NOAA/WDS Paleoclimatology - Touchan - Bordjem - CDAT - ITRDB DZA012

The first large-scale network of tree-ring chronologies from the western Mediterranean (WM; 32°N–43°N, 10°W–17°E) is described and analyzed to identify the seasonal climatic signal in indices of annual ring width. Correlation and rotated empirical orthogonal function analyses are applied to 85 tree-ring series and corresponding gridded climate data to assess the climate signal embedded in the network. Chronologies range in length from 80 to 1129 years. Monthly correlations and partial correlations show overall positive associations for Pinus halepensis (PIHA) and Cedrus atlantica (CDAT) with winter (December–February) and spring (March–May) precipitation across this network. In both seasons, the precipitation correlation with PIHA is stronger, while CDAT chronologies tend to be longer. A combination of positive correlations between growth and winter–summer precipitation and negative partial correlations with growing season temperatures suggests that chronologies in at least part of the network reflect soil moisture and the integrated effects of precipitation and evapotranspiration signal. The range of climate response observed across this network reflects a combination of both species and geographic influences. Western Moroccan chronologies have the strongest association with the North Atlantic Oscillation.本研究针对西地中海（WM；32°N–43°N，10°W–17°E）首个大规模树轮年表网络展开描述与分析，旨在识别年轮宽度指数中的季节性气候信号。研究采用相关分析与旋转经验正交函数（rotated empirical orthogonal function）分析方法，对85组树轮序列及对应网格化气候数据进行处理，以评估该网络中蕴含的气候信号。各树轮年表的时长跨度为80至1129年。月尺度相关分析与偏相关分析结果表明，该网络内的阿勒颇松（Pinus halepensis，PIHA）与大西洋雪松（Cedrus atlantica，CDAT）的生长指标，与区域冬季（12月—2月）、春季（3月—5月）降水整体呈正相关关系。在冬、春两季中，阿勒颇松与降水的相关性均更强，而大西洋雪松的年表时长普遍更长。树木生长与冬夏降水呈正相关、同时与生长季温度呈负偏相关的组合特征，表明该网络至少部分区域的年表能够反映土壤湿度状况，以及降水与蒸散（evapotranspiration）的综合影响信号。该网络中观测到的气候响应差异，是物种特性与地理区位因素共同作用的结果。西摩洛哥地区的树轮年表与北大西洋涛动（North Atlantic Oscillation）的相关性最强。