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Interannual variability of Antarctic Oscillation and its influence on East Asian climate during boreal winter and spring

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Science china Earth sciences 2006年第5期49卷 554-560页

作者： fan ke1,2,3 & WANG Huijun2 1. Nansen-Zhu International Research Center, institute of atmospheric physics, chinese academy of sciences, beijing 10002., china 2. Department of atmospheric Science, Yunnan University, Kunming 650091, china 3. Graduate University of the chinese academy of sciences, beijing 100049, china Nansen-Zhu International Research Center Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Department of atmospheric Science Yunnan University Kunming China Graduate University of the chinese academy of sciences Beijing China

The interannual variability of Antarctic Oscillation (AAO) and its influence on East Asian climate during both boreal winter and spring are addressed. The results show that the positive AAO anomaly decreases the cold activity over East Asia during both boreal winter and spring. AAO-related barotropic meridional teleconnection from Antarctic to Arctic is found through analysis of mean me- ridional circulations. This meridional teleconnection is remarkable over Eurasia during boreal winter and over the Pacific Ocean during boreal spring. The results also show that zonal mean zonal wind at high latitudes in Southern Hemisphere has well positive correlation with that of Eurasia during boreal winter and has negative correlation with Pacific North American teleconnection (PNA) during boreal spring, which again display the meridional teleconnection. Thus, local meridional teleconnection is a possible linkage for interaction of circulations at mid-high latitudes between both hemispheres.

关键词： Antarctic Oscillation, Eurasian west wind, meridional teleconnection, mean meridional circulation.

Projecting Wintertime Newly Formed Arctic Sea Ice through Weighting CMIP6 Model Performance and Independence

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Advances in atmospheric sciences 2024年第8期41卷 1465-1482页

作者： Jiazhen ZHAO Shengping HE ke fan Huijun WANG Fei LI key Laboratory of Meteorological Disaster Ministry of Education/Joint International Research Laboratory of Climate and Environment Change(ILCEC)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD)Nanjing University of Information Science&TechnologyNanjing 210044China Geophysical institute University of Bergen and Bjerknes Centre for Climate ResearchBergen 5007Norway School of atmospheric Science Sun Yat-sen Universityand Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)Zhuhai 519082China Nansen Environmental and Remote Sensing Center and Bjerknes Centre for Climate Research Bergen 5007Norway Nansen-Zhu International Research Center Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519082China

Precipitous Arctic sea-ice decline and the corresponding increase in Arctic open-water areas in summer months give more space for sea-ice growth in the subsequent cold seasons. Compared to the decline of the entire Arctic multiyear sea ice,changes in newly formed sea ice indicate more thermodynamic and dynamic information on Arctic atmosphere–ocean–ice interaction and northern mid–high latitude atmospheric teleconnections. Here, we use a large multimodel ensemble from phase 6 of the Coupled Model Intercomparison Project(CMIP6) to investigate future changes in wintertime newly formed Arctic sea ice. The commonly used model-democracy approach that gives equal weight to each model essentially assumes that all models are independent and equally plausible, which contradicts with the fact that there are large interdependencies in the ensemble and discrepancies in models' performances in reproducing observations. Therefore, instead of using the arithmetic mean of well-performing models or all available models for projections like in previous studies, we employ a newly developed model weighting scheme that weights all models in the ensemble with consideration of their performance and independence to provide more reliable projections. Model democracy leads to evident bias and large intermodel spread in CMIP6 projections of newly formed Arctic sea ice. However, we show that both the bias and the intermodel spread can be effectively reduced by the weighting scheme. Projections from the weighted models indicate that wintertime newly formed Arctic sea ice is likely to increase dramatically until the middle of this century regardless of the emissions ***, it may decrease(or remain stable) if the Arctic warming crosses a threshold(or is extensively constrained).

