天文古气候理论及其进展—从米兰柯维奇到贝尔杰

扼要介绍了天文古气候学的创立和发展简史。太阳是地球大气运动的第一驱动力，地球气候的长期演变在很大程度上受到入射太阳辐射变化的影响。入射太阳辐的变化主要和三个地球轨道参数有关，即地球绕太阳运行的椭圆轨道偏心率，地球自转轴倾角及岁差。太阳辐射的长期振荡主要集中在与这三个参数有关的频率上，这些频率通常被称为米兰柯维奇频率，数值模拟和地学记录都证实地质时间尺度的古气候的演化大多位于米兰柯维奇频率带上。

ASTRONOMICAL THEORY OF PALEOCLIMATE AND ITS PROGRESS: FROM MILUTIN MILANKOVITCH TO ANDRE BERGER

The astronomical theory of the paleoclimate serves for interpreting the paleoclimate flactuations and,especially,the Ice Age problem basing on the variations of astronomical orbital elements.It initiated in nineteenth century, but was formally astablished in 1941 when Milankovitch’s Kanon was published.Milankovitch emplasized the importance of caloric summer insolation on glaciation,i.e.,the cool and short summer is in favour of the development of glaciers.His computation comfirmed his idea.Unfortunately,his theory was argued for many years because of the insufficient geological records dated with poor accurant techniques.It was not until the implementation of CLIMAP(Climate Mapping Project) that found the paleoclimate oscillations really occurred in Milankovitch frequency belts.Meanwhile,A.Berger,a Belgian astr geoscientist,re calculated long term variation of the insolation with simpler method and more accuracy than ever before.The insolation he computed has even been dated up to past 10 000 000 years or more.His spectral analysis for the insolation clearly shows the 400 and 100 41 23 and 19 ka cycles corresponding to the astronomical elements of the eccentricity,obliquity and astronomical precession,respectively.In addition,his calculation scheme could be easily applied in numerical climate model as an orbital forcing which drives the general circulation of atmosphere. On the other hand,numerical simulation of paleoclimate is rapidly developing.A sectorially averaged two dimensional climate model like LLN 2D model consisting of coupled atmospheric,ocean and ice sheet models has been built,it can be run from remote geological past up to now,and some of which results may be compared directly with geological records or other proxy data,for instance,the δ 18 O,so as to re exame the Milankovitch’s theory as well as the impacts of other factors in paleoclimate.