Current Issue

• A Numerical Study on Distribution of Sulfate,Nitrate and Ammonium Aerosols over East Asia during the TRACE-P Campaign
• ZHANG Mei-gen;HAN Zhi-wei
• 2003 Vol. 22 (1): 1-6. 
• Abstract ( ) PDF (272KB) ( )
• Based on the recently estimated emission inventory in East Asia with a resolution of 1°×1°,specially prepared for TRACE-P(TRAnsport and Chemical Evolution over the Pacific),the Models-3 Community Multi-scale Air Quality modeling system(CMAQ) coupled with the Regional Atmospheric Modeling System(RAMS) was used to study the transport and chemical transformation of aerosols in the springtime over East Asia.Model calculated concentrations of aerosols,e.g.,sulfate,nitrate,and ammonium,were compared with observed ones obtained on the ground and aboard the aircrafts of DC8-13 and P3B-15 during the TRACE-P campaign.Comparison shows that model calculations agree reasonably well with observations,and the model catches temporal and spatial variations of aerosol concentrations well and reproduces many of the observed important features.Model results show that high concentrations of sulfate aerosols in China are mainly caused by human activities,and over the broad area of China to the east of 100°E,column burden of sulfate aerosols exceeds 6 mg·m ^-2 with maximum value of 24 mg·m ^-2.The areas with concentration higher than 16 mg ·m ^-2 even extend to the East China Sea,which implies that human activities in East Asia result in a rapid increase in sulfate column burden not only in the source regions of its precursors but also in offshore water.The development of this model system provides a useful tool in future study on air pollution in the region.

• A Simple Study on Relation of Winter-Spring Greenland Sea Ice Chang with Air Temperature/Precipitation in Early Summer of China
• CHEN Ming-xuan;GUAN Zhao-yong;XU Hai-ming
• 2003 Vol. 22 (1): 7-13. 
• Abstract ( ) PDF (365KB) ( )
• The winter-spring mean sea ice extent oscillations nearby Greenland island and their relationships to surface air temperature and precipitation in early summer of China have been examined in the present paper using the GISST sea ice extent dataset released by Hadley center,UK,and NCEP/NCAR 40-year reanalysis as well as the recorded surface air temperature and rainfall in China,empirical orthogonal function(EOF) analysis and wavelet analysis,etc.The results point out that the sea ice extent oscillations on the west and east sides of Greenland island show inverse variation with distinct interannual and interdecadal circles.The winter-spring sea ice extent oscillation over Greenland-Norwegian Sea is positively correlated to June surface air temperature to the north and rainfall to the south along Yangtze River in China,whereas is negatively correlated to the reverse and vice versa to sea ice extent over Davis Strait-Labrador sea.The composed analyses based on the NH 500 hPa general circulation show that the winter-spring sea ice extent oscillations nearby Greenland island are in contact with the persistent Arctic polar vortex and northern hemisphere blocking high anomalies.The sea ice extent oscillations are one of factors to affect precipitation and surface air temperature in early summer of China.

• Contrast Analyses on Water Vapor and EASM between Dry and Wet Years of Northwest and North China
• CAI Ying;QIAN Zheng-an;SONG Min-hong
• 2003 Vol. 22 (1): 14-23. 
• Abstract ( ) PDF (666KB) ( )
• In order to better understand the precipitation climate over North China(hereafter NC) and Northwest China(NWC) in summer months(JJA),in this paper,the linkages between the water vapor fields and moving northward of East Asia Summer Monsoon(EASM) during five dry and wet years(months) over NC and NWC regions have been investigated by utilizing the NCEP reanalysis gridded data.The main results are as follows:(1) The precipitable water in NC and the east part of NWC was obviously decreasing since 1950's,it may relate to the getting weak EASM in the same period.(2) There are considerable differences in the summer column precipitable water over NC and NWC in dry and wet years(months).(3) The EASM circulation,the position and strength of water vapor transport channels,along with the convergence and divergence of water vapor flux are quite different from each other during the dry and wet years(months) over NC and NWC.(4) It seems that the different land-sea thermal contrasts cause firstly the different conditions of moving northward of the EASM,then cause again the different dry and wet years(months) over NC and NWC.And also the upper air temperature difference index between Qinghai-Xizang Plateau and West Pacific Ocean and the surface EASM index have certainly ability to explain the abrupt seasonal change and the interannual variation of EASM.

