Experiments based on blue intensity for reconstructing North Pacific temperatures along the Gulf of Alaska
Experiments based on blue intensity for reconstructing North Pacific temperatures along the Gulf of Alaska
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基于蓝色强度重建阿拉斯加湾沿岸北太平洋温度的实验
DOI：
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
N. Davi
中科院分区：
文献类型：
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作者：
R. Wilson;R. D’Arrigo;L. Andreu‐Hayles;R. Oelkers;G. Wiles;K. Anchukaitis;N. Davi
抽象的。在以前的研究中，阿拉斯加湾(GOA)的环宽度(RW)记录为北太平洋从年代际到更长时间尺度的变化提供了一个有价值的长期视角，但包含了从冬季到夏末的广泛的季节性气候反应。与高度气候敏感的最大晚材密度(MXD)指标类似，蓝色强度(BI)参数最近被证明与北纬一些地点的年度暖季温度有很好的相关性。由于BI记录比MXD的劳动密集度低得多，生成成本也高得多，这种数据对果阿地区和其他中高纬度地区未来的树木年轮研究具有巨大的潜在价值。在这里，我们探索了使用RW和BI相关参数(晚材BI和增量BI)的组合来改进基于树轮的重建的潜力，这些参数来自果阿沿线八个山地铁杉(Tsuga Mertensiana)站点的实验样本子集。这是首次使用BI数据对铁杉属进行研究。我们发现，使用倒置晚材BI(LWBinv)或增量BI(DB)都可以比单独使用RW提高>； 10 %的可解释温度变异量，尽管最佳目标季节缩短到6-9月，这可能对研究该地区的海洋-大气变率有意义。建立这些BI记录的一个挑战是，树脂提取并没有消除心材和边材之间的颜色差异；因此，在使用LWBinv数据时，注意到了长期趋势偏差，以18世纪相对温暖的温度表示。使用DB似乎克服了这些趋势偏差，导致重建的18-19世纪的温度比20-21世纪低约0.5 °C。这一凉爽时期与以前的树枝气候研究和该地区的冰川推进记录相吻合。在果阿地区继续进行BI测量必须侧重于对每个站点(>； 20)进行更多的树木采样和测量，汇编更多的站点以克服影响气候响应的特定站点因素，并使用亚化石材料来延长记录。虽然LWBinv比DB更能捕捉到年际气候信号，但DB似乎更好地捕捉到了与该地区其他代理档案一致的长期长期趋势。然而，在实施不同的去趋势选择时，需要非常小心，有必要进行更多的实验，以评估DB对北半球不同针叶树种的效用。
Abstract. Ring-width (RW) records from the Gulf of Alaska (GOA) have yielded a valuable long-term perspective for North Pacific changes on decadal to longer timescales in prior studies but contain a broad winter to late summer seasonal climate response. Similar to the highly climate-sensitive maximum latewood density (MXD) proxy, the blue intensity (BI) parameter has recently been shown to correlate well with year-to-year warm-season temperatures for a number of sites at northern latitudes. Since BI records are much less labour intensive and expensive to generate than MXD, such data hold great potential value for future tree-ring studies in the GOA and other regions in mid- to high latitudes. Here we explore the potential for improving tree-ring-based reconstructions using combinations of RW- and BI-related parameters (latewood BI and delta BI) from an experimental subset of samples at eight mountain hemlock (Tsuga mertensiana) sites along the GOA. This is the first study for the hemlock genus using BI data. We find that using either inverted latewood BI (LWBinv) or delta BI (DB) can improve the amount of explained temperature variance by > 10 % compared to RW alone, although the optimal target season shrinks to June–September, which may have implications for studying ocean–atmosphere variability in the region. One challenge in building these BI records is that resin extraction did not remove colour differences between the heartwood and sapwood; thus, long term trend biases, expressed as relatively warm temperatures in the 18th century, were noted when using the LWBinv data. Using DB appeared to overcome these trend biases, resulting in a reconstruction expressing 18th–19th century temperatures ca. 0.5 °C cooler than the 20th–21st centuries. This cool period agrees well with previous dendroclimatic studies and the glacial advance record in the region. Continuing BI measurement in the GOA region must focus on sampling and measuring more trees per site (> 20) and compiling more sites to overcome site-specific factors affecting climate response and using subfossil material to extend the record. Although LWBinv captures the inter-annual climate signal more strongly than DB, DB appears to better capture long-term secular trends that agree with other proxy archives in the region. Great care is needed, however, when implementing different detrending options and more experimentation is necessary to assess the utility of DB for different conifer species around the Northern Hemisphere.
影响因子：
2.2
作者：
M. Rydval;D. Druckenbrod;K. Anchukaitis;R. Wilson
通讯作者：
M. Rydval;D. Druckenbrod;K. Anchukaitis;R. Wilson
影响因子：
8.9
作者：
Cowtan, Kevin;Way, Robert G.
通讯作者：
Way, Robert G.
影响因子：
3
作者：
T. Melvin;K. Briffa
通讯作者：
T. Melvin;K. Briffa