounting for memory effects, climate model data can reproduce long-term cooling after volcanic eruptions, as seen in proxy reconstructions. Results of detection and attribution studies show that signals in reconstructions as well as residual unforced variability are consistent with those in climate models when the model fingerprints are adjusted to reflect autoregressive memory as found in tree rings.

scholarly journals A data assimilation approach to last millennium temperature field reconstruction using a limited high-sensitivity proxy network

2021 ◽  
pp. 1-64
Author(s):  
Jonathan M. King ◽  
Kevin J. Anchukaitis ◽  
Jessica E. Tierney ◽  
Gregory J. Hakim ◽  
Julien Emile-Geay ◽  
...  
Keyword(s):  
Data Assimilation ◽  
Tree Ring ◽  
Radiative Forcing ◽  
Climate Model ◽  
Volcanic Eruptions ◽  
Spatial Uncertainty ◽  
Ice Age ◽  
Temperature Sensitive ◽  
Last Millennium ◽  
Uncertainty Estimates

AbstractWe use theNorthern Hemisphere Tree-RingNetwork Development (NTREND) tree-ring database to examine the effects of using a small, highly-sensitive proxy network for paleotemperature data assimilation over the last millennium. We first evaluate our methods using pseudo-proxy experiments. These indicate that spatial assimilations using this network are skillful in the extratropical Northern Hemisphere and improve on previous NTREND reconstructions based on Point-by-Point regression. We also find our method is sensitive to climate model biases when the number of sites becomes small. Based on these experiments, we then assimilate the real NTREND network. To quantify model prior uncertainty, we produce 10 separate reconstructions, each assimilating a different climate model. These reconstructions are most dissimilar prior to 1100 CE, when the network becomes sparse, but show greater consistency as the network grows. Temporal variability is also underestimated before 1100 CE. Our assimilation method produces spatial uncertainty estimates and these identify treeline North America and eastern Siberia as regions that would most benefit from development of new millennial-length temperature-sensitive tree-ring records. We compare our multi-model mean reconstruction to five existing paleo-temperature products to examine the range of reconstructed responses to radiative forcing. We find substantial differences in the spatial patterns and magnitudes of reconstructed responses to volcanic eruptions and in the transition between the Medieval epoch and Little Ice Age. These extant uncertainties call for the development of a paleoclimate reconstruction intercomparison framework for systematically examining the consequences of proxy network composition and reconstruction methodology and for continued expansion of tree-ring proxy networks.

Climate control of cambial dynamics and tree-ring width in two tropical pines in Thailand

2021 ◽  
Vol 303 ◽  
pp. 108394
Author(s):  
Nathsuda Pumijumnong ◽  
Piyarat Songtrirat ◽  
Supaporn Buajan ◽  
Sineenart Preechamart ◽  
Uthai Chareonwong ◽  
...  
Keyword(s):  
Tree Ring ◽  
Ring Width ◽  
Tree Ring Width ◽  
Climate Control

Climatic implications of a 3585-year tree-ring width chronology from the northeastern Qinghai-Tibetan Plateau

2010 ◽  
Vol 29 (17-18) ◽  
pp. 2111-2122 ◽  
Author(s):  
X. Shao ◽  
Y. Xu ◽  
Z.-Y. Yin ◽  
E. Liang ◽  
H. Zhu ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Tree Ring ◽  
Ring Width ◽  
Tree Ring Width

Tree growth across the Nepal Himalaya during the last four centuries

2017 ◽  
Vol 41 (4) ◽  
pp. 478-495 ◽  
Author(s):  
UK Thapa ◽  
S St. George ◽  
DK Kharal ◽  
NP Gaire
Keyword(s):  
Tree Ring ◽  
Tree Growth ◽  
Environmental Changes ◽  
Ring Width ◽  
High Elevation ◽  
Forest Growth ◽  
Tree Ring Width ◽  
Early 19Th Century ◽  
Tree Ring Data ◽  
Instrumental Records

The climate of Nepal has changed rapidly over the recent decades, but most instrumental records of weather and hydrology only extend back to the 1980s. Tree rings can provide a longer perspective on recent environmental changes, and since the early 2000s, a new round of field initiatives by international researchers and Nepali scientists have more than doubled the size of the country’s tree-ring network. In this paper, we present a comprehensive analysis of the current tree-ring width network for Nepal, and use this network to estimate changes in forest growth nation-wide during the last four centuries. Ring-width chronologies in Nepal have been developed from 11 tree species, and half of the records span at least 290 years. The Nepal tree-ring width network provides a robust estimate of annual forest growth over roughly the last four centuries, but prior to this point, our mean ring-width composite fluctuates wildly due to low sample replication. Over the last four centuries, two major events are prominent in the all-Nepal composite: (i) a prolonged and widespread growth suppression during the early 1800s; and (ii) heightened growth during the most recent decade. The early 19th century decline in tree growth coincides with two major Indonesian eruptions, and suggests that short-term disturbances related to climate extremes can exert a lasting influence on the vigor of Nepal’s forests. Growth increases since AD 2000 are mainly apparent in high-elevation fir, which may be a consequence of the observed trend towards warmer temperatures, particularly during winter. This synthesis effort should be useful to establish baselines for tree-ring data in Nepal and provide a broader context to evaluate the sensitivity or behavior of this proxy in the central Himalayas.

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