DOI: 10.5194/cp-10-877-2014
Scopus记录号: 2-s2.0-84899689529
论文题名: Blue intensity and density from northern fennoscandian tree rings, exploring the potential to improve summer temperature reconstructions with earlywood information
作者: Björklund J.A. ; Gunnarson B.E. ; Seftigen K. ; Esper J. ; Linderholm H.W.
刊名: Climate of the Past
ISSN: 18149324
出版年: 2014
卷: 10, 期: 2 起始页码: 877
结束页码: 885
语种: 英语
英文摘要: Here we explore two new tree-ring parameters, derived from measurements of wood density and blue intensity (BI). The new proxies show an increase in the interannual summer temperature signal compared to established proxies, and present the potential to improve long-term performance. At high latitudes, where tree growth is mainly limited by low temperatures, radiodensitometric measurements of wood density, specifically maximum latewood density (MXD), provides a temperature proxy that is superior to that of tree-ring widths. The high cost of developing MXD has led to experimentation with a less expensive method using optical flatbed scanners to produce a new proxy, herein referred to as maximum latewood blue absorption intensity (abbreviated MXBI). MXBI is shown to be very similar to MXD on annual timescales but less accurate on centennial timescales. This is due to the fact that extractives, such as resin, stain the wood differentially from tree to tree and from heartwood to sapwood. To overcome this problem, and to address similar potential problems in radiodensitometric measurements, the new parameters δblue intensity (δBI) and δdensity are designed by subtracting the ambient BI/density in the earlywood, as a background value, from the latewood measurements. As a case-study, based on Scots pine trees from Northern Sweden, we show that δdensity can be used as a quality control of MXD values and that the reconstructive performance of warm-season mean temperatures is more focused towards the summer months (JJA-June, July, August), with an increase by roughly 20% when also utilising the interannual information from the earlywood. However, even though the new parameter δBI experiences an improvement as well, there are still puzzling dissimilarities between δdensity and Î"BI on multicentennial timescales. As a consequence, temperature reconstructions based on δBI will presently only be able to resolve information on decadal-to-centennial timescales. The possibility of trying to calibrate BI into a measure of lignin content or density, similarly to how radiographic measurements are calibrated into density, could be a solution. If this works, only then can δBI be used as a reliable proxy in multicentennial-scale climate reconstructions. © 2014 Author(s). Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/49274
Appears in Collections: 气候变化与战略
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Recommended Citation:
Björklund J.A.,Gunnarson B.E.,Seftigen K.,et al. Blue intensity and density from northern fennoscandian tree rings, exploring the potential to improve summer temperature reconstructions with earlywood information[J]. Climate of the Past,2014-01-01,10(2)