Midlatitude cooling caused by geomagnetic field minimum during polarity reversal
Midlatitude cooling caused by geomagnetic field minimum during polarity reversal
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DOI：
10.1073/pnas.1213389110
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发表时间：
2013-01-22
影响因子：
11.1
通讯作者：
Sato, Hiroshi
中科院分区：
文献类型：
--
作者：
Kitaba, Ikuko;Hyodo, Masayuki;Sato, Hiroshi
银河宇宙射线（CR）引起的云形成对气候的影响最近成为人们广泛讨论的话题。 CR 与云的联系表明，地磁场强度的变化可能通过调节 CR 通量来改变气候。然而，这一假设尚未得到可靠的地质证据的充分检验。在这里，我们展示了五个间冰期的古气候和古环境记录，其中包括两次地磁极性反转。海洋氧同位素阶段 19 和 31 分别包含海平面高位期间以及松山-布伦赫斯和下哈拉米洛反转期间的异常冷却区间。这与典型的间冰期气候形成鲜明对比，典型的间冰期气候在海平面峰值处温度最高。当场强下降至 CR 通量增加 40% 时发生冷却。当场强恢复时，气候迅速变暖。我们认为地磁场强度可以通过CR通量的调制影响全球气候。
The climatic effects of cloud formation induced by galactic cosmic rays (CRs) has recently become a topic of much discussion. The CR-cloud connection suggests that variations in geomagnetic field intensity could change climate through modulation of CR flux. This hypothesis, however, is not well-tested using robust geological evidence. Here we present paleoclimate and paleoenvironment records of five interglacial periods that include two geomagnetic polarity reversals. Marine oxygen isotope stages 19 and 31 contain both anomalous cooling intervals during the sea-level highstands and the Matuyama-Brunhes and Lower Jaramillo reversals, respectively. This contrasts strongly with the typical interglacial climate that has the temperature maximum at the sea-level peak. The cooling occurred when the field intensity dropped to 40% increase in CR flux. The climate warmed rapidly when field intensity recovered. We suggest that geomagnetic field intensity can influence global climate through the modulation of CR flux.