Frederick Iat-Hin Tam


Project Research Assistant


Curriculum vitae


[email protected]

Meteorology Building - C205
National Taiwan University
No.1, Sec. 4, Roosevelt Rd., Taipei, 10617, Taiwan



Sensitivity of a simulated nocturnal convective system to hydrometeor sedimentation and pre-convective moisture heterogeneity


Unpublished


Frederick Iat-Hin Tam, Ming-Jen Yang, Wen-Chau Lee
In preparation, 2021

Cite

Cite

APA
Tam, F. I.-H., Yang, M.-J., & Lee, W.-C. (2021). Sensitivity of a simulated nocturnal convective system to hydrometeor sedimentation and pre-convective moisture heterogeneity.

Chicago/Turabian
Tam, Frederick Iat-Hin, Ming-Jen Yang, and Wen-Chau Lee. “Sensitivity of a Simulated Nocturnal Convective System to Hydrometeor Sedimentation and Pre-Convective Moisture Heterogeneity.” In preparation, 2021.

MLA
Tam, Frederick Iat-Hin, et al. Sensitivity of a Simulated Nocturnal Convective System to Hydrometeor Sedimentation and Pre-Convective Moisture Heterogeneity. 2021.


Motivation:
Process-limiting studies that explore how a particular parameterized physical process impact convective strength and precipitation intensity are plentiful in the literature. However, most of these studies are highly idealized and assume environmental homogeneity. We ask the following question: Are convective sensitivities towards microphysical processes always the same, or can they change in accordance with ambient environment?

Methodology:
We performed WRF simulations on a nocturnal convective system occurred during the 2015 PECAN field campaign. This MCS was subjected to drastic changes in ambient moisture and instability characteristics associated with a developing synoptic-scale low-level jet (LLJ) during the MCS mature phase. In this study, we examine how convective dynamics and thermodynamics respond to hydrometeor fallout assumptions in an evolving heterogeneous environment.

Preliminary findings:

The most interesting findings thus far lie in the temporal evolution of low-level downward motion (related to water loading and diabatic cooling). Blue lines represent a sensitivity experiment where rain fallout more easily than the Control simulation (black line). Downward motion in the sensitivity experiment was initially stronger than the Control run, but changed completely after 0500 UTC. 

Incidentally, 0500 UTC was also the time when the synoptic-scale LLJ was strongest and deepest. We are current investigating if the results shown above can be attributed to the moistening from LLJ.