Identification

Title

On the interannual variability of African easterly waves and its relationship with El NiÃ±o-Southern Oscillation

Abstract

African easterly waves (AEWs) have important impacts on rainfall, drought, and the development of tropical cyclones in the Atlantic basin. However, the interannual variability of AEWs and their near-environmental characteristics are still poorly understood. Using an object-oriented AEW tracker, this study investigates the interannual variability of AEW characteristics and its association with El Niño–Southern Oscillation (ENSO) and Atlantic tropical cyclone activity. The variability of tracked AEW characteristics was found to be largely comparable across two reanalysis datasets, suggesting these fields are reliable indicators of AEW activity. ENSO is shown to impact AEW strength, moisture content, convective activity, and vertical structure on interannual time scales. Supporting this finding is an inverse correlation between these wave attributes and the oceanic Niño index, as well as vertical composites indicating an enhancement of these attributes during La Niña years versus El Niño years. Additionally, the ENSO–AEW relationship is mostly confined to the African continent. It is hypothesized that ENSO influences AEW activity through the modification of regional circulations including the tropical easterly jet, the African easterly jet, and the West African monsoon. These circulations are stronger and displaced during La Niña years, potentially increasing convection in the vicinity of AEWs and enhancing thermodynamic instabilities. Additionally, differences in AEW characteristics between active and inactive Atlantic tropical cyclone years are similar to the differences found between ENSO phases. Overall, these findings demonstrate that the ENSO–AEW relationship is a distinct teleconnection that may have important impacts on local weather and downstream tropical cyclogenesis.

Resource type

document

Resource locator

Unique resource identifier

code

https://n2t.net/ark:/85065/d7h136g1

codeSpace

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

Classification of spatial data and services

Topic category

geoscientificInformation

Keywords

Keyword set

keyword value

Text

originating controlled vocabulary

title

Resource Type

reference date

date type

publication

effective date

2016-01-01T00:00:00Z

Geographic location

West bounding longitude

East bounding longitude

North bounding latitude

South bounding latitude

Temporal reference

Temporal extent

Begin position

End position

Dataset reference date

date type

publication

effective date

2025-10-15T00:00:00Z

Frequency of update

Quality and validity

Lineage

Conformity

Data format

name of format

version of format

Constraints related to access and use

Constraint set

Use constraints

Limitations on public access

None

Responsible organisations

Responsible party

contact position

OpenSky Support

organisation name

UCAR/NCAR - Library

full postal address

PO Box 3000

Boulder

80307-3000

email address

opensky@ucar.edu

web address

http://opensky.ucar.edu/

name: homepage

responsible party role

pointOfContact

Metadata on metadata

Metadata point of contact