Diagnosing initial condition sensitivity of Typhoon Sinlaku (2008) and Hurricane Ike (2008)

William A. Komaromi, Sharanya J Majumdar, Eric D. Rappin

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

The response of Weather Research and Forecasting (WRF) model predictions of two tropical cyclones to perturbations in the initial conditions is investigated. Local perturbations to the vorticity field in the synoptic environment are created in features considered subjectively to be of importance to the track forecast. The rebalanced analysis is then integrated forward and compared with an unperturbed "control" simulation possessing similar errors to those in the corresponding operational model forecasts. In the first case, Typhoon Sinlaku (2008), the premature recurvature in the control simulation is found to be corrected by a variety of initial perturbations; in particular, the weakening of an upper-level low directly to its north, and the weakening of a remote short-wave trough in the midlatitude storm track. It is suggested that one or both of the short waves may have been initialized too strongly. In the second case, the forecasts for Hurricane Ike (2008) initialized 4 days prior to its landfall in Texas were not sensitive to most remote perturbations. The primary corrections to the track of Ike arose from a weakening of a midlevel ridge directly to its north, and the strengthening of a short-wave trough in the midlatitudes. For both storms, the targets selected by the ensemble transform Kalman filter (ETKF) were often, but not always, consistent with the most sensitive regions found in this study. Overall, the results can be used to retrospectively diagnose features in which the initial conditions require improvement, in order to improve forecasts of tropical cyclone track.

Original languageEnglish (US)
Pages (from-to)3224-3242
Number of pages19
JournalMonthly Weather Review
Volume139
Issue number10
DOIs
StatePublished - Oct 2011

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Hurricane Ike 2008
typhoon
perturbation
tropical cyclone
trough
storm track
Kalman filter
vorticity
simulation
transform
weather
forecast
prediction

Keywords

  • Hurricanes
  • Kalman filters
  • Tropical cyclones
  • Vorticity

ASJC Scopus subject areas

  • Atmospheric Science

Cite this

Diagnosing initial condition sensitivity of Typhoon Sinlaku (2008) and Hurricane Ike (2008). / Komaromi, William A.; Majumdar, Sharanya J; Rappin, Eric D.

In: Monthly Weather Review, Vol. 139, No. 10, 10.2011, p. 3224-3242.

Research output: Contribution to journalArticle

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