海洋沉积证据在低纬过程气候变化中的应用及展望

    Application and prospect of marine sedimentary evidence toclimate change in low-latitude processes

    • 摘要: 在国内外研究的基础上, 对印太暖池区的沃克环流和厄尔尼诺-南方涛动(ENSO)、热带辐合带(ITCZ)等低纬过程的空间分布和随时间的变化规律及其研究方法进行初步归纳,并指出研究中存在的问题。本文论述了厄尔尼诺-南方涛动变率在全新世早期及中世纪气候异常期(1 000~700 a BP)的晚期逐渐增强,介绍了热带辐合带在BA暖期(Bølling-Allerød Warm Period)和前北方期(pre-Boreal,10.3~9.5 ka BP)的北移,以及在新仙女木事件(Younger Dryas Event,12.5~11.5 ka BP)和北大西洋冷期(距今7.5~5 ka BP)期间的南移。对低纬过程长时间尺度轨道周期的探讨表明, 末次冰盛期赤道东太平洋出现了较偏南的热带辐合带锋面系统,甚至在1.65 Ma冰期,热带辐合带也有快速南移的证据。海洋沉积的粒度、黏土矿物、陆源粉尘、元素和同位素、有孔虫分析等研究方法在推测厄尔尼诺-南方涛动和热带辐合带位移中有很好的应用,建议以陆源生态系统对气候的响应为切入点、以孢粉为手段来探讨陆源植被、气候、火灾和海-陆大气环流等低纬过程的变化特征,进而反演沃克环流(或厄尔尼诺-南方涛动)演化和热带辐合带位移的影响。

       

      Abstract: Based on domestic and international research, this paper preliminarily summarizes the spatial distribution and temporal changes of the Walker circulation, El Niño Southern Oscillation (ENSO), Tropical Convergence Zone (ITCZ), and other low-latitude processes in the Indo-Pacific Warm Pool (IPWP) region, as well as their research methods, and points out current problems in the research. We found that the ENSO variability gradually increased in the early Holocene and the late medieval climate anomaly period (1000–700 a BP), and then introduced the northward movement of ITCZ during the Bølling-Allerød Warm Period and the pre-Boreal period (10.3 ka BP–9.5 ka BP), and the southward movement during the Younger Dryas event (12.5–11.5 ka BP) and the North Atlantic cold period (7.5 to 5 ka BP from now). In addition, we discussed the long-term orbital period of the low-latitude process. During the LGM (Last Glacial Maximum), a southerly ITCZ frontal system appeared in the equatorial eastern Pacific Ocean; and even during the 1.65 Ma ice age, there was evidence of rapid southward movement of ITCZ. At present, there are many research methods for marine sediments. The good applications of grain size analysis, clay minerals, terrestrial dust, elements and isotopes, and foraminifera in the prediction of ENSO and ITCZ displacement in marine sediments were summarized. Finally, based on the progress of marine pollen research, it is suggested to use the response of terrestrial ecosystems to climate changes as a starting point, and conduct palynological analysis to explore the changes in low-latitude processes such as terrestrial vegetation, climate, fires, and sea-land atmospheric circulation, to clarify the evolution of the Walker circulation (ENSO) and the impact of ITCZ displacement.

       

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