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Advances in Atmospheric Sciences 2016年第8期33卷 945-954页

作者： guanghua chen Center for Monsoon System Research Institute of Atmospheric PhysicsChinese Academy of Sciences

The sensitivity of TC intensification and track to the initial inner-core structure on a β plane is investigated using a numerical model. The results show that the vortex with large inner-core winds（CVEX-EXP） experiences an earlier intensification than that with small inner-core winds（CCAVE-EXP）, but they have nearly the same intensification rate after spin-up. In the early stage, the convective cells associated with surface heat flux are mainly confined within the inner-core region in CVEXEXP, whereas the vortex in CCAVE-EXP exhibits a considerably asymmetric structure with most of the convective vortices being initiated to the northeast in the outer-core region due to the β effect. The large inner-core inertial stability in CVEX-EXP can prompt a high efficiency in the conversion from convective heating to kinetic energy. In addition, much stronger straining deformation and PBL imbalance in the inner-core region outside the primary eyewall ensue during the initial development stage in CVEX-EXP than in CCAVE-EXP, which is conducive to the rapid axisymmetrization and early intensification in CVEX-EXP. The TC track in CVEX-EXP sustains a northwestward displacement throughout the integration, whereas the TC in CCAVE-EXP undergoes a northeastward recurvature when the asymmetric structure is dominant. Due to the enhanced asymmetric convection to the northeast of the TC center in CCAVE-EXP, a pair of secondary gyres embedded within the large-scale primary β gyres forms, which modulates the ventilation flow and thus steers the TC to move northeastward.

关键词： inner-core structure tropical cyclone intensification track β plane

Reexamination of the Relationship between Tropical Cyclone Size and Intensity over the Western North Pacific

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Advances in Atmospheric Sciences 2022年第11期39卷 1956-1968页

作者： Kexin chen guanghua chen Donglei SHI Key Laboratory of Cloud-Precipitation Physics and Severe Storms Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China University of Chinese Academy of Sciences Beijing 100049China Shanghai Typhoon Institute China Meteorological AdministrationShanghai 200030China

This study reexamines the correlation between the size and intensity of tropical cyclones(TCs) over the western North Pacific from the perspective of individual TCs, rather than the previous large-sample framework mixing up all TC *** show that the positive size-intensity correlation based on individual TCs is relatively high. However, this correlation is obscured by mixing large samples. The weakened correlation based on all TC records is primarily due to the diversity in the size change relative to the same intensity change among TCs, which can be quantitatively measured by the linear regression coefficient(RC) of size against intensity. To further explore the factors that cause the variability in RCs that weakens the size-intensity correlation when considering all TC records, the TCs from 2001 to 2020 are classified into two groups according to their RC magnitudes, within which the high-RC TCs have a larger size expansion than the low-RC TCs given the same intensity change. Two key mechanisms responsible for the RC differences are proposed. First, the highRC TCs are generally located at higher latitudes than the low-RC TCs, resulting in higher planetary vorticity and thus higher planetary angular momentum import at low levels. Second, the high-RC TCs are susceptible to stronger environmental vertical wind shear, leading to more prolific outer convection than the low-RC TCs. The positive feedback between outer diabatic heating and boundary layer inflow favors the inward import of absolute angular momentum in the outer region, thereby contributing to a larger size expansion in the high-RC TCs.

关键词： tropical cyclone size and intensity composite analysis absolute angular momentum flux budget

Impact of the Spring SST Gradient between the Tropical Indian Ocean and Western Pacific on Landfalling Tropical Cyclone Frequency in China

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Advances in Atmospheric Sciences 2018年第6期35卷 682-688页

作者： Lei WANG guanghua chen Center for Monsoon System Research Institute of Atmospheric Physics Chinese Academy of Sciences

The present study identifies a significant influence of the sea surface temperature gradient（SSTG） between the tropical Indian Ocean（TIO; 15°S-15°N, 40°-90°E） and the western Pacific warm pool（WWP; 0°-15°N, 125°-155°E） in boreal spring on tropical cyclone（TC） landfall frequency in China's Mainland in boreal summer. During the period 1979-2015, a positive spring SSTG induces a zonal inter-basin circulation anomaly with lower-level convergence, mid-tropospheric ascendance and upper-level divergence over the west-central TIO, and the opposite situation over the WWP, which produces lower-level anomalous easterlies and upper-level anomalous westerlies between the TIO and WWP. This zonal circulation anomaly further warms the west-central TIO by driving warm water westward and cools the WWP by inducing local upwelling, which facilitates the persistence of the anomaly until the summer. Consequently, lower-level negative vorticity, strong vertical wind shear and lower-level anticyclonic anomalies prevail over most of the western North Pacific（WNP）, which decreases the TC genesis frequency. Meanwhile, there is an anomalous mid-tropospheric anticyclone over the main WNP TC genesis region,meaning a westerly anomaly dominates over coastal regions of China's Mainland, which is unfavorable for steering TCs to make landfall in China's Mainland during summer. This implies that the spring SSTG may act as a potential indicator for TC landfall frequency in China's Mainland.

