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Application of the frequency-matching method in the probability forecast of landfalling typhoon rainfall

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Frontiers of Earth Science 2022年第1期16卷 52-63页

作者： Rong GUO Hui YU Zifeng YU Jie TANG Lina BAI Shanghai typhoon Institute and Key Laboratory of Numerical Modeling for Tropical Cyclone of China Meteorological AdministrationShanghai 200030China

In this paper,a revised method for typhoon precipitation probability forecast,based on the frequencymatching method,is developed by combining the screening and the neighborhood *** frequency of the high-resolution precipitation forecasts is used as the reference frequency,and the frequency of the lowresolution ensemble forecasts is used as the forecast *** on frequency–matching method,the frequency of rainfall above the rainstorm magnitude *** forecast members are then selected by using the typhoon tracks of the short-term predictions,and the precipitation probability is calculated for each member using a combination of the neighbor and the traditional probability statistical ***,four landfalling typhoons(i.e.,STY Lekima and STS Bailu in 2019,and TY Hagupit and Higos in 2020)were chose to test the rainfall probability *** results show that the method performs well with respect to the forecast rainfall area and magnitude for the four *** Brier and Brier skill scores are almost entirely positive for the probability forecast of 0.1–250 mm rainfall during Bailu,Hagupit and Higos(except for 0.1mm of Hagupit),and for<100 mm rainfall(except for 25 mm)during Lekima.

关键词： frequency-matching method landfalling typhoon rainfall probability Brier score

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Cloud type identification for a landfalling typhoon based on millimeter-wave radar range-height-indicator data

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Frontiers of Earth Science 2019年第4期13卷 829-835页

作者： Zhoujie CHENG Ming WEI Yaping ZHU Jie BAI Xiaoguang SUN Li GAO Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science&TechnologyNanjing 210001China Beijing Institute of Aviation Meteorology Beijing 100085China Beijing Marine Hydrometeorologic Centre Beijing 100071China Beijing Meteorological Centre Beijing 100038China Taizhou Meteorological Bureau of Zhejiang Province Taizhou 317000China

As a basic property of cloud,accurate identification of cloud type is useful in forecasting the evolution of landfalling ***-wave cloud radar is an important means of identifying cloud ***,we develop a fuzzy logic algorithm that depends on radar range-height-indicator(RHI)data and takes into account the fundamental physical features of different cloud *** algorithm is applied to a ground-based Ka-band millimeter-wave cloud *** input parameters of the algorithm include average reflectivity factor intensity,ellipse long axis orientation,cloud base height,cloud thickness,presence/absence of precipitation,ratio of horizontal extent to vertical extent,maximum echo intensity,and standard variance of *** identified cloud types are stratus(St),stratocumulus(Sc),cumulus(Cu),cumulonimbus(Cb),nimbostratus(Ns),altostratus(As),altocumulus(Ac)and high *** cloud types identified using the algorithm are in good agreement with those identified by a human *** a case study,the algorithm was applied to typhoon Khanun(1720),which made landfall in south-eastern China in October *** identification results from the algorithm clearly reflected changes in cloud type and provided indicative information for forecasting of the typhoon.

关键词： landfalling typhoon identification of cloud type millimeter-wave cloud radar RHI data fuzzy logic

A CLOUD-RESOLVING MODELING STUDY OF SURFACE RAINFALL PROCESSES ASSOCIATED WITH landfalling typhoon KAEMI(2006)

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Journal of Tropical Meteorology 2009年第2期15卷 181-191页

作者：崔晓鹏许凤雯 Laboratory of Cloud-Precipitation Physics and Severe Storms (LACS) Institute of Atmospheric Physics Chinese Academy of Sciences National Meteorological Center China Meteorological Administration

The detailed surface rainfall processes associated with landfalling typhoon Kaemi（2006） are investigated based on hourly data from a two-dimensional cloud-resolving model simulation. The model is integrated for 6 days with imposed large-scale vertical velocity, zonal wind, horizontal temperature and vapor advection from National Center for Environmental Prediction （NCEP） / Global Data Assimilation System （GDAS） data. The simulation data are validated with observations in terms of surface rain rate. The Root-Mean-Squared （RMS） difference in surface rain rate between the simulation and the gauge observations is 0.660 mm h^-1, which is smaller than the standard deviations of both the simulated rain rate （0.753 mm h^-1） and the observed rain rate （0.833 mm h^-1）. The simulation data are then used to study the physical causes associated with the detailed surface rainfall processes during the landfall. The results show that time averaged and model domain-mean Ps mainly comes from large-scale convergence （QWVF） and local vapor loss （positive QWVT）. Large underestimation （about 15%） of Ps will occur if QWVT and QCM （cloud source/sink） are not considered as contributors to Ps ,QWVF accounts for the variation of P during most of the integration time, while it is not always a contributor to Ps,Sometimes surface rainfall could occur when divergence is dominant with local vapor loss to be a contributor to Ps - Surface rainfall is a result ofmulti-timescale interactions. QWVE possesses the longest time scale and the lowest frequeney the second and QCM of variation with time and may exert impact on P on longer time scales. QWVF possesses longest time scale and lowest frequency and can explain most of the variation of Ps. QWVT possess shorter time scales and higher frequencies, which can explain more detailed variations in Ps. Partitioning analysis shows that stratiform rainfall is dominant from the morning of 26 July till the late night of 27 July. After that, convective rainfall

