A comparison of pre-Millennium eruption (946 AD) and modern temperatures from tree rings in the Changbai Mountain, northeast Asia
Abstract. High-resolution temperature reconstructions in the prior millennium are limited in northeast Asia, but important for assessing regional climate dynamics. Here, we present, for the first time, a reconstruction of April temperature for ~300 years before the Millennium volcanic eruption in 946 AD, using tree rings of carbonized logs buried in the tephra in Changbai Mountain, northeast Asia. The reconstructed temperature changes were consistent with previous reconstructions in China and Northern Hemisphere. The influences of large-scale oscillations (e.g., El Niño-Southern Oscillation) on temperature variability were not significantly different between the period preceding the eruption and that of the last ~170 years. However, compared to the paleotemperature of the prior millennium, the temperature changes were more complex with stronger temperature fluctuations, more frequent temperature abruptions, and a weaker periodicity of temperature variance during the last one and half centuries. These recent changes correspond to long-term anthropogenic influences on regional climate.
Haibo Du et al.
Status: open (extended)
- RC1: 'Comment on cp-2022-51', Anonymous Referee #1, 06 Mar 2023 reply
Haibo Du et al.
Haibo Du et al.
Viewed (geographical distribution)
The authors developed a floating tree-ring width chronology covering ca. 300 years in Middle Age and ca.200 years in modern time, using living trees and carbonized logs in Changbai Mountain, northeast Asia and then reconstructed air temperatures based on these tree-ring materials in this region. The work with the materials of tree rings from carbonized logs is important to the studies of climate, but the shortcomings of this manuscript are also clear, especially in quality control and the standardization of the data. Here, some main points need to be addressed:
Dendroclimatology is based on the high quality cross-dating tree-ring data and reliable fidelity of growth-climate response. The cross-dating, especially the process and results, is the most crucial step in the dendrochronological study. However, the authors seemed deliberately evading the question, and did not give sufficient details on their samples, for example:
1) line128-129, authors did not show the clear information that “these trees” were 18 Korean pines or the total of 55 trees.
2) line 148-157, authors presented that they did cross-dating, tree-ring width measurements and chronology development, however, they did not illustrate the quality control criteria of the cross-dating, measuring process, measurement accuracy and instruments, quality statistics of the chronologies (e.g., the correlation between cores and correlation between trees and so on) and the main statistics of chronologies.
Without the information on the quality statistics, the readers and the referees, cannot give an objective evaluation for your manuscript, and the subsequent results, analyses, discussions, and conclusions in this manuscript become doubtful.
For tree species identification of carbonized logs:
Line126-128, the authors did not give a reliable information for the species identification. Authors should present the main anatomical features of their samples matching Korean pine wood attributes briefly and professionally in the manuscript because some readers may not have sufficient wood anatomy knowledge. The presentation in sentence like line126-128, and the three planes (cross-sectional, radial, and tangential) in Fig S1 are insufficient to show the species being Korean pine.
For the reconstruction:
RES chronology emphasizes high-frequency variations using autoregressive prewhitening that removes autocorrelation from the series, but temperature usually contains multi-band signals, especially low frequency information, with high autocorrelation. Thus, reconstruction of temperature variables using RES chronology with only the statistical correlation sounds unscientific, and lack of biophysical basis.
In addition, authors used the documented growth-climate response with the current climate response of Korean pine by Zhu et al., (2009) as a current climate response of the pine in this manuscript. Do you and Zhu et al., (2009) use the same samples in the manuscript? If not, it is unscientific and unacceptable to use the assessed and verified data to match or as the using base of your unassessed new data.