Observed and simulated inter-decadal changes in the structure of Southern Hemisphere large-scale circulation

Verfasser / Beitragende:
[Ana Freitas, Jorgen Frederiksen, Jennifer Whelan, Terence O'Kane, Tércio Ambrizzi]
Ort, Verlag, Jahr:
2015
Enthalten in:
Climate Dynamics, 45/11-12(2015-12-01), 2993-3017
Format:
Artikel (online)
ID: 605472645
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024 7 0 |a 10.1007/s00382-015-2519-z  |2 doi 
035 |a (NATIONALLICENCE)springer-10.1007/s00382-015-2519-z 
245 0 0 |a Observed and simulated inter-decadal changes in the structure of Southern Hemisphere large-scale circulation  |h [Elektronische Daten]  |c [Ana Freitas, Jorgen Frederiksen, Jennifer Whelan, Terence O'Kane, Tércio Ambrizzi] 
520 3 |a Several studies have identified that, in the mid-1970s to early 1980s, a major shift occurred in the structure of the large-scale circulation in both hemispheres. This work employs the CSIRO Mk3L general circulation model in ensemble simulations with observed sea surface temperatures (SSTs) and historical time-evolving carbon dioxide (CO2) concentrations to investigate the inter-decadal changes found observationally in the jet streams, temperature, Hadley circulation, mean sea level pressure and precipitation. First, the performance of the model in simulating these changes for the mean July climate fields of 1949-1968 and 1975-1994, in comparison with the corresponding observations (NCEP/NCAR Reanalysis I and the Twentieth Century Reanalysis V2), is investigated. We find that the model is quite skilful in reproducing the broad features of the important inter-decadal changes that occurred in the mid-1970s. The model simulations and the NCEP/NCAR and twentieth century reanalyses agree in the eastern hemisphere; whereas in the western hemisphere the reanalyses show differences, and the simulations combine aspects of these two datasets. The role of the direct radiative forcing due to CO2 in driving the inter-decadal changes is also examined. Results indicate that, in comparison with the indirect effect of CO2 carried by the changing SSTs, there is little additional impact of the direct radiative forcing due to CO2 on the changes in the latter period. However, our simulations with fixed CO2 concentration have shown clearly that the atmospheric simulations with historical time-evolving CO2 concentrations are more skilful in reproducing the inter-decadal changes. The sensitivity of the ensemble results to employing the same or different time evolving sea ice boundary conditions in the ensemble members is also studied. The contributions of internal and external variability are discussed. 
540 |a Springer-Verlag Berlin Heidelberg, 2015 
690 7 |a Jet streams  |2 nationallicence 
690 7 |a Hadley circulation  |2 nationallicence 
690 7 |a Temperature  |2 nationallicence 
690 7 |a Mean sea level pressure  |2 nationallicence 
690 7 |a Precipitation  |2 nationallicence 
700 1 |a Freitas  |D Ana  |u Institute of Astronomy, Geophysics and Atmospheric Sciences, University of Sao Paulo, 05508-090, São Paulo, SP, Brazil  |4 aut 
700 1 |a Frederiksen  |D Jorgen  |u CSIRO Oceans and Atmosphere Flagship, Aspendale, VIC, Australia  |4 aut 
700 1 |a Whelan  |D Jennifer  |u CSIRO Oceans and Atmosphere Flagship, Aspendale, VIC, Australia  |4 aut 
700 1 |a O'Kane  |D Terence  |u CSIRO Oceans and Atmosphere Flagship, Hobart, TAS, Australia  |4 aut 
700 1 |a Ambrizzi  |D Tércio  |u Institute of Astronomy, Geophysics and Atmospheric Sciences, University of Sao Paulo, 05508-090, São Paulo, SP, Brazil  |4 aut 
773 0 |t Climate Dynamics  |d Springer Berlin Heidelberg  |g 45/11-12(2015-12-01), 2993-3017  |x 0930-7575  |q 45:11-12<2993  |1 2015  |2 45  |o 382 
856 4 0 |u https://doi.org/10.1007/s00382-015-2519-z  |q text/html  |z Onlinezugriff via DOI 
898 |a BK010053  |b XK010053  |c XK010000 
900 7 |a Metadata rights reserved  |b Springer special CC-BY-NC licence  |2 nationallicence 
908 |D 1  |a research-article  |2 jats 
949 |B NATIONALLICENCE  |F NATIONALLICENCE  |b NL-springer 
950 |B NATIONALLICENCE  |P 856  |E 40  |u https://doi.org/10.1007/s00382-015-2519-z  |q text/html  |z Onlinezugriff via DOI 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Freitas  |D Ana  |u Institute of Astronomy, Geophysics and Atmospheric Sciences, University of Sao Paulo, 05508-090, São Paulo, SP, Brazil  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Frederiksen  |D Jorgen  |u CSIRO Oceans and Atmosphere Flagship, Aspendale, VIC, Australia  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Whelan  |D Jennifer  |u CSIRO Oceans and Atmosphere Flagship, Aspendale, VIC, Australia  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a O'Kane  |D Terence  |u CSIRO Oceans and Atmosphere Flagship, Hobart, TAS, Australia  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Ambrizzi  |D Tércio  |u Institute of Astronomy, Geophysics and Atmospheric Sciences, University of Sao Paulo, 05508-090, São Paulo, SP, Brazil  |4 aut 
950 |B NATIONALLICENCE  |P 773  |E 0-  |t Climate Dynamics  |d Springer Berlin Heidelberg  |g 45/11-12(2015-12-01), 2993-3017  |x 0930-7575  |q 45:11-12<2993  |1 2015  |2 45  |o 382