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| 1 | Analysis of the Winter Cloud-to-Ground Lightning Activity and Its Synoptic Background in China during 2010-20显示文摘Cloud-to-ground(CG)lightning data and the ECMWF ERA-Interim reanalysis dataset are analyzed to gain insight into the spatiotemporal distribution and synoptic background of winter-season CG flashes between December 2010 and February 2020 in China.We identify three Winter Lightning Frequent Areas(WLAs):the southwest side of the Yunnan-Guizhou Plateau(WLA1),the east side of the Yunnan-Guizhou Plateau(WLA2),and the Poyang Lake Plain(WLA3).The CG lightning flashes most frequently occur at local midnight and have a monthly peak in February.The CG lightning in WLA1 is mostly generated in non-frontal weather;however,the lightning in WLA2 and WLA3 mostly occurs in frontal systems.The frontal circulation situation is divided into four typical types:transversal trough after high pressure,low vortex,confrontational convergence,and asymptotic convergence.In all typical weather patterns,the lightning occurs downstream of a 500 hPa trough and is accompanied by a southwesterly low-level jet.The convective parameters of winter thunderstorms differ greatly from those of summer thunderstorms.The maximum convective available potential energy(MCAPE)and K-index(KI)are more useful metrics than convective available potential energy(CAPE)and Showalter index(SI)during winter.This study further deepens the understanding of the distribution characteristics of winter CG lightning in China,which motivates further research to improve the ability of winter thunderstorm prediction. | Manman MA Xiaogang HUANG Jianfang FEI Chi ZHANG Chao LI Xiaoping CHENG | 2022 | Advances in Atmospheric Sciences2022，39，6： | 2 |
| 2 | Asymmetric Distribution of Convection in Tropical Cyclones over the Western North Pacific Ocean显示文摘Forecasts of the intensity and quantitative precipitation of tropical cyclones(TCs) are generally inaccurate, because the strength and structure of a TC show a complicated spatiotemporal pattern and are affected by various factors. Among these, asymmetric convection plays an important role. This study investigates the asymmetric distribution of convection in TCs over the western North Pacific during the period 2005–2012, based on data obtained from the Feng Yun 2(FY2)geostationary satellite. The asymmetric distributions of the incidence, intensity and morphology of convections are analyzed.Results show that the PDFs of the convection occurrence curve to the azimuth are sinusoidal. The rear-left quadrant relative to TC motion shows the highest occurrence rate of convection, while the front-right quadrant has the lowest. In terms of intensity, weak convections are favored in the front-left of a TC at large distances, whereas strong convections are more likely to appear to the rear-right of a TC within a 300 km range. More than 70% of all MCSs examined here are elongated systems, and meso-β enlongated convective systems(MβECSs) are the most dominant type observed in the outer region of a TC. Smaller MCSs tend to be more concentrated near the center of a TC. While semi-circular MCSs [MβCCSs, MCCs(mesoscale convective complexes)] show a high incidence rate to the rear of a TC, elongated MCSs [MβECSs, PECSs(persistent elongated convective systems)] are more likely to appear in the rear-right quadrant of a TC within a range of 400 km. | Lu YANG Jianfang FEI Xiaogang HUANG Xiaoping CHENG Xiangrong YANG Juli DING Wenli SHI | 2016 | Advances in Atmospheric Sciences2016，33，11： | 2 |
| 3 | Impacts of the Lowest Model Level Height on Tropical Cyclone Intensity and Structure显示文摘Variable thicknesses in the lowest half-η model level(LML) are often used in atmospheric models to compute surface diagnostic fields such as surface latent and sensible heat fluxes. The effects of the LML on simulated tropical cyclone(TC)evolution were investigated in this study using the Weather Research and Forecasting(WRF) model. The results demonstrated notable influences of the LML on TC evolution when the LML was placed below 12 m. The TC intensification rate decreased progressively with a lowering of the LML, but its ultimate intensity change was relatively small. The maximum 10-m winds showed different behavior to minimum sea level pressure and