Baroclinic Instability in an Euler Equations–Based Column Model: The Coexistence of a Deep Synoptic-Scale Mode and Shallow Subsynoptic-Scale Modes
Bibliographic record
Abstract
The authors provide a detailed analysis of a shallow mode of subsynoptic-scale baroclinic instability by analyzing a one-dimensional column model in which the assumption of balance is applied to the basic-state flow but in which nongeostrophic unbalanced effects are retained in the description of the evolution of the perturbation under the Boussinesq approximation. This model is employed to analyze the stability of a meridionally confined mean state that is based upon hydrodynamic fields extracted from the central columns of a tropospheric cross section of the midlatitude jet stream. Numerical solutions are obtained at very high resolution through application of a sparse matrix method for solution of the corresponding cubic eigenvalue problem. Thereby the existence of a deep synoptic-scale mode and boundary-confined subsynoptic-scale modes is confirmed. The spatial scale and phase speed of these modes agree with those previously obtained on the basis of both nonseparable stability analysis and solution of the associated initial value problem in the companion paper by Yamazaki and Peltier. Both one-dimensional and nonseparable shallow modes share the property that they are characterized by the presence of an inertial critical layer, and the lack of a short-wave cutoff of the subsynoptic-scale modes suggested by analyses of the nonseparable models is more clearly shown in the column model. However, the growth rate of the shallow mode in the column model is approximately 1 order of magnitude smaller than those of the structures delivered by the nonseparable analyses, and the vertical structure and the energy budget of these modes vary dramatically depending on the sign of the meridional wavenumber that determines the direction of meridional propagation.
Stored with the screening record, where it is evidence for the labels above.
How this classification was reachedexpand
The three-model screen
all 5,600 screened works →All three models called this out of scope.
Baroclinic instability column model in atmospheric dynamics; a geophysical fluid-dynamics question.
This analyzes atmospheric instability and meteorological models, not research practice.
Atmospheric dynamics analysis of baroclinic instability modes; domain geophysical fluid dynamics.
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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 source (direct Gemma or distilled Codex), 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".