关键词： wintertime newly formed Arctic sea ice model democracy model weighting scheme model performance model independence

Forecasting the summer rainfall in North china using the year-to-year increment approach

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Science china Earth sciences 2009年第4期52卷 532-539页

作者： fan ke1, LIN MeiJing1,2 & GAO YuZhong3 1 Nansen-Zhu International Research Center, institute of atmospheric physics, chinese academy of sciences, beijing 10002., china 2 Graduate University of the chinese academy of sciences, beijing 100049, china 3 Heilongjiang Meteorological Administration, Harbin 150030, china Nansen-Zhu International Research Center Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Graduate University of the chinese academy of sciences Beijing China Heilongjiang Meteorological Administration Harbin China

A new approach to forecasting the year-to-year increment of rainfall in North china in July-August (JA) is proposed. DY is defined as the difference of a variable between the current year and the preceding year (year-to-year increment). NR denotes the seasonal mean precipitation rate over North china in JA. After analyzing the atmospheric circulation anomalies associated with the DY of NR, five key predictors for the DY of NR have been identified. The prediction model for the DY of NR is established by using multi-linear regression method and the NR is obtained (the current forecasted DY of NR added to the preceding observed NR). The prediction model shows a high correlation coefficient (0.8) between the simulated and the observed DY of NR throughout period 1965-1999, with an average relative root mean square error of 19% for the percentage of precipitation rate anomaly over North china. The prediction model makes a hindcast for 2000-2007, with an average relative root mean square error of 21% for the percentage of precipitation rate anomaly over North china. The model reproduces the downward trend of the percentage of precipitation rate anomaly over North china during 1965-2006. Because the current operational prediction models of the summer precipitation have average forecast scores of 60%-70%, it has been more difficult to forecast the summer rainfall over North china. Thus this new approach for predicting the year-to-year increment of the summer precipitation (and hence the summer precipitation itself) has the potential to significantly improve operational forecasting skill for summer precipitation.

关键词： annual increment North china precipitation prediction prediction skill

Numerical simulation of Meiyu front and the diagnosis of moist vorticity vector

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Progress in Natural Science:Materials International 2007年第11期17卷 1341-1347页

作者： Ping fan1,2 and Luo Zhexian2(1. institute of atmospheric physics, chinese academy of sciences, beijing 10002., china 2. Nanjing University of Information sciences & Technology, Nanjing 210044, china) institute of atmospheric physics Chinese Acad. of Sci. Beijing 100029 China Nanjing University of Information sciences and Technology Nanjing 210044 China

Moist vorticity vector is introduced to study the development and evolution of mesoscale convective vortex (MCV) in the Meiyu front precipitation with the Advanced Regional Predication System (ARPS). In this study, the heavy rainfall is simulated to investigate the genesis, development and dissipation of middle scale convective vortex, which occurred from 0000 UTC 3 July to 1200 UTC 5 July over the Jianghuai River valley. Moist vorticity vector (MVV) has zonal, radial and vertical components in its 3D spatial distribution. The simulation shows that the vertical component of moist vorticity vector well demonstrates the spatial distribution characteristics of middle scale convective vortex, especially in the process of Meiyu front precipitation. Diagnosis upon zonal, radial averaged and mass-integrated quantities of MVV shows that its vertical component and the surface precipitating ratio are in phase with a correlation coefficient of 0.68, indicating that the vertical component of MVV is closely associated with the Meiyu front precipitation. In addition, the tendency of the vertical component of MVV is mainly determined by the interaction between the vorticity and the zonal and radial gradient of condensational or depositional heating.

关键词： moist vorticity vector mesoscale convective vortex Meiyu front precipitation

Zonal propagation of kinetic energy and convection in the South china Sea and Indian monsoon regions in boreal summer

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Science china Earth sciences 2004年第12期47卷 1076-1084页

作者： CHEN Longxun 1 ,GAO Hui 2 ,HE Jinhai 2 ,TAO Shiyan 3 & JIN Zuhui 3 1.chinese academy of Meteorological sciences,beijing 100081,china 2.Nanjing institute of Meteorology,Nanjing 210044,china 3.institute of atmospheric physics,chinese academy of sciences,beijing 10002.,china chinese academy of Meteorological sciences Beijing China Nanjing institute of Meteorology Nanjing China chinese academy of sciences Institute of Atmospheric Physics Beijing China