• The Determination of Roughness Length over City Surface
• ZHANG Qiang;Lü Shi-hua
• 2003 Vol. 22 (1): 24-32. 
• Abstract ( ) PDF (582KB) ( )
• The difference between momentum roughness and scalar(vapor water and sensible heat) roughness in form and in physical essence is discussed.The simplified formula to determine momentum roughness is given out,after the several factors of the controlling momentum roughness are analyzed.And based on the principle of conservation of energy and momentum of inertial sublayer and city canopy sublayer the relationship between scalar(vaporwater and sensible heat) roughness and momentum roughness is established and the simplified formulae to calculate scalar(vapor water and sensible heat) roughness are obtained.Finally,by the numerical experiment,the characteristics of variation of momentum and scalar roughness with some key parameters and dynamic relation of scalar roughness to momentum roughness are shown.

• A Numerical Study on the Stratocumulus-Topped Planetary Boundary Layer Part(I):Model Development
• ZUO Hong-chao;Lü Shi-hua;HU Yin-qiao;QING Wang
• 2003 Vol. 22 (1): 33-44. 
• Abstract ( ) PDF (628KB) ( )
• Stratocumulus is a kind cloud formed by turbulent force in boundary layer.The cloud top is the boundary layer top,so it is called stratocumulus-topped boundary layer.The cloud layer and cloudless layer coupled in this kind boundary layer.For understanding the stratocumulus-topped boundary layer,a numbers of field observation and numerical simulation have been made.But,there is a fatal defect in some coupled model,that is the turbulent model and cloud physical model do not coupled properly.For overcoming this problem,a new numerical model of the cloud-topped planetary boundary layer is developed by using cloud drop equation in the turbulent equations.The model is one-dimensional with special emphasis on a detailed description of cloud microphysical processes.(1) The interaction between turbulent and cloud microphysics is considered.(2) The model has third-order turbulence closure planetary boundary layer model coupled with size-resolved cloud microphysical model.The simulation made by the new model on the case which was proposed by C.-H.Moeng in "the stratocumulustopped planetary-boundary layer:Intercomparison among different numerical codes" is presented and compared with some observations and some simulations.The result shows that the new model can simulate the turbulent structure and the cloud microphysical processes of the marine stratocumulus-topped planetary boundary layer.

• Correlation Analyses between Intensity of Solar Ultraviolet Radiation and Meteorological Elements
• LIU Jing-miao;DING Yu-guo;HUANG Yong-de;HUANG Lei
• 2003 Vol. 22 (1): 45-50. 
• Abstract ( ) PDF (259KB) ( )
• The correlation relationship beween solar ultraviolet radiation and weather elements under daytime are analyzed by means of common meteorological observation data.Based on above data,the prediction equation to UV from routine observation data are obtained,which can forecast daily UV intensity by using predicted daily weather elements.In this paper,we also assess the contributions of each weather elements to UV intensity.

• Climatic Characteristics of Strong and Very Strong Sandstorms in the Middle and West Parts of Inner Mongolia
• LIU Jing-tao;ZHENG Ming-qian
• 2003 Vol. 22 (1): 51-64. 
• Abstract ( ) PDF (1009KB) ( )
• From the observation data of sandstorms over past 40 years(1957-1996) from 74 meteorological stations located in the west and middle parts of Inner Mongolia,China,184 strong and very strong sandstorm cases with different scopes were recorded according to a given standard of intensity.Detailed statistical analysis on their characteristics of geographic distribution and temporal distribution are performed.The results show that there are three centers of strong and very strong sandstorm in the west and middle parts of Inner Mongolia.They are located in the Guaizhihu,Alashan Plateau;Zhurihe,west Xilinguole and Yikewusu,North West Yikezhao respectively.The variations of sandstorm on decade,year and season scales are considerable.After reaching the peak in the 1960's and the 1970's,their times and intensity began reducing in the 1980s.However,strong and very strong sandstorms increased suddenly in 2000 and 2001 and appear mainly in March to May of spring,meanwhile in one day they appear mainly in afternoon to early evening.Furthermore,a preliminary study on the climatic causes of forming above statistical characteristics is given.

• Climate Characteristics Analysis of Guizhou Precipitation Anomaly in Recent 49 Years
• WU Hong-yu;WANG Qian-qian
• 2003 Vol. 22 (1): 65-70. 
• Abstract ( ) PDF (266KB) ( )
• The monthly precipitation data of 19 stations in Guizhou and 160 stations in China during the last 49 years(1951-1999) are used to study the spatial-temporal distribution,characteristics of climate anomalies of Guizhou by vague assemble analysis,Empirical Orthogonal Function analysis,power spectral analysis and the composite analysis methods,The results show that there are obvious interannual variations of Guizhou precipitation,There is principal rainfall anomaly period around 2.8 years in Guizhou summer.The tendency of precipitation in Guizhou summer is same as it in Yangtze River and Huaihe River,but contrary,to the tendency of rainfall in the area among Shaanxi,Gansu and Lingxia.

