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Effect of the Vertical Diffusion of Moisture in the Planetary Boundary Layer on an Idealized Tropical Cyclone

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Advances in Atmospheric Sciences 2021年第11期38卷 1889-1904页

作者： Hongxiong XU dajun zhao State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesChina Meteorological AdministrationBeijing 100081China

Previous numerical studies have focused on the combined effect of momentum and scalar eddy diffusivity on the intensity and structure of tropical *** separate impact of eddy diffusivity estimated by planetary boundary layer(PBL)parameterization on the tropical cyclones has not yet been systematically *** have examined the impacts of eddy diffusion of moisture on idealized tropical cyclones using the Advanced Research Weather Research and Forecasting model with the Yonsei University PBL *** results show nonlinear effects of moisture eddy diffusivity on the simulation of idealized tropical *** the eddy diffusion of moisture increases the moisture content of the PBL,with three different effects on tropical cyclones:(1)an decrease in the depth of the PBL;(2)an increase in convection in the inner rain band and eyewall;and(3)drying of the lowest region of the PBL and then increasing the surface latent heat *** three processes have different effects on the intensity and structure of the tropical cyclone through various physical *** increased surface latent heat flux is mainly responsible for the decrease in *** show that moisture eddy diffusivity has clear effects on the pressure in tropical cyclones,but contributes little to the intensity of *** largely influences the wind-pressure relationship,which is crucial in tropical cyclones *** results improve our understanding of moisture eddy diffusivity in the PBL and its influence on tropical cyclones,and provides guidance for interpreting the variation of moisture in the PBL for tropical cyclone simulations.

关键词： tropical cyclones moisture eddy diffusivity boundary layer wind-pressure relationship

Climatology of Tropical Cyclone Extreme Rainfall over China from 1960 to 2019

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Advances in Atmospheric Sciences 2022年第2期39卷 320-332页

作者： Ying LI dajun zhao National Climate Centre Beijing 100081China State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China

Tropical cyclone extreme rainfall(TCER)causes devastating floods and severe damage in China and it is therefore important to determine its long-term climatological distribution for both disaster prevention and operational *** on the tropical cyclone(TC)best-track dataset and TC precipitation data from 1960 to 2019,the spatiotemporal distribution of TCER affecting China is *** show that there were large regional differences in the threshold for TCER in China,decreasing from the southeastern coast to the northwest *** occurred infrequently in northern China but had a high intensity and was highly *** frequency and intensity of TCER showed slightly increasing trends over time and was most likely to occur in August(41.0%).Most of the TC precipitation processes with extreme rainfall lasted for four to six days,with TCER mainly occurring on the third to fourth *** with wide areas showed a northwestward prevailing track and a westward prevailing *** TCs are not always accompanied by extreme precipitation while some weak TCs can lead to very extreme rainfall.A total of 64.7%(35.3%)of the TCER samples occurred when the TC was centered over the land(sea).TCER≥250 mm was located within 3°of the center of the *** the center of the TC was located over the sea(land),the extreme rainfall over land was most likely to appear on its northwestern(northeastern)side with a dispersed(concentrated)*** has unique climatic characteristics relative to the TC precipitation.

关键词： tropical cyclones extreme rainfall threshold track characteristics intensity characteristics

Autumn Tropical Cyclones over the Western North Pacific during 1949–2016:A Statistical Study

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Journal of Meteorological Research 2020年第1期34卷 150-162页

作者： Xiuping YAO dajun zhao Ying LI China Meteorological Administration Training Centre China Meteorological AdministrationBeijing 100081 State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesChina Meteorological AdministrationBeijing 100081 National Climate Center China Meteorological AdministrationBeijing 100081

We used tropical cyclone(TC)best track data for 1949–2016,provided by the Shanghai Typhoon Institute,China Meteorological Administration(CMA-STI),and a TC size dataset(1980–2016)derived from geostationary satellite infrared images to analyze the statistical characteristics of autumn TCs over the western North Pacific(WNP).We investigated TC genesis frequency,location,track density,intensity,outer size,and landfalling features,as well as their temporal and spatial evolution *** average,the number of autumn TCs accounted for 42.1%of the annual total,slightly less than that of summer TCs(42.7%).However,TCs classified as strong typhoons or super typhoons were more frequent in autumn than in *** most years of the 68-yr study period,there was an inverse relationship between the number of autumn TCs and that of summer *** genesis of autumn TCs was concentrated at three centers over the WNP:the first is located near(14°N,115°E)over the northeastern South China Sea and the other two are located in the vast oceanic area east of the Philippines around(14°N,135°E)and(14°N,145°E),*** terms of intensity,the eight strongest TCs during the study period all occurred in *** is revealed that autumn TCs were featured with strong typhoons and super typhoons,with the latter accounting for28.1%of the total number of autumn ***,the average 34-knot radius(R34)of autumn TCs increased with TC *** 1949 to 2016,164 autumn TCs made landfall in China,with an average annual number *** TCs were most likely to make landfall in Guangdong Province,followed by Hainan Province and Taiwan Island.

