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| DOI | 10.1016/j.epsl.2020.116677 |
| Water isotopic constraints on the enhancement of the mid-Holocene West African monsoon | |
| Thompson A.J.; Tabor C.R.; Poulsen C.J.; Skinner C.B. | |
| 发表日期 | 2021 |
| ISSN | 0012821X |
| 卷号 | 554 |
| 英文摘要 | During the early to mid-Holocene, changes in orbital precession led to considerable increases in West African monsoon (WAM) rainfall compared to today and shifted its reach further north. However, climate proxies and paleoclimate model simulations disagree over fundamental aspects of the mid-Holocene (MH; 6 ka BP) enhancement of the WAM. Here, we use a water isotope-enabled Earth system model (iCESM1) to, for the first time, directly compare simulated northern African hydroclimatic change between the mid-Holocene and pre-industrial era (PI) with the hydroclimate signal inferred from leaf wax n-alkanes in order to study the WAM's past spatial change. iCESM1 simulates a northernmost WAM extent of ∼24°N, which broadly agrees with the extent inferred from pollen and dust records (23–28°N) but falls short of that from leaf wax n-alkanes (27–31°N). While the isotopic composition of rainfall (δDP) inferred from leaf wax n-alkanes is lower during the MH than the PI, simulated MH δDP is higher in northwestern Africa, especially in boreal fall. This discrepancy can be reconciled by interpreting the inferred signal of leaf wax n-alkanes as being reflective of the isotopic composition of soil water (δDS) and its subsequent influence by soil evaporation. We postulate that leaf wax n-alkanes may overestimate inferred mean annual precipitation rates in the MH by not incorporating the enrichment of precipitation shown by iCESM1. Our results have broad implications for reconstruction of past hydrologic change in northern Africa and lend further support to the northernmost WAM extents inferred from pollen and dust records. © 2020 Elsevier B.V. |
| 关键词 | Green Saharaleaf wax n-alkanesmodel-proxy comparisonwater isotope-enabled Earth system modelsWest African monsoon |
| 英文关键词 | Atmospheric thermodynamics; Climate models; Dust; Hydrocarbons; Isotopes; Orbits; Rain; Soil moisture; Earth system model; Hydrologic changes; Isotopic composition; Mean annual precipitation; Model simulation; Orbital precession; Soil evaporations; West African Monsoon; Paraffins; climate modeling; comparative study; Holocene; isotopic composition; monsoon; paleoclimate; paleohydrology; palynology; proxy climate record; reconstruction; soil water; water chemistry; West Africa |
| 语种 | 英语 |
| 来源期刊 | Earth and Planetary Science Letters
 |
| 文献类型 | 期刊论文 |
| 条目标识符 | http://gcip.llas.ac.cn/handle/2XKMVOVA/203311 |
| 作者单位 | University of Michigan, Department of Earth and Environmental Sciences, United States; University of Connecticut, Department of Geosciences, United States; University of Massachusetts Lowell, Department of Environmental, Earth and Atmospheric Sciences, United States |
| 推荐引用方式 GB/T 7714 | Thompson A.J.,Tabor C.R.,Poulsen C.J.,et al. Water isotopic constraints on the enhancement of the mid-Holocene West African monsoon[J],2021,554. |
| APA | Thompson A.J.,Tabor C.R.,Poulsen C.J.,&Skinner C.B..(2021).Water isotopic constraints on the enhancement of the mid-Holocene West African monsoon.Earth and Planetary Science Letters,554. |
| MLA | Thompson A.J.,et al."Water isotopic constraints on the enhancement of the mid-Holocene West African monsoon".Earth and Planetary Science Letters 554(2021). |
| 条目包含的文件 | 条目无相关文件。 | |||||
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