Zonal propagation of kinetic energy (ke) and convection in the South china Sea (SCS) and Indian summer monsoon areas are examined in present study. Results suggest that the SCS and Indian summer monsoon prevailed regions (5 —15°N) are dominated by the southwesterly wind, however, the disturbances of ke at 850 hPa and convection are observed mainly coming from the western Pacific Ocean (140—150°E), after passing through the SCS, and westward propagated into the Bay of Bengal (90—100°E). In the Indian summer monsoon domain, where the disturbances of ke are found mainly coming from the Arabian Sea (AS) and eastward propagated into the Bay of Bengal. Therefore, the SCS and the Indian summer mon- soon are quite different in zonal propagation of ke and convection. The SCS summer monsoon is mainly affected by the ke and convection coming from the tropical western Pacific. The Indian summer monsoon, however, can be partly influenced by the AS and the SCS summer monsoon. The analysis also suggests that the interaction region between the SCS and the Indian summer monsoon is around 90—95°E, rather than 105°E as proposed by earlier studies.

关键词： zonal propagation of ke and convection, East Asian monsoon, Indian monsoon.

Relative Impacts of Sea Ice Loss and atmospheric Internal Variability on the Winter Arctic to East Asian Surface Air Temperature Based on Large-Ensemble Simulations with NorESM2

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Advances in atmospheric sciences 2024年第8期41卷 1511-1526页

作者： Shengping HE Helge DRANGE Tore FUREVIK Huijun WANG ke fan Lise Seland GRAFF Yvan J.ORSOLINI Geophysical institute University of Bergen and Bjerknes Centre for Climate ResearchBergen 5020Norway Nansen Environmental and Remote Sensing Center Bergen 5007Norway key Laboratory of Meteorological Disaster Ministry of Education/Joint International Research Laboratory of Climate and Environment Change(ILCEC)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD)Nanjing University of Information Science&TechnologyNanjing 211544China Nansen-Zhu International Research Center Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 511458China School of atmospheric Science Sun Yat-Sen Universityand Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)Zhuhai 519082China Norwegian Meteorological institute Oslo 0313Norway Norwegian institute for Air Research Kjeller 2007Norway

To quantify the relative contributions of Arctic sea ice and unforced atmospheric internal variability to the “warm Arctic, cold East Asia”(WACE) teleconnection, this study analyses three sets of large-ensemble simulations carried out by the Norwegian Earth System Model with a coupled atmosphere–land surface model, forced by seasonal sea ice conditions from preindustrial, present-day, and future periods. Each ensemble member within the same set uses the same forcing but with small perturbations to the atmospheric initial state. Hence, the difference between the present-day(or future) ensemble mean and the preindustrial ensemble mean provides the ice-loss-induced response, while the difference of the individual members within the present-day(or future) set is the effect of atmospheric internal variability. Results indicate that both present-day and future sea ice loss can force a negative phase of the Arctic Oscillation with a WACE pattern in winter. The magnitude of ice-induced Arctic warming is over four(ten) times larger than the ice-induced East Asian cooling in the present-day(future) experiment;the latter having a magnitude that is about 30% of the observed cooling. Sea ice loss contributes about 60%(80%) to the Arctic winter warming in the present-day(future) experiment. atmospheric internal variability can also induce a WACE pattern with comparable magnitudes between the Arctic and East Asia. Ice-lossinduced East Asian cooling can easily be masked by atmospheric internal variability effects because random atmospheric internal variability may induce a larger magnitude warming. The observed WACE pattern occurs as a result of both Arctic sea ice loss and atmospheric internal variability, with the former dominating Arctic warming and the latter dominating East Asian cooling.

关键词： Arctic sea ice loss warm Arctic–cold East Asia atmospheric internal variability large-ensemble simulation NorESM2 PAMIP

Kinetic and mechanism of the reaction between Cl and several mono-methyl branched alkanes

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Journal of Environmental sciences 2024年第1期135卷 474-482页

作者： Yan Chen Weigang Wang Junling Li Li Zhou Bo Shi Cici fan ke Wang Hao Zhang Hong Li Maofa Ge State key Laboratory for Structural Chemistry of Unstable and Stable Species Beijing National Laboratory for Molecular Sciences(BNLMS)CAS Research/Education Center for Excellence in Molecular SciencesInstitute of ChemistryChinese Academy of SciencesBeijing 100190China University of chinese academy of sciences Beijing 100049China State key Laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental SciencesBeijing 100012China National Engineering Research Center for Flue Gas Desulfurization Department of Environmental Science and EngineeringSichuan UniversityChengdu 610065China College of Chemistry and Materials Science Hebei Normal UniversityShijiazhuang 050024China