关键词： western North Pacific autumn tropical cyclone statistical characteristics

Impact of the Monsoonal Surge on Extreme Rainfall of Landfalling Tropical Cyclones

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Advances in Atmospheric Sciences 2021年第5期38卷 771-784页

作者： dajun zhao Yubin YU Lianshou CHEN State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China University of Chinese Academy of Sciences Beijing 100049China

A comparative analysis and quantitative diagnosis has been conducted of extreme rainfall associated with landfalling tropical cyclones(ERLTC)and non-extreme rainfall(NERLTC)using the dynamic composite analysis *** data and the tropical cyclone precipitation dataset derived from the objective synoptic analysis technique were *** show that the vertically integrated water vapor transport(Q_(vt))during the ERLTC is significantly higher than that during the *** Q_(vt)reaches a peak 1−2 days before the occurrence of the ERLTC and then decreases *** is a stronger convergence for both the Q_(vt)and the horizontal wind field during the *** Q_(vt)convergence and the wind field convergence are mainly confined to the lower *** water vapor budget on the four boundaries of the tropical cyclone indicates that water vapor is input through all four boundaries before the occurrence of the ERLTC,whereas water vapor is output continuously from the northern boundary before the occurrence of the *** water vapor inflow on both the western and southern boundaries of the ERLTC exceeds that during the NERLTC,mainly as a result of the different intensities of the southwest monsoonal surge in the surrounding environmental *** the background of the East Asian summer monsoon,the low-level jet accompanying the southwest monsoonal surge can increase the inflow of water vapor at both the western and southern boundaries during the ERLTC and therefore could enhance the convergence of the horizontal wind field and the water vapor flux,thereby resulting in the *** the other hand,the southwest monsoonal surge decreases the zonal mean steering flow,which leads to a slower translation speed for the tropical cyclone associated with the ***,a dynamic monsoon surge index(DMSI)defined here can be simply linked with the ERLTC and could be used as a new predictor for future operational forecasting of ERLTC.

关键词： landfalling tropical cyclones extreme rainfall monsoon surge dynamic composite analysis

Effects of Microphysical Latent Heating on the Rapid Intensification of Typhoon Hato(2017)

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Journal of Meteorological Research 2020年第2期34卷 368-386页

作者： dajun zhao Yubin YU Jinfang YIN Hongxiong XU State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesChina Meteorological AdministrationBeijing 100081 University of Chinese Academy of Sciences Beijing 100049 China Meteorological Administration Beijing 100081

A 72-h cloud-resolving numerical simulation of Typhoon Hato(2017)is performed by using the Weather Research and Forecasting(WRF)model with the Advanced Research WRF(ARW)core(V3.8.1)on a horizontal resolution of2 *** enhance the background tropical cyclone structure and intensity,a vortex dynamic initialization scheme with a terrain-filtering algorithm is *** model reproduces reasonably well the track,structure,and intensity change of Typhoon *** specifically,the change trend of simulated maximum wind speed is consistent with that of best-track analysis,and the simulated maximum wind of 49 ms^-1 is close to that(52 ms^-1)of the best-track analysis,indicating that the model has successfully captured the rapid intensification(RI)of Typhoon Hato(2017).Analyses of the model outputs reveal that the total microphysical latent heating of the inner-core region associated with enhanced vertical upward motion reaches its maximum at 9-km height in the upper troposphere during the RI *** dominant microphysical processes with positive latent heat contributions(i.e.,heating effect)are water vapor condensation into cloud water(67.6%),depositional growth of ice(12.9%),and generation(nucleation)of ice from vapor(7.9%).Those with negative latent heat contributions(cooling effect)are evaporation of rain(47.6%),melting of snow(27.7%),and melting of graupel(9.8%).Sensitivity experiments further show that the intensification speed and peak intensity of this typhoon are highly correlated to the dominant heating effect.A significant increase in graupel over 5-10-km height and snow at 10-14-km height in the inner-core region of Typhoon Hato corresponds well with its RI stage,and the latent heating from nucleation and depositional growth is crucial to the RI of simulated Hato.

