We analyzed a number of Antarctic climatic proxies including: 1) an annual proxy covering the time interval 1800-2003, 2) four low-resolution (tens to hundreds of years) ice core records covering the last 242,000 year...We analyzed a number of Antarctic climatic proxies including: 1) an annual proxy covering the time interval 1800-2003, 2) four low-resolution (tens to hundreds of years) ice core records covering the last 242,000 years. The main goal of the work was to search for traces of solar influence on Antarctic climate. Both Fourier and wavelet approaches were used in the statistical analyses. We found no evident fingerprints of solar cycles of Schwabe (ca 11 years), Hale (ca 22 years), Gleissberg (century-scale) or Hallstatt (ca 2000 years). Instead a strong variation with period ca 9800 - 11,600 years is present in the long temperature proxies during the last 242,000 years. It was shown that this variation likely was the result of varying CO2 concentration in the atmosphere, although some solar influence cannot be fully excluded. No features of a quasi 10,000 year variation were found in the Greenland δ18O record. The results show that solar-climatic relationship in Antarctica is weaker than in the high-latitude areas of the Northern Hemisphere.展开更多
Currently available proxies were studied as networks for building reconstruction models of the Atlantic Multidecadal Oscillation (AMO). Only proxies that would double the current record length (backwards in time from ...Currently available proxies were studied as networks for building reconstruction models of the Atlantic Multidecadal Oscillation (AMO). Only proxies that would double the current record length (backwards in time from AD 1564) were included. We present two proxy networks and corresponding reconstruction (transfer) models, one for tree-growth based proxies only and another for multiproxies. Both of them show a useful match in timing as well as amplitude with the AMO. These model structures demonstrated reasonable model performance (overall r<sup>2</sup> = 0.45 - 0.36). The time stability of proxy-AMO relationships was also validated. The new models produced acceptable results in cross-calibration-verification (reduction of error and coefficient of efficiency statistics in 1856-1921 and 1922-1990 vary between 0.41 and 0.21). The spatial distribution of these data series indicate that proxies respond to an AMO-like climatic oscillation over much of the Northern Hemisphere.展开更多
文摘We analyzed a number of Antarctic climatic proxies including: 1) an annual proxy covering the time interval 1800-2003, 2) four low-resolution (tens to hundreds of years) ice core records covering the last 242,000 years. The main goal of the work was to search for traces of solar influence on Antarctic climate. Both Fourier and wavelet approaches were used in the statistical analyses. We found no evident fingerprints of solar cycles of Schwabe (ca 11 years), Hale (ca 22 years), Gleissberg (century-scale) or Hallstatt (ca 2000 years). Instead a strong variation with period ca 9800 - 11,600 years is present in the long temperature proxies during the last 242,000 years. It was shown that this variation likely was the result of varying CO2 concentration in the atmosphere, although some solar influence cannot be fully excluded. No features of a quasi 10,000 year variation were found in the Greenland δ18O record. The results show that solar-climatic relationship in Antarctica is weaker than in the high-latitude areas of the Northern Hemisphere.
文摘Currently available proxies were studied as networks for building reconstruction models of the Atlantic Multidecadal Oscillation (AMO). Only proxies that would double the current record length (backwards in time from AD 1564) were included. We present two proxy networks and corresponding reconstruction (transfer) models, one for tree-growth based proxies only and another for multiproxies. Both of them show a useful match in timing as well as amplitude with the AMO. These model structures demonstrated reasonable model performance (overall r<sup>2</sup> = 0.45 - 0.36). The time stability of proxy-AMO relationships was also validated. The new models produced acceptable results in cross-calibration-verification (reduction of error and coefficient of efficiency statistics in 1856-1921 and 1922-1990 vary between 0.41 and 0.21). The spatial distribution of these data series indicate that proxies respond to an AMO-like climatic oscillation over much of the Northern Hemisphere.
