General Atmospheric Circulation Studies

这个研究项目旨在提高对 和预测具有较长时间尺度的大气变率 一个多星期 这种“低频变异性”是由以下因素产生的： 外部强迫（如年周期），动力过程 大气层内部，如阻塞，以及相互作用 大气层和底层介质（主要是 海洋混合层和陆面水文学）。 研究 包括使用统计学方法对观测数据集进行诊断， 技术，如合成，数字滤波，主要 分量分析、奇异值分解和聚类 分析. 结果根据当前的 对天气和气候系统的理论理解。 的 研究将解决（1）检测和解释 北方气候年际和年代际变率 半球温度场和压力场，（2）非线性方面 低频变异性，包括是否 北方冬季环流表现出明显的 “循环制度”表现在真正的双峰频率 分布;（3）海面格局之间的关系 在不同季节和不同地区观测到的温度异常 世界海洋的不同部分，（4）一些知之甚少 气候平均年周期的各个方面;（5）系统 大范围数值天气预报中的错误。 这 研究之所以重要，是因为它试图增进我们对 天气和气候过程，因此有可能 提高我们预测天气和气候的能力。

This research project is directed at improved understanding and prediction of atmospheric variability with time scales longer than a week. This 'low-frequency variability' is generated by external forcing (as in the annual cycle), dynamical processes internal to the atmosphere such as blocking, and by interactions between the atmosphere and the underlying media (primarily the oceanic mixed layer and the land-surface hydrology). The research involves the diagnosis of observational data sets using statistical techniques such as compositing, digital filtering, principal component analysis, singular value decomposition, and cluster analysis. Results are interpreted in light of the current theoretical understanding of weather and climate systems. The research will address (1) detection and interpretation of interannual and interdecadal climate variability in Northern Hemisphere temperature and pressure fields, (2) nonlinear aspects of low-frequency variability including the question of whether the Northern Hemisphere winter circulation exhibits distinct 'circulation regimes' manifested in truly bimodal frequency distributions, (3) relationships between patterns of sea-surface temperature anomalies observed in different seasons and in different parts of the world ocean, (4) some poorly understood aspects of the climatological mean annual cycle and (5) systematic errors in extended-range numerical weather prediction. This research is important because it seeks to improve our understanding of weather and climate processes and hence has the potential for improving our ability to predict weather and climate.