Current Issue

• Review of Study on Interaction between Underlying Surface with Sparse Vegetation and Atmosphere
• HU Yin-qiao;SUN Shu-fen;ZHENG Yuan-run;ZHANG Qiang;FU Pei-jian;ZUO Hong-chao
• 2004 Vol. 23 (3): 281-296. 
• Abstract ( ) PDF (766KB) ( )
• The studies of a key project, entitled "study of interaction between underlying surface with sparse vegetation and atmosphere" supported by National Natural Science Foundation of China from 1999 to 2003 are reviewed.The mechanisms of transport processes of water, heat, and CO ₂ over complex underlying surface with sparse vegetation, the complex nonlinear effects caused by the heterogeneous underlying surface, the oasis stability, the development and thermal-dynamic conditions of strong dust storm, the countermeasure building the ecological environment in the arid and semi-arid area are studied using the data analyses, the numerical experiment, and the theory analyses.The main results are as follows: (1)Revealing the sensitivity of the net first productive power and the biomass to the climate, especially to the mean annual precipitation.These can provide a better interface to future study the interaction between the underlying surface with sparse vegetation and the atmosphere.(2)Developing a physic former, which expresses across coupling between the water transportation and the heat transportation in the soil, and the influence of phase transition on movements of water and heat in the soil, to be applicable to the arid and semi-arid area.A physic former that express variation of the seasonal snow cover based on the conversation law of energy and the conservation law of mass is developed, its simulated results are very good consistent with the observation results, which is one among several international typical delaminating formers of snow cover to achieve in-phase with international advanced level.(3)Developing the nonequilibrium thermodynamics.A theorem of minimum entropy production and a theorem of minimum generalized energy of the force-dissipative dynamic system are proved in thermodynamic linear and nonlinear region.These theory advances offer potential new idea and new method to deal with the kind of complex climate and environment system.The nonequilibrium linear thermodynamics reveals that the atmospheric vertical movement (namely the horizontal convergence or divergence movement) influences on the vertical turbulent transport fluxes of maroscopic quantities.This is very important for the boundary layer of heterogeneous underlying surface and the convection boundary layer.This research provides important clue to overcome difficulties in application of the atmospheric boundary layer physics to heterogeneous underlying surface, and in the parameterization of land surface process of heterogeneous underlying surface.Theoasis microclimate, the oasis critical scale and the oasis stability are studied using the theory of nonlinear thermodynamics.The oasis physic scale and the oasis wet island intensity are important control parameters of thermodynamic and dynamic processes of the oasis.The results of numerical simulation of the atmospheric dynamic model show that the critical scale of forming the oasis cold island effect is about 3~6 km;The oasis wet island intensity is about 2~5 g·kg~(-1).On the basis of the above research stockpile, we suggest countermeasure of protecting and building the ecological environment in arid area.(4)The development mechanism of strong dust storm, the atmospheric dynamic condition and the surface thermodynamic condition of forming strong dust storm are studied, on the basis of demand of economy build, and on the basis of trend of continually increasing of the dust storm in Western China and Northern China in the recent years.These simulated and observed results unveil a positive feedback process of the radiation cooling, among the dust, the radiation, the air temperature, air pressure, and strong wind, in the dust storm development process.These theoretical results validate the physic mechanism of forming the dust storm, and reveal good foreground of predicting the strong dust storm.

• Studies on Interaction between Urban Eco-environment and Urban Afforestation
• HE Yun-ling;ZHANG Yi-ping
• 2004 Vol. 23 (3): 297-304. 
• Abstract ( ) PDF (343KB) ( )
• The great attentions have been paid to the studies on the urban eco-environment and urban afforestation vegetation by investigators from different fields for many years.Based on the discussion about variable characteristics of urban climate, water and soil environment, as well as the ecological effects of urban vegetation, this paper reviews the advances in this field, and the some points to be reinforced in future study.It is intented that through above-mentioned profound and comprehensive discussion will offer some valuable references for promoting the studies on urban environment and ecology in China.

