The Experts below are selected from a list of 60513 Experts worldwide ranked by ideXlab platform
Hailiang Dong - One of the best experts on this subject based on the ideXlab platform.
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deglacial and holocene archaeal lipid inferred paleohydrology and paleotemperature history of lake qinghai northeastern qinghai tibetan plateau
Quaternary Research, 2015Co-Authors: Huanye Wang, Hailiang Dong, Chuanlun Zhang, Hongchen Jiang, Zhonghui Liu, Meixun Zhao, Weiguo LiuAbstract:Abstract We investigate the distribution of archaeal lipids in a 5.8-m-long sedimentary core recovered from Lake Qinghai to extract regional hydroclimate and temperature signals since the last deglaciation for this important region. The paleohydrology was reconstructed from the relative abundance of thaumarchaeol (%thaum) and the archaeol and caldarchaeol ecometric (ACE) index. The %thaum-inferred lake-level record was extended to deglaciation, showing three periods (11.9–13.0, 14.1–14.7 and 15.1–17.2 cal ka BP) with relatively higher lake levels than those during the early Holocene. The ACE record demonstrates three periods (10.6–11.2, 13.2–13.4 and 17.4–17.6 cal ka BP) of elevated salinity when the lake was shallow. Filtered TEX86 record based on archaeal lipid distributions corresponded to relatively higher lake levels, implying that a certain lake size is required for using the TEX86 paleothermometer. At 1–4 cal ka BP, the reconstructed temperature fluctuated significantly and correlated negatively with inferred lake level, indicating that lake temperature and Hydrological Change might be coupled during this period. We attribute this co-variance to the importance of summer temperature in controlling evaporation for this arid/semi-arid region. Moreover, our results indicate that archaeal lipids have potential in reconstructing paleoclimate patterns from lacustrine sedimentary cores, but the data should be interpreted with care.
Chuanlun Zhang - One of the best experts on this subject based on the ideXlab platform.
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deglacial and holocene archaeal lipid inferred paleohydrology and paleotemperature history of lake qinghai northeastern qinghai tibetan plateau
Quaternary Research, 2015Co-Authors: Huanye Wang, Hailiang Dong, Chuanlun Zhang, Hongchen Jiang, Zhonghui Liu, Meixun Zhao, Weiguo LiuAbstract:Abstract We investigate the distribution of archaeal lipids in a 5.8-m-long sedimentary core recovered from Lake Qinghai to extract regional hydroclimate and temperature signals since the last deglaciation for this important region. The paleohydrology was reconstructed from the relative abundance of thaumarchaeol (%thaum) and the archaeol and caldarchaeol ecometric (ACE) index. The %thaum-inferred lake-level record was extended to deglaciation, showing three periods (11.9–13.0, 14.1–14.7 and 15.1–17.2 cal ka BP) with relatively higher lake levels than those during the early Holocene. The ACE record demonstrates three periods (10.6–11.2, 13.2–13.4 and 17.4–17.6 cal ka BP) of elevated salinity when the lake was shallow. Filtered TEX86 record based on archaeal lipid distributions corresponded to relatively higher lake levels, implying that a certain lake size is required for using the TEX86 paleothermometer. At 1–4 cal ka BP, the reconstructed temperature fluctuated significantly and correlated negatively with inferred lake level, indicating that lake temperature and Hydrological Change might be coupled during this period. We attribute this co-variance to the importance of summer temperature in controlling evaporation for this arid/semi-arid region. Moreover, our results indicate that archaeal lipids have potential in reconstructing paleoclimate patterns from lacustrine sedimentary cores, but the data should be interpreted with care.
Weiguo Liu - One of the best experts on this subject based on the ideXlab platform.
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deglacial and holocene archaeal lipid inferred paleohydrology and paleotemperature history of lake qinghai northeastern qinghai tibetan plateau
Quaternary Research, 2015Co-Authors: Huanye Wang, Hailiang Dong, Chuanlun Zhang, Hongchen Jiang, Zhonghui Liu, Meixun Zhao, Weiguo LiuAbstract:Abstract We investigate the distribution of archaeal lipids in a 5.8-m-long sedimentary core recovered from Lake Qinghai to extract regional hydroclimate and temperature signals since the last deglaciation for this important region. The paleohydrology was reconstructed from the relative abundance of thaumarchaeol (%thaum) and the archaeol and caldarchaeol ecometric (ACE) index. The %thaum-inferred lake-level record was extended to deglaciation, showing three periods (11.9–13.0, 14.1–14.7 and 15.1–17.2 cal ka BP) with relatively higher lake levels than those during the early Holocene. The ACE record demonstrates three periods (10.6–11.2, 13.2–13.4 and 17.4–17.6 cal ka BP) of elevated salinity when the lake was shallow. Filtered TEX86 record based on archaeal lipid distributions corresponded to relatively higher lake levels, implying that a certain lake size is required for using the TEX86 paleothermometer. At 1–4 cal ka BP, the reconstructed temperature fluctuated significantly and correlated negatively with inferred lake level, indicating that lake temperature and Hydrological Change might be coupled during this period. We attribute this co-variance to the importance of summer temperature in controlling evaporation for this arid/semi-arid region. Moreover, our results indicate that archaeal lipids have potential in reconstructing paleoclimate patterns from lacustrine sedimentary cores, but the data should be interpreted with care.
