Atmospheric circulation reconstruction based on glaciochemical records requires knowledge of chemical concentration controls,such as source,transport pathway and strength.To gain insight into these processes,the relat...Atmospheric circulation reconstruction based on glaciochemical records requires knowledge of chemical concentration controls,such as source,transport pathway and strength.To gain insight into these processes,the relationships between glaciochemical records from two Northern Hemisphere sites(Mt.Logan in Yukon Territory and 20D in southern Greenland)and instrumental sea level pressure(SLP)series are investigated.Calibrations between Mt.Logan sea-salt sodium(ssNa+)concentration and SLP series show that ssNa+concentrations are closely correlated with the autumntime(SON)Aleutian Low and the summertime(JJA)North Pacific Subtropical High.Both the deepened Aleutian Low and enhanced North Pacific Sub-tropical High strengthen the transport of sea-salt aerosols from the North Pacific to the Mt.Logan region.Calibrations between 20D ssNa+concentrations and SLP series indicate that ssNa+concentrations are closely related to the wintertime(Jan.)Icelandic Low.A deepening of the Icelandic Low strengthens winter storms and frequent cyclogenesis over the North Atlantic and pushes more sea-salt laden air masses to the Greenland ice sheet.Therefore,ice core ssNa+records from the Mt.Logan region can be considered as a proxy for reconstructing the au-tumntime Aleutian Low and summertime North Pacific Subtropical High,and the ssNa+records from Greenland ice core(20D)may provide a proxy for reconstructing the wintertime Icelandic Low.展开更多
Calibrations between sodium （Na^＋） concentrations from a Mt. Logan ice core and sea level pressure （SLP） series show that Na^＋ concentrations are closely correlated with the autumn-time （September-October-Novem...Calibrations between sodium （Na^＋） concentrations from a Mt. Logan ice core and sea level pressure （SLP） series show that Na^＋ concentrations are closely correlated with the autumn-time （September-October-November） Aleutian low （AleuLow）. A deepening of the AleuLow strengthens the transport of sea-salt aerosols from the North Pacific to the Mt. Logan region. The Mt. Logan Na^＋ record is used to develop a 292 a （1688-1979） reconstruction of the AleuLow revealing a dramatic intensification of atmospheric circulation over the North Pacific region since the 20th century. Mean SLP of the AleuLow was about 1 hPa lower during the 20th century than during prior periods. The strongest deepening of the AleuLow appeared in the 1950s. Significant correlations are also found between the Mt. Logan AleuLow proxy series and the Pacific decadal oscillation （PDO） and Pacific circulation （PC） index during the 20th century. Evolutionary spectral analysis of the proxy record shows significant periodicities from 15 to 30 a consistent with PDO fluctuations and the bidecadal oscillation of North Pacific atmosphere-ocean circulation. A period of 11 a in the AleuLow record may be associated with the Schwabe 11-a cycle of sunspot activity. Additional longer ice core records from this region will aid in the efforts to further understand the climatic change over the North Pacific region.展开更多
The most reliable archive of atmospheric CO_(2) information comprises ice core records spanning the last 800 ka(thousand years ago).The connection between temperature and greenhouse gases,as deduced from ice core reco...The most reliable archive of atmospheric CO_(2) information comprises ice core records spanning the last 800 ka(thousand years ago).The connection between temperature and greenhouse gases,as deduced from ice core records,may help better simulate CO_(2) variations.This research aimed to explore the model methods to precisely predict the atmospheric CO_(2) concentrations and fill the CO_(2) data gaps with CH4 concentration and temperature proxies(δD andδ18O)from Antarctica ice cores,employing Artificial Neural Network(ANN)and Wavelet Transform(WT)techniques.This study was divided into three sections to examine various timescales and resolutions.First,coarse-resolution CO_(2) records from the Vostok and EPICA Dronning Maud Land cores from 70–120 ka were used.Second,the models were applied to the Dome Fuji core for 9–120 ka.Finally,a high-resolution West Antarctic Ice Sheet(WAIS)Divide ice core record,focusing on the 9–70 ka,was employed.The results showed that between 70–120 ka,the hybrid method surpasses the traditional ANN approach.The hybrid method maintained superior performance in the last phase by utilizing high-resolution WAIS record.The results indicated improved accuracy(r=0.98),reinforcing the notion that hybrid methods yield better outcomes than those relying solely on AI methods.展开更多
GREENHOUSE gases such as CH<sub>4</sub> in the ancient atmospheric concentration can be reconstructed by extracting and analyzing the gases trapped in polar ice core bubbles. It is a new attempt to extract...GREENHOUSE gases such as CH<sub>4</sub> in the ancient atmospheric concentration can be reconstructed by extracting and analyzing the gases trapped in polar ice core bubbles. It is a new attempt to extract and analyze the CH<sub>4</sub> concentration in Dunde ice core for the study of mountain glacier. Samples were taken from the about 140-m ice core drilled in 1987 in Dunde ice cap in Qilian Mountain. The ice core has been well preserved in cold room. 12 samples were taken from the upper 95 m, and cut to 15 cm in length and 5cm in diameter. CH<sub>4</sub> concentrations were measured in CNRS Laboratory of Glaciology, Grenoble, France.展开更多
基金supported by the Nati onal Natural Science Foundation of China(Distinguis lbed Innovat ion Group,40071025)Chinese Academy of Sci ences(Grant Nos.Talent Project KZCX1-10-09,KZCX3-SW-339)+5 种基金Diector Fund of Key Laboratory of Ice Core and Cold Regions Fnvironment,Cold and Arid Regions Environmental and Engineeni ng Research Institute,CASThe First Chinese National Arctic R es earch ExpeditionUS Nat ional Science Founda tion(ATM-0139481,ESE-9904069)the Electric Power Research Ins titutethe US Environmental Protection Agency,and Environment Canadasupport from the Arctic Institute of North America,University of Calgary,and S.Whitlow,M.Spencer and C.Buck for analyzing samples from both cores.