• Experimental Study on Bulk Drag and Transfer Coefficients over Gobi
• ZHANG Qiang;WEI Guo-an
• 2004 Vol. 23 (3): 305-312. 
• Abstract ( ) PDF (352KB) ( )
• Utilizing the data of the intensive observation period of Dunhuang land-surface process field experiment that belongs to Land-atmosphere Interactive Field Experiment over Arid Region of Northwest China, the bulk drag coefficient C _d, bulk sensible heat transfer coefficient C _h and bulk latent heat transfer coefficient C _q between surface and atmosphere in Gobi over arid region are obtained by three different methods.The resultshows that, these bulk transfer coefficients are different from each other, but they are the same order of magnitude, especially the mean values of C _d and C _h are very closer.However the bulk latent transfer coefficient is three time magnitudes smaller than dynamics and bulk sensible heat transfer coefficient.Moreover, through analyzing wind direction, the interference of the buildings near observational site and influence of oasis to the east of the site are eliminated.From this, the relation between the bulk transfer coefficients (or bulk drag coefficient) and the bulk Richardson number and the range of the typical values of the bulk transfer coefficients over desert and Gobi in typical arid region are obtained.

• Precipitation Character of Rainy Season of Qinghai-Xizang Plateau and Onset over East Asia Monsoon
• GONG Yuan-fa;JI Li-ren;DUAN Ting-yang
• 2004 Vol. 23 (3): 313-322. 
• Abstract ( ) PDF (623KB) ( )
• The wavelet transform is of good resolvable ability for the sudden change between active and break periods of the rainfall, and it is found that there is a large difference for the change features of Plateau rainfall between strong and weak monsoon years.A wavelet transform is employed to investigate multi-time scale variations of summer precipitation over Qinghai-Xizang Plateau in 1993/1994.In 1993, the East Asia monsoon is weak and its onset is late, the precipitation of Qinghai-Xizang Plateau mainly occur in July and August, which has characters of the quasi-biweekly variations.In 1994, the East Asia monsoon is strong and its onset is early, which relates to the precipitation of Qinghai-Xizang Plateau in May and June, marked by the 30~60 day oscillations.In addition, comparing with active and break periods of the rainfall and the NCEP data, the beginning of rainy season over Qinghai-Xizang Plateau related to the East Asia monsoon onset very well in two years, which is in good correspondence to the monsoon onset during the first active-rainfall.

• Relation between Upper-Level Thermodynamic Anomaly over Qinghai-Xizang and Iranian Plateaus in Spring and Summer and China Air Temperature in Summer
• XU li;BI Yun;QIAN Yong-fu
• 2004 Vol. 23 (3): 323-329. 
• Abstract ( ) PDF (338KB) ( )
• Firstly, thetemporal and spatial variations of temperature fields of 100, 150, 200, 250, 300, 400 and 500 hPain 0°~180°E, 0°~60°N were analyzed by using EOF method.Resultsshow that 300 hPa temperature field can reflect the thermodynamic anomaly of Iranian and Qinghai-Xizang Plateaus.Secondly, the relationbetween 300 hPa temperature and regional air temperature of China is analyzed by using SVD expansion.Results show:(1) There is a positive correlation between 300 hPatemperature in the most of Iranian Plateau, thecenter and north-west of Qinghai-Xizang Plateau and air temperature in Changjiang River and Huaihe valley in June~August.(2) 300 hPa temperature in the east, northwestof Qinghai-Xizang Plateau in April~May positively correlates to air temperature in the southern-toward area in Changjiang River valley in June~August.

• Temporal and Spatial Patterns of Surface Sensible Heat Flux and Their Relationship with the SST Anomaly over Adjacent Oceans
• ZHANG Yan;QIAN Yong-fu
• 2004 Vol. 23 (3): 330-338. 
• Abstract ( ) PDF (547KB) ( )
• Using the NCEP/NCAR reanalysis monthly mean sensible heat fluxes from 1949 to 2000,the temporal and spatial patterns of the global surface heat fluxes are analyzed.The results show that the surface sensible heat of the Qinghai-Xizang Plateau (QXP) is the main part of the global surface sensible heat, and has remarkable asymmetric characters with opposite time variations in the west-QXP and east-QXP.It is found that the west-QXP and east-QXP and the north Africa are the key regions with evident interannual and interdecadal variations of the surface sensible heat fluxes.Using SVD technique, it is also found that there are good relations between the sensible heat anomalies of the west- and east-QXP, and the SSTA in the Northwestern Pacific Ocean and the equatorial central Indian Ocean.

