Polarimetric size sorting signatures in the convective regions of PECAN MCSs: their implications on convective kinematics, thermodynamics, and precipitation pathways

In revision

Frederick Iat-Hin Tam, Ming-Jen Yang, Wen-Chau Lee
In revision, Journal of Geophysical Research: Atmospheres, 2021

Cite

APA Click to copy
Tam, F. I.-H., Yang, M.-J., & Lee, W.-C. (2021). Polarimetric size sorting signatures in the convective regions of PECAN MCSs: their implications on convective kinematics, thermodynamics, and precipitation pathways. Journal of Geophysical Research: Atmospheres. In revision.

Chicago/Turabian Click to copy
Tam, Frederick Iat-Hin, Ming-Jen Yang, and Wen-Chau Lee. “Polarimetric Size Sorting Signatures in the Convective Regions of PECAN MCSs: Their Implications on Convective Kinematics, Thermodynamics, and Precipitation Pathways.” Journal of Geophysical Research: Atmospheres. In revision. In revision., 2021.

MLA Click to copy
Tam, Frederick Iat-Hin, et al. “Polarimetric Size Sorting Signatures in the Convective Regions of PECAN MCSs: Their Implications on Convective Kinematics, Thermodynamics, and Precipitation Pathways.” Journal of Geophysical Research: Atmospheres, In revision., 2021.

BibTeX Click to copy

@unpublished{frederick2021a,
  title = {Polarimetric size sorting signatures in the convective regions of PECAN MCSs: their implications on convective kinematics, thermodynamics, and precipitation pathways},
  year = {2021},
  journal = { Journal of Geophysical Research: Atmospheres},
  series = {In revision},
  author = {Tam, Frederick Iat-Hin and Yang, Ming-Jen and Lee, Wen-Chau},
  howpublished = {In revision.}
}

Motivation: Explore the use of a relatively novel radar observable to diagnose hard-to-observe microphysical contributions to storm thermodynamics.

The novel radar observable:
Separation distance, the spatial distance between localized areas with larger but less numerous rain drops, and areas with smaller but more numerous rain drops.

Graphical representation of "separation distance"

What have we done:
We processed and analyzed 74.5 hours of polarimetric radar observations on 10 MCSs. Rain diameter-concentration separation distances are identified and compared to observable proxies (e.g., echo top height, cloud water content). We performed all the previous steps to validated WRF simulation on one of the 10 MCSs for a more directed comparison to thermodynamic and microphysical characteristics.

Our findings:

Separation distances are positively correlated to the convective depth and the amount of extreme rainfall produced in the MCS convective regions.
WRF results suggest that areas with larger separation distances tend to have more freezing heating and melting cooling.
Fundamentally, low-level separation distances seem to be determined by how easy can graupel grow via freezing aloft. If the graupel drop size distribution contains more large particles, there will be more low-level rain diameter-concentration separation, and vice versa.