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THE TIMING OF SOUTH-ASIAN HIGH ESTABLISHMENT AND ITS RELATION TO TROPICAL ASIAN SUMMER MONSOON AND PRECIPITATION OVER EAST-CENTRAL CHINA IN SUMMER

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Journal of Tropical Meteorology 2016年第2期22卷 136-144页

作者：王黎娟郭帅宏葛静 key laboratory of Meteorological Disaster Ministry of Education/Joint International Research Laboratory of Climate and Environment Change/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters/Science and Technology Innovation Team on Climate Simulation and ForecastNanjing University of Information Science&TechnologyNanjing 210044 China Meteorological Observatory of No.95147 Unit of PLA MeizhouGuangdong 514593 China

The timing of the South Asian High(SAH) establishment over the Indochina Peninsula(IP) from April to May and its relations to the setup of the subsequent tropical Asian summer monsoon and precipitation over eastern-central China in summer are investigated by using NCEP/NCAR daily reanalysis data,outgoing longwave radiation(OLR)data and the daily precipitation data from 753 weather stations in *** is found that the transitions of the zonal wind vertical shear and convection establishment over tropical Asia are earlier(later) in the years of early(late) establishment of *** the lower troposphere,anti-cyclonic(cyclonic) anomaly circulation dominates the equatorial Indian ***,the tropical Asian summer monsoon establishes earlier(later).Furthermore,the atmospheric circulation and the water vapor transport in the years of advanced SAH establishment are significantly different from the delayed years in Asia in ***-of-phase distribution of precipitation in eastern-central China will appear with a weak(strong) SAH and western Pacific subtropical high,strong(weak) ascending motion in the area south of Yangtze River but weak(strong) ascending motion in the area north of it,and cyclonic(anti-cyclonic) water vapor flux anomaly circulation from the eastern-central China to western ***,the timing of the SAH establishment at the upper levels of IP is indicative of the subsequent onset of the tropical Asian summer monsoon and the flood-drought pattern over eastern-central China in summer.

关键词： South-Asian High Indochina Peninsula tropical Asian summer monsoon precipitation over eastern-central China in summer

Improving sampling depth of laser speckle imaging by topical optical clearing:A theoretical and in vivo study

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Journal of Innovative Optical Health Sciences 2020年第2期13卷 33-43页

作者： D.Li Y.Zhang B.Chen State key laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an Shaanxi 710049P.R.China

The effect of optical cleaning method combined with laser speckle imaging(LSI)was discussed to improve the detection depth of LSI due to high scattering characteristics of skin,which limit its clinical application.A double-layer skin tissue model embedded with a single blood vessel was established,and the Monte Carlo method was used to simulate photon propagation under the action of light-permeating agent.808 nm semiconductor and 632.8 nm He–Ne lasers were selected to study the e®ect of optical clearing agents(OCAs)on photon deposition in *** show that the photon energy deposition density in the epidermis increases with the amount of tissue°uid replaced by *** with glucose solution,polyethylene glycol 400(PEG 400)and glycerol can considerably increase the average penetration depth of photons in the skin tissue,thereby raising the sampling depth of the *** the action of glycerol,PEG 400,and glucose,the average photon penetration depth is increased by 51.78%,51.06%,and 21.51%for 808nm,68.93%,67.94%,and 26.67%for 632.8 nm lasers,*** vivo experiment by dorsal skin chamber proves that glycerol can cause a substantial decrease in blood°ow rate,whereas PEG 400 can signicantly improve the capability of light penetration without a®ecting blood velocity,which exhibits considerable potential in the monitoring of blood°ow in skin tissues.

关键词： Laser speckle image topical optical clearing imaging depth Monte-Carlo simulation dorsal skin experiment

An Assessment of ENSO Stability in CAMS Climate System Model simulations

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Journal of Meteorological Research 2019年第1期33卷 80-88页

作者： Lijuan HUA Lin CHEN Xinyao RONG Jian LI Guo ZHANG Lu WANG State key laboratory of Severe Weather Chinese Academy of Meteorological SciencesChina Meteorological Administration key laboratory of Meteorological Disaster Ministry of Education/Joint International Research Laboratory of Climate and Environmental Change/Collaborative Innovation Center on Forecast and Evaluation of Meteorological DisastersNanjing University of Information Science &Technology State key laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences

