2003), Interannual Antarctic tropospheric circulation and precipitation variability

• Main Authors: Christophe Genthon, Gerhard Krinner, Michel Sacchettini
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Antarctic; The Antarctic; Antarc*
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.691.5668; http://lgge.obs.ujf-grenoble.fr/%7Echristo/antvar/climdyn.pdf

Main modes of variability of the Antarctic tropospheric circulation (500 hPa geopotential height) and precipitation are identified through their Empirical Orthogonal Functions (EOF). This is done by combining various sources of information, including meteorological analyses and forecasts (NCEP and ECMWF), atmospheric general circulation model (LMDZ) simula-tions, and satellite data (GPCP). Unlike previous similar work on circulation variability, the mode analyses are restricted to the Antarctic region. The main modes that relate the Antarctic region to the mid and tropical latitudes, e.g. in association with ENSO, are nonetheless clearly identified and thus robust. The contribution of the sea-surface or of the circumpolar Antarctic atmospheric dynamics to the occurrence and to the chronology of these modes is evaluated 3 / 47 through various atmospheric model simulations. EOF analyses results are somewhat less sta-ble, across the various datasets, and more noisy for precipitation than for circulation. Yet, through moisture advection considerations, the 2 most significant precipitation modes can be well related to the 3 main modes of circulation variability. The signatures of both the Southern