azimuthally-averaged tangential winds, and thus the wind–pressure relationship was changed accordingly by varying the LML. The TC circulation was more contracted in association with a higher LML.Surface latent heat fluxes were enhanced greatly by elevating the LML, wherein the wind speed at the LML played a dominant role. The changes in the wind speed at the LML were dependent not only on their profile differences, but also the different heights they were taken from. Due to the enhanced surface heat fluxes, more intense latent heat release occurred in the eyewall, which boosted the storm's intensification. A higher LML tended to produce a stronger storm, and therefore the surface friction was reinforced, which in turn induced stronger boundary layer inflow together with increased diabatic heating. | MA Zhanhong FEI Jianfang HUANG Xiaogang CHENG Xiaoping | 2014 | Advances in Atmospheric Sciences2014，31，2： | 2 |
| 4 | Maintenance and Sudden Change of a Strong Elevated Ducting Event Associated with High Pressure and Marine Low-Level Jet显示文摘Capture of a strong elevated ducting event,especially its maintenance and sudden change,is of great value to airborne radar to achieve its beyond-the-line-of-sight detection.However,the knowledge is not easily accessible over the open ocean and hence very rare.During the Air–Sea Interaction Survey(ASIS)over the western North Pacific(WNP)in May 2016,a strong elevated ducting event with a long-life period and sudden change in its evolution was observed.Measurements from the ASIS,images from the Himawari-8 satellite,reanalysis data from the ECMWF,and Weather Research and Forecasting(WRF)model,were used to analyze the maintenance and sudden change of this strong ducting event,together with the model performance on simulating it.The results showed that the maintenance of strong elevated ducts,with their tops ranging from 750 to 1050 m and average strength of approximately 38 M units,was caused by a strong dry air mass capping over the wet marine atmospheric boundary layer(MABL),together with the subsidence inversion associated with high pressure.The WRF model performs well in simulating them.However,a sudden increase in duct height with a slight decrease of strength was recorded by the subsequent GPS radiosonde,which was finally contributed to the mechanical turbulent inversion and hydrolapse associated with the marine low-level jet(MLLJ).The height of the maximum horizontal wind speed(Umh)of the MLLJ corresponds well with the bottom of the trapping layer.However,these jet-relevant ducts are generally weak and it is difficult to accurately simulate them by using the mesoscale numerical model,since the wind-shear produced eddies are too small to be properly parameterized. | Zhichao LIANG Juli DING Jianfang FEI Xiaoping CHENG Xiaogang HUANG | 2020 | Journal of Meteorological Research2020，34，6： | 2 |
| 5 | Disease severity dictates SARS-CoV-2-specific neutralizing antibody responses in COVID-19显示文摘COVID-19 patients exhibit differential disease severity after SARS-CoV-2 infection.It is currently unknown as to the correlation between the magnitude of neutralizing antibody(NAb)responses and the disease severity in COVID-19 patients.In a cohort of 59 recovered patients with disease severity including severe,moderate,mild,and asymptomatic,we observed the positive correlation between serum neutralizing capacity and disease severity,in particular,the highest NAb capacity in sera from the patients with severe disease,while a lack of ability of asymptomatic patients to mount competent NAbs.Furthermore,the compositions of NAb subtypes were also different between recovered patients with severe symptoms and with mild-tomoderate symptoms.These results reveal the tremendous heterogeneity of SARS-CoV-2-specific NAb responses and their correlations to disease severity,highlighting the needs of future vaccination in COVID-19 patients recovered from asymptomatic or mild illness. | Xiangyu Chen Zhiwei Pan Shuai Yue Fei Yu Junsong Zhang Yang Yang Ren Li Bingfeng Liu Xiaofan Yang Leiqiong Gao Zhirong Li Yao Lin Qizhao Huang Lifan Xu Jianfang Tang Li Hu Jing Zhao Pinghuang Liu Guozhong Zhang Yaokai Chen Kai Deng Lilin Ye | 2020 | Signal Transduction and Targeted Therapy2020，5，1： | 1 |
