Idealized Tropical Cyclones in Cloud Model 1 (CM1)

Analysis: TCBL Response to Prescribed Background Steering and Shear

Analyses of several simulations conducted using background-profile nudging in CM1, with simulations varying in their use of background steering and shear. All experiments use mean-layer steering and deep-layer (2 to 14 km height) shear magnitudes of either 0, 3, or 6 m/s.

Script: CM1 background wind profile generator and visualizer (GrADS)

A script that produces a custom background momentum profile for nudging in CM1. Options include vertical shear-layer and steering-layer specification. Background shear is confined to the shear layer, and uniform profiles of u and v exist outside the shear layer. Helicity may be added to sheared profiles via secondary waveforms. The change of u and/or v with height within the shear layer is sinusoidal, and any momentum added within the steering layer by shear and helicity is offset uniformly (i.e., they do not directly add a steering-layer mean component). Uses thermodynamic and mass profiles from CM1's input_sounding file.

Peer-reviewed Publications

Ahern, K., R. E. Hart, and M. A. Bourassa (2022): Asymmetric hurricane boundary layer structure during storm decay. Part II: Secondary eyewall formation. Mon. Wea. Rev., 150 (8), 1915–1936, doi:10.1175/MWR-D-21-0247.1

Ahern, K., R. E. Hart, and M. A. Bourassa (2021): Asymmetric hurricane boundary layer structure during storm decay. Part I: Formation of descending inflow. Mon. Wea. Rev., 149 (11), 3851–3874, doi:10.1175/MWR-D-21-0030.1.

Ahern, K., M. A. Bourassa, R. E. Hart, J. A. Zhang, and R. F. Rogers (2019): Observed kinematic and thermodynamic structure in the hurricane boundary layer during intensity change. Mon. Wea. Rev., 147 (8), 2765–2785, doi:10.1175/MWR-D-18-0380.1.

Ahern, K. and L. Cowan (2018): Minimizing errors when projecting geospatial data onto a vortex-centered space. Geophys. Res. Lett., 45, doi:10.1029/2018GL079953.