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large scale Hydrological Change drove the late miocene c4 plant expansion in the himalayan foreland and arabian peninsula
Geology, 2007Co-Authors: Yongsong Huang, Steven C Clemens, Weiguo Liu, Yi Wang, Warren L PrellAbstract:Carbon isotope Changes in paleosols from Siwalik, Pakistan, and marine sediments from the Bengal Fan indicate a major C 4 plant expansion in the Himalayan foreland during the late Miocene. However, the timing and mechanisms behind the C 4 plant expansion remain enigmatic. Here we present high-resolution (∼60 k.y.) biomarker and compound-specific isotope data spanning the past 11 m.y. from Ocean Drilling Program Site 722 in the Arabian Sea. An ∼5‰–6‰ increase in leaf wax δ 13 C values indicates a marked rise of C 4 plants from 10 to 5.5 Ma, with accelerated expansion from 7.9 to 5.5 Ma. A concurrent ∼50‰ rise in leaf wax δD values is attributed to a combined effect of Changes in precipitation amount and evaporation, indicating that source regions for the plant waxes became progressively drier from 10 to 5.5 Ma. In contrast to earlier reports, our isotope records, biomarker abundances, alkenone U K′ 37 , and Globigerina bulloides abundance data do not suggest enhanced summer monsoon circulation during this time interval. Rather, our results suggest that large-scale Hydrological Changes drove the late Miocene expansion of C 4 plants in the Himalayan foreland and Arabian Peninsula.
Huanye Wang - One of the best experts on this subject based on the ideXlab platform.
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deglacial and holocene archaeal lipid inferred paleohydrology and paleotemperature history of lake qinghai northeastern qinghai tibetan plateau
Quaternary Research, 2015Co-Authors: Huanye Wang, Hailiang Dong, Chuanlun Zhang, Hongchen Jiang, Zhonghui Liu, Meixun Zhao, Weiguo LiuAbstract:Abstract We investigate the distribution of archaeal lipids in a 5.8-m-long sedimentary core recovered from Lake Qinghai to extract regional hydroclimate and temperature signals since the last deglaciation for this important region. The paleohydrology was reconstructed from the relative abundance of thaumarchaeol (%thaum) and the archaeol and caldarchaeol ecometric (ACE) index. The %thaum-inferred lake-level record was extended to deglaciation, showing three periods (11.9–13.0, 14.1–14.7 and 15.1–17.2 cal ka BP) with relatively higher lake levels than those during the early Holocene. The ACE record demonstrates three periods (10.6–11.2, 13.2–13.4 and 17.4–17.6 cal ka BP) of elevated salinity when the lake was shallow. Filtered TEX86 record based on archaeal lipid distributions corresponded to relatively higher lake levels, implying that a certain lake size is required for using the TEX86 paleothermometer. At 1–4 cal ka BP, the reconstructed temperature fluctuated significantly and correlated negatively with inferred lake level, indicating that lake temperature and Hydrological Change might be coupled during this period. We attribute this co-variance to the importance of summer temperature in controlling evaporation for this arid/semi-arid region. Moreover, our results indicate that archaeal lipids have potential in reconstructing paleoclimate patterns from lacustrine sedimentary cores, but the data should be interpreted with care.
Bjorn Stevens - One of the best experts on this subject based on the ideXlab platform.
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missing iris effect as a possible cause of muted Hydrological Change and high climate sensitivity in models
Nature Geoscience, 2015Co-Authors: Thorsten Mauritsen, Bjorn StevensAbstract:An iris effect in tropical cloud-cover was controversially proposed as a negative climate Change feedback that is not represented in climate models. If such an effect exists, it could go some way to reconciling climate models and observations.
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Missing iris effect as a possible cause of muted Hydrological Change and high climate sensitivity in models
Nature Geoscience, 2015Co-Authors: Thorsten Mauritsen, Bjorn StevensAbstract:An iris effect in tropical cloud-cover was controversially proposed as a negative climate Change feedback that is not represented in climate models. If such an effect exists, it could go some way to reconciling climate models and observations. Equilibrium climate sensitivity to a doubling of CO_2 falls between 2.0 and 4.6 K in current climate models, and they suggest a weak increase in global mean precipitation. Inferences from the observational record, however, place climate sensitivity near the lower end of this range and indicate that models underestimate some of the Changes in the Hydrological cycle. These discrepancies raise the possibility that important feedbacks are missing from the models. A controversial hypothesis suggests that the dry and clear regions of the tropical atmosphere expand in a warming climate and thereby allow more infrared radiation to escape to space. This so-called iris effect could constitute a negative feedback that is not included in climate models. We find that inclusion of such an effect in a climate model moves the simulated responses of both temperature and the Hydrological cycle to rising atmospheric greenhouse gas concentrations closer to observations. Alternative suggestions for shortcomings of models — such as aerosol cooling, volcanic eruptions or insufficient ocean heat uptake — may explain a slow observed transient warming relative to models, but not the observed enhancement of the Hydrological cycle. We propose that, if precipitating convective clouds are more likely to cluster into larger clouds as temperatures rise, this process could constitute a plausible physical mechanism for an iris effect.
