Publication Abstracts

Inoue et al. 2020

Inoue, K., Á. Adames, and K. Yasunaga, 2020: Vertical velocity profiles in convectively coupled equatorial waves and MJO: New diagnoses of vertical velocity profiles in the wavenumber-frequency domain. J. Atmos. Sci., 77, no. 6, 2139-2162, doi:10.1175/JAS-D-19-0209.1.

A new diagnostic framework is developed and applied to ERA-Interim to quantitatively assess vertical velocity (omega) profiles in the wavenumber-frequency domain. Two quantities are defined with the first two EOF-PC pairs of omega profiles in the tropical ocean: a top-heaviness ratio and a tilt ratio. The top-heaviness and tilt ratios are defined, respectively, as the cospectrum and quadrature spectrum of PC1 and PC2 divided by the power spectrum of PC1. They represent how top-heavy an omega profile is at the convective maximum, and how much tilt omega profiles contain in the spatiotemporal evolution of a wave. The top-heaviness ratio reveals that omega profiles become more top-heavy as the time scale (spatial scale) becomes longer (larger). The MJO has the most top-heavy profile while the eastward inertio-gravity (EIG) and westward inertio-gravity (WIG) waves have the most bottom-heavy profiles. The tilt ratio reveals that the Kelvin, WIG, EIG, and mixed Rossby-gravity (MRG) waves, categorized as convectively coupled gravity waves, have significant tilt in the omega profiles, while the equatorial Rossby (ER) wave and MJO, categorized as slow-moving moisture modes, have less tilt. The gross moist stability (GMS), cloud-radiation feedback, and effective GMS were also computed for each wave. The MJO with the most top-heavy omega profile exhibits high GMS, but has negative effective GMS due to strong cloud-radiation feedbacks. Similarly, the ER wave also exhibits negative effective GMS with a top-heavy omega profile. These results may indicate that top-heavy omega profiles build up more moist static energy via strong cloud-radiation feedbacks, and as a result, are more preferable for the moisture mode instability.

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BibTeX Citation

@article{in08000i,
  author={Inoue, K. and Adames, Á. and Yasunaga, K.},
  title={Vertical velocity profiles in convectively coupled equatorial waves and MJO: New diagnoses of vertical velocity profiles in the wavenumber-frequency domain},
  year={2020},
  journal={J. Atmos. Sci.},
  volume={77},
  number={6},
  pages={2139--2162},
  doi={10.1175/JAS-D-19-0209.1},
}

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RIS Citation

TY  - JOUR
ID  - in08000i
AU  - Inoue, K.
AU  - Adames, Á.
AU  - Yasunaga, K.
PY  - 2020
TI  - Vertical velocity profiles in convectively coupled equatorial waves and MJO: New diagnoses of vertical velocity profiles in the wavenumber-frequency domain
JA  - J. Atmos. Sci.
VL  - 77
IS  - 6
SP  - 2139
EP  - 2162
DO  - 10.1175/JAS-D-19-0209.1
ER  -

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