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Snow/Rainfall Anomaly in Winter of Northern China and Associated Atmospheric Circulation and Aerosol Distribution Features

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Acta meteorologica Sinica 2011年第6期25卷 783-796页

作者：李多王继志李泽椿刘华 center for Atmosphere Watch and Service Chinese Academy of Meteorological Sciences National Climate center China Meteorological Administration National meteorological center China Meteorological Administration China meteorological Administration Training center

Based on the NCEP/NCAR reanalysis data, China station precipitation data from 1960 to 2008, and aerosol optical depth （AOD） data in northern China from 1980 to 2004, this paper investigates the variability of winter snow/rainfall in northern China and the associated atmospheric circulation and aerosol distribution characteristics by using composite analysis. The results show that winter precipitation in northern China has been generally increasing since the 1960s. Among the winters of 1990 2008, the years with more rain/snow （MRSYs） are 1998, 2003, and 2006, while the years with less rain/snow （LRSYs） are 2005, 1997, and 2001. Composite analysis finds that MRSYs and LRSYs are as follows the main differences of atmospheric 1） In MRSYs, strong low-level cold circulation in East Asia between air over the northern polar region and Taymyr Peninsula migrates southward to northern China （Northwest, North, and Northeast China）, establishing a channel favoring continuous southward tronsport of cold air. In LRSYs, however, this cold air channel does not exist. 2） In MRSYs, the frontal zone and westerlies are over North China, and the low-level geopotential height field from eastern China to West Pacific exhibits an ＂east high, west low＂ pattern, which is conducive to easterly and southerly airflows moving northward along 110°E. In LRSYs, the 500-hPa prevailing westerly winds stay far away from China and the low-level southeasterlies move to higher latitudes, which are disadvantageous to the development of precipitation in northern China. 3） In MRSYs, large-scale upward motions combined with local-scale updrafts develop into strong slanted climbing airflows, forming a vertical circulation that favors the generation of heavy snows in eastern China. In LRSYs, the vertical circulation moves eastward into the Pacific Ocean. Furthermore, the correlation analysis on AOD and winter precipitation during the period 1980 2004 in northern China reveals that AOD differs significantly b

关键词： winter snow/rainfall frontal zone slanted climbing airflows aerosol effect

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A Comparison of Breeding and Ensemble Transform Vectors for Global Ensemble Generation

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Acta meteorologica Sinica 2012年第1期26卷 52-61页

作者：邓国田华李晓莉陈静龚建东矫梅燕 National meteorological center China Meteorological Administration China meteorological Administration

To compare the initial perturbation techniques using breeding vectors and ensemble transform vectors, three ensemble prediction systems using both initial perturbation methods but with different ensemble member sizes based on the spectral model T213/L31 are constructed at the National meteorological center, China meteorological Administration （NMC/CMA）. A series of ensemble verification scores such as forecast skill of the ensemble mean, ensemble resolution, and ensemble reliability are introduced to identify the most important attributes of ensemble forecast systems. The results indicate that the ensemble transform tech- nique is superior to the breeding vector method in light of the evaluation of anomaly correlation coefficient （ACC）, which is a deterministic character of the ensemble mean, the root-mean-square error （RMSE） and spread, which are of probabilistic attributes, and the continuous ranked probability score （CRPS） and its decomposition. The advantage of the ensemble transform approach is attributed to its orthogonality among ensemble perturbations as well as its consistence with the data assimilation system. Therefore, this study may serve as a reference for configuration of the best ensemble prediction system to be used in operation.

关键词： breeding ensemble transform ensemble prediction system

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Thermodynamic Characteristics of Tropical Cyclones with Rapid Intensity Change over the Coastal Waters of China

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Acta meteorologica Sinica 2011年第4期25卷 467-477页

