气候变化的天文理论

ASTRONOMICAL THEORY OF CLIMATIC CHANGES

地球气候变化在 10～ 10 0ka (千年 )的时间尺度上表现出规则的周期性 ,它们主要受轨道日射变化控制 ,并能被很精确地计算到几百万年 .根据Milankovitch创立的天文理论 ,轨道变化是通过改变日射的季节分布和纬度分布来影响气候的 .黄赤夹角以 4 1ka的周期改变日射的纬度分布 ,而气候岁差以 19ka和 2 3ka的两个周期改变日射的季节分布 .作为对轨道日射变化的响应 ,全球气候在 10～ 10 0ka的时间尺度上按照气候岁差和黄赤夹角的周期变化 ,这一点已经为全新世气候的地质记录所验证 .轨道日射变化已经被证明是全新世冰期交替的重要原因 ,而且它仍然是现在和将来气候长期变化的重要原因 .因此 ,研究气候变化天文理论的重要性不仅仅在于了解过去年代的气候变化 ,也是为了更好地理解现在和将来的气候变化 .本文将简要介绍这个理论和相关的进展 .

The earth's climatic changes show regular periodicities on the time scale of 10～100 ka, which are controlled by orbitally modulated variations in insolation and which can be calculated with great precision for several Ma. According to the astronomical theory of climatic changes that Milankovitch founded, the variations in the earth's orbit influence climate by changing the seasonal and latitudinal distribution of insolation. The obliquity of the ecliptic mainly controls the latitudinal distribution of insolation with a period of 41 ka. The climatic precession mainly controls seasonal distribution of insolation with two periods of 19 ka and 23 ka. In response to orbitally modulated variations in insolation, the global climate changes on the time scale of 10～100 ka with the periods of the precession and obliquity, which has been tested and verified by the geologic records in Pleistocene climate. Orbitally modulated variations in insolation have been shown to be the fundamental cause of the succession of Pleistocene ice age and continue to be the fundamental cause of the long term variations in the present and future climate. Therefore the importance of studying the astronomical theory of climatic changes is not only to learn the climatic changes in the past age but also to understand better the climatic changes in the present and future time. This paper presents a brief outline of the theory and relevant progress.