Large, Long-Lived Convective Systems Over Subtropical South America and Their Relationships With Atmospheric Teleconnections

This study provides a climatological assessment of persistent elongated convective systems (PECS) over subtropical South America during the austral warm seasons of 1998-2007 and a comparison of PECS frequency and physical characteristics to mesoscale convective complexes (MCCs) in the region. Relati...

Full description

Bibliographic Details
Main Author: Mattingly, Kyle
Format: Text
Language:unknown
Published: TopSCHOLAR® 2012
Subjects:
Climatology
Meteorology
South America
Mesoscale Convective Systems
Atmospheric Teleconnections
Atmospheric Sciences
Environmental Sciences
Antarctic
Austral
The Antarctic
Antarc*
Online Access:https://digitalcommons.wku.edu/stu_hon_theses/353
https://digitalcommons.wku.edu/cgi/viewcontent.cgi?article=1359&context=stu_hon_theses
Description
Summary:This study provides a climatological assessment of persistent elongated convective systems (PECS) over subtropical South America during the austral warm seasons of 1998-2007 and a comparison of PECS frequency and physical characteristics to mesoscale convective complexes (MCCs) in the region. Relationships between the Antarctic Oscillation (AAO) and El Niño – Southern Oscillation (ENSO) teleconnections and large, long-lived convective systems (LLCSs) are explored. An average of 143 PECS and 37 MCCs occurred per warm season. PECS lasted longer on average than MCCs (17 hrs. vs. 14 hrs.) and reached a greater average maximum cloud-shield extent than MCCs (297,300 km2 vs. 256,500 km2). PECS frequency was maximized over the La Plata river basin during December – February. The relative frequency of LLCS occurrence was greatest during negative AAO phases (0.906 LLCSs/day) and positive ENSO phases (28.1 LLCS/month). LLCS maximum cloud-shield extent was greatest during negative AAO phases and positive ENSO phases. LLCSs tended to be displaced southward during negative AAO phases and neutral ENSO phases. These results suggest that AAO and ENSO phases have at least some influence on LLCSs over SSA. Additionally, the high relative frequency of PECS compared to MCCs suggests they may contribute substantially to yearly precipitation totals in the region.

Similar Items