关键词： surface rainfall processes landfalling typhoon cloud-resolving modeling study

An Analysis of the Low Moving Speed of landfalling typhoon In-Fa in 2021

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Journal of Tropical Meteorology 2024年第1期30卷 51-60页

作者：郑丽娜吕新刚李瑞 Jinan Meteorological Bureau of Shandong Province Jinan 250102 China

The movement speed of typhoon In-Fa(2021)was notably slow,at 10 km h-1or less,for over 20 hours following its landfall in Zhejiang,China,in contrast to other typhoons that have made *** study examines the factors contributing to the slow movement of typhoon In-Fa,including the steering flow,diabatic heating,vertical wind shear(VWS),and surface synoptic situation,by comparing it with typhoons Yagi(2018)and Rumbia(2018)which followed similar *** findings reveal that the movement speed of typhoons Yagi and Rumbia is most closely associated with their respective 500 h Pa environmental winds,with a steering flow of 10^(-12)m s^(-1).In contrast,typhoon InFa’s movement speed is most strongly correlated with the 850 h Pa environmental wind field,with a steering flow speed of only 2 m s^(-1).Furthermore,as typhoon In-Fa moves northwest after landfall,its intensity is slightly greater than that of typhoons Yagi and Rumbia,and the pressure gradient in front of typhoon In-Fa is notably smaller,leading to its slow ***,the precipitation distribution of typhoon In-Fa differs from that of the other two typhoons,resulting in a weak asymmetry of wavenumber-1 diabatic heating,which indirectly affects its movement *** analysis indicates that VWS can alter the typhoon’s structure,weaken its intensity,and ultimately impact its movement.

关键词： landfalling typhoon steering flow diabatic heating VWS

The T-TREC Technique for Retrieving the Winds of landfalling typhoons in China

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Acta meteorologica Sinica 2011年第1期25卷 91-103页

作者：王明筠赵坤吴丹 Key Laboratory for Mesoscale Severe Weather/MOE and School of Atmospheric Sciences Nanjing University

In this study, an extension of the TREC （Tracking Radar Echo by Correlations） technique, named Tropical Cyclone （TC） circulation TREC （T-TREC）, is developed to retrieve the winds of landfalling typhoons in China. The T-TREC analysis is performed on a polar grid centered at the TC center, using arc-shaped correlation cells and an arc-shaped search area. The search for the best correlation match is confined along the cyclonic direction with a limited search distance in the radial direction based on the cyclonic circulation characteristics of TCs in the Northern Hemisphere. The TC center is determined objectively using reflectivity data while the Doppler radar radial velocities are incorporated to estimate the search range and create a velocity correlation matrix as auxiliary constraints. The T-TREC was applied to the landfalling typhoon Saomai （0608） observed by Chinese next generation Weather Surveillance Radar 1998 Doppler （CINRAD WSR-98D） on the southeast coast of China. The results show that the T-TREC has the ability to estimate the typhoon circulation with an average bias of 4 m s -1 . The incorporation of radial velocity data could distinctively improve wind retrievals for intense typhoons, especially by reducing the underestimation caused by fairly uniform reflectivity patterns in the vicinity of the eyewall and the outer rainband. A quantitative evaluation of the influence of typhoon center and cell size on the wind estimation demonstrates that the quality of the T-TREC retrieved wind circulation depends on the estimation of the typhoon center. A 4-km deviation of the TC center may result in a 10% increase in the retrieved wind error. The effect of cell size depends on the typhoon scale： better wind retrieval results can be obtained for a smaller typhoon.

关键词： landfalling typhoon T-TREC technique Doppler radar

Variations in gust factor with wind direction and height based on the measurements from a coastal tower during three landfalling typhoons

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Tropical Cyclone Research and Review 2024年第3期13卷 187-195页

作者： Pingzhi Fang Tao Huo Junjun Pan Guihan Luan Shanghai typhoon Institute of China Meteorological Administration ShanghaiChina Asia-Pacific typhoon Collaborative Research Center ShanghaiChina China Construction Eighth Engineering Division Corp. LTD.ShanghaiChina Aolai Guoxin(Beijing)Testing Technology Corp.LTD. BeijingChina

