Analyzing the Structure and Evolution of Southern Hemisphere Synoptic Variability Using a New Reanalysis Observations Database

Suny At Stony Brook, Stony Brook NY

Investigators

Abstract

Weather and climate in the mid-latitudes are dominated by synoptic scale storms, i.e. cyclones and anticyclones. Associated with baroclinic waves that constitute the tropospheric extension of these storms, they are responsible for heat, momentum and moisture exchanges that make up important parts of the general circulation. Historically, the three-dimensional structure of baroclinic waves was only appreciated when upper air soundings became available. More recently, global datasets derived from the operational databases of weather services using data assimilation techniques (40 years of re-analyses) have attempted to describe the four-dimensional aspects of the general circulation. As the coverage of in-situ data is far less than in the Northern Hemisphere, the representation of the statistics of baroclinic waves in the Southern Hemisphere in those re-analyses differ considerably between products from different weather services. The PI will study these statistics using the original observations database that has just become available. The PI will investigate the true amplitude of the Southern Hemisphere storm track, and the structure and evolution of synoptic scale perturbations. The work will have implications beyond the immediate goal of understanding temporally and vertically correlated features at individual Southern Hemisphere observing sites. The most important features will be the calibration of re-analyses that are often used to study large-scale atmospheric variability, and possible implications of the results for future data assimilation products.