作者：于玉斌姚秀萍 China meteorological Administration Training center

In order to investigate the different thermodynamic mechanisms between rapid intensifying （RI） and rapid weakening （RW） tropical cyclones （TCs）, the thermodynamic structures of two sets of composite TCs are analyzed based on the complete-form vertical vorticity tendency equation and the NCEP/NCAR reanalysis data. Each composite is composed of five TCs, whose intensities change rapidly over the coastal waters of China. The results show that the maximum apparent heating source Q1 exists in both the upper and lower troposphere near the RI TC center, and Q1 gets stronger at the lower level during the TC intensification period. But for the RW TC, the maximum Q1 exists at the middle level near the TC center, and Q1 gets weaker while the TC weakens. The maximum apparent moisture sink Q2 lies in the mid troposphere. Q2 becomes stronger and its peak-value height rises while TC intensifies, and vice versa. The increase of diabatic heating with height near the TC center in the mid-upper troposphere and the increase of vertical inhomogeneous heating near the TC center in the lower troposphere are both favorable to the TCs＇ rapid intensification; otherwise, the intensity of the TC decreases rapidly.

关键词： coastal waters tropical cyclone rapid intensity change thermodynamic mechanism

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Variations of Winter Precipitation over Southeastern China in Association with the North Atlantic Oscillation

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Journal of meteorological Research 2017年第3期31卷 476-489页

作者： Maoyuan LOU Chao LI Shifeng HAO Juan LIU Zhejiang Provincial meteorological Observatory Zhejiang Institute of meteorological Sciences Zhejiang meteorological Service center

The synoptic-scale winter precipitation variations over southeastem China （22°-32°N, 105°-125°E） and their asso- ciation with the North Atlantic Oscillation （NAO） during 1951-2007 are investigated in this paper. The variability of wintertime precipitation is characterized by meridional displacement of its maximum center. Two precipitation re- gimes, with maximum centers located over the Yangtze and Pearl River basins, are identified via cluster analysis. Time-lagged analyses suggest that the two precipitation regimes are connected with the decaying phases of positive NAO （NAO＋） events of different amplitudes. A strong （medium） NAO＋ event is defined as one when the maximum amplitude of the NAO index exceeds 1.0 （in the range of 0.7-1.0） for at least 4 consecutive days and drops to less than 0.3 within 7 days following the peak index. After the peak of a strong NAO＋, southerly winds expand north- ward to the Yangtze River （about 30°N）, a northeast-southwest-tilted trough migrates to east of Lake Baikal, and cold air intrudes into central eastern China; thus, precipitation is strengthened over the Yangtze River basin where warm and cold air masses converge. In comparison, during the decaying phase of medium NAO＋ events, the south- erly winds are relatively weak, and precipitation tends to be enhanced at lower latitudes （around 25°N）. Further ana- lysis indicates that downstream Rossby-wave propagation may account for the latitudinal expansion of the southerly wind anomalies over the eastern coastal area of China during the decaying phase of NAO＋ events of different strengths.

关键词： precipitation regime North Atlantic Oscillation (NA0) cluster analysis westerly jet stream

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Comparison of Different Order Adams-Bashforth Methods in an Atmospheric General Circulation Model

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Acta meteorologica Sinica 2011年第6期25卷 754-764页

作者：赵滨张博 National meteorological center China Meteorological Administration

The Asselin-Robert time As an attractive alternative filter used in the leaptYog scheme does degrade the accuracy of calculations. to leapfrog time differencing, the second-order Adams-Bashforth method is not subject to time splitting instability and keeps excellent calculation accuracy. A second-order Adams- Bashforth model has been developed, which represents better stability, excellent convergence and improved simulation of prognostic variables. Based on these results, the higher-order Adams-Bashforth methods are developed on the basis of NCAR （National center for Atmospheric Research） CAM 3.1 （Community Atmosphere Model 3.1） and the characteristics of dynamical cores are analyzed in this paper. By using Lorenz nonlinear convective equations, the filtered leapfrog scheme shows an excellent pattern for eliminating 2At wave solutions after 20 steps but represents less computational solution accuracy. The fourth-order Adams- Bashforth method is closely converged to the exact solution and provides a reference against which other methods may be compared. Thus, the Adams-Bashforth methods produce more accurate and convergent solution with differencing order increasing. The Held-Suarez idealized test is carried out to demonstrate that all methods have similar climate states to the results of many other global models for long-term integration. Besides, higher-order methods perform better in mass conservation and exhibit improvement in simulating tropospheric westerly jets, which is likely equivalent to the advantages of increasing horizontal resolutions. Based on the idealized baroclinic wave test, a better capability of the higher-order method in maintaining simulation stability is convinced. Furthermore, after the baroclinic wave is triggered through overlaying the steady-state initial conditions with the zonal perturbation, the higher-order method has a better ability in the simulation of baroclinic wave perturbation.

