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Statistical Reconstruction of the Antarctic Oscillation Index Based on Multiple Proxies
Atmospheric and Oceanic Science Letters, Volume 3 Number 5. Zhang Zi-Yin; Gong Dao-Yi; He Xue-Zhao; et al. - Science Press, 2010Based on multiple proxies from the Southern Hemisphere, an austral summer (December-January-February: DJF) Antarctic Oscillation Index (AAO) since 1500 A.D. was reconstructed with a focus on interannual to interdecadal variability (< 50 a). By applying a multivariate regression method, the observational AAO-proxy relations were calibrated and cross-validated for the period of 1957-89. The regressions were employed to compute the DJF-AAO index for 1500-1956. To verify the results, the authors checked the explained variance (r2), the reduction of error (RE), and the standard error (SE). Cross-va ...
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Available online: http://www.iapjournals.ac.cn/aosl/ch/reader/view_abstract.aspx?file_no=AOSL10053
Zi-Yin Zhang ; Dao-Yi Gong ; Xue-Zhao He ; Yang-Na Lei ; Sheng-Hui Feng
in Atmospheric and Oceanic Science Letters > Volume 3 Number 5 (16 September 2010) . - p.283-287Based on multiple proxies from the Southern Hemisphere, an austral summer (December-January-February: DJF) Antarctic Oscillation Index (AAO) since 1500 A.D. was reconstructed with a focus on interannual to interdecadal variability (< 50 a). By applying a multivariate regression method, the observational AAO-proxy relations were calibrated and cross-validated for the period of 1957-89. The regressions were employed to compute the DJF-AAO index for 1500-1956. To verify the results, the authors checked the explained variance (r2), the reduction of error (RE), and the standard error (SE). Cross-validation was performed by applying a leave-one-out validation method. Over the entire reconstruction period, the mean values of r2, RE, and SE are 59.9%, 0.47, and 0.67, respectively. These statistics indicate that the DJF-AAO reconstruction is relatively skillful and reliable for the last ~460 years. The reconstructed AAO variations on the interannual and interdecadal timescales compare favorably with those of several shorter sea level pressure (SLP)-based AAO indices. The leading periods of the DJF-AAO index over the last 500 years are ~2.4, ~2.6, ~6.3, ~24.1, and ~37.6 years, all of which are significant at the 95% level as estimated by power spectral analysis.
Language(s): English
Format: Digital (Free), Hard copyTags: Meteorology ; Antarctic Oscillation (AAO) ; Research ; Numerical simulation
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Possible Impact of the Boreal Spring Antarctic Oscillation on the North American Summer Monsoon
This study examined the relationship between the boreal spring (April-May) Antarctic Oscillation (AAO) and the North American summer monsoon (NASM) (July-September) for the period of 1979-2008. The results show that these two systems are closely related. When the spring AAO was stronger than normal, the NASM tended to be weaker, and there was less rainfall over the monsoon region. The opposite NASM situation corresponded to a weaker spring AAO. Further analysis explored the possible mechanism for the delayed impact of the boreal spring AAO on the NASM. It was found that the tropical Atlantic s ...
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Available online: http://www.iapjournals.ac.cn/aosl/ch/reader/view_abstract.aspx?file_no=AOSL10041
in Atmospheric and Oceanic Science Letters > Volume 3 Number 4 (16 July 2010) . - p.232-236This study examined the relationship between the boreal spring (April-May) Antarctic Oscillation (AAO) and the North American summer monsoon (NASM) (July-September) for the period of 1979-2008. The results show that these two systems are closely related. When the spring AAO was stronger than normal, the NASM tended to be weaker, and there was less rainfall over the monsoon region. The opposite NASM situation corresponded to a weaker spring AAO. Further analysis explored the possible mechanism for the delayed impact of the boreal spring AAO on the NASM. It was found that the tropical Atlantic sea surface temperature (SST) plays an important role in the connection between the two phenomena. The variability of the boreal spring AAO can produce anomalous SSTs over the tropical Atlantic. These SST anomalies can persist from spring to summer and can influence the Bermuda High, affecting water vapor transportation to the monsoon region. Through these processes, the boreal spring AAO exerts a significantly delayed impact on the amount of NASM precipitation. Thus, information about the boreal spring AAO is valuable for the prediction of the NASM.
Language(s): English
Format: Digital (Free), Hard copyTags: North America ; Region IV - North America, Central America and the Caribbean ; Aurora ; Monsoon ; Antarctic Oscillation (AAO)
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