关键词： tropical cyclone landfall sea surface temperature gradient air-sea interaction

Interdecadal variation of tropical cyclone activity in association with summer monsoon,sea surface temperature over the western North Pacific

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Chinese Science Bulletin 2009年第8期54卷 1417-1421页

作者： chen guanghua Center for Monsoon System Research Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100190 China

Based on geographic division over the western North Pacific(WNP),the interdecadal relationships between summer monsoon,sea surface temperature(SST) and tropical cyclones activity(including number,track and intensity) are *** the past several decades,the western Pacific subtropical high(WPSH) and tropical westerlies contribute to the interdecadal variation of TC number in the northwest and southeast of WNP *** increased TC occurrence density to the east of Philippines related to TC track appears during the 1990s,in terms of both steer flow induced by WPSH and genesis *** the interdecadal viewpoint,the tendency of TC intensity,measured by averaged accumulated cyclone energy,does well agree with that of SST,implying that SST plays an important role in TC intensity.

关键词：热带气旋活动西北太平洋海面温度西部夏季风西太平洋副热带高压海洋表面温度热电偶

Modulation of the Wind Field Structure of Initial Vortex on the Relationship between Tropical Cyclone Size and Intensity

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Advances in Atmospheric Sciences 2023年第9期40卷 1707-1721页

作者： Kexin chen guanghua chen Donglei SHI Key Laboratory of Cloud-Precipitation Physics and Severe Storms Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Shanghai Typhoon Institute China Meteorological AdministrationShanghai 200030China University of Chinese Academy of Sciences Beijing 100049China Department of Atmospheric Science School of Environmental StudiesChina University of GeosciencesWuhan 430074China

This study investigates the modulation of initial wind field structure on the relationship between the size and intensity of a simulated vortex.A series of idealized experiments are conducted by varying the radius of maximum wind(RMW)and shape parameter of the initial *** size–intensity relationship is quantified by the linear regression coefficient of the azimuthally-averaged gale-force wind radius against the maximum wind during the development stage,reflecting the degree of size expansion at the same intensity *** regression coefficient increases with increased RMW and decreased,with the RMW being the primary *** effect of lowering on the elevation of the regression coefficient gradually stands out when the initial RMW is *** the RMW leads to a secondary circulation with a horizontally elongated structure,which retards the intensification while promoting size expansion,thus substantially enhancing size expansion as the vortex *** the wind field outside the RMW by reducing results in abounding convection in the outer region,which promotes size *** on the axisymmetric tangential wind tendency and Sawyer–Eliassen equations,when the RMW is large,the active convection in the outer region can weaken the radial inflow induced by the eyewall heating in the inner region,thus retarding the intensification by reducing the radial imports of vorticity near the RMW.

关键词： tropical cyclone size and intensity initial wind field structure tangential wind tendency equation Sawyer-Eliassen equation

Impact of Interannual Variation of Synoptic Disturbances on the Tracks and Landfalls of Tropical Cyclones over theWestern North Pacific

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Advances in Atmospheric Sciences 2018年第12期35卷 1469-1477页

作者： Xingyan ZHOU Riyu LU guanghua chen State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China University of the Chinese Academy of Sciences Beijing 100049China Center for Monsoon System Research Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China

This study investigates the tropical cyclone(TC)activity associated with the two leading modes of interannual variability in synoptic *** leading modes are found to be related to a dipole pattern of TC occurrence between the subtropical western North Pacific and the South China ***,in this study we performed composite analyses on TC tracks and landfalls,based on the cases of combined modes,to highlight the *** composite results indicate that these cases are characterized by distinct features of TC tracks and landfalls:more TCs tend to take recurving tracks and attack eastern China,Korea and Japan,or more TCs exhibit straight-moving tracks and hit the Philippines,Vietnam and southern *** analyses suggest that these distinctions in the TC prevailing tracks and landfalls can be attributed to the differences in large-scale steering flow and TC genesis location.

