Evaluation and Modification of a TKE-based PBL Scheme in HMON

A TKE-based PBL scheme is evaluated in the NCEP’s Multi-scale Ocean coupled Non-hydrostatic hurricane model (HMON). In an idealized configuration of the model, the length scale, diffusivity, and TKE from the PBL scheme during five-day integration are compared with those derived from observations. Preliminary results suggested that the length scale and diffusivity are larger than observation-derived values, and TKE in the upper atmosphere is smaller than observations. A modification of the length scale parameterization is proposed so that diffusivity and TKE in the scheme are consistent with observations. Sensitivity tests are conducted to understand the impact of the modification on hurricane structure and intensity as well as their evolutions. The performance of HMON using the TKE scheme for several hurricanes in the retrospective runs will also be shown and compared with that using the default operational configuration.