Mounting evidence suggests that the Southern Westerly Winds were significantly equatorially displaced and more intense during the last glacial maximum (LGM), prompting deliberate research identifying proxies to reconstruct these changes. This has focused on rainfall seasonality to track changes in major circulation patterns across the southern hemisphere midlatitude regions. Using a common methodology to reconstruct climatic changes aids comparability and makes it easier to draw significant conclusions regarding general circulation movements. We assess the applicability of Coetzee's (1967) Poaceae:Asteraceae pollen ratio, which has been used successfully in South Africa, in the Australian context. The ratio scores from modern samples fail to capture the weak seasonality in the southeast and on Tasmania but is successful for the rest of the continent. The periods of greatest change compared to present day match known periods of distinct climatic events, namely the mid-Holocene (6–7 cal ka BP), the last deglacial period (15–17 cal ka BP), and two periods during the LGM (20–22 and 31–33 cal ka BP), suggesting large parts of Australia experienced a “double peak” of rainfall seasonality change during the LGM. This confirms that the Poaceae:Asteraceae pollen ratio can be used on records outside of South Africa.

中文翻译：

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使用禾本科：菊科花粉比量化澳大利亚第四纪晚期降雨季节性变化

越来越多的证据表明，在末次盛冰期 (LGM) 期间，南西风明显地向赤道偏移且强度更高，这促使人们进行了深思熟虑的研究，以确定重建这些变化的代理。这侧重于降雨季节性，以跟踪南半球中纬度地区主要环流模式的变化。使用通用方法来重建气候变化有助于可比性，并且更容易得出有关一般环流运动的重要结论。我们评估了 Coetzee (1967) 禾本科：菊科花粉比率的适用性，该比率已在南非成功使用，在澳大利亚的背景下。现代样本的比率分数未能捕捉到东南部和塔斯马尼亚岛的弱季节性，但在大陆其他地区是成功的。与今天相比，变化最大的时期与已知的不同气候事件时期相匹配，即全新世中期（6-7 cal ka BP）、最后一个冰期（15-17 cal ka BP）和 LGM 期间的两个时期（20-22 和 31-33 cal ka BP），表明澳大利亚大部分地区在 LGM 期间经历了降雨季节性变化的“双峰”。这证实了禾本科：菊科花粉比率可用于南非以外的记录。和 LGM 期间的两个时期（20-22 和 31-33 cal ka BP），表明澳大利亚大部分地区在 LGM 期间经历了降雨季节性变化的“双峰”。这证实了禾本科：菊科花粉比率可用于南非以外的记录。和 LGM 期间的两个时期（20-22 和 31-33 cal ka BP），表明澳大利亚大部分地区在 LGM 期间经历了降雨季节性变化的“双峰”。这证实了禾本科：菊科花粉比率可用于南非以外的记录。