关键词： microphysical latent heating rapid intensification typhoon budget analysis

Super Typhoon Hinnamnor(2022)with a Record-Breaking Lifespan over the Western North Pacific

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Advances in Atmospheric Sciences 2023年第9期40卷 1558-1566页

作者： Qian WANG dajun zhao Yihong DUAN Shoude GUAN Lin DONG Hongxiong XU Hui WANG Department of Atmospheric and Oceanic Sciences and Institute of Atmospheric Sciences Fudan UniversityShanghai 200433China State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China National Meteorological Centre Beijing 100081China Frontier Science Center for Deep Ocean Multispheres and Earth System(FDOMES)and Physical Oceanography Laboratory/Sanya Oceanographic Institution Ocean University of ChinaQingdao 266100China Shanghai Typhoon Institute China Meteorological AdministrationShanghai 200030China

Super Typhoon Hinnamnor(2022)was a rare and unique western North Pacific typhoon,and throughout its lifespan,it exhibited all of the major features that pose current challenges in typhoon ***,during different stages of its lifespan,it experienced a sudden change of track,underwent rapid intensification,interacted and merged with another vortex,expanded in size,underwent rapid weakening,produced a strong cold wake,exhibited eyewall replacement,and underwent extratropical ***,a timely identification and review of these features of Hinnamnor(2022),as reported in this article,will help update and enrich the case sets for each of these scientific issues and provide a background for more in-depth mechanistic studies of typhoon track,intensity,and structural changes in the *** also believe that Hinnamnor(2022)can serve as an excellent benchmark to quickly evaluate the overall performance of different numerical models in predicting typhoon’s track,intensity,and structural changes.

关键词： sudden track change rapid intensification rapid weakening vortex merging extratropical transition

Unusual Evolution of the Multiple Eyewall Cycles in Super Typhoon Hinnamnor(2022)

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Journal of Meteorological Research 2023年第4期37卷 431-440页

作者： Hui WANG Yubin YU dajun zhao Tzu-Hsiung YEN Hongxiong XU Qian WANG Zhiqiang CAO State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesChina Meteorological AdministrationBeijing 100081 China Meteorological Administration Training Centre Beijing 100081 Shanghai Typhoon Institute China Meteorological AdministrationShanghai 200030 Department of Atmospheric Sciences “National”Taiwan UniversityTaipei 10617 National Meteorological Centre China Meteorological AdministrationBeijing 100081 Key Laboratory of Radiometric Calibration and Validation for Environmental Satellites National Satellite Meteorological Center/National Center for Space WeatherChina Meteorological AdministrationBeijing 100081

Hinnamnor was the first super typhoon in the western North Pacific basin in *** had several prominent characteristics,such as rapid intensification after its formation,three eyewall cycles,and a sudden recurvature of its *** on multi-source observational and reanalysis datasets,two secondary eyewall formation(SEF)cycles occurred during Super Typhoon Hinnamnor’s *** first SEF happened near the time when Hinnamnor achieved its maximum intensity,and it seems that its internal dynamics dominated the SEF process after the development of shear-induced asymmetric spiral *** merger of a tropical depression with Hinnamnor led to a continuous increase in both its inner-core size and outer-core circulation,causing generation of the second *** is inferred that the external and internal dynamics worked together during the second SEF *** concentric eyewall structure maintained for approximately 84 h under the moderate vertical wind ***,unique changes in intensity accompanied the two structural changes.

关键词： concentric eyewall secondary eyewall formation tropical cyclone intensity change

STRUCTURE CHARACTERISTICS OF MICROALLOYING AS-CAST MARTENSITIC CAST IRON

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Acta Metallurgica Sinica(English Letters) 1991年第9期4卷 179-183页

作者： ZHANG Jinghui LI dajun zhao Jiuzhou JIA Jun Harbin Institute of Technology,Harbin,ChinaLI Jianhui Heilongjiang Association for Science and Technology,Harbin,China Harbin Inst of Technology Harbin China

The microstructure and martensite substructure of as-cast martensitic high-Cr cast iron by injection microalloying have been studied by usig SEM and *** relationship between distribution of alloying elements and phase formation of carbide,as well as various branching and distortion of carbide,have been analysed by X-ray diffractometer and EPMA.

关键词： high-Cr cast iron microalloying martensite substructure carbide

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纯铜浇注铜阳极模铸件的裂纹及气孔浅析

特种铸造及有色合金 2010年第3期30卷 288-289页

作者：赵大军云南铜业集团公司铜材有限公司

采用感应电炉熔化高纯阴极铜,铸造浇注阳极板用铜阳极模铸件,对试验过程中阳极模的裂纹和气孔的生成机理及影响因素等进行了分析,并提出了预防和改进措施,为浇注铜阳极模铸件生产提供了借鉴和参考。

关键词：阳极模裂纹气孔