Southern hemisphere winter cold-air mesocyclones: Climatic environments and associations with teleconnections

C. Claud, Andrew Mark Carleton, B. Duchiron, P. Terray

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

Cold-air mesocyclones remain a forecasting challenge in the southern hemisphere middle and higher latitudes, where conventional observations are lacking. One way to improve mesocyclone predictability is to determine their larger-scale circulation environments and associations with teleconnection patterns. To help realize this objective, reanalysis datasets on atmospheric and upper-ocean synoptic variables important in mesocyclone development are composited and compared to previously published mesocyclone spatial inventories. These analyses demonstrate a consistent association between higher frequencies of mesocyclones, greater sea ice extent and large positive differences in the SST minus low-altitude air temperature fields, coinciding with enhanced westerly low-level winds having a southerly component. Composites in the 1979-2001 period also were formed for opposite phases of El Niño Southern Oscillation (ENSO), the Southern Annular Mode (SAM) and the Trans-Polar Index (TPI). Regions likely to be favorable for mesocyclone development relative to climatology were identified. The largest (smallest) variations in meso-cyclogenesis occur in the South Pacific (South Indian Ocean, south of Australia), and are dominated by ENSO. The SAM and TPI are of secondary importance, yet still influential, and exhibit strong regional-scale variations.

Original languageEnglish (US)
Pages (from-to)383-408
Number of pages26
JournalClimate Dynamics
Volume33
Issue number2-3
DOIs
StatePublished - Jan 1 2009

All Science Journal Classification (ASJC) codes

  • Atmospheric Science

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