文摘Atmospheric circulation reconstruction based on glaciochemical records requires knowledge of chemical concentration controls,such as source,transport pathway and strength.To gain insight into these processes,the relationships between glaciochemical records from two Northern Hemisphere sites(Mt.Logan in Yukon Territory and 20D in southern Greenland)and instrumental sea level pressure(SLP)series are investigated.Calibrations between Mt.Logan sea-salt sodium(ssNa+)concentration and SLP series show that ssNa+concentrations are closely correlated with the autumntime(SON)Aleutian Low and the summertime(JJA)North Pacific Subtropical High.Both the deepened Aleutian Low and enhanced North Pacific Sub-tropical High strengthen the transport of sea-salt aerosols from the North Pacific to the Mt.Logan region.Calibrations between 20D ssNa+concentrations and SLP series indicate that ssNa+concentrations are closely related to the wintertime(Jan.)Icelandic Low.A deepening of the Icelandic Low strengthens winter storms and frequent cyclogenesis over the North Atlantic and pushes more sea-salt laden air masses to the Greenland ice sheet.Therefore,ice core ssNa+records from the Mt.Logan region can be considered as a proxy for reconstructing the au-tumntime Aleutian Low and summertime North Pacific Subtropical High,and the ssNa+records from Greenland ice core(20D)may provide a proxy for reconstructing the wintertime Icelandic Low.
基金This research was supported by the National Natural Science Foundation of China under contract No.40401054the Talent Project and Innovation Project of the Chinese Academy of Sciences under contract Nos KZCX3-SW-339 and KZCX1-10-09the US National Science Foundation under contract No.ATM0139491.
文摘Calibrations between sodium （Na^＋） concentrations from a Mt. Logan ice core and sea level pressure （SLP） series show that Na^＋ concentrations are closely correlated with the autumn-time （September-October-November） Aleutian low （AleuLow）. A deepening of the AleuLow strengthens the transport of sea-salt aerosols from the North Pacific to the Mt. Logan region. The Mt. Logan Na^＋ record is used to develop a 292 a （1688-1979） reconstruction of the AleuLow revealing a dramatic intensification of atmospheric circulation over the North Pacific region since the 20th century. Mean SLP of the AleuLow was about 1 hPa lower during the 20th century than during prior periods. The strongest deepening of the AleuLow appeared in the 1950s. Significant correlations are also found between the Mt. Logan AleuLow proxy series and the Pacific decadal oscillation （PDO） and Pacific circulation （PC） index during the 20th century. Evolutionary spectral analysis of the proxy record shows significant periodicities from 15 to 30 a consistent with PDO fluctuations and the bidecadal oscillation of North Pacific atmosphere-ocean circulation. A period of 11 a in the AleuLow record may be associated with the Schwabe 11-a cycle of sunspot activity. Additional longer ice core records from this region will aid in the efforts to further understand the climatic change over the North Pacific region.
基金supported by the Brain Pool Program through the National Research Foundation of Korea(NRF)and funded by the Ministry of Science and ICT[Grant numbers:2020H1D3A1A04081353,2020M1A5A1110607,2018R1A5A1024958,and RS-2023-00291696].
文摘The most reliable archive of atmospheric CO_(2) information comprises ice core records spanning the last 800 ka(thousand years ago).The connection between temperature and greenhouse gases,as deduced from ice core records,may help better simulate CO_(2) variations.This research aimed to explore the model methods to precisely predict the atmospheric CO_(2) concentrations and fill the CO_(2) data gaps with CH4 concentration and temperature proxies(δD andδ18O)from Antarctica ice cores,employing Artificial Neural Network(ANN)and Wavelet Transform(WT)techniques.This study was divided into three sections to examine various timescales and resolutions.First,coarse-resolution CO_(2) records from the Vostok and EPICA Dronning Maud Land cores from 70–120 ka were used.Second,the models were applied to the Dome Fuji core for 9–120 ka.Finally,a high-resolution West Antarctic Ice Sheet(WAIS)Divide ice core record,focusing on the 9–70 ka,was employed.The results showed that between 70–120 ka,the hybrid method surpasses the traditional ANN approach.The hybrid method maintained superior performance in the last phase by utilizing high-resolution WAIS record.The results indicated improved accuracy(r=0.98),reinforcing the notion that hybrid methods yield better outcomes than those relying solely on AI methods.
文摘GREENHOUSE gases such as CH<sub>4</sub> in the ancient atmospheric concentration can be reconstructed by extracting and analyzing the gases trapped in polar ice core bubbles. It is a new attempt to extract and analyze the CH<sub>4</sub> concentration in Dunde ice core for the study of mountain glacier. Samples were taken from the about 140-m ice core drilled in 1987 in Dunde ice cap in Qilian Mountain. The ice core has been well preserved in cold room. 12 samples were taken from the upper 95 m, and cut to 15 cm in length and 5cm in diameter. CH<sub>4</sub> concentrations were measured in CNRS Laboratory of Glaciology, Grenoble, France.
