Oxygen stable isotopic and ionic records, cov- ering a period of 1745—1996, are recovered in DT001 ice core drilled in Princess Elizabeth Land, East Antarctica. Using empirical orthogonal function (EOF) analysis of t...Oxygen stable isotopic and ionic records, cov- ering a period of 1745—1996, are recovered in DT001 ice core drilled in Princess Elizabeth Land, East Antarctica. Using empirical orthogonal function (EOF) analysis of the annually resolved glaciochemical time series, we find the first EOF (EOF1) represents sea-salt aerosols and is the proxy of sea level pressure (SLP) over a quasi-stationary low in the Southern Indian Ocean (SIO). δ O represents the sea sur- 18 face temperature (SST) of the same ocean area. In the past two decades, four climatic waves as represented by SLP and SST proxies are found in the DT001 ice core, which in coin- cident with four Antarctic Circum-polar Waves (ACW) as revealed by NCEP/NCAR reanalysis. The phase difference between SST and SLP in the ice core is also coincident with that in ACW. Both ice-core record and reanalysis suggest that there were no signals of ACW during 1958—1980, none during the overall recording period between 1745—1996, as there is no regular phase difference between SST and SLP. The ACW signal after early 1980s is probably attributable to the climate shift occurring over Antarctic Peninsula-Drake Passage region.展开更多
The surface-snow geochemical characteristics are discussed on the East Antarctic Ice Sheet, depending on the stable isotopes ratios of oxygen and hydrogen, concentra-tion of impurities (soluble-ions and insoluble micr...The surface-snow geochemical characteristics are discussed on the East Antarctic Ice Sheet, depending on the stable isotopes ratios of oxygen and hydrogen, concentra-tion of impurities (soluble-ions and insoluble micro-particle) in surface snow collected on the ice sheet. The purpose is to study geochemical zones on the East Antarctic Ice Sheet and to research sources and transportation route of the water vapor and the impurities in surface snow. It has been found that the ratio coefficients, as S1, d1 in the equation dD = S1d18O + d1, are changed near the elevation 2000 m on the ice sheet. The weight ratio of Cl-/Na+ at the area below the ele-vation of 2000 m is close to the ratio in the sea salt; but it is about 2 times that of the sea salt, at the inland area up to the elevation of 2000 m. The concentrations of non-sea-salt Ca2+ ion (nssCa2+) and fine-particle increase at the interior up to the elevation 2000 m. At the region below the elevation of 2000 m, the impurity concentration is decreasing with the elevation increasing. Near coastal region, the surface snow has a high concentration of impurity, where the elevation is below 800 m. Combining the translating processes of wa-ter-vapor and impurities, it suggests that the region up to the elevation 2000 m is affected by large-scale circulation with longitude-direction, and that water-vapor and impurities in surface snow come from long sources. The region below the elevation 2000 m is affected by some strong cyclones acting at peripheral region of the ice sheet, and the sources of water and impurities could be at high latitude sea and coast. The area below elevation 800 m is affected by local coastal cy-clones.展开更多
Formate and acetate are ubiquitous in the troposphere. Their occurrence is closely related to processes in the biosphere and contributes to an understanding of carbon biogeochemical cycles. A 43-year record of formate...Formate and acetate are ubiquitous in the troposphere. Their occurrence is closely related to processes in the biosphere and contributes to an understanding of carbon biogeochemical cycles. A 43-year record of formate and acetate in an ice core from Glacier 1 (43?6′N, 86?9′E) at Urumqi river head, Tianshan, west China was investigated. Fluctuating between 22.7 ng·g-1 and 2830.7 ng·g-1, acetate concentration averages 373.2 ?376.1 ng·g-1 (mean ?1s, N = 541) and is the highest anion in the record. Next to acetate, the concentration for formate varies between 2.1 ng·g-1 and 795.5 ng·g-1 and averages 61.1 ?89.0 ng·g-1 (N = 541). The formate to acetate ratio averages 0.22 ?0.25 (N = 541), indicating that the chief source is from fossil fuel combustion, coal burning in particular. The two species co-varied in the past four decades and exhibited periods of high concentration from the early 1960s to the middle of 1970s and from the early 1980s to the middle of 1990s, separated by a time of the lower concentration between 1975—1980. These variations may reflect the local/regional anthropogenic pollution to the atmosphere as well as the economic development of northwestern China.展开更多
基金This study was supported by the National Natural Science Foundation of China(Grant No.40305007)Ministry of Science and Technology of China(Grant No.2001CB711003).
