Science. 1993 Mar 5;259(5100):1433-6. doi: 10.1126/science.259.5100.1433.
Tree ring data have been used to reconstruct the mean late-season (June through January) temperature at a timberline site in the Sierra Nevada, California, for each of the past 2000 years. Long-term trends in the temperature reconstruction are indicative of a 125-year periodicity that may be linked to solar activity as reflected in radiocarbon and auroral records. The results indicate that both the warm intervals during the Medieval Warm Epoch ( approximately A.D. 800 to 1200) and the cold intervals during the Little Ice Age ( approximately A.D. 1200 to 1900) are closely associated with the 125-year period. Significant changes in the phase of the 125-year temperature variation occur at the onset and termination of the most recent radiocarbon triplet and may indicate chaotic solar behavior.
树木年轮数据被用来重建过去 2000 年来加利福尼亚内华达山脉林线位置的 6 月至 1 月后期（晚季）平均温度。该温度重建的长期趋势表明存在 125 年的周期性，这可能与太阳活动有关，这在放射性碳和极光记录中有所反映。结果表明，中世纪暖期（约公元 800 年至 1200 年）的温暖期和小冰期（约公元 1200 年至 1900 年）的寒冷期都与 125 年的周期密切相关。在最近的放射性碳三重奏开始和结束时，125 年温度变化的相位发生了显著变化，这可能表明太阳活动存在混沌行为。