• Performance Verification of Mesoscale Model MM5V3 to Regional Climate Simulation
• LIU Dong
• 2003 Vol. 22 (1): 71-77. 
• Abstract ( ) PDF (406KB) ( )
• The regional climate model second generation(RegCM2) is a research tool aimed at enhancing the modeling ability to identify regional scale anomalous climate variations.RegCM2 was developed on the base of Mesoscale Model Version 4(MM4),its dynamical component is hydrostatic,so its simulation has the big bias in the rainstorm simulation resulting from strong convection.The rainstorm has resulted in the flood in South China in June,July and August 1998.Thus,this simulation provides an excellent case study for evaluating the model's ability to reproduce the features of anomalous precipitation at the regional scale.An important conclusion from strong rainfall simulation in June 1998 is that,MM5V3 is capable of reproducing the feature of local planetary atmospheric circulation and regional scale rain area resulting from strong convection,the position and intensity of strong rainfall centers.But simulated precipitation quantity is different with real precipitation quantity.So MM5V3 may be developed to be regional numerical prediction model system.The simulation reproduces the feature of anomalous precipitation in South China during June of 1998.This simulation has stronger intensity of two planetary-scale monsoon systems than their actual one,as a result,much more amount water vapor came into rain area and overestimation of rainfall amount.

• Study on Palaeosol Features in Xi'an Area and Climatic Change during the Last 10000 Years
• PANG Jiang-li;HUANG Chun-chang
• 2003 Vol. 22 (1): 79-83. 
• Abstract ( ) PDF (213KB) ( )
• A higher resolution loess-palaeosol sequence was found at Liwan,Xi'an area.Detailed micromorphological analysis,as well as magnetic susceptibility,total organic carbon(TOC) and CaCO ₃,in the loess profile,shows that the Holoence palaeosol S ₀ was a soil complex which is composed of two distinct soils layers,namely S ₀ ² and S ₀ ¹.The soil S ₀ ¹ and S ₀ ² were brown earth with distinct argillic horizons,strong leaching and pedogensis,high magnetic susceptibility and TOC,low CaCO ₃.They were formed in the warm-wet forest environment.Overburden layer(L ₀+TS) above soil complex S ₀ has loess's basic micro-texture feature though it was affected by human activity.It indicate that it was a remarkable aridity interval between 6000 and 5000 aB.P.It has been another relative aridity period since 3100 years,with accelerated aeolian dust deposition.The soil complex S ₀ thus has been buried and becomes palaeosol of the Holocene.

• The Seasonal Variation of Aerosol Optical Depth in Dunhuang Area
• LI Ren;JI Guo-liang
• 2003 Vol. 22 (1): 84-87. 
• Abstract ( ) PDF (181KB) ( )
• A method of retrieving aerosol optical depth from direct solar radiation is discussed in climatologic statistical procedures.By using of the data observed from 1981 to 1983,we calculate the seasonal variation of the aerosol optical depth in Dunhuang area.The results are that the aerosol optical depths are small in winter and high in spring;the optical thickness in summer and autumn are between those in winter and spring,respectively;but the value in summer is higher than that in autumn.

• CEOF Analysis on Distribution and Variation of Soil Temperature of China and Mongolia
• WANG Zhong-rui;TANG Mao-cang
• 2003 Vol. 22 (1): 88-91. 
• Abstract ( ) PDF (211KB) ( )
• By using the Complex Empirical Orthogonal Function(CEOF) analysis,the spatial and temporal distribution of the soil temperature of China andMongolia are investigated.It is found that there are structures of wave motion in the soil temperature field.The disturbance in Qinghai-Xizang plateau is prior to the other regions.

• Calculation of Possible Direct Solar Radiation Around Qinghai Lake Based on DEM
• DENG Zi-wang;NI Shao-xiang;ZHOU Xiao-lan;ZHANG Hong-liang;TU Qi-pu
• 2003 Vol. 22 (1): 92-96. 
• Abstract ( ) PDF (321KB) ( )
• The digital elevationmodel(DEM) of the region around Qinghai Lake was estalished.Based on the DEM andMountain Climatology theories,the effects of slope,aspect,height above sea level and geographic location on spatial distribution of total possible direct solar radiation( Q) of different seasons in a year were studied.The results showed that the mean Q over the area in spring,summer,autumn and winter are 323 KJ·cm ^-2,378.7 KJ·cm ^-2,225 KJ·cm ^-2 and 166 KJ·cm ² respectively.In a small area,the effects of height and latitude on Q are ignorable,however the influences of slope and aspect are significant.The biggest spatial variations of Q caused by aspect and slope appears in winter(170KJ·cm ^-2) and the smallest in summer(19 KJ·cm ^-2).The Q of the southward slope on the north mountains is higher than the mean Q(equal the value of flat region around the lake) and that of the northward slope on south mountains is low than the averaged Q.