| 6 | Direct/indirect effects of aerosols and their separate contributions to Typhoon Lupit(2009):Eyewall versus peripheral rainbands显示文摘As a typhoon approaches the continent,the position where anthropogenic aerosols penetrate,the convection competition between the eyewall and peripheral rainbands,and the separate contributions of direct aerosol-radiation interactions(ARI)and indirect aerosol-cloud interactions(ACI),yield uncertainties in the convection intensification area and hence the typhoon intensity.Typhoon Lupit(2009)was simulated using the Weather Research and Forecasting Model with Chemistry(WRF-Chem)to investigate and isolate the direct and indirect effects of aerosols on the intensity,convection,and precipitation of the typhoon.Three simulations(CTL,CLEAN,and CTLARIOFF)were designed,representing a polluted case(CTL,considering the ingestion of anthropogenic aerosols with ARI and ACI),a clean maritime case(CLEAN,mainly with sea salt aerosols),and a polluted case without aerosol radiative forcing(CTLARIOFF,as per CTL but without ARI).The results showed that anthropogenic aerosols could penetrate into both the peripheral rainbands and the eyewall when the typhoon was approaching the Asian continent.Owing to the representation of the real aerosol scenario,the simulated typhoon intensity weakened and was closer to observed values in the CTL experiment.The ARI dominated over ACI with the opposite effects.Specifically,the ACI mainly enhanced the formation of ice-phase hydrometeors within the upper level of the eyewall with more freezing latent heat releases,leading to an invigoration of eyewall convection.These excess ice-phase particles melted after they descended into the warm layer below the 0°C level,which accelerated the accretion of cloud droplets by raindrops(Pcacr)and hence the mixed phase precipitation process in the eyewall.The dynamic feedback induced by the ACI enhanced the boundary layer inflow and the upper layer outflow,supporting the maintenance of strong eyewall convection and intensification of the typhoon.Inversely,the ARI heated the distant periphery low-level atmosphere at an altitude of 1-2 km by the absorbing polluted aerosols.The heated air,driven by the radial inflow,firstly went through the periphery rainbands of the typhoon and invigorated convection there due to the low-level warming.Then,the enhanced periphery convection inhibited the further transport of warm moist air into the eyewall,resulting in weakening of the eyewall convection and hence typhoon intensity.In sum,for the polluted scenario,as the typhoon approached the continent,ARI played a dominant role over ACI.The WRF-Chem model with full consideration of aerosol-cloud-radiation interactions is advantageous in terms of reliably simulating typhoon intensity and precipitation distribution. | Zhichao LIANG Juli DING Jianfang FEI Xiaoping CHENG Xiaogang HUANG | 2021 | Science China Earth Sciences2021，64，12： | 1 |
| 7 | An improved QuikSCAT wind retrieval algorithm and eye locating for typhoon显示文摘This paper proposes a rain considered geophysical model function (GMF), to be noted as GMF plus Rain. GMF plus Rain is based on the basic raidative transfer model with attenuation and scattering effects of rain on radar signal considered. Combined with the NSCAT2 GMF and the rain correction model, the GMF plus Rain model is used to retrieve the ocean wind vectors from the collocated QuikSCAT and SSM/I rain rate data for typhoon Melor. The resulting wind speed estimates of typhoon Melor show improved agreement with the wind fields derived from the best track analysis of Japan Meteorological Agency (JMA). The results imply that compared with the GMF model, the GMF plus Rain model can improve the precision of wind retrieval under the rain condition. Then, a new general algorithm of locating the eye of typhoon through the normalized radar cross section (NRCS) is proposed. The implementation of this algorithm in the ten QuikSCAT observations of typhoon Melor suggests that this algorithm is effective. | ZHONG Jian FEI Jianfang HUANG Sixun DU Huadong ZHANG Liang | 2012 | Acta Oceanologica Sinica2012，31，1： | 1 |
| 8 | Controllable synthesis,optical and photocatalytic properties of CuS nanomaterials with hierarchical structures显示文摘 | Li Fei Wu Jianfang Qin Oinghua | 2010 | Powder Tecimol2010，198，： | 1 |
