Department of Geography and Planning, Appalachian Tree-Ring Laboratory, Appalachian State University, Boone, NC, USA.
Department of Geography, Environment, and Sustainability, Carolina Tree-Ring Science Laboratory, University of North Carolina-Greensboro, Greensboro, NC, USA.
Int J Biometeorol. 2019 Sep;63(9):1217-1229. doi: 10.1007/s00484-019-01739-5. Epub 2019 Jun 17.
We examined relationships between wintertime Arctic sea-ice extent (ASIE) and radial growth rates of alpine larch trees (LALY) in the northern Rockies, USA, during 1979-2015 (r = - 0.71, p < 0.01) and reconstructed ASIE fluctuations from 1613 to 2015. Wintertime ASIE corresponds with summertime mid-latitude upper-level atmospheric flow patterns with ridging (troughing) and warmer (cooler) conditions prevailing in the Rockies when ASIE are below (above) average. In turn, warmer (cooler) summertime conditions favor (disfavor) growth of LALY, thus "recording" interannual variations in ASIE. Both 1000 hPa temperatures and 500 hPa geopotential heights during years of anomalously high or low radial growth negatively correspond with ASIE, suggesting that a disjunct spatial influence on atmospheric conditions may be associated with interannual variability of ASIE. Reconstructed ASIE values show that 1996-2015 was the lowest 20-year period on record, but the mean value is not significantly different from six other distinct periods of below-average ASIE.
我们研究了 1979 年至 2015 年期间美国落基山脉北极海冰范围（ASIE）与高山落叶松树木径向生长率（LALY）之间的关系（r=-0.71，p<0.01），并重建了 1613 年至 2015 年的 ASIE 波动。冬季北极海冰范围与夏季中纬度高层大气流型相关，当海冰低于（高于）平均水平时，落基山脉盛行隆起（槽）和暖（冷）条件。反过来，温暖（凉爽）的夏季条件有利于（不利于）高山落叶松的生长，从而“记录”了北极海冰的年际变化。在径向生长异常高或低的年份，1000 hPa 温度和 500 hPa 位势高度与北极海冰呈负相关，这表明大气条件的不连续空间影响可能与北极海冰的年际变化有关。重建的北极海冰值表明，1996 年至 2015 年是有记录以来的最低 20 年，但平均值与其他六个明显低于平均水平的北极海冰时期没有显著差异。
