The South American monsoon variability over the last millennium in climate models
| Autor: | Mathias Vuille, Anji Seth, Maisa Rojas, Paola A. Arias, Valentina Flores-Aqueveque |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
010504 meteorology & atmospheric sciences
Atmospheric circulation Stratigraphy lcsh:Environmental protection 010502 geochemistry & geophysics Monsoon 01 natural sciences lcsh:Environmental pollution Tropical monsoon climate lcsh:TD169-171.8 Precipitation Modelos climáticos lcsh:Environmental sciences 0105 earth and related environmental sciences lcsh:GE1-350 Global and Planetary Change Intertropical Convergence Zone Paleontology Climatología 13. Climate action Anticyclone Climatology lcsh:TD172-193.5 Climate model South Atlantic Convergence Zone Monzones Geology |
| Zdroj: | Climate of the Past, Vol 12, Iss 8, Pp 1681-1691 (2016) Repositorio UdeA Universidad de Antioquia instacron:Universidad de Antioquia |
| ISSN: | 1814-9332 1814-9324 |
| Popis: | In this paper we assess South American monsoon system (SAMS) variability in the last millennium as depicted by global coupled climate model simulations. High-resolution proxy records for the South American monsoon over this period show a coherent regional picture of a weak monsoon during the Medieval Climate Anomaly and a stronger monsoon during the Little Ice Age (LIA). Due to the small external forcing during the past 1000 years, model simulations do not show very strong temperature anomalies over these two specific periods, which in turn do not translate into clear precipitation anomalies, in contrast with the rainfall reconstructions in South America. Therefore, we used an ad hoc definition of these two periods for each model simulation in order to account for model-specific signals. Thereby, several coherent large-scale atmospheric circulation anomalies are identified. The models feature a stronger monsoon during the LIA associated with (i) an enhancement of the rising motion in the SAMS domain in austral summer; (ii) a stronger monsoon-related upper-tropospheric anticyclone; (iii) activation of the South American dipole, which results in a poleward shift of the South Atlantic Convergence Zone; and (iv) a weaker upper-level subtropical jet over South America. The diagnosed changes provide important insights into the mechanisms of these climate anomalies over South America during the past millennium. |
| Databáze: | OpenAIRE |
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