关键词： tropical cyclone landfall track interannual variability synoptic disturbance

Intensified Impact of Northern Tropical Atlantic SST on Tropical Cyclogenesis Frequency over the Western North Pacific after the Late 1980s

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Advances in Atmospheric Sciences 2016年第8期33卷 919-930页

作者： Xi CAO Shangfeng chen guanghua chen Renguang WU Center for Monsoon System Research Institute of Atmospheric Physics Chinese Academy of Sciences State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences

Previous studies suggest that spring SST anomalies over the northern tropical Atlantic（NTA） affect the tropical cyclone（TC） activity over the western North Pacific（WNP） in the following summer and fall. The present study reveals that the connection between spring NTA SST and following summer–fall WNP TC genesis frequency is not stationary. The influence of spring NTA SST on following summer–fall WNP TC genesis frequency is weak and insignificant before, but strong and significant after, the late 1980 s. Before the late 1980 s, the NTA SST anomaly-induced SST anomalies in the tropical central Pacific are weak, and the response of atmospheric circulation over the WNP is not strong. As a result, the connection between spring NTA SST and following summer–fall WNP TC genesis frequency is insignificant in the former period. In contrast,after the late 1980 s, NTA SST anomalies induce pronounced tropical central Pacific SST anomalies through an Atlantic–Pacific teleconnection. Tropical central Pacific SST anomalies further induce favorable conditions for WNP TC genesis,including vertical motion, mid-level relative humidity, and vertical zonal wind shear. Hence, the connection between NTA SST and WNP TC genesis frequency is significant in the recent period. Further analysis shows that the interdecadal change in the connection between spring NTA SST and following summer–fall WNP TC genesis frequency may be related to the climatological SST change over the NTA region.

关键词： northern tropical Atlantic SST tropical cyclone western North Pacific

Stability of flow between rotating cylinders with axial buoyancy effect

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Science China(Physics,Mechanics & Astronomy) 2006年第5期49卷 564-575页

作者： chen Jianguo chen Haixin ZHANG guanghua FU Song Department of Engineering Mechanics School of AerospaceTsinghua UniversityBeijing 100084China Department of Engineering MechanicsSchool of AerospaceTsinghua UniversityBeijing 100084China Department of Engineering MechanicsSchool of AerospaceTsinghua UniversityBeijing 100084China Department of Engineering MechanicsSchool of AerospaceTsinghua UniversityBeijing 100084China

The linear stability of a fluid confined between two coaxial cylinders rotating independently with axial buoyancy induced flow is examined. Buoyancy is included through the Boussinesq approximation. The numerical investigation is restricted to radius ratio 0.5 at Prandtl number 0.709 with co-rotation situation. The outer rotating cylinder’s Couette flow Reynolds number is restricted to 200. Zeroth-order discontinuities are found in the critical surface, which are explained as the result of the competition between the centrifugal and axial buoyancy induced shear instability mechanisms. Due to the competition, the neutral stability curves develop islands of instability, which considerably lower the instability threshold. Specific and robust numerical methods to handle these geometrical complexities are developed.

关键词： island of instability cylinder rotation buoyancy flow

Surface Free Energies and Morphologies of Chemical Vapor Deposited Diamond Films

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Chinese Physics Letters 1994年第8期11卷 502-505页

作者： ZHANG Yafei ZHANG Fangqing chen guanghua Department of Physics Lanzhou UniversityLanzhou 730001

We have calculated the surface free energies of the chemical vapor deposited diamond crystals during the preparation process,using the model that a fraction of carbon dangling bonds on the growth surface are saturated by *** results show that the surface free energies of the three most energetically favored crystal planes,i.e.(100),(110)and(111),can be used to interpret the changes of predominant facets in the surface morphology from{100}to{111}with increasing substrate *** chemical vapor deposition conditions,it is found that the growth surfaces of diamond are more stable than that of graphite.

关键词： temperature Diamond surface

On the Weakened Relationship between Spring Arctic Oscillation and Following Summer Tropical Cyclone Frequency over the Western North Pacific:A Comparison between 1968–1986 and 1989–2007

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Advances in Atmospheric Sciences 2015年第10期32卷 1319-1328页

作者： CAO Xi chen Shangfeng chen guanghua chen Wen WU Renguang Center for Monsoon System Research Institute of Atmospheric PhysicsChinese Academy of Sciences

This study documents a weakening of the relationship between the spring Arctic Oscillation （AO） and the following summer tropical cyclone （TC） formation frequency over the eastern part （150°-180°E） of the western North Pacific （WNP）. The relationship is strong and statistically significant during 1968-1986, but becomes weak during 1989-2007. The spring AO- related SST, atmospheric dynamic, and thermodynamic conditions are compared between the two epochs to understand the possible reasons for the change in the relationship. Results indicate that the spring AO leads to an E1 Nifio-like SST anomaly, lower-level anomalous cyclonic circulation, upper-level anomalous anticyclonic circulation, enhanced ascending motion, and a positive midlevel relative humidity anomaly in the tropical western-central Pacific during 1968-1986, whereas the AOrelated anomalies in the above quantities are weak during 1989-2007. Hence, the large-scale dynamic and thermodynamic anomalies are more favorable for TC formation over the eastern WNP during 1968-1986 than during 1989-2007.

关键词： spring Arctic Oscillation summer tropical cyclone western North Pacific SST