Using high-frequency onshore wind data from four different heights of a coastal tower,the variations in gust factor with turbulence intensity,height and wind speed were studied under typhoon *** gust factor increases with increasing turbulence intensity and,most often,can be described by a linear relationship with the turbulence *** gust factor decreases with height and is relatively small compared with those presented in the national codes and other studies.A value of 2.5 is acceptable for the peak factor,which is close to the recommended value of the national code in *** gust factor increases with increasing wind speed and is also affected by the wind *** gust factor has a value to that of previously published results when the wind flows roughly perpendicular to the shoreline,and has a smaller value when the wind flows roughly parallel to the *** phenomenon is caused by the confinement of shoreline on the sea wave *** waves tend to propagate normal to the shoreline because of the refraction *** a result,a shorter roughness length exists in the parallel direction to the *** can be further explained by the weakness in the momentum flux exchange between the air and sea based on the wave form drag theory when the wind flows parallel to the shoreline.

关键词： Gust factor landfalling typhoon Peak factor Roughness length Wind direction

Numerical Experiments for typhoon Dan Incorporating AMSU-A Retrieved Data with 3DVM

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Advances in Atmospheric Sciences 2008年第4期25卷 692-703页

作者：赵颖王斌 State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of Sciences

Two sets of assimilation experiments on a landfalling typhoon--typhoon Dan （1999） over the western North Pacific were designed to compare the performances of two kinds of variational data assimilation schemes that are the 3-Dimensional Variational data assimilation of Mapped observation （3DVM） and the 4-dimensional variational data assimilation （4DVar）. Results show that：（1） both the 3DVM and 4DVar successfully improved the simulations of typhoon intensity and track incorporating the satellite AMSU-A retrieved temperature and wind data into the initial conditions, and the 3DVM more significantly due to the flow-dependent of background error covariance matrix and observation error covariance matrix like 3- dimensional variational data assimilation （3DVar） circle; （2） inclusions of extra model integration iterations at each observation time in the 3DVM make it more consistent with prediction model; （3） the 3DVM is much more time-saving due to the exclusion of the adjoint technique in it.

关键词： landfalling typhoon AMSU-A 3DVM 4D-Var numerical simulation

VERIFICATION OF typhoon FORECASTS BY THE GRAPES MODEL

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Journal of Tropical Meteorology 2010年第1期16卷 77-81页

作者：宋煜叶成志黄振濮文耀 Dalian Meteorological Observatory Hunan Meteorological Observatory Dalian Weather Modification Office

Four landfalling typhoon cases in 2005 were selected for a numerical simulation study with the Global/Regional Assimilation and Prediction System(GRAPES) *** preliminary assessment results of the performance of the model,including the predictions of typhoon track,landfall time,location and intensity,etc.,are presented and the sources of errors are *** 24-hour distance forecast error of the typhoon center by the model is shown to be about 131 km,while the 48-hour error is 252 *** model was relatively more skilful at forecasts of landfall time and locations than those of intensity at *** average,the 24-hour forecasts were slightly better than the 48-hour *** analysis of data impacts indicates that the assimilation of unconventional observation data is essential for the improvement of the model *** model could also be improved by increasing model resolution to simulate the mesoscale and fine scale systems and by improving methods of terrain refinement processing.

关键词： GRAPES model landfalling typhoon verification

The cloud-microphysical cause of torrential rainfall amplification associated with Bilis(0604)

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Science China Earth Sciences 2014年第9期57卷 2100-2111页

作者： REN ChenPing CUI XiaoPeng Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters/Key Laboratory of Meteorological Disaster of Ministry of Education Nanjing University of Information Science & Technology LACS Institute of Atmospheric Physics Chinese Academy of Sciences

After its landfall in China＇s mainland in 2006, typhoon Bilis brought about torrential rainfall amplification at the edge of Guangdong, Jiangxi, and Hunan provinces, causing severe disasters. From a cloud-microphysical perspective, we discuss the differences of cloud-microphysical processes before and during the precipitation amplification and possible causes of the rain- fall amplification by using high-resolution simulation data. The results show that the cloud-microphysical characteristics dur- ing the above two periods are significantly different. With the distinct increase in the rainfall intensity, the cloud hydrometeor contents increase markedly, especially those of the ice-phase hydrometeors including ice, snow and graupel, contributing more to the surface rainfall. The clouds develop highly and vigorously. Comparisons of conversion rates of the cloud hydrometeors between the above two periods show that the distinct increases in the cloud water content caused by the distinct enhancement of the water vapor condensation rate contribute to the surface rainfall mainly in two ways. First, the rain water content increas- es significantly by accretion of cloud water by rain water, which thus contributes to the surface rainfall. Second, the accretion of cloud water by snow increases significantly the content of snow, which is then converted to graupel by accretion of snow by graupel. And then the graupel melts into rain water, which subsequently contributes to the surface rainfall amplification. In summary, a flow chart is given to clarify the cloud-micropbysical cause of the torrential rainfall amplification associated with Bills.

关键词： landfalling typhoon torrential rainfall amplification cloud microphysics

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