Tropospheric Circulation Variability over Central and Southern South America
Tropospheric Circulation Variability over Central and Southern South America作者机构：Centro Nacional Patagónico CNP (CONICET) Puerto Madryn Argentina Centro de Investigaciones del Mar y la Atmósfera CIMA (CONICET/UBA) Buenos Aires Argentina
出 版 物：《Atmospheric and Climate Sciences》 (大气和气候科学（英文）)
年 卷 期：2014年第4卷第5期
页 面：956-978页
学科分类：07[理学] 070601[理学-气象学] 0706[理学-大气科学]
主 题：Tropospheric Circulation Variability SESA
摘 要：Combined Empirical Orthogonal Function Analysis of low-level atmospheric circulation after filtering the synoptic scale was performed for the period 1981-2006 over Central and Southern South America. Modes with 40 and near 70 days frequency associated with swings in longitude of the South Pacific and South Atlantic Ocean heights were identified. Their extreme values were related to drought and to high anomalous precipitation associated to floods in South East South America (SESA). These modes were independent of other sources of variability of the Southern Hemisphere atmosphere, namely MJO (Madden-Julian Oscillation), ENSO (El Nino Southern Oscillation) and AAO (Antarctic Oscillation). Mode one, which in its positive phase has a circulation similar to the mean winter, has a trend that explains part of the winter warming observed since 1980’s in Central and Eastern Argentina. Variance was calculated for the intra-annual variability, the one associated to the inter-annual variability including trends and jumps, and that of the annual cycle. The partition of the total variance was roughly 70%, 10% and 20% respectively. This partition implies that predictability of the regional climate is more critically dependent on the predictability of the intra-annual variability than of the inter-annual variability.
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