Glacial cycles are driven by cyclical changes in Earth's orbital parameters: obliquity, precession, and eccentricity. A common interpretation of Milankovitch's orbital theory suggests high-latitude June insolation is the dominant forcing in driving glacial cycles, which places emphasis on the importance of precession. However, there is abundant evidence for the importance of obliquity. Here, we use linear reconstructions based on single-forcing climate model simulations to produce time series of climate variables important in the growth and decay of ice sheets to examine the relative influences of obliquity and precession in locations important to glacial inception. We show that obliquity can cause changes in positive degree-days (sum of mean daily temperatures above 0°C) of larger magnitude than those of precession for Scandinavia and Baffin Island. Our positive degree-day time series were best represented by Milankovitch's caloric summer insolation metric. Snowfall is dominated by obliquity in Scandinavia and by precession in Baffin Island.

中文翻译：

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轨道对冰川形成有利条件的影响

冰川周期是由地球轨道参数的周期性变化驱动的：倾角、进动和离心率。米兰科维奇轨道理论的一个普遍解释表明，高纬度六月日照是驱动冰川周期的主要动力，这强调了进动的重要性。然而，有大量证据证明倾斜的重要性。在这里，我们使用基于单强迫气候模型模拟的线性重建来生成对冰盖生长和衰退很重要的气候变量的时间序列，以检查对冰川开始重要的位置的倾斜度和进动的相对影响。我们表明，与斯堪的纳维亚半岛和巴芬​​岛的岁差相比，倾角会导致正度日（高于 0°C 的日平均温度之和）的变化幅度更大。米兰科维奇的夏季热量日照指标最能代表我们的正度数-日时间序列。降雪主要是斯堪的纳维亚的倾角和巴芬岛的岁差。