关键词： Adams-Bashforth method Lorenz nonlinear convection equations baroclinic wave test am-plitude accuracy

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Mesoscale Analysis of a Heavy Rainfall Event Along the Huaihe River Valley During 8-9 July 2007

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Acta meteorologica Sinica 2010年第3期24卷 365-379页

作者：张小玲矫梅燕陈涛 National meteorological center China Meteorological Administration China meteorological Administration

During 8-9 July 2007,several successively developed rainstorms along the Meiyu front produced heavy rainfall in the Huaihe River Valley,which led to the most catastrophic flooding in this region since 1954. Through mesoscale analysis of both conventional and intensive observations from upper air and surface stations,automatic weather stations,Doppler radars,and the FY-2C satellite,the current study examines the developing style and environmental conditions of the mesoscale convective systems（MCSs） that led to the development of the rainstorms. Our analysis showed that this event went through three *** first phase of the heavy rainfall （PhaseⅠ） was caused by a meso-α-scale wind shear in the lower troposphere during 0200-1700 BT（Beijing Time） 8 ***Ⅱwas characterized by a reduction in rain rate and the formation of a low-level vortex between 1700 BT 8 and 0200 BT 9 *** PhaseⅢ,the well-organized mature meso-a-scale low-level vortex brought about intensified rains during 0200-0800 BT 9 *** and radar observations showed a backward development of MCSs（new convective cells were generated at the back of the system） in PhaseⅠ,a forward development in PhaseⅢ,and a spiral organization of the convective lines in PhaseⅡ. The heavy rainstorm systems were initiated continuously along a surface mesoscale dew-point front with a horizontal scale of～300 km（as part of the Meiyu front） in the upper reaches of the Huaihe River Valley near Fuyang City,Anhui Province and then gradually decayed in the middle and lower *** is hypothesized that lifting by strong low-level convergence is sufficient to trigger convection in the high CAPE（convective available potential energy） environment.

关键词： rainstorm mesoscale convective system(MCS) wind shear low-level vortex

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Improvements on global meteorological observations from the current Fengyun 3 satellites and beyond

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International Journal of Digital Earth 2012年第3期5卷 251-265页

作者： Jun Yang Peng Zhang Naimeng Lu Zhongdong Yang Jinming Shi Chaohua Dong National Satellite meteorological center Chinese Meteorological AdministrationBeijingChina

The Fengyun 3(FY-3)series is the second generation of Chinese sun-synchronous meteorological *** first two,FY-3A and FY-3B,were launched successfully on 27 May 2008 and 5 November 2010,***-3A and FY-3B share the same design,equipped with 11 payloads to observe the Earth system,but FY-3A is on a monitoring-orbit and FY-3B is on an *** a satellite constellation,FY-3A and FY-3B comprehensively improved meteorological observations in spectral wavelength,spatial coverage,and temporal *** paper summarizes the improvements of the FY-3A and FY-3B *** features,including optical imaging capacity from kilometer to hundred-meter resolution,passive microwave imaging,atmospheric temperature and moisture sounding,atmospheric chemistry remote sensing,and Earth radiation budget measurement,are presented with demonstrations of their *** scheduled for the FY-3C and beyond are introduced as well.

关键词： FY-3 sun-synchronous meteorological satellite satellite constellation

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Impact of FY-3D MWRI Radiance Assimilation in GRAPES 4DVar on Forecasts of Typhoon Shanshan

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Journal of meteorological Research 2020年第4期34卷 836-850页

作者： Hongyi XIAO Wei HAN Hao WANG Jincheng WANG Guiqing LIU Changshan XU Numerical Weather Prediction center China Meteorological AdministrationBeijing 100081 National meteorological center China Meteorological AdministrationBeijing 100081 Tai’an City meteorological Bureau Shandong Meteorological BureauTai’an 271000

