The Impact of Tropical Remnants on Extratropical Cyclogenesis: Case Study of Hurricanes Danielle and Earl (1998)
Bibliographic record
Abstract
The importance of remnant tropical cyclone (TC) circulation and moisture structures is investigated for a simultaneous extratropical transition (ET) event involving ex-Hurricanes Danielle and Earl (September 1998). Although both storms undergo prolonged periods of reintensification following ET, the forcings involved in each of their redevelopment processes differ fundamentally. A review of the tropical and baroclinic ET modes in the North Atlantic stresses the importance of jet/front structures to the nature of the reintensification process. Ex-Hurricane Danielle begins to redevelop in the eastern half of the basin in the downstream, poleward sector of an intensifying polar jet. The system undergoes a tropical mode of reintensification, resulting in a troposphere-deep warm environment surrounding the storm, devoid of near-surface fronts and maintained by strong tropopause folds at its periphery. Ex-Hurricane Earl reintensifies near the eastern seaboard according to a baroclinic mode, under the influence of an upshear upper-level trough. A rapid cyclonic rollup of upper-level potential vorticity over the reintensifying low-level center results in a strong baroclinic system with well-defined frontal boundaries. The two elements of the remnant TCs considered here are circulation and moisture. Potential vorticity-based modifications are made to the initial atmospheric state of the Mesoscale Compressible Community model in order to remove either one or both of these possible cyclogenetic forcings. The resulting set of sensitivity tests is analyzed in terms of system intensity and structure. It is found that the tropical-mode reintensification (ex-Hurricane Danielle) process requires the presence of the remnant's circulation and moisture for rapid redevelopment. However, the baroclinic-mode transition studied (ex-Hurricane Earl) is remarkably insensitive to the removal of the ex-tropical vorticity and moisture structures of the TC remnant.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".