末次冰期-间冰期蒙古高原与黄土高原对全球变化的重要贡献

地球环境-气候系统的长周期变化是随日-地相对位置的周期性变化而变化的。但是仍有15%~20%的长周期变化没有得到解释。至于中短周期变化的机制,目前的解释仍然是众说纷纭。与北美冰盖动力相关的北大西洋洋面温度一直被认为是这些中短周期变化的调控仪。然而,赤道太平洋的长周期厄尔尼诺波动被表明是更为有效的调控仪。由于海洋研究的优势地位,陆地的相关研究近20~30 a来没有得到足够的重视。实际上,陆地下垫面控制的反射率的变化可能更有效地改变地球表面的能量平衡,从而导致全球性的变化。中亚的干旱、半干旱区范围的时空变化及其对大气粉尘的贡献很可能在中短周期的全球变化中起着举足轻重的作用,因为该区的南界和北界的变幅可达300~500 km。更为重要的是,作为地球上最有效的向大气输送粉尘的源区,蒙古高原和黄土高原可能很大程度地调控着大气中的CO₂含量,因此全球的温度也受到了调控。这个思路的逻辑是:干旱、半干旱区向大气输送含铁粉尘,此粉尘沉积于海洋;这些含铁粉尘控制着浅海的铁化肥供给。铁化肥的供给又控制着浅水中的固氮过程。固氮过程又控制着浅海的植物生产量。植物生产量通过储存碳和沉积碳(碳酸钙)来控制大气中的CO₂。

Contribution to Global Change of Mongolian Plateau and Loess Plateau in the Last Glaciation and Interglacial Periods

It is well known that the long-term variations of the Earth's climate are controlled by the geometric relationships between the Earth and the Sun. However, 15%~20% of the long term variations remain unexplained. As for the short term variations, many hypotheses are circulating. Among them, dominant is the North Atlantic related. It states that the short term variations have been controlled by the variations of the sea surface temperature in the North Atlantic. Nevertheless, variations of sub orbital timescale in ENSO of the Tropical Pacific may be more qualified in modulating the global sub orbital changes. Furthermore, the biggest continent, Eurasia, might have played much more important role than it has been thought. For instance, the changes in both the extent of the arid semiarid areas and the efficiency of atmospheric dust supply from these areas in the east central Asia might have been very significant in affecting the albedo and dust supply to the mid latitude oceans. The albedo controls the temperature and the dust supply modulates the atmospheric CO-2 level through providing the iron fertilization to nitrogen and carbon fixation that consumes atmospheric CO-2.