ABRUPT POSTGLACIAL CLIMATE EVENTS IN WEST ASIA AND NORTH-AFRICA MONSOON DOMAINS
ABRUPT POSTGLACIAL CLIMATE EVENTS IN WEST ASIA AND NORTH-AFRICA MONSOON DOMAINS
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DOI：
10.1016/0012-821x(94)90123-6
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发表时间：
1994-09-01
影响因子：
5.3
通讯作者：
VANCAMPO, E
中科院分区：
文献类型：
--
作者：
GASSE, F;VANCAMPO, E
在印度和非洲季风目前或过去渗透范围之外的地区，在过去13 -14年间经历了几次大而突然的气候波动。在全新世早期至中期，气候条件比现在湿润，但在11.0 ~ 9.5 kyr BP、8 ~ 7 kyr BP和3 ~ 4 kyr BP的时间间隔内，所有地点都记录到了主要的干旱期。一些记录也表明，在6千万年BP左右发生了幅度较小的干旱事件。讨论了日晒、海面和热带陆面条件的潜在边界强迫。太阳辐射解释了冰期后季风波动的大致范围，但不能解释短期变化的时间和幅度。尽管北大西洋海表条件的波动与季风记录之间存在明显的共变，但没有发现将海洋热盐输送带强度与季风强度联系起来的直接机制。热带陆地表面条件的变化（土壤湿度负反馈和湿地CH4产量的变化）为解释突变逆转事件提供了更令人满意的假设。
Regions beyond the present or past penetration of the Indian and African monsoons have experienced several large and abrupt climatic fluctuations over the past 13 C-14 kyr.Pollen and lake records from West Asia (Western Tibet and Rajasthan), East Africa (Ethiopia) and West Africa (Western Sahara, Sahel and subequatorial Africa) were selected on the basis of chronological control, sensitivity of both site and environmental indicators to climate change, the continuity of the record, and interdisciplinary control of the palaeoclimatic interpretation.Conditions wetter than those of today prevailed during the early-mid-Holocene period, but major dry spells are recorded at all sites during the intervals similar to 11.0-9.5 kyr BP, similar to 8-7 kyr BP and 3-4 kyr BP. Several records also suggest dry events of minor amplitude around 6 kyr BP. Potential boundary forcings of insolation and sea surface and tropical land surface conditions are discussed. The solar radiation accounts for the general envelop of the post-glacial monsoon fluctuations, but explains neither the timing nor the amplitude of the short-term changes. In spite of apparent covariation between fluctuations in sea surface conditions in the North Atlantic and the monsoon record, no direct mechanism could be found relating the intensity of the oceanic thermohaline conveyor belt to the monsoon strength. Changes in tropical land surface conditions (soil moisture negative feedback, and changes in CH4 production from wetlands) provide a more satisfactory hypothesis for explaining abrupt reversal events.