We present an overview of the El Ni?o–Southern Oscillation(ENSO) stability simulation using the Chinese Academy of Meteorological Sciences climate system model(CAMS-CSM). The ENSO stability was quantified based on the Bjerknes(BJ) stability index. Generally speaking, CAMS-CSM has the capacity of reasonably representing the BJ index and ENSO-related air–sea feedback processes. The major simulation biases exist in the underestimated thermodynamic damping and thermocline feedbacks. Further diagnostic analysis reveals that the underestimated thermodynamic feedback is due to the underestimation of the shortwave radiation feedback, which arises from the cold bias in mean sea surface temperature(SST) over central–eastern equatorial Pacific(CEEP). The underestimated thermocline feedback is attributed to the weakened mean upwelling and weakened wind–SST feedback(μ_a) in the model simulation compared to observation. We found that the weakened μ_a is also due to the cold mean SST over the *** study highlights the essential role of reasonably representing the climatological mean state in ENSO simulations.

关键词： coupled general circulation model(CGCM) Bjerknes(BJ) stability index air–sea feedback

Assimilating FY-4A AGRI Radiances with a Channel-Sensitive Cloud Detection Scheme for the Analysis and Forecasting of Multiple Typhoons

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Advances in Atmospheric Sciences 2024年第5期41卷 937-958页

作者： Feifei SHEN Aiqing SHU Zhiquan LIU Hong LI Lipeng JIANG Tao ZHANG Dongmei XU key laboratory of Meteorological Disaster Ministry of Education(KLME)/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 Shanghai Typhoon Institute China Meteorological AdministrationShanghai 200030China China Meteorological Administration Basin Heavy Rainfall key laboratory/Hubei key laboratory for Heavy Rain monitoring and Warning Research Institute of Heavy RainChina Meteorological AdministrationWuhan 430205China National Center for Atmospheric Research Boulder 80307COUSA State key laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China National Meteorological Information Center Beijing 100081China Fujian key laboratory of Severe Weather and key laboratory of Straits Severe Weather China Meteorological AdministrationFuzhou 350001China

This paper presents an attempt at assimilating clear-sky FY-4A Advanced Geosynchronous Radiation Imager(AGRI)radiances from two water vapor channels for the prediction of three landfalling typhoon events over the West Pacific Ocean using the 3DVar data assimilation(DA)method along with the WRF model.A channel-sensitive cloud detection scheme based on the particle filter(PF)algorithm is developed and examined against a cloud detection scheme using the multivariate and minimum residual(MMR)algorithm and another traditional cloud mask–dependent cloud detection *** show that both channel-sensitive cloud detection schemes are effective,while the PF scheme is able to reserve more pixels than the MMR scheme for the same *** general,the added value of AGRI radiances is confirmed when comparing with the control experiment without AGRI ***,it is found that the analysis fields of the PF experiment are mostly improved in terms of better depicting the typhoon,including the temperature,moisture,and dynamical *** typhoon track forecast skill is improved with AGRI radiance DA,which could be explained by better simulating the upper *** impact of assimilating AGRI radiances on typhoon intensity forecasts is *** the other hand,improved rainfall forecasts from AGRI DA experiments are found along with reduced errors for both the thermodynamic and moisture fields,albeit the improvements are limited.

关键词： FY-4A AGRI radiance particle filter multiple typhoons data assimilation numerical weather prediction

IMPACT OF CONVECTION OVER THE SOUTH CHINA SEA ON TROPICAL CYCLONE MOTION OVER THE WESTERN NORTH PACIFIC DURING SUMMER MONSOON

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Journal of Tropical Meteorology 2017年第1期23卷 58-67页

作者：霍利微郭品文 key laboratory of Meteorological Disaster Ministry of Education/Joint International Research Laboratory of Climate and Environment Change/Collaborative Innovation Center on Forecast and Evaluation of Meteorological DisastersNanjing University of Information Science and TechnologyNanjing 210044 China

The intraseasonal oscillation(ISO) of the South China Sea(SCS, 105-120°E, 5-20°N) convection and its influences on the genesis and track of the western North Pacific(WNP) tropical cyclones(TCs) were explored, based on the daily average of NCEP/NCAR reanalysis data, the OLR data and the western North Pacific tropical cyclone best-track data from 1979 to 2008. The mechanism of the influences of ISO on TC movement and the corresponding large-scale circulation were discussed by a trajectory model. It was found as follows.(1) During the SCS summer monsoon, the SCS convection exhibits the ISO features with active phases alternating with inactive phases. The monsoon circulation patterns are significantly different during these two phases. When the SCS convection is active(inactive), the SCS-WNP monsoon trough stretches eastward(retreats westward) due to the activity(inactivity) of SCS monsoon, and the WNP subtropical high retreats eastward(stretches westward), which enhances(suppresses) the monsoon circulation.(2) The amount of TC genesis in the active phase is much more than that in the inactive phase. A majority of TCs form west of 135 °E during the active phases but east of 135 °E in the inactive phases.(3) The TCs entering the area west of 135 °E and south of 25 °N would move straight into the SCS in the active phase, or recurve northward in the inactive phase.(4) simulation results show that the steering flow associated with the active(inactive)phases is in favor of straight-moving(recurving) TCs. Meanwhile, the impacts of the locations of TC genesis on the characteristics of TC track cannot be ignored. TCs that occurred father westward are more likely to move straight into the SCS region.