• Study on Effect of Asian Surface Air Temperature Anomaly on Position of Rainy Belt in Chinese Flood Season
• TIAN Yong-li;CAO Jie
• 2004 Vol. 23 (3): 339-343. 
• Abstract ( ) PDF (222KB) ( )
• Using the surface air temperature data of NECP/NCAR reanalysis and the rainy belt data in Chinese flood season of National Meteorological Center, Chinese Meteorological Administration in 1980-1999, the relationship between surface air temperature in Asia and rain belt's location in Chinese flood season is analyzed and calculated.The result showed that the closest linkage region between surface air temperature in Asia and rainy belt position in Chinese flood season is in the Qinghai-Xizang Plateau, the positive correlations between them have good persistence, the maximum correlation coefficients appear in May.Through the composite analyses of relevant atmospheric general circulation, it is found when the surface air temperature over Qinghai-Xizang Plateau in May is warmer, the thermal effect makes ascending air current to enhance, and a branch of relative strong descending air current was forced near 115°E, 25°N, causing the relative anticyclonic is appeared near 110°~120°E, 20°~25°N, which is favorable for West Pacific Subtropical High jumping to the north so that the location of rainy belt in Chinese flood season moves north toward.

• Coupling of Atmospheric General Circulation Model with Oceanic General Circulation Model under Sub-Grid Scale Sea Ice Inhomogenities
• LIU Xi-ying;ZHANG Xue-hong;YU Yong-qiang;YU Ru-cong
• 2004 Vol. 23 (3): 344-347. 
• Abstract ( ) PDF (214KB) ( )
• A sea ice effect representation scheme which consider the nonlinear dependence of sea-air flux exchange on underlying surface characteristics better is used here to deal with the sub-grid scale sea ice inhomogenities in a coupled model.The coupled model has been integrated for 50 years and the simulated results of sea ice in high northern latitudes have been analyzed and validated.The results show that the sea ice effect representation scheme is rational and that the coupled model can reproduce the main geographical distribution features of sea ice in high northern latitudes well.

• Analyses on Surface Radiation Budget in Northern Tibetan Plateau
• MA Wei-qiang;MA Yao-ming;HU Ze-yong;LI Mao-shan;WANG Jie-min;QIAN Ze-yu
• 2004 Vol. 23 (3): 348-352. 
• Abstract ( ) PDF (251KB) ( )
• Using GAME/Tibet (GEWEX Asian Monsoon Experiment in the Tibetan Plateau) IOP data of 1998, K↓(downward shortwave radiation), K↑(upward shortwave radiation), L↑(upward longwave radiation), L↓(downward longwave radiation), R _n(net radiation flux) and surface reflectance of pre- and mid- and post-summer monsoons in the northern Tibetan plateau are analyzed in this paper.Some new results are obtained in the northern Tibetan plateau.

• Annual and Diurnal Variations of Surface Fluxes in Western Qinghai-Xizang Plateau
• YU Jin-hua;LIU Jin-miao;DING Yu-guo
• 2004 Vol. 23 (3): 353-359. 
• Abstract ( ) PDF (288KB) ( )
• Using the hourly observed data of in wind speed, temperature and moisture at two auto-meteorological stations in Gerze and Shiquanhe of western Qinghai-Xizang Plateau in 1998, and applying the turbulent similarity theory, the momentum, sensible and latent heat fluxes in Gerze and Shiquanhe are evaluated.The results show that the surface turbulent fluxes have characteristics of significant diurnal and annual variations.The monthly sensible fluxes are maxima in May and minima in Juanuary.The latent fluxes in Gerze and Shiquanhe are maxima in August, and that of Gerze is minima in December and that of Shiquanhe is negative during January to May, taking main as the condensation.The monthly and yearly evaporation in Gerze is larger than that in Shiquanhe, but the former sensible flux is smaller than the latter.The variation of diurnal amplitude is obsvious with season, showing that the flux amplitude in summer is larger and smaller in winter.

• The Characteristic of Temporal and Spatial Distribution of the Differences between Ground and Air Temperature in the Arid Region of Northwest China
• FAN Li-jun;WEI Zhi-gang;DONG Wen-jie
• 2004