全新世北大西洋海面温度变化趋势：重建-模拟对比研究

发布时间：2018-03-03 14:38

本文选题：全新世　切入点：北大西洋　出处：《兰州大学》2017年硕士论文　论文类型：学位论文

【摘要】：第四纪中最近的一次气候转暖、冰川消融期-全新世,对人类的生存和发展有着重要的影响,并且掀开了地质历史上崭新的一页。全新世作为和现在环境变化相类似的“历史相似型”,具有很重要的研究价值和意义,因此,全新世时期气候变化的研究是过去全球变化研究的重点。北大西洋海域具有独特的地理位置,是对全新世气候变化响应敏感的关键区域。众所周知,大洋环流系统及冰川活动在很大程度上对北大西洋及其邻近区域产生剧烈的影响,同时影响全球气候变化的重要因素也是这些气候变化因子。因此把北大西洋地区作为全球气候变化的源头之一。然而对北大西洋海面温度以及气候变化的研究是了解过去全球环境变化的关键所在。所以,研究全新世北大西洋的海温变化对理解全新世气候变化有极其重要的作用。为此,本文利用Kiel Climate Model(KCM模式)对全新世气候的模拟结果及其与北大西洋表层海水温度(Sea Surface Temperature,简称SST)重建记录的对比,探讨了全新世北大西洋SST的变化趋势。浮游植物的长链烯酮不饱和度显示低纬北大西洋SST在全新世期间有升高趋势,而在中纬和高纬地区表现为显著的下降趋势,尤其是在中纬北大西洋西部,最大降温幅度达到7.9°C/9.5ka。浮游有孔虫壳体的镁钙比值显示中纬北大西洋东部及高纬北大西洋有增温趋势,而在中纬北大西洋西部及低纬北大西洋则有降温趋势,但变化幅度均比较小,绝大部分在2°C/9.5ka以下。气候模拟结果显示全新世北大西洋SST变化呈现明显的“三核型”经向模态,在冬春季以增温为主,降温限于拉布拉多海东南部的北大西洋海域;在夏秋季以降温为主,增温限于低纬和高纬北大西洋海域。模拟结果与重建资料的对比显示,中纬和低纬北大西洋的长链烯酮不饱和度指标以及低纬西部的镁钙比指标可能反映夏秋季海温,中纬北大西洋东部的镁钙比指标可能反映冬春季海温,而中纬西部和高纬的镁钙比指标可能对4个季节的SST都有所反映。
[Abstract]:The most recent warming in the Quaternary, the melting of glaciers in the Holocene, had an important impact on the survival and development of mankind. And turned a new page in geological history. The Holocene as a "historical similarity" similar to the present environmental change has very important research value and significance. The study of climate change during the Holocene was the focus of past studies on global change. The North Atlantic Sea, with its unique geographical location, is a key area sensitive to the response of the Holocene to climate change. Ocean circulation systems and glacier activity have had a significant impact on the North Atlantic and its adjacent regions, Therefore, the North Atlantic region is one of the sources of global climate change. However, the study of sea surface temperature and climate change in the North Atlantic is. Understand the key to global environmental change in the past. The study of sea surface temperature changes in the North Atlantic during the Holocene is of great importance in understanding the climate change of the Holocene. In this paper, Kiel Climate Model(KCM model is used to simulate the Holocene climate and its comparison with the North Atlantic Sea Surface temperature reconstruction records. The variation trend of SST in the North Atlantic during Holocene is discussed. The long chain ketene unsaturation of phytoplankton indicates that SST in low latitude North Atlantic increased during Holocene, but decreased significantly in middle latitude and high latitude. Especially in the western part of the mid-latitude North Atlantic, the maximum cooling range is 7.9 掳C / 9.5 KA. The magnesium-calcium ratio of planktonic foraminifera shell shows a tendency to increase temperature in the east of the mid-latitude North Atlantic and in the high-latitude North Atlantic. However, in the western part of the mid-latitude North Atlantic and the low-latitude North Atlantic, the trend of cooling is relatively small, most of which are below 2 掳C / 9.5 ka. The results of climate simulation show that the North Atlantic SST changes in the Holocene show an obvious "trikaryotypic" meridional mode. In winter and spring, the temperature is mainly increased, and the cooling is limited to the North Atlantic Sea in the southeast of Labrador Sea, and in summer and autumn, the temperature increase is limited to the North Atlantic Sea at low latitude and high latitude. The comparison between the simulation results and the reconstruction data shows that. The index of long chain ketene unsaturation in the middle latitude and low latitude North Atlantic and the ratio of magnesium to calcium in the west of low latitude may reflect the summer and autumn sea surface temperature, and the index of the ratio of magnesium to calcium in the east of the middle latitude of the North Atlantic may reflect the winter and spring sea surface temperature. The Mg-Ca ratio in the western and high latitudes may reflect the SST of the four seasons.
【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P736.22;P731

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