Snowpack‐ and Soil Water Content‐Related Hydrologic Indices and Their Association With Radial Growth of Conifers in the Sierra Nevada, California
Snowpack‐ and Soil Water Content‐Related Hydrologic Indices and Their Association With Radial Growth of Conifers in the Sierra Nevada, California
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DOI：
10.1029/2019jg005331
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发表时间：
2020-01
期刊：
影响因子：
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通讯作者：
E. Shamir;D. Meko;R. Touchan;K. Lepley;R. Campbell;R. Kaliff;K. Georgakakos
中科院分区：
文献类型：
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作者：
E. Shamir;D. Meko;R. Touchan;K. Lepley;R. Campbell;R. Kaliff;K. Georgakakos
本文介绍了利用高分辨率雪水文模型推导气候指数的方法，这些气候指数描述了内华达山脉两个地点四种针叶树径向生长的变化。建立了与径向生长有关的9个年际指标，以反映冬季休眠、积雪和土壤含水量特征以及季节持续时间。研究了山铁杉（Tsuga mertensiana）、红杉（Abies magnifica）、白杉（Abies concolor）和黄松（Pinus ponderosa）在背风坡和逆风坡2个样地的早木（EW）和晚木（LW）环宽年代学。结合主成分分析，采用相关回归方法对模式输出的年度气候指数信号强度进行了检验。结果表明，树木年轮数据中存在显著的雪相关气候信号，且在物种间、EW和LW之间存在显著差异。铁杉和红杉的EW依赖于前一年的积雪和土壤湿度（滞后响应）。这些树种的主要EW - LW信号对比是LW转向依赖当年的湿度条件，尤其是红杉。白杉和黄松的滞后气候响应不明显。树木年轮序列对气候指数主成分的回归表明，东西部（R2 = 0.48）的平均信号强于西部（R2 = 0.35）。两个站点树木年轮水文信号的差异归因于小气候和雪况的差异。结果证明了水文模型在研究树木年轮与当地气候之间的时间关系方面的有效性。
The utility of a high‐resolution snow‐hydrologic model to derive climatological indices that describe the variability in radial growth of four conifer species in two Sierra Nevada sites is presented herein. Nine annual indices associated with radial growth were developed to represent the winter dormancy, characteristics of the snowpack and soil water content, and the duration of the seasons. Site chronologies of earlywood (EW) and latewood (LW) ring widths were developed for mountain hemlock (Tsuga mertensiana), red fir (Abies magnifica), white fir (Abies concolor), and ponderosa pine (Pinus ponderosa) at two sites on leeward and windward slopes. The signal strength for annual climatological indices derived from model output was tested with correlation and regression, in combination with principal components analysis. Results show significant snow‐related climate signal in the tree‐ring data, with substantial differences between species and between EW and LW. Dependence on previous year's snow and soil moisture (a lagged response) were found for EW of hemlock and red fir. The primary EW‐LW signal contrast for those species is a shift toward dependence on current‐year moisture conditions for LW, especially for red fir. Lagged climate response was less evident for white fir and ponderosa pine. Regression of tree‐ring series on principal components of climatological indices showed a stronger average signal in EW (R2 = 0.48) than in LW (R2 = 0.35). Differences in tree‐ring hydrologic signal at the two sites are attributed to microclimate and contrasts in snow regime. Results attest to the hydrologic model usefulness for investigating temporal relationships between tree rings and local climate.