The middle Holocene climatic records from Arabia: Reassessing lacustrine environments, shift of ITCZ in Arabian Sea, and impacts of the southwest Indian and African monsoons
The middle Holocene climatic records from Arabia: Reassessing lacustrine environments, shift of ITCZ in Arabian Sea, and impacts of the southwest Indian and African monsoons
复制标题
阿拉伯半岛全新世中期气候记录：重新评估湖泊环境、阿拉伯海 ITCZ 的转变以及西南印度和非洲季风的影响
DOI：
10.1016/j.gloplacha.2015.03.004
复制
发表时间：
2015
影响因子：
3.9
通讯作者：
J. Quade
中科院分区：
文献类型：
--
作者：
Y. Enzel;Y. Kushnir;J. Quade
在全新世中期（约2000年），阿拉伯半岛夏季降水量急剧增加。9-5 ka BP）基于湖相沉积物、推断的湖平面、洞穴沉积物和花粉。这种降雨量的增加被认为主要是由于印度夏季风的加强，作为太阳辐射驱动的一部分，热带辐合带（ITCZ）的北方夏季位置北移到北非，阿拉伯半岛和印度西北部的沙漠。我们研究了阿拉伯半岛气候剧烈变化的基础和夏季季风降雨的变化，通过回顾阿拉伯半岛的古水文湖泊记录。我们评估并重新解释了单个湖盆的湖泊状沉积物、自然地理、海岸线、动物群和植物群状况，并得出结论，这些湖盆没有被湖泊占据，而是被浅沼泽环境占据。支持这种有限湿地所需的降雨量增加远远小于形成和维持高度蒸发的湖泊所需的降雨量增加，我们认为降雨量变化主要发生在西南部的高架边缘，南部和阿拉伯半岛东南部。降雨量和当地的这些相对较小的变化也得到了该地区花粉和洞穴沉积物的支持。这些变化并不需要北移的北方半球夏季ITCZ和印度季风降水的加强。我们建议，（a）纬度和轻微的内陆扩张的北非夏季季风降雨在红海，（B）上升的潮湿空气的季风西南部阿拉伯高地，而不是与印度夏季季风的加强，如前所述，在该地区的降雨增加，这些非洲季风降雨产生了适度的古湿地下游超干旱盆地。此外，我们假设，在今天，ITCZ在印度洋保持在赤道或附近全年，和印度夏季季风，通过动态引起的空气沉降，可以减少而不是增加夏季降水在黎凡特和邻近的沙漠，包括阿拉伯半岛。我们的总结表明，扩大到北部的纬度范围的降雨与北非夏季季风水分穿越红海以东。我们讨论了其他机制，可能有潜在的形成和维持温和的古湿地。
A dramatic increase in regional summer rainfall amount has been proposed for the Arabian Peninsula during the middle Holocene (ca. 9-5 ka BP) based on lacustrine sediments, inferred lake levels, speleothems, and pollen. This rainfall increase is considered primarily the result of an intensified Indian summer monsoon as part of the insolation-driven, northward shift of the boreal summer position of the Inter-Tropical Convergence Zone (ITCZ) to over the deserts of North Africa, Arabia, and northwest India.We examine the basis for the proposed drastic climate change in Arabia and the shifts in the summer monsoon rains, by reviewing paleohydrologic lacustrine records from Arabia. We evaluate and reinterpret individual lake-basin status regarding their lacustrine-like deposits, physiography, shorelines, fauna and flora, and conclude that these basins were not occupied by lakes, but by shallow marsh environments.Rainfall increase required to support such restricted wetlands is much smaller than needed to form and maintain highly evaporating lakes and we suggest that rainfall changes occurred primarily at the elevated edges of southwestern, southern, and southeastern Arabian Peninsula. These relatively small changes in rainfall amounts and local are also supported by pollen and speleothems from the region. The changes do not require a northward shift of the Northern Hemisphere summer ITCZ and intensification of the Indian monsoon rainfall. We propose that (a) latitudinal and slight inland expansion of the North African summer monsoon rains across the Red Sea, and (b) uplifted moist air of this monsoon to southwestern Arabia highlands, rather than rains associated with intensification of Indian summer monsoon, as proposed before, increased rains in that region; these African monsoon rains produced the modest paleo-wetlands in downstream hyperarid basins. Furthermore, we postulate that as in present-day, the ITCZ in the Indian Ocean remained at or near the equator all year round, and the Indian summer monsoon, through dynamically induced air subsidence, can reduce rather than enhance summer rainfall in the Levant and neighboring deserts, including Arabia. Our summary suggests a widening to the north of the latitudinal range of the rainfall associated with the North African summer monsoon moisture crossing the Red Sea to the east. We discuss other mechanisms that could have potentially contributed to the formation and maintaining of the modest paleo-wetlands.
影响因子：
2.2
作者：
Engel, Max;Brueckner, Helmut;Frenzel, Peter
通讯作者：
Frenzel, Peter
非洲湿润期（15-5 ka BP）期间太阳辐射变化对刚果空气边界迁移和肯尼亚北部裂谷古苏古塔湖水位的影响
DOI：
10.1016/j.palaeo.2013.12.007
发表时间：
2014
期刊：
Palaeogeography, Palaeoclimatology, Palaeoecology
影响因子：
--
作者：
Junginger;Roller;Trauth
通讯作者：
Trauth