Tree-ring cellulose δ18O records similar large-scale climate influences as precipitation δ18O in the Northwest Territories of Canada
Tree-ring cellulose δ18O records similar large-scale climate influences as precipitation δ18O in the Northwest Territories of Canada
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DOI：
10.1007/s00382-021-05932-4
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发表时间：
2021-10-24
期刊：
影响因子：
4.6
通讯作者：
Levesque, M.
中科院分区：
文献类型：
--
作者：
Field, Robert D.;Andreu-Hayles, Laia;Levesque, M.
在树木年轮中测量的稳定氧同位素有助于重建气候变异性和解释森林中发生的生理过程的变化，补充其他树木年轮参数，如年轮宽度。在这里，我们分析了不同气候参数与白云杉年轮O-18记录(增量O-18(TR))之间的关系，并使用NASA GISS ModelE2同位素配置的大气环流模式(GCM)更好地解释了观测到的关系。我们发现，O-18(Tr)序列主要与春季和夏季温度变化有关，可能是通过春季温度对降水增量O-18的影响，以及夏季叶水平上的蒸发富集。GCM模拟表明，模拟的降水增量O-18与北美西北部的地面温度和位势高度之间存在显著的正相关，但秋冬季比春夏季的强度更大。模拟的降水增量O-18只与秋冬季节的水汽输送显著相关。在水分对树木影响较大的春夏季节，Delta O-18(Tr)与模拟降水Delta O-18表现出相似的相关模式，与地表温度和位势高度呈显著正相关，而与水分输送无显著相关。总体而言，加拿大西北部的德尔塔O-18(TR)记录反映了与春季和夏季降水德尔塔O-18相同的显著大尺度气候模式，因此除了该地区的温度变率外，还有可能重建过去的大气动力学。
Stable oxygen isotopes measured in tree rings are useful for reconstructing climate variability and explaining changes in physiological processes occurring in forests, complementing other tree-ring parameters such as ring width. Here, we analyzed the relationships between different climate parameters and annually resolved tree-ring delta O-18 records (delta O-18(TR)) from white spruce (Picea glauca [Moench]Voss) trees located near Tungsten (Northwest Territories, Canada) and used the NASA GISS ModelE2 isotopically-equipped general circulation model (GCM) to better interpret the observed relationships. We found that the delta O-18(TR) series were primarily related to temperature variations in spring and summer, likely through temperature effects on the precipitation delta O-18 in spring, and evaporative enrichment at leaf level in summer. The GCM simulations showed significant positive relationships between modelled precipitation delta O-18 over the study region and surface temperature and geopotential height over northwestern North America, but of stronger magnitudes during fall-winter than during spring-summer. The modelled precipitation delta O-18 was only significantly associated with moisture transport during the fall-winter season. The delta O-18(TR) showed similar correlation patterns to modelled precipitation delta O-18 only during spring-summer when water matters more for trees, with significant positive correlations with surface temperature and geopotential height, but no correlations with moisture transport. Overall, the delta O-18(TR) records for northwestern Canada reflect the same significant large-scale climate patterns as precipitation delta O-18 for spring-summer, and therefore have potential for reconstructing past atmospheric dynamics in addition to temperature variability in the region.