| 9 | Effect of wind-current interaction on ocean response during Typhoon KAEMI(2006)显示文摘天气研究并且(WAVEWATCH III ) 预报(WRF ) 模特儿,普林斯顿海洋模型(POM ) ,和波浪当模特儿被用来开发 a coupled atmosphere-wave-ocean 模型,它包括 air-forcing,海洋反馈,导致波浪的混合和波浪水流相互作用包含不同物理过程。在这篇论文,台风 KAEMI (2006 ) 被检验了基于联合 atmosphere-ocean-wave 模型在海洋反应上调查风水流相互作用的效果,即,就海表面而言,在风的计算的水流强调。结果证明风水流相互作用在 10 m 弯屈的模拟上有显著影响。包含风水流相互作用的效果的模型能戏剧性地改进台风预言。风水流相互作用阻止过多的动量流动被变成上面的海洋,它贡献小得多的骚乱动能(TKE ) ,垂直扩散性,和水平移流和散开。冷却在台风开发的起始的阶段期间由风水流相互作用导致了的海表面温度(SST ) 是那么次要的台风紧张不对它很敏感。当台风到达它的山峰时,它的风能扰乱 thermocline,并且在 thermocline 下面的冷水被打气。然而,这个冷却过程被风水流相互作用削弱,当海洋反馈推迟台风的腐烂。同时,在 30 m 的深度下面的温度与一个时期显示出惯性的摆动大约 40 个小时(17 瘠癩? 敲灳湯吗? | LIU Lei FEI JianFang CHENG XiaoPing HUANG XiaoGang | 2013 | Science China Earth Sciences2013，56，3： | 1 |
| 10 | Controllable synthesis, optical and photocatalytic properties of CuS nanomaterials with hierarchical structures显示文摘 | Fei Li Jianfang Wu Qinghua Qin Zhen Li Xintang Huang | 2009 | Powder Technology2009，，2： | 1 |
| 11 | A regional simulation study on dispersion of nuclear pollution from the damaged Fukushima Nuclear Power Plant显示文摘A nuclear accident involving the leaking of radioactive pollutants occurred at the Fukushima Nuclear Power Plant in Japan,following an earthquake and subsequent tsunami on March 11,2011.Using official Japanese data on pollutant emissions during the accident,this study simulates the dispersion of nuclear pollutants.The source term of the nuclear leakage of radioactive material is designed using PM2.5as the tracer of radioactive pollutants,and the study considers dry and wet deposition processes.A coupled-model system is constructed from the air-quality model Models-3/CMAQ and the Weather Research and Forecasting atmospheric model.The transport path and distribution of radioactive pollutants over long and short distances are simulated with different model horizontal resolutions of 30 and 4 km respectively.The long-distance simulation shows that,following the Fukushima nuclear accident,under the effect of westerly winds,radioactive pollutants are transported generally towards the eastern Pacific and reach the American continent after 5 days,but their concentration is only about 10–7 times the concentration near the Fukushima Nuclear Power Plant.The time required for pollutants to reach the United States is basically consistent with measurements made in California on March 18.Because the upper westerly wind is faster than the lower westerly wind,the distribution of pollutants tilts eastward in terms of its vertical structure.The short-distance(local)highresolution simulation indicates that strong winds and precipitation associated with a cyclone can accelerate the deposition,diffusion and transport of pollutions,and local cyclonic circulation can change the transport path of pollutants,even resulting in repeated effects of pollution in some areas.Pollutants disperse to southeastern Honshu,Japan,on March 14,2011,agreeing well with the timing of local observations of increases in the absorbed dose rate.Results also show that radioactive pollutants from the Fukushima nuclear accident are mainly transported and diffuse eastward,resulting in a relatively short-term impact on the Japanese mainland even under the influence of the cyclone system.Therefore,in terms of atmospheric conditions,the location of the Fukushima Nuclear Power Plant is appropriate and could serve as a reference to site selection and protection of other nuclear facilities. | FEI JianFang WANG PengFei CHENG XiaoPing HUANG XiaoGang WANG YiBai | 2014 | Science China Earth Sciences2014，57，7： | 1 |
| 12 | Research of Super Typhoon Lekima: forecast, observation, numerical simulation and disaster survey显示文摘Tropical cyclones(TCs)are among the most destructive natural disasters in the world,and the TCs in the North-west Pacific(NWP)are most frequent among all ocean basins.The TCs that induce disastrous weather such as destructive winds,heavy precipitation,tornadoes,lightning and storm surges sometimes cause significant economic losses and heavy casualties to human beings,which are also called high-impact TCs due to their influences on human society.Generally,TCs in the NWP generate in tropical oceans and move northwestward,which then strike the south-eastern coastal regions of Asia continent,densely populated areas with developed economy. | Jie TANG Jianfang FEI Hui YU | 2022 | Frontiers of Earth Science2022，16，1： | 1 |
