Submonthly Convective Variability over South America and the South Atlantic Convergence Zone
Submonthly Convective Variability over South America and the South Atlantic Convergence Zone
复制标题
南美洲和南大西洋辐合区的次月对流变化
DOI：
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发表时间：
1999
期刊：
影响因子：
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通讯作者：
John D. Glick
中科院分区：
文献类型：
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作者：
B. Liebmann;G. Kiladis;J. Marengo;T. Ambrizzi;John D. Glick
本文研究了南美洲上空深对流与大气环流的关系，着重分析了南大西洋辐合带（SACZ）在南半球夏季的次月变化。向外的长波辐射（OLR）被用作对流的替代，而相关的环流模式由国家环境预测再分析中心描述。在南美洲和邻近的海洋，OLR波动周期小于90天，在SACZ和南美洲中部在12月至2月期间显示出最大的变化。在亚马逊盆地南部，平均对流最大的地方，方差最小。OLR谱显示了几个统计相关的峰值对应于热带南美洲不到30天的时间，随着基网格点向东南移动，高频功率的相对比例增加。亚月（2-30天）OLR与大气环流的相关性
Abstract Relationships between deep convection over South America and the atmospheric circulation are examined, with emphasis on submonthly variations of the South Atlantic convergence zone (SACZ) during austral summer. Outgoing longwave radiation (OLR) is used as a proxy for convection, while the associated circulation patterns are depicted by the National Centers for Environmental Prediction Reanalysis. Over South America and the adjacent oceans, OLR fluctuations with periods less than 90 days show maximum variance in the SACZ and over central South America during December–February. There is a local minimum in variance over the southern Amazon Basin, where mean convection is at a maximum. OLR spectra display several statistically relevant peaks corresponding to periods of less than 30 days over tropical South America, with the relative proportion of higher-frequency power increasing as the base grid point is moved to the southeast within the SACZ. Correlations between submonthly (2–30-day) OLR in the vi...