In this study, Fengyun-3 D(FY-3 D) Micro Wave Radiation Imager(MWRI) radiance data were directly assimilated into the Global/Regional Assimilation and Pr Ediction System(GRAPES) four-dimensional variational(4 DVar) system. Quality control procedures were developed for MWRI applications by using algorithms from similar microwave instruments. Compared with the FY-3 C MWRI, the bias of FY-3 D MWRI observations did not show a clear node-dependent difference from the numerical weather prediction background simulation. A conventional bias correction approach can therefore be used to remove systematic biases before the assimilation of data. After assimilating the MWRI radiance data into GRAPES, the geopotential height and humidity analysis fields were improved relative to the control experiment. There was a positive impact on the location of the subtropical high, which led to improvements in forecasts of the track of Typhoon Shanshan.

关键词： Fengyun-3D(FY-3D) Microwave Radiation Imager(MWRI) Global/Regional Assimilation and Pr Ediction System(GRAPES) four-dimensional variational(4DVar) typhoon forecast

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REASONS FOR THE LATE ONSET AND ANOMALOUS SOUTHWARD PERSISTENCE OF THE SOUTH CHINA SEA SUMMER MONSOON IN 2005

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Journal of Tropical Meteorology 2010年第1期16卷 27-34页

作者：鲍媛媛琚建华金荣花康志明 National meteorological center Yunnan meteorological Bureau

Features of atmospheric circulation and thermal structures are discussed using the NCAR/NCEP data to reveal the reasons for the late onset and anomalous southward persistence of the South China Sea Summer Monsoon(SCSSM) in *** results show that three factors are ***,a strong Arabian High overlaps with a high-latitude blocking high and channels strong cold air to southern ***,the Tibetan Plateau has a bigger snow cover than usual in spring and the melting of snow cools down the ***,the Somali Jet breaks out at a much later date,being not conducive to convection over *** former two factors restrict atmospheric sensible heating over the Tibetan Plateau and nearby regions while the third one limits latent heating over *** of the factors slow down atmospheric warming and postpone the onset of *** after the onset of SCSSM,strong cold air over India advances the Southwest Monsoon northward slowly,resulting in weaker convection and latent heating over the Tibetan Plateau and nearby *** negative feedback conversely inhibits further northward movement of Southwest Monsoon.

关键词： South China Sea summer monsoon Arabian High Somali Jet snow cover

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Analysis on the Long-Lasting Freezing Rain and Snowstorm Event at the Beginning of 2008

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Acta meteorologica Sinica 2010年第3期24卷 380-396页

作者：杨贵名孔期毛冬艳张芳华康志明宗志平 National meteorological center China Meteorological Administration

In this paper,main characteristics of the long-lasting freezing rain and snowstorm event in southern China at the beginning of 2008,features of the related atmospheric circulation and the causes thereof are *** the event,patterns of the atmospheric circulation stayed stable;the polar vortex located in the northern part of the Eastern Hemisphere was strong with little movement;the cold front from the polar region and the active warm air mass from the tropical ocean confronted each other for a long time;the blocking high to the west of Baikal remained strong and steady;the trough over central and western Asia maintained its position for quite long with a group of little troughs splitting from it frequently;the dominant wind at 700 hPa was southwesterly while shears and vortexes at 850 hPa developed continually,providing the necessary low-level convergence for subsequent ***,in the mid troposphere,eddies were generated over the Tibetan Plateau and positive vorticity disturbances in the Sichuan Basin propagated eastward to the coastal regions of eastern *** western Pacific subtropical high was intensive with westward and northward *** subtropical frontal zone was puissant and the north-south temperature gradient was ***-stationary fronts over South China and the Yunnan-Guizhou Plateau remained *** air masses over the tropical ocean were active,so was the trough in the southern branch of the westerlies over the Bay of *** were four episodes associated with this *** first one was featured with the interaction of strong cold and warm air,while the other three with the quasi-stationary fronts over South China and the Yunnan-Guizhou Plateau as well as vigorous penetration of cold air from the *** existence of the inversion layer and the thick melting layer were one of the main reasons for the long-lasting freezing *** main reason for the snowstorms was that the positive vorticity over

关键词： freezing rain and snowstorm circulation characteristics cold and warm air inversion western Pacific subtropical high

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