| 13 | Statistical Characteristics and Mechanistic Analysis of Suddenly Reversed Tropical Cyclones over the Western North Pacific Ocean显示文摘Based on best track data of tropical cyclones(TCs) from the Japan Meteorological Agency, the characteristics of suddenly reversed TCs(SRTCs), which have turning angles usually approaching 180°, are statistically analyzed from 1949 to 2011 over the western North Pacific Ocean. The typical large-scale circulation patterns of SRTCs are investigated using reanalysis data and dynamical composite analysis. Results show that turnings mainly occur in low latitudes between 10°N and 20°N,and mainly west of 135°E. The majority of SRTCs reach their peak intensity at, or slightly before, the turning time and subsequently decrease at some variable rate. Specifically, SRTCs are divided into four types, each containing two groups(i.e.eight groups in total) in terms of the moving-direction changes. The moving speed of all SRTC types except the south–north type decreases to its lowest during the 24 h, corresponding to a significant reduction in the primary steering components.According to the analysis of the 13 typical flow patterns found in this study, we suggest that sudden track changes are caused by the reversal steering flow. The original balance of the background flow patterns are broken up by new systems, e.g. binary TCs or dispersion-induced anticyclones. Additionally, sudden track changes are often due to double ridge variations of the subtropical high or weakened/strengthened high pressure in the east and west, respectively. | LUO Xia FEI Jianfang HUANG Xiaogang CHENG Xiaoping DING Juli HE Yiqiang | 2015 | Advances in Atmospheric Sciences2015，32，4： | 1 |
| 14 | Effect of Sea Spray on the Numerical Simulation of Super Typhoon ‘Ewiniar’显示文摘To study the potential effect of sea spray on the evolution of typhoons,two kinds of sea spray flux parameterization schemes developed by Andreas (2005) and Andreas and Wang (2006) and Fairall et al. (1994) respectively are incorporated into the regional atmospheric Mesoscale Model version 3.6 (MM5V3) of Pennsylvania State University/National Center for Atmospheric Research (PSU/NCAR) and the coupled atmosphere-sea spray modeling system is applied to simulate a Western Pacific super ty-phoon Ewiniar in 2006. The simulation results demonstrate that sea spray can lead to a significant increase in heat fluxes at the air-sea interface and the simulated typhoon’s intensity. Compared with the results without sea spray,the minimum sea level pressure reduces about 8hPa after taking account of sea spray by Fairall et al.’s parameterization (1994) and about 5hPa by Andreas’ (2005) and Andreas and Wang’s (2006) parameterization at the end of the model integration,while the maximum 10m wind speed increases about 17% and 15% on average,respectively,through the entire simulation time period. Taking sea spray into account also causes significant changes in Tropical Cyclone (TC) structure due to an enhancement of water vapor and heat transferred from the sea sur-face to the air; therefore,the center structure of the typhoon becomes more clearly defined and the wind speed around the typhoon eye is stronger in numerical experiments. The simulations show that different sea spray flux parameterizations make different modi-fications to the TC structure. | ZHENG Jing FEI Jianfang DU Tao WANG Yuan CUI Xiaoyan HUANG Xiaogang Qiming | 2008 | Journal of Ocean University of China2008，7，4： | 1 |
| 15 | Remote Impact of Blocking Highs on the Sudden Track Reversal of Tropical Cyclones显示文摘Previous work showed that some tropical cyclones(TCs) in the western Pacific Ocean undergo sudden track reversal, and the onset, maintenance and decay of blocking highs(BHs) coexisted with 19 of the studied TCs with sudden track reversal.In these cases, the phase relations between the BH, the continental high(CH), the subtropical high(SH) and the suddenly reversed TCs could be classified into types A, B, C and D. Types C and D were the focal point of this follow-up study, in which Typhoon Pabuk(2007) and Lupit(2009) were employed to conduct numerical simulations.The results showed that the reversed tracks of Pabuk(2007) and Lupit(2009) could have been affected by the BH,particularly in terms of the turning