The Dynamics of the ENSO–Atlantic Hurricane Teleconnection: ENSO-Related Changes to the North African–Asian Jet Affect Atlantic Basin Tropical Cyclogenesis Public Deposited

http://ir.library.oregonstate.edu/concern/defaults/4m90dx09f

Descriptions

Attribute NameValues
Creator
Abstract or Summary
  • The nature of the teleconnection linking ENSO variability with Atlantic basin tropical storm formation is investigated. Solutions of the linearized barotropic vorticity equation forced with August–October El Niño event divergence produce upper-tropospheric vorticity anomalies over the Sahel and at the mouth of the North African–Asian (NAA) jet over the tropical Atlantic. These responses are similar in magnitude and orientation to observed ENSO vorticity variability for this region. Further investigation reveals that the vorticity anomalies over the subtropical Atlantic develop primarily in response to very low wavenumber, westward-propagating stationary Rossby waves excited by El Niño–related convective activity over the equatorial Pacific Ocean. However, the dynamics of this teleconnection change as the Atlantic basin hurricane season progresses. In August and September the response is dominated by the westward-propagating stationary Rossby waves that alter vorticity within the NAA jet and to its south. The upper-tropospheric nondivergent zonal wind anomalies produced by these vorticity anomalies are similar in pattern to observed zonal wind and vertical zonal wind shear anomalies, which suppress Atlantic basin tropical cyclogenesis. By October, eastward-propagating signals also develop over the tropical Atlantic Ocean in response to El Niño conditions. Over the main development region of Atlantic basin tropical cyclogenesis, these eastward-propagating Rossby waves appear to destructively interfere with the vorticity changes produced by the westward-propagating Rossby waves within the NAA jet. In addition, the NAA jet has shifted south by October. Consequently, the resultant upper-tropospheric nondivergent zonal wind perturbations for October are weak and suggest that ENSO should have little effect on rates of Atlantic basin tropical cyclogenesis during October. Statistical analyses of monthly ENSO-related changes in Atlantic basin tropical storm formation support this hypothesis.
Resource Type
DOI
Date Available
Date Issued
Citation
  • Shaman, Jeffrey, Steven K. Esbensen, Eric D. Maloney, 2009: The Dynamics of the ENSO–Atlantic Hurricane Teleconnection: ENSO-Related Changes to the North African–Asian Jet Affect Atlantic Basin Tropical Cyclogenesis. Journal of Climate, 22, 2458–2482.
Series
Keyword
Rights Statement
Funding Statement (additional comments about funding)
Publisher
Peer Reviewed
Language
Replaces
Additional Information
  • description.provenance : Made available in DSpace on 2012-02-14T21:52:34Z (GMT). No. of bitstreams: 1 ShamanJeffrey.CEOAS.DynamicsENSOAtlantic.pdf: 3966923 bytes, checksum: a42af3c666666a028c73a515bdce4152 (MD5) Previous issue date: 2009-05
  • description.provenance : Submitted by Deborah Campbell (deborah.campbell@oregonstate.edu) on 2012-02-14T21:52:34Z No. of bitstreams: 1 ShamanJeffrey.CEOAS.DynamicsENSOAtlantic.pdf: 3966923 bytes, checksum: a42af3c666666a028c73a515bdce4152 (MD5)

Relationships

In Administrative Set:
Last modified: 07/25/2017

Downloadable Content

Download PDF
Citations:

EndNote | Zotero | Mendeley

Items