CAJ | 학술논문

关于上新世阶段青藏高原北部是否存在显著隆升事件这一问题目前依然存在较大的争议.本研究尝试利用沙尘气候模拟方法对上新世高原隆升的可能性做一评估.北太平洋风尘记录显示亚洲内陆干旱化在三到四百万年存在非常显著的增强,这可能是由于全球气候变冷和/或青藏高原隆升引起的.基于此,我们利用一个耦合了沙尘模块的气候模式,通过一系列敏感性试验测试大气沙尘沉积通量对于上新世以来主要气候强迫,包括冰盖变化,海表温度,大气二氧化碳浓度和青藏高原北部地形的响应.可能引起粉尘通量变化的大气环流和沙尘源区面积两个因素的改变在试验中都被考虑.模拟结果表明,冰盖扩张、海表温度下降和大气二氧化碳浓度下降这些全球变冷因素仅能解释中上新世和末次盛冰期北太地区粉尘沉积通量改变量的约三分之二,而剩下的三分之一需要归因于青藏高原北部的隆升.高原北部的隆升可以显著恶化内陆干旱状况从而提升大气粉尘浓度,支持了上新世高原北部存在明显隆升事件这一观点.
관우상신세계단청장고원북부시부존재현저륭승사건저일문제목전의연존재교대적쟁의.본연구상시이용사진기후모의방법대상신세고원륭승적가능성주일평고.북태평양풍진기록현시아주내륙간한화재삼도사백만년존재비상현저적증강,저가능시유우전구기후변랭화/혹청장고원륭승인기적.기우차,아문이용일개우합료사진모괴적기후모식,통과일계렬민감성시험측시대기사진침적통량대우상신세이래주요기후강박,포괄빙개변화,해표온도,대기이양화탄농도화청장고원북부지형적향응.가능인기분진통량변화적대기배류화사진원구면적량개인소적개변재시험중도피고필.모의결과표명,빙개확장、해표온도하강화대기이양화탄농도하강저사전구변랭인소부능해석중상신세화말차성빙기북태지구분진침적통량개변량적약삼분지이,이잉하적삼분지일수요귀인우청장고원북부적륭승.고원북부적륭승가이현저악화내륙간한상황종이제승대기분진농도,지지료상신세고원북부존재명현륭승사건저일관점.
Different opinions have been derived from geological evidence on whether there was significant tectonic uplift in the northern Tibetan Plateau (NTP) during the Pliocene.We made the first attempt in this paper to explore the possibility of the Pliocene uplift by climate modeling.Previous studies on eolian sediment records show that the inland Asian aridity was largely intensified 4-3 million years ago,which was proposed to be induced by global cooling and/or the Tibetan uplift.Employing a coupled climate-dust model,we conducted a series of experiments in order to test the sensitivity of atmospheric dust deposition fluxes to different forcings including the ice sheets,sea surface temperature,atmospheric CO2 concentration and the NTP topographic height.Both changes in atmospheric circulations and dust source areas are considered.The results show that,global cooling induced by all the above-mentioned factors except the NTP uplift can only explain approximately 2/3 of the increase in the dust deposition fluxes in the downwind North Pacific from mid-Pliocene to the last glacial maximum and the remaining 1/3 of the increase can be attributed to NTP uplift.The NTP uplift has remarkably strengthened the inland aridity and raised the dust levels,suggesting that considerable tectonic uplift events should have occurred in the NTP during Pliocene.