location and the trend of movement after turning. Specifically, the two main features for Pabuk(2007) in the BH perturbations were the deflection of its turning point and a distinct anticlockwise rotation. Lupit(2009) deviated to the southwest and finally made landfall in the Philippines, or experienced further eastward movement,in the perturbed BH. The impact mechanisms can be attributed to the change in the vorticity field transported from the BH, leading to an intensity variation of midlatitude systems. BHs may have a positive feedback effect on the strength of the westerly trough(TR), as indicated by a weakened and strengthened TR corresponding to negative and positive BH perturbations, respectively. | LUO Xia FEI Jianfang HUANG Xiaogang CHENG Xiaoping YU Kun | 2015 | Advances in Atmospheric Sciences2015，32，11： | 1 |
| 16 | Analysis of Pressure Forcings for the Vertical Turbulent Fluxes in the Convective Boundary Layer at Gray Zone Resolutions显示文摘At kilometer and sub-kilometer resolutions,known as the numerical gray zone for boundary layer turbulence,the atmospheric boundary layer turbulence becomes partially resolved and partially subgrid-scale(SGS) in a numerical model,thus requiring scale-adaptive turbulence schemes.Such schemes are often built by modifying the existing parameterizations,either the planetary boundary layer(PBL) schemes or the large-eddy simulation(LES) closures,to produce the right SGS turbulent fluxes at gray zone resolutions.However,the underlying forcings responsible for the changes in the vertical turbulent fluxes are largely ignored in these approaches.This study follows the original approach of Wyngaard(2004) and analyzes the turbulent buoyancy and momentum flux budgets,to gain a better understanding of the variations of flux forcings at gray zone resolutions.The investigation focuses on the pressure covariance term,which is one of the most dominant terms in the budget equations.By using the coarse-grained LES of a dry convective boundary layer(CBL) case as reference,two widely-used pressure covariance models are evaluated and optimized across the gray zone resolution range.The optimized linear model is further evaluated a priori against another dry CBL case with a different bulk stability,and a shallow-cumulus-topped boundary layer case.The model applies well to both cases,and notably shows good performance for the cloud layer.Based on the analysis of the flux forcings and the optimized pressure model,a scale-adaptive turbulence model for the gray zone is derived from the steady-state flux budgets. | Yahua WANG Xiaoping CHENG Jianfang FEI Bowen ZHOU | 2023 | Journal of Meteorological Research2023，37，6： | 0 |
| 17 | Roles of Multisourced Fluids in the Formation of Sandstone-Hosted Uranium Deposits in the SW Songliao Basin, NE China显示文摘The sandstone-hosted uranium deposits in the SW Songliao Basin differ from typical sandstone-hosted uranium deposits in terms of the geological features of the ore-deposits,including the geometry of the orebodies,mineral assemblage and petrography.Detailed drill core and microscopic observations,scanning electron microscopy(SEM),electron microprobe analysis(EMPA),heavy mineral concentrates,and fluid inclusion studies of the Upper Cretaceous Yaojia Formation,i.e.,the uranium-bearing layer,were integrated to investigate the roles of hydrothermal fluids in the formation of these uranium deposits.We found that the kaolinite alteration is developed in the mineralized zones,but it is less common in the peripheral areas.The fluid inclusions are hydrothermal fluids with a medium-low temperature(67 to 179 ℃) and a high salinity(5.9 wt.% to 20.1 wt.%).According to the analyses,three kinds of hydrothermal fluids,i.e.,the acid fluid,the groundwater heated by the mafic magma,and the alkaline fluid rich in Ca^(2+) and CO_(3)^(2-),were identified.The fluids might have low U content,but they have participated in the formation of the uranium deposits successively.Kaolinite formed by the acid-hydrothermal fluid absorbed large amounts of uranium.Subsequently,the thermal energy from the hydrothermal fluids changed the intrastratal redox environment and increased the solubility of the uranium minerals in the fluid.The alkaline-hydrothermal fluid rich in Ca^(2+) and C0_(3)^(2-) facilitated the formation of stable Ca-U(Ⅵ)-CO_(3) complex,which led to the enrichment of soluble uranium in solution,and final precipitation as pitchblende,brannerite and Ti-bearing uranium minerals in the uranium ores. | Zhibing Feng Fengjun Nie Li Jiang Fei Xia Jianfang Cai Bocheng Zhang Yayun Lu Liangliang Zhang | 2023 | Journal of Earth Science2023，34，1： | 0 |
