Publications

Submitted articles

• Lubis, S. W., Harrop, B., Lu J., Leung, L. R., Chen, Z., Huang, C. S. Y., Omrani, N. (2024). Cloud-Radiative Effects Significantly Increase Wintertime Atmospheric Blocking in the Euro-Atlantic Sector, under review.
• Huang, C. S. Y., Polster, C., and Nakamura, N.(2024). falwa: Python package to implement Finite-amplitude Local Wave Activity diagnostics on climate data, under review. [Preprint]

Accepted/Published articles

• Neal, E., Huang C. S. Y., Nakamura N. (2022). The 2021 Pacific Northwest heat wave and associated blocking: meteorology and the role of an upstream diabatic source of wave activity. Geophysical Research Letters, 49, e2021GL097699.
• Lubis, S., Huang C. S. Y., Nakamura N. (2018). Role of finite-amplitude eddies and mixing in the life cycle of stratospheric sudden warmings. Journal of the Atmospheric Sciences, 75, 3987-4003.
• Nakamura, N., Huang C. S. Y. (2018). Atmospheric blocking as a traffic jam in the jet stream. Science.
• Lubis, S.W., Huang C. S. Y., Nakamura N., Omrani N., and Jucker M. Role of Finite-Amplitude Rossby Waves and Nonconservative Processes in Downward Migration of Extratropical Flow Anomalies. Journal of the Atmospheric Sciences, 75, 1385–1401.
• Huang, C. S. Y., & Nakamura, N. (2017). Local wave activity budgets of the wintertime Northern Hemisphere: Implication for the Pacific and Atlantic storm tracks. Geophysical Research Letters, 44(11), 5673-5682. [Supporting Materials]
  • Read this post for a brief summary of my results.

• Nakamura, N., & Huang, C. S. Y. (2017). Local wave activity and the onset of blocking along a potential vorticity front. Journal of the Atmospheric Sciences, 74, 2341–2362.

  • A quasilinear 1D theory based on the conservation of local wave activity predicts that no steady wavetrain can be maintained where the westerly zonal flow is decelerated below one half of the initial value.
  • Fully nonlinear, high-resolution 2D calculations show that the wavetrain indeed undergoes a significant transformation once the zonal flow along the jet axis is decelerated below the threshold.
  • Whether the discontinuity in the basic-state of PV is due to (i) vorticity profile and (ii) layer thickness variation, determined the subsequent evolution of the flow.
  • In the latter case (layer thickness variation), the incident wavetrain is blocked and split into two tracks at the stagnation point.

• Huang, C. S. Y., & Nakamura, N. (2016). Local finite-amplitude wave activity as a diagnostic of anomalous weather events. Journal of the Atmospheric Sciences, 73(1), 211-229.

  • We generalized the finite-amplitude wave activity proposed in Nakamura and Zhu (2010) to a longitudinally local quantity.
  • The Local finite-amplitude wave activity (LWA) identifies both the locations and magnitudes of anomalous wave events (e.g. blocking, wave breaking).
  • The LWA flux expression we derived in Quasi-geostrophic (QG) framework consists of a non-linear advective flux and the generalized E-P flux.
  • The LWA satisfies an approximate non-acceleration relation, i.e. the sum of zonal wind and LWA is approximately conserved when averaging across a wave packet.
  • We compare our theory with the eularian formalism of Kilworth and McIntyre’s (1978) local wave activity diagnosing a barotropic decay in a shear flow.
  • The block that steered Sandy in-shore in Oct 2012 is examined using ERA-Interim data. The deceleration of zonal flow over the block was half of the growth in LWA, implying the role of non-conservative processes fueling the formation of the block.

Others/Preprint

Nakamura, N. & Huang, C. S. Y. Generalized Dispersion Relation and Critical Lines for a conservative, finite-amplitude Rossby wave in Slowly Varying Barotropic Shear Flow.

• The definitions of both pseudoenergy and pseudomomentum are reformulated in the framework of finite-amplitude wave theory.
• The zonal phase speed of finite-ampltude wave is given by the functional derivative of pseudoenergy with respect to pseudomomentum.
• The theory is tested in a model of barotropic decay in a shear flow. Phase line reconstruction with the theoretically given phase speed resembles the observed phase line patterns, except in regions where the meridional eddy momentum flux changes sign.