IR Home
CR
Home
Editors
Forthcoming
Information
CR Online
Subscribe
CR SPECIAL 1
CR SPECIAL 2
CR SPECIAL 3
CR SPECIAL 4
CR SPECIAL 5
CR SPECIAL 6
Journals
Home
MEPS
AME
CR
DAO
ESEP
Search
Subscribe
Book Series
EE Books
Top Books
Order
Discussion Forums
Home
Research
Endangered Species Programs
Institutions
International Ecology Institute
Eco-Ethics International Union
Foundation
Otto Kinne Foundation
| |
CR 10:115-125 (1998)
|
Abstract
|
![](../../../../images/hline.gif)
The Gulf of Mexico mid-tropospheric response to El Niño and La Niña forcing
Anthony J. Vega1,*, Robert V. Rohli2, Keith G. Henderson3
1Department of Anthropology, Geography and Earth Science, Clarion University of Pennsylvania, Clarion, Pennsylvania 16214, USA
2Department of Geography, Kent State University, Kent, Ohio 44242, USA
3Department of Geography and Anthropology, Louisiana State University, Baton Rouge, Louisiana 70803, USA
*E-mail: avega@clarion.edu
![](../../../../images/hline.gif)
ABSTRACT: This analysis further refines Ropelewski & Halpert's (1987; Mon Wea Rev 115:1606-1626) analysis which investigates the relationship between El Niño-La Niña/Southern Oscillation events and southern United States precipitation. Comparisons are
made between eigenvector-derived mid-tropospheric (500 mb) flow patterns over North America during extreme El Niño and La Niña months and a base climatology. In addition, the patterns are correlated to regional precipitation anomalies for the southern
United States to determine mean surface responses. Cool season (November to March) months are divided into all winter months (AWM), positive anomaly months (PAM), and negative anomaly months (NAM). The extreme anomaly months were determined as any month
with a Southern Oscillation Index (SOI) ± 1 standard deviation from the standardized mean. Therefore, the PAM and NAM anomalies represent the La Niña and El Niño extreme phases of the SOI, respectively. Results suggest that the positive (La Niña) SOI
phase elicits a greater surface precipitation response than the El Niño phase. This is caused by substantial changes in the primary longwave flow during opposite SOI phases. During AWMs and NAMs, similar flow patterns, dominated by the Pacific/North
American (PNA) teleconnection, prevail which induce similar regional precipitation responses. During PAMs, the mid-tropospheric flow shifts to a hybrid flow pattern which is between the PNA and the Tropical Northern Hemisphere teleconnections. Such
displacement in the longwave flow variation centers ultimately affects jet stream flow and precipitation forcing, resulting in negative precipitation anomalies across the southern United States.
KEY WORDS: El Niño · La Niña · Precipitation · Climatology · Gulf of Mexico
Full text in pdf format
![](../../../../images/hline.gif)
Published in CR Vol.
10, No. 2
(1998) on August 14
ISSN: 0936-577X.
Copyright © Inter-Research, Oldendorf/Luhe, 1998
|