| 18 | The four dimensional variational data assimilation with multiple regularization parameters as a weak constraint(Tikh-4D-Var) and its preliminary application on typhoon initialization显示文摘Traditional variational data assimilation(VDA) with only one regularization parameter constraint cannot produce optimal error tuning for all observations. In this paper, a new data assimilation method of 'four dimensional variational data assimilation(4D-Var) with multiple regularization parameters as a weak constraint(Tikh-4D-Var)' is proposed by imposing different regularization parameters for different observations. Meanwhile, a new multiple regularization parameters selection method, which is suitable for actual high-dimensional data assimilation system, is proposed based on the posterior information of 4D-Var system. Compared with the traditional single regularization parameter selection method, computation of the proposed multiple regularization parameters selection method is smaller. Based on WRF3.3.1 4D-Var data assimilation system, initialization and simulation of typhoon Chaba(2010) with the new Tikh-4D-Var method are compared with its counterpart 4D-Var to demonstrate the effectiveness of the new method. Results show that the new Tikh-4D-Var method can accelerate the convergence with less iterations. Moreover, compared with 4D-Var method, the typhoon track, intensity(including center surface pressure and maximum wind speed) and structure prediction are obviously improved with Tikh-4D-Var method for 72-h prediction. In addition, the accuracy of the observation error variances can be reflected by the multiple regularization parameters. | ZHONG Jian FEI JianFang CHENG XiaoPing HUANG XiaoGang | 2014 | Science China Earth Sciences2014，57，11： | 0 |
| 19 | International Silica Cycle Workshop held in Hangzhou显示文摘Silicon is the second most abundant element on the planet Earth. Its electronic configuration is close to that of carbon, but the aqueous environment prevailing on our planet gives advantages to carbon compounds at the expenses of siliceous compounds.Silicified organisms, however, are everywhere on Earth, particularly in the marine realm where siliceous diatoms play a key role in the ocean biological carbon pump. Thus, a better understanding of the processes that control the silica cycle at global scale is crucial. | TREGUER Paul RAN Lihua CHAI Fei CHEN Jianfang | 2018 | Acta Oceanologica Sinica2018，37，12： | 0 |
| 20 | Uncertainty in TC Maximum Intensity with Fixed Ratio of Surface Exchange Coefficients for Enthalpy and Momentum显示文摘The classical tropical cyclone(TC)maximum intensity theory of Emanuel suggests that the maximum azimuthal wind of TC depends linearly on the ratio of surface exchange coefficients for enthalpy and momentum(C_(k)and C_(d)).In this study,a series of sensitivity experiments are conducted with the three-dimensional Cloud Model 1(CM1),by fixing the ratio of C_(k)/C_(d)but varying the specific values of C_(k)and C_(d)simultaneously.The results show significant variations in the simulated TC maximum intensity by varying C_(k)and C_(d),even if their ratio is fixed.Overall,the maximum intensity increases steadily with increasing C_(k)and C_(d)when their value is smaller than 1.00×10^(-3),and then this increasing trend slows down with further increases in the coefficients.Two previous theoretical frameworks—one based on gradient wind balance and the other incorporating the unbalanced terms-are applied to calculate the maximum potential intensity(PI).The calculated value of the former shows little variation when varying the specific values of C_(k)and C_(d),while the latter shows larger values with increases in both C_(k)and C_(d).Further examination suggests that the unbalanced effect plays a key role in contributing to the increasing intensity with increasing C_(k)and C_(d). | Hexin YE Zhanhong MA Jianfang FEI | 2022 | Journal of Meteorological Research2022，36，1： | 0 |
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