[Paper Review] Impacts of Jet Stream Structure on Cyclone Merging and Persistent Anticyclones: Insights from Dry Idealized Simulations

Mingfei Ren, Gan Zhang+4 more|arXiv (Cornell University)|Mar 9, 2026

Tropical and Extratropical Cyclones Research0 citations

TL;DR

The paper uses dry, adiabatic idealized simulations with analytically specified jets to show how jet latitude, width, and depth control cyclone intensification, cyclone merging, and persistent anticyclones. Poleward-shifted, broader, and higher jets enhance cyclone merging and precondition persistent stationary anticyclones.

ABSTRACT

Midlatitude jet streams exhibit substantial variability in latitude, width, and vertical depth on synoptic to multi-decadal timescales. While the upper-level dynamics of baroclinic waves have been extensively studied, the sensitivity of the extreme-generating, low-level phenomena to these variations remains underexplored. Here, we systematically investigate this sensitivity using dry, adiabatic idealized experiments with the GFDL FV3 dry dynamical core initialized with analytically specified jets. We identify jet variations that control synoptic-scale features of interest. Results indicate that poleward-shifted jets accelerate initial cyclone intensification and favor anticyclonic Rossby Wave Breaking (RWB). These wave-breaking tendencies are consistent with established baroclinic paradigms, validating the newly configured idealized simulations. Additionally, jet width regulates the likelihood of surface cyclone merging. Poleward-shifted, broader, and higher jets produce more frequent cyclone merging, generating intense wind extremes. Finally, we show that poleward-shifted, broad, deep jets dynamically precondition the flow for persistent stationary anticyclones in the absence of diabatic contributions. Together, these findings illustrate how changes in jet stream structure may modulate midlatitude weather extremes.

Motivation & Objective

• Motivate the need to understand how variations in midlatitude jet structure influence extreme weather phenomena beyond conventional baroclinic wave theory.
• Systematically test the sensitivity of synoptic-scale features to jet latitude, width, and vertical depth using idealized dry dynamics.

Proposed method

• Use dry, adiabatic experiments with the GFDL FV3 dry dynamical core.
• Initialize simulations with analytically specified jets to probe jet-structure variations.
• Identify jet configurations that control synoptic-scale features of interest.
• Assess how jet changes influence cyclone intensification, cyclone merging, and anticyclone persistence.

Experimental results

Research questions

• RQ1 How do changes in jet latitude, width, and depth modify the development and merging of midlatitude cyclones?
• RQ2 Under what jet configurations do persistent stationary anticyclones arise in the absence of diabatic forcing?
• RQ3 What dynamical mechanisms link jet structure to anticyclonic Rossby Wave Breaking and cyclone interactions?

Key findings

• Poleward-shifted jets accelerate initial cyclone intensification and favor anticyclonic Rossby Wave Breaking (RWB).
• Jet width regulates the likelihood of surface cyclone merging.
• Poleward-shifted, broader, and higher jets produce more frequent cyclone merging, generating intense wind extremes.
• Poleward-shifted, broad, and deep jets dynamically precondition the flow for persistent stationary anticyclones without diabatic contributions.