Search

Your search keyword '"Wu, Zuhang"' showing total 21 results
Start Over Author "Wu, Zuhang"
21 results on '"Wu, Zuhang"'

4. Raindrop Deformation in Turbulence.

Author

Zheng, Hepeng, Zhang, Yun, Li, Haoran, Wu, Zuhang, Xie, Yanqiong, and Zhang, Lifeng

Subjects
HYDROLOGIC cycle, TERMINAL velocity, TURBULENCE, FLUID dynamics, MICROPHYSICS
Abstract

The physical behavior of a falling raindrop is governed by delicate fluid dynamics and thermodynamics, and oscillates with time. Despite this time‐variant nature, past observational and simulation studies have aimed to generalize parameterizations for describing rain microphysics bearing the assumption that raindrops fall at terminal speeds with an equilibrium shape. However, the applicability of this hypothesis in a realistic atmosphere that is inherently turbulent remains an open question. Here, we employ novel retrieval techniques to quantify the impact of turbulence on raindrop microphysics using long‐term in situ observations with careful assessment of the wind effect. We find that raindrop microphysics increasingly deviate from the equilibrium state as the turbulence dissipation rate increases, and this effect is more pronounced for large raindrops. We present turbulence‐invoked rain microphysical parameterizations which shed light on the complex interactions between turbulence dynamics and raindrop microphysics. Plain Language Summary: Raindrops are omnipresent in the atmosphere and play an essential role in the global hydrological cycle. The microphysics of raindrops, namely, shape, orientation and fall speed, have long been represented as a function of diameter with an equilibrium state. This simplification omits the impact of ubiquitous turbulence in the atmosphere. This study quantifies the deformation of raindrops under turbulent conditions. We find that the shape of large raindrops is more rounded and that raindrop oscillation is more pronounced in response to strong turbulence. Their fall speeds are significantly lower than the terminal speed, and the corresponding standard deviations are greater. Our work demonstrates the necessity of physically representing turbulence dynamics for accurate parameterization of raindrop microphysics via numerical simulations. Key Points: Raindrop microphysics increasingly deviate from the equilibrium state as the turbulence dissipation rate increasesLarge raindrops exhibit rounder shapes and lower fall speeds under strong turbulenceTurbulence‐invoked raindrop microphysics parameterizations are given [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

10. A Comparison of Spectral Bin Microphysics versus Bulk Parameterization in Forecasting Typhoon In-Fa (2021) before, during, and after Its Landfall

Author

Wu Zuhang and Zhang Yun

Abstract

Typhoon In-Fa hit continental China in July 2021 and caused an unprecedented rainfall amount, making it a typical case to examine the ability of numerical models in forecasting landfalling typhoons. The record-breaking storm was simulated using a 3-km-resolution weather research and forecast (WRF) model with spectral bin microphysics scheme (BIN) and two-moment seven-class bulk parameterization scheme (BULK). The simulations were then separated into three different typhoon landfall periods (i.e., pre-landfall, landfall, and post-landfall). At present, the ability of WRF and other mesoscale models to accurately simulate the typhoon precipitation hydrometeors is still limited. To evaluate the performances of BIN and BULK schemes of WRF model in simulating the condensed water in Typhoon In-Fa, the observed microwave brightness temperature and radar reflectivity from the core observatory of Global Precipitation Mission (GPM) satellite are directly used for validation with the help of a satellite simulator. It is suggested that BIN scheme has better performance in estimating the spatial structure, overall amplitude, and precise location of the condensed water in typhoons before landfall. During typhoon landfall, the performance of BIN scheme in simulating the structure and location of the condensate is close to that of BULK scheme, but the condensate intensity prediction by BIN scheme is still better; BULK scheme performs even better than BIN scheme in the prediction of condensate structure and location after typhoon landfall. Both schemes seem to have poorer performances in simulating the spatial structure of precipitation hydrometeors during typhoon landfall than before/after typhoon landfall. Moreover, BIN scheme simulates more (less) realistic warm (cold) rain processes than BULK scheme, especially after typhoon landfall. BULK scheme simulates more cloud water and larger convective updraft than BIN scheme, and this is also reported in many model studies comparing BIN and BULK schemes.

Published
2023

14. Precipitation Microphysics and Rainfall Retrieval in Three Typical Regions of Western Pacific

Author

Wu Zuhang and Wang Jing

Subjects
Hydrology (agriculture), Disdrometer, Microphysics, Environmental science, Precipitation, Atmospheric sciences
Abstract

Raindrop size distribution (DSD) measurements were taken with an onboard OTT Particle Size Velocity (Parsivel) disdrometer over the western Pacific during a marine survey from June to July 2014. Th...

Published
2020

Catalog

Books, media, physical & digital resources
See catalog results