文摘Oxygen stable isotopic and ionic records, cov- ering a period of 1745—1996, are recovered in DT001 ice core drilled in Princess Elizabeth Land, East Antarctica. Using empirical orthogonal function (EOF) analysis of the annually resolved glaciochemical time series, we find the first EOF (EOF1) represents sea-salt aerosols and is the proxy of sea level pressure (SLP) over a quasi-stationary low in the Southern Indian Ocean (SIO). δ O represents the sea sur- 18 face temperature (SST) of the same ocean area. In the past two decades, four climatic waves as represented by SLP and SST proxies are found in the DT001 ice core, which in coin- cident with four Antarctic Circum-polar Waves (ACW) as revealed by NCEP/NCAR reanalysis. The phase difference between SST and SLP in the ice core is also coincident with that in ACW. Both ice-core record and reanalysis suggest that there were no signals of ACW during 1958—1980, none during the overall recording period between 1745—1996, as there is no regular phase difference between SST and SLP. The ACW signal after early 1980s is probably attributable to the climate shift occurring over Antarctic Peninsula-Drake Passage region.
文摘The surface-snow geochemical characteristics are discussed on the East Antarctic Ice Sheet, depending on the stable isotopes ratios of oxygen and hydrogen, concentra-tion of impurities (soluble-ions and insoluble micro-particle) in surface snow collected on the ice sheet. The purpose is to study geochemical zones on the East Antarctic Ice Sheet and to research sources and transportation route of the water vapor and the impurities in surface snow. It has been found that the ratio coefficients, as S1, d1 in the equation dD = S1d18O + d1, are changed near the elevation 2000 m on the ice sheet. The weight ratio of Cl-/Na+ at the area below the ele-vation of 2000 m is close to the ratio in the sea salt; but it is about 2 times that of the sea salt, at the inland area up to the elevation of 2000 m. The concentrations of non-sea-salt Ca2+ ion (nssCa2+) and fine-particle increase at the interior up to the elevation 2000 m. At the region below the elevation of 2000 m, the impurity concentration is decreasing with the elevation increasing. Near coastal region, the surface snow has a high concentration of impurity, where the elevation is below 800 m. Combining the translating processes of wa-ter-vapor and impurities, it suggests that the region up to the elevation 2000 m is affected by large-scale circulation with longitude-direction, and that water-vapor and impurities in surface snow come from long sources. The region below the elevation 2000 m is affected by some strong cyclones acting at peripheral region of the ice sheet, and the sources of water and impurities could be at high latitude sea and coast. The area below elevation 800 m is affected by local coastal cy-clones.
基金This work was joint-supported by the National Natural Science Foundation of China(Grant No.40073035)Chinese Academy of Sciences(Grant No.CAS 2002-43)Tianshan Glaciological Station.
文摘Formate and acetate are ubiquitous in the troposphere. Their occurrence is closely related to processes in the biosphere and contributes to an understanding of carbon biogeochemical cycles. A 43-year record of formate and acetate in an ice core from Glacier 1 (43?6′N, 86?9′E) at Urumqi river head, Tianshan, west China was investigated. Fluctuating between 22.7 ng·g-1 and 2830.7 ng·g-1, acetate concentration averages 373.2 ?376.1 ng·g-1 (mean ?1s, N = 541) and is the highest anion in the record. Next to acetate, the concentration for formate varies between 2.1 ng·g-1 and 795.5 ng·g-1 and averages 61.1 ?89.0 ng·g-1 (N = 541). The formate to acetate ratio averages 0.22 ?0.25 (N = 541), indicating that the chief source is from fossil fuel combustion, coal burning in particular. The two species co-varied in the past four decades and exhibited periods of high concentration from the early 1960s to the middle of 1970s and from the early 1980s to the middle of 1990s, separated by a time of the lower concentration between 1975—1980. These variations may reflect the local/regional anthropogenic pollution to the atmosphere as well as the economic development of northwestern China.