关键词： tropical cyclone genesis and track climatological statistics South China Sea convection intraseasonal oscillation monsoon trough trajectory model

Performance of CMIP5 Models in the simulation of Climate Characteristics of Synoptic Patterns over East Asia

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Journal of Meteorological Research 2015年第4期29卷 594-607页

作者：王永弟江志红陈威霖 key laboratory of Meteorological Disaster of Ministry of Education Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science & Technology School of Geography and Remote Sensing Nanjing University of Information Science & Technology

The evolution of daily synoptic weather patterns is the main driver of day-to-day weather change. These patterns are generally associated with changes in temperature, precipitation, etc., especially during extreme weathers. Evaluating the ability of climate models to reproduce the frequency and intensity of daily synoptic patterns is essential for increasing confidence in future projections. In this study, we investigated the ability of 34 global climate models （GCMs） included in the Coupled Model Intercomparison Project Phase 5 （CMIP5） to simulate synoptic patterns over East Asia and their evolution features in winter and summer. Daily synoptic patterns in sea level pressure and their occurrence frequencies were identified by using an objective clustering algorithm, self-organizing maps （SOMs）. The evaluation consists of correlating the frequencies of these patterns in the 34 CMIP5 models with the frequencies in the NCEP reanalysis during the baseline period of 1980-1999. The results illustrated that most of these models were able to reproduce the synoptic patterns of the NCEP reanalysis. In addition, the frequencies of temporal sea level pressure （SLP） anomaly patterns were reproduced by most of the models over the baseline period, but the frequencies of spatial SLP anomaly patterns were only reproduced by a few GCMs. Overall, the models performed better in summer than in winter. Comprehensive evaluation shows that the four top-performing models for both winter and summer are bcc-csml-l-m, NorESM1-M, MRI-CGCM3, and CCSM4. They show good performance in simulating the daily synoptic patterns in SLP and in reproducing their occurrence frequencies. The results showed that the SOM was an effective tool for differentiating characteristics of synoptic circulation patterns and for evaluating the ability of climate models to simulate the frequency of daily synoptic patterns. The results can also help users to choose a better model for future climate projection and downscal

关键词： CMIP5 climate model evaluation self-organizing maps atmospheric circulation pattern

Reaction mechanism of fluoride conversion into BF^(4-) during sulphuric acid leaching of roasted bastnaesite

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Journal of Rare Earths 2021年第2期39卷 186-193页

作者： Hongcheng Zhang Dairui Xie Heng Zhang Meng Jiang Hao Huang Yu Wan Yang Liao Shilin Zhao College of Chemistry and Material Science Sichuan Normal UniversityChengdu 610068China key laboratory of Land Resources Evaluation and monitoring in Southwest Ministry of Education of ChinaChengdu 610068China

The bastnaesite used in hydrometallurgy usually contains 7%-11% fluorine,and the conversion of fluorine into high-value products is the key to achieving green production of rare earths and improving the comprehensive utilization of *** order to recover fluorine from bastnaesite in the form of KBF4,the mechanism of F^(-)conversion to BF^(4-)in sulphuric acid leaching solution of roasted bastnaesite was studied by using Eh-pH diagram and simulation *** shows that the formation of BF^(4-)is affected by pH in the absence of rare ***^(4-)is hydrolyzed to BF3 OH-and F-when the pH is greater than 3.9,and part of F-exists as HF^(2-)when pH is lower than *** the presence of La^(3+),the formation of BF^(4-)is mainly affected by LaF_(3) when pH is greater than 0,and in the case that the pH is lower than 2,it is mainly affected by HF^(2-).When Ce4+is present in solution,CeF_(2)^(2+) can exist stably in sulphuric acid *** down the pH can reduce the stability of CeF_(2)^(2+) and increase the BF^(4-)conversion *** on these results,KBF4 was prepared in the alkaline solution of bastnaesite,and the conversion of BF^(4-)is 84.31%.This provides a theoretical basis for the recovery of fluorine from bastnaesite in the form of KBF_(4).

