Precipitation microphysics characteristics of a Typhoon Matmo (2014) rainband after landfall over eastern China based on polarimetric radar observations

Abstract

The evolution of microphysical characteristics of a rainband in Typhoon Matmo (2014) over eastern China, through its onset, developing, mature, and dissipating stages, is documented using observations from an S band polarimetric Doppler radar and a two‐dimensional video disdrometer (2DVD). The drop size distributions observed by the 2DVD and retrieved from the polarimetric radar measurements indicate that the convection in the rainband generally contains smaller drops and higher number concentrations than the typical maritime type convection described in Bringi et al. (2003). The average mass‐weighted mean diameter (Dm) of convective precipitation in the rainband is about 1.41 mm, and the average logarithmic normalized intercept (Nw) is 4.67 log10 mm−1 m−3. To further investigate the dominant microphysical processes, the evolution of the vertical structures of polarimetric variables is examined. Results show that complex ice processes are involved above the freezing level, while it is most likely that the accretion and/or coalescence processes dominate below the freezing level throughout the rainband life cycle. A combined examination of the polarimetric measurements and profiles of estimated vertical liquid and ice water contents indicates that the conversion of cloud water into rainwater through cloud water accretion by raindrops plays a dominant role in producing heavy rainfall. The high estimated precipitation efficiency of 50% also suggests that cloud water accretion is the dominant mechanism for producing heavy rainfall. This study represents the first time that radar and 2DVD observations are used together to characterize the microphysical characteristics and precipitation efficiency for typhoon rainbands in China.

Precipitation Microphysics of Tropical Cyclones Over the Western North Pacific Based on GPM DPR Observations: A Preliminary Analysis

“…Generally, the concentrations of droplets ( N w ) decrease sharply as the raindrop size ( D m ) increases, irrespective of rain type or PEI (Figures d and h). This indicates that both convective and stratiform precipitating clouds in TCs have low number concentrations of large drops and high concentrations of relatively small drops, which is in good agreement with many previous studies (Kumjian & Prat, ; Wang et al, ). When compared to the mean values of DSDs for convective precipitation, stratiform precipitation is characterized by smaller mean values of D m and slightly larger mean values of N w .…”

“… where RR represents the near‐surface rain rate. Note that this definition of PEI is different from the precipitation efficiency used in previous studies, which is the ratio of rainfall to precipitable water (Sui et al, ; Wang et al, ). Despite the difference, PEI used in this study also represents how much the column‐integrated liquid water contributed to rain rate qualitatively.…”

Microphysical Characteristics of an Asymmetric Eyewall in Major Hurricane Harvey (2017)

“…The characteristic DSD of high concentrations of small raindrops in a TC was consistent with earlier in situ observations from airborne probes (Jorgensen & Willis, 1982) and surface disdrometers (Tokay et al, 2008;Ulbrich & Lee, 2002;Wilson & Pollock, 1974). The DSD variation in TC rainbands (Wang et al, 2016(Wang et al, , 2018Wen et al, 2018) and variability in ice distributions (Didlake & Kumjian, 2017;Kalina et al, 2017) have also been recently investigated. The DSD variation in TC rainbands (Wang et al, 2016(Wang et al, , 2018Wen et al, 2018) and variability in ice distributions (Didlake & Kumjian, 2017;Kalina et al, 2017) have also been recently investigated.…”

An Extreme Rainfall Event in Coastal South China During SCMREX‐2014: Formation and Roles of Rainband and Echo Trainings

“…The magnitude of the upward motion in the rainbands at 2 km MSL is about 2–5 m/s (Figures b and d), which is larger than its standard deviation (1.6 m/s). The magnitude of the vertical velocity in the present case is comparable to those in the convective regions of typhoon Matmo over Eastern China (Wang et al, ) and a southwesterly monsoon MCS (Chang et al, ), but slightly weaker than that in a prefrontal squall line (Chang et al, ) over southwest Taiwan. All these suggest that the retrieved vertical velocity can be used to demonstrate the lifting of the MOB.…”