Diagnosing the Downstream Impact of Extratropical Transition Using Multimodel Operational Ensemble Prediction SystemsThe study examines the predictability during the extratropical transition (ET) of tropical cyclones using the THORPEX Interactive Grand Global Ensemble (TIGGE), a multimodel ensemble prediction system (EPS). It is shown that TIGGE exhibits more possible development scenarios than a single EPS. By analysing the eddy kinetic energy budget of forecast scenarios for two ET cases, extracted from an EPS, the impact of the transitioning tropical cyclones on the midlatitude flow is studied in detail. |
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21 September 500 hPa geopotential ageo ageostrophic geopotential fluxes amplification Anwender atmospheric baroclinic conversion baroclinic zone central North Pacific cluster analysis cluster mean cluster solutions contours contribution to EOF data set defined div-ageo downstream baroclinic development downstream dispersion downstream regions downstream trough eastern North Pacific ECMWF EPS eddy kinetic energy energy fluxes ensemble forecasts ensemble mean ensemble members equation Ex-Hanna extratropical cyclone extratropical transition Figure first geopotential height field GPH-cluster Harr hPa geopotential height Hurricane Hanna identified individual ensemble individual EPS influence initialised interaction K6 centre Ke-cluster kinetic energy budget mid-latitude flow pattern mid-latitude wave pattern mslp numerical weather prediction output resolution perturbations phase space possible development scenarios predictability Rand Index reintensification remnants of Choi-Wan representative member ridge Rossby wave trains September 2008 shortwave trough specific standard deviation strongest synoptic developments TIGGE data set transitioning storm tropical cyclone Typhoon Typhoon Choi-Wan upstream vertical western North