关键词： BF^(4-) Bastnaesite E_(h)-pH diagram Sulphuric acid leaching Rare earths

A semi-idealized modeling study on the long-lived eastward propagating mesoscale convective system over the Tibetan Plateau

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Science China Earth Sciences 2021年第11期64卷 1996-2014页

作者： Shenming FU Zi MAI Jianhua SUN Wanli LI Qi ZHONG Jiaren SUN Yuanchun ZHANG International Center for Climate and Environment Sciences Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Heavy Rain and Drought-Flood disasters in Plateau and Basin key laboratory of Sichuan Province Chengdu 610225China National Meteorological Center of China Meteorological Administration Beijing 100081China key laboratory of Cloud-Precipitation Physics and Severe Storms Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China China Meteorological Administration Training Center Beijing 100081China key laboratory of Urban Ecological Environmental simulation and Protection of Ministry of Environmental Protection South China Institute of Environmental Sciencesthe Ministry of Environmental Protection of ChinaGuangzhou 501530China

Based on a 16-warm-season statistical study on the mesoscale convective systems(MCSs)that were generated over the Tibetan Plateau(TP),11 long-lived eastward propagating MCSs of the same type were selected for a composite semiidealized simulation and a corresponding no-latent-heating sensitivity run by using the Weather Research and Forecasting(WRF)*** evolutionary features and associated mechanisms of this type of long-lived eastward propagating MCS were *** results are as follows:(i)This type of MCS was generated in a favorable background environment which was characterized by a notable upper-tropospheric divergence south of an upper-level jet,a strong warm advection around a middle-level shortwave trough’s central area,and an instable convective stratification below the *** of the MCS featured rapid increase of cyclonic vorticity in the middle and lower *** convergence-related vertical stretching and tilting were key factors for the cyclonic-vorticity’s production,and convection-related upward cyclonic-vorticity transport contributed to the upward extending of the MCS.(ii)During the vacating stage of the MCS,it first coupled with a quasistationary Tibetan Plateau vortex(TPV)over the TP’s eastern section,and then decoupled from the *** the former stage,the MCS contributed to maintaining ascending motions and convergence associated with the TPV,which favored its persistence;whereas,in the latter stage,decoupling weakened the TPV-associated convection *** reduced the upward transport of cyclonic vorticity notably,which,together with the negative tilting effect,finally led to the vortex’s dissipation.(iii)After vacating TP,the MCS first weakened due to the disappearance of strong direct sensible heating from the TP on its bottom,and then,under the favorable conditions associated with the shortwave trough over the eastern section of the TP,the MCS redeveloped ***-related cyclonic-vor

关键词： Tibetan Plateau Mesoscale convective system Tibetan Plateau vortex Heavy rainfall Vorticity budget Sensitivity simulation

Volunteered remote sensing data generation with air passengers as sensors

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International Journal of Digital Earth 2021年第2期14卷 158-180页

作者： Chisheng Wang Yongquan Wang Leyang Wang Zhongwen Hu Shaobiao Zhang Shuanglong Wang Wenqun Xiu Hongxing Cui Dan Wang Qingquan Li key laboratory for Geo-Environmental monitoring of Great Bay Area Ministry of Land and ResourcesShenzhen UniversityShenzhenPeople’s Republic of China key laboratory of Urban Land Resources monitoring and simulation Ministry of Land and ResourcesShenzhenPeople’s Republic of China Faculty of Geomatics East China University of TechnologyNanchangPeople’s Republic of China Shenzhen Urban Public Safety and Technology Institute ShenzhenPeople’s Republic of China Shenzhen Integrated Geotechnical Investigation&Surveying Co.Ltd ShenzhenPeople’s Republic of China

Remote sensing satellites are playing very important roles in diverse earth observation ***,long revisit period,high cost and dense cloud cover have been the main limitations of satellite remote sensing for a long *** paper introduces the novel volunteered passenger aircraft remote sensing(VPARS)concept,which can partly overcome these *** obtaining aerial imaging data from passengers using a portable smartphone on a passenger aircraft,it has various advantages including low cost,high revisit,dense coverage,and partial anti-cloud,which can well complement conventional remote sensing *** paper examines the concept of VPARS and give general data processing framework of *** cases were given to validate this processing *** preliminary applications on land cover classification and economic activity monitoring validate the applicability of the VPARS ***,we examine the issues about data maintenance,potential applications,limitations and *** conclude the VPARS can benefit both scientific and industrial communities who rely on remote sensing data.

关键词： Volunteered geographic information remote sensing handheld cameras passenger aircraft