Impact of Synthetic Wind Retrieval on Tropical Cyclone Structures at the Extratropical Transition Stage in the JRA-25 Reanalysis

Abstract

Structures of 266 tropical cyclones (TCs) that completed extratropical transition (ET) in the western North Pacific during 1979-2004 are examined using the JRA-25 dataset, in relation to the removal of TC wind profile retrievals (TCR) from each TC after its recurvature. The TCR is a kind of “TC bogusing” techniques, and it was expected that its removal may lead to an artificial change in the TC structure at the ET stage. Nearly half of the examined TCs have cold-core structures before the removal of the TCR. On average, the structural change associated with ET starts more than one day before the removal of the TCR. Direct impact of the warm-core structure of the TCR is limited within a radius of about 200 km from the TC center. Although discontinuity in the TC structure between the periods with and without TCR may be statistically significant, the differences in the indices are practically negligible.