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Characteristics and Possible Formation Mechanisms of severe storms in the Outer Rainbands of Typhoon Mujigae(1522)

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Journal of Meteorological Research 2017年第3期31卷 612-624页

作者： Bingyun WANG Ming WEI Wei HUA Yongli ZHANG Xiaohang WEN Jiafeng ZHENG Nan LI Han LI Yu WU Jie ZHU Mingjun ZHANG Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science &Technology College of Atmospheric Sciences Chengdu University of Information Technology/Plateau Atmosphere and Environment Key Laboratory of Sichuan Province Hainan Meteorological Observatory National Satellite Meteorological Center

To better understand how severe storms form and evolve in the outer rainbands of typhoons, in this study, we in- vestigate the evolutionary characteristics and possible formation mechanisms for severe storms in the rainbands of Typhoon Mujigae, which occurred during 2-5 October 2015, based on the NCEP-NCAR reanalysis data, conventional observations, and Doppler radar data. For the rainbands far from the inner core （eye and eyewall） of Mujigae （dis- tance of approximately 70-800 kin）, wind speed first increased with the radius expanding from the inner core, and then decreased as the radius continued to expand. The Rankine Vortex Model was used to explore such variations in wind speed. The areas of strong stormy rainbands were mainly located in the northeast quadrant of Mujigae, and overlapped with the areas of high winds within approximately 300-550 km away from the inner core, where the strong winds were conducive to the development of strong storms. A severe convective cell in the rainbands de- veloped into waterspout at approximately 500 km to the northeast of the inner core, when Mujigae was strengthening before it made landfall. Two severe convective cells in the rainbands developed into two tornadoes at approximately 350 km to the northeast of the inner core after Mujigae made landfall. The radar echo bands enhanced to 60 dBZ when mesocyclones occurred in the rainbands and induced tornadoes. The radar echoes gradually weakened after the mesocyclones weakened. The tops of parent clouds of the mesocyclones elevated at first, and then suddenly dropped about 20 min before the tornadoes appeared. Thereby, the cloud top variation has the potential to be used as an early warning of tornado occurrence.

关键词： strong typhoon rainband severe storm tomado Rankine Vortex Model

Correlation Structures between Satellite All-Sky Infrared Brightness Temperatures and the Atmospheric State at storm Scales

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Advances in Atmospheric Sciences 2022年第5期39卷 714-732页

作者： Yunji ZHANG Eugene E.CLOTHIAUX David J.STENSRUD Center for Advanced Data Assimilation and Predictability Techniques and Department of Meteorology and Atmospheric ScienceThe Pennsylvania State UniversityUniversity ParkPennsylvania 16802USA

This study explores the structures of the correlations between infrared(IR)brightness temperatures(BTs)from the three water vapor channels of the Advanced Baseline Imager(ABI)onboard the GOES-16 satellite and the atmospheric ***-based data assimilation techniques such as the ensemble Kalman filter(EnKF)rely on correlations to propagate innovations of BTs to increments of model state *** the three water vapor channels are sensitive to moisture in different layers of the troposphere,the heights of the strongest correlations between these channels and moisture in clear-sky regions are closely related to the peaks of their respective weighting *** cloudy regions,the strongest correlations appear at the cloud tops of deep clouds,and ice hydrometeors generally have stronger correlations with BT than liquid *** magnitudes of the correlations decrease from the peak value in a column with both vertical and horizontal *** how the correlations decrease depend on both the cloud scenes and the cloud structures,as well as the model *** correlations between BTs and moisture,as well as hydrometeors,in fully cloudy regions decrease to almost 0 at about 30 *** horizontal correlations with atmospheric state variables in clear-sky regions are broader,maintaining non-zero values out to~100 *** results in this study provide information on the proper choice of cut-off radii in horizontal and vertical localization schemes for the assimilation of *** also provide insights on the most efficient and effective use of the different water vapor channels.

关键词： severe storm remote sensing data assimilation numerical modeling

Numerical Study on a severe Downburst-Producing Thunderstorm on 23 August 2001 in Beijing

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Advances in Atmospheric Sciences 2007年第2期24卷 227-238页

作者：付丹红郭学良 Laboratory of Cloud-Precipitation Physics and severe storms （LACS） Institute of Atmospheric PhysicsChinese Academy of Sciences Beijing 100029 Graduate University of the Chinese Academy of Sciences Beijing 100039 不详

A thunderstorm that produced severe wind, heavy rain and hail on 23 August 2001 in Beijing was studied by a three-dimensional cloud model including hail-bin microphysics. This model can provide important information for hail size at the surface, which is not available in hail parameterization cloud models. The results shows that the cloud model, using hail-bin microphysics, could reasonably reflect the storm＇s characteristics such as life cycle, rainfall distribution and the diameter of the hailstones and also can reproduce developing processes of downbursts, where they can then be compared with the observed features of the storm. The downburst formation mechanism was investigated based on the cloud microphysics of the simulated storm and it was found that the downburst was primarily produced by hail-loading and enhanced by cooling processes that were due to hail melting and rain evaporation. The loading and melting of hail played crucial roles in the formation of downbursts within the storm.

关键词： hail-bin microphysics severe storm downburst

The role of dynamic transport in the formation of the inverted charge structure in a simulated hailstorm

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Science China Earth Sciences 2016年第7期59卷 1414-1426页

作者： XU Liang Tao ZHANG Yi Jun LIU Heng Yi ZHENG Dong WANG Fei State Key Laboratory of severe Weather Chinese Academy of Meteorological Sciences College of Earth Sciences University of Chinese Academy of Sciences Laboratory of Lightning Physics and Protection Engineering Chinese Academy of Meteorological Sciences

The inverted charge structure formation of a hailstorm was investigated using the Advanced Weather Research and Forecasting(WRF-ARW) model coupled with electrification and discharge schemes. Different processes may be responsible for inverted charge structure in different storms and regions. A dynamical-derived mechanism of inverted charge structure formation was confirmed by the numerical model: the inverted structure was formed by strong updraft and downdraft under normal-polarity charging conditions such that the graupel charged negatively in the main charging region in the middle-upper level of the cloud. The simulation results showed the storm presented a normal charge structure before and after hail-fall; while during the hail-fall stage, it showed an inverted charge structure—negative charge region in the upper level of the cloud and a positive charge region in the middle level of the cloud—appearing at the front edge near the strong updraft in the hailstorm. The charging processes between the two particles mainly occurred at the top of the cloud, where the graupel charged negatively and ice crystals positively due to the strong updraft. When the updraft air reached the top of the storm, it would spread to the rear and front. The light ice crystals were transported backward and forward more easily. Meanwhile, the positively charged ice crystals were transported downward by the frontal subsidence, and then a positive charge region formed between the ?10 and ?25°C levels. Subsequently, a negative charge region materialized in the upper level of the cloud, and the inverted charge structure formed.

关键词： severe storm Mesoscale model Inverted charge structure

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