Branched alkanes are ubiquitous in the troposphere and play an important role in the chemical *** this work,the rate constants and products for the reaction of Cl atoms with 3-methylhexane and 2-methylheptane were measured at room temperature(298±0.2K)and atmospheric pressure using a conventional relative rate *** rate constants of 3-methylhexane and 2-methylheptane in units of cm~3/(mol·sec)are(3.09±0.31)×10^(-10)and(3.67±0.40)×10^(-10),***,the corresponding atmospheric lifetime of the studied branched alkanes with Cl was 6.92-89.90 hours and 5.82-75.69 hours,*** estimated atmospheric lifetimes indicated that the reaction with Cl atoms could be the most important atmospheric degradation pathway for 3-methylhexane *** gas-phase products of the reactions were identified and quantified,and particle-phase products were also *** atmosphere oxidation mechanism of Cl atoms with 3-methylhexane and 2-methylheptane is *** SOA yields of 3-methylhexane and 2-methylheptane from the reaction of Cl atoms were determined to be7.96%±0.89%and 13.35%±1.50%***,the results reveal that the primary loss process of branched alkanes is the reaction with Cl atoms,which impacts its degradation on a regional scale.

关键词： 3-Methylhexane 2-Methylheptane Chlorine atoms Kinetics Mechanism

A NUMERICAL CALCULATION METHOD FOR EIGENVALUE PROBLEMS OF NONLINEAR INTERNAL WAVES

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Journal of Hydrodynamics 2009年第3期21卷 373-378页

作者： SHI Xin-gang fan Zhi-song LIU Hai-long College of Physical and Environmental Oceanography Ocean University of China Qingdao 266100 China State key Laboratory of Numerical Modeling for atmospheric sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

Generally speaking, the background shear current U（z） must be taken into account in eigenvalue problems of nonlinear internal waves in ocean, as is different from those of linear internal waves. A numerical calculation method for eigenvalue problems of nonlinear internal waves is presented in this paper on the basis of the Thompson-Haskell＇s calculation method. As an application of this method, at a station （21°N, 117°15′E） in the South china Sea, a modal structure and parameters of nonlinear internal waves are calculated, and the results closely agree with the calculated results based on observation by Yang et al..

关键词： internal waves eigenvalue problem modal structure numerical method

Investigation of fine and complex vortex circulation structures

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Science china Earth sciences 2010年第10期53卷 1552-1558页

作者： LUO ZheXian1,MA GeLan1 & PING fan2 1 Remote Sensing College,Nanjing University of Information Science and Technology,Nanjing 210044,china 2 Laboratory of Cloud-Precipitation physics and Severe Storms(LACS),institute of atmospheric physics,chinese academy of sciences,beijing 10002.,china Remote Sensing College Nanjing University of Information Science and Technology Nanjing China Laboratory of Cloud-Precipitation physics and Severe Storms (LACS) Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China

The formation and evolution of fine and complicated vortex circulation structures were investigated using a two-dimensional quasi-geostrophic barotropic model *** find that the highly localized asymmetric and complex configuration of energy transfer flux between large-and small-scale components is caused by the nonlinear interaction between a large-scale vortex with an initial axi-symmetric flow and four beta meso-scale *** complex structure is characterized by a fine pattern,which contains seven closed systems with spatial scales of less than 100 km,embedded in a positive flux wave train and a negative wave train,*** average wind speed decreased with time in the positive flux region,but was nearly unchanged in the negative flux *** pattern reveals the evolutionary asymmetry and localization of wind speed of the major *** track of the major vortex center has a trend toward the center of the negative flux center,indicating that there is a certain relation between the complex structure of the energy transfer flux and the motion of the major vortex *** results imply that the formation and evolution of the fine and complex structure should be attributed to the nonlinear interaction between the vortices at different spatial scales.

关键词： vortex complex structure non-linear interaction energy cascade