Slow translation speed causes rapid collapse of northeast Pacific Hurricane Kenneth over cold core eddy

Nan D. Walker, Robert R. Leben, Chet T. Pilley, Michael Shannon, Derrick C. Herndon, Iam Fei Pun, I. I. Lin, Chelle L. Gentemann

Research output: Contribution to journalArticlepeer-review

69 Scopus citations

Abstract

Category 4 Hurricane Kenneth (HK) experienced unpredicted rapid weakening when it stalled over a cold core eddy (CCE) on 19-20 September 2005, 2800 km SE of Hawaii. Maximum sea surface temperature (SST) cooling of 8-9°C and a minimum aerially averaged SST of 18.3°C (over 8750 km2) characterized its cool wake. A 3-D mixed-layer model enabled estimation of enthalpy fluxes (latent and sensible heat), as well as the relative importance of slow translation speed (Uh) compared with the preexisting CCE. As Uh dropped below 1.5 m s-1, enthalpy fluxes became negative, cutting off direct ocean energy flux to HK. Although HK's weakening was attributed to wind shear, our results indicate that slow Uh and consequent intense SST cooling were the main causes. The tropical cyclone-intensified CCE experienced rapid growth in magnitude (-6 to -40 cm), increased diameter (60 to 350 km), elevated chlorophyll a for 4 months, and 12 month longevity.

Original languageEnglish
Pages (from-to)7595-7601
Number of pages7
JournalGeophysical Research Letters
Volume41
Issue number21
DOIs
StatePublished - 16 Nov 2014

Keywords

  • air-sea interactions
  • eddies and mesoscale processes
  • enthalpy flux
  • microwave SST
  • satellite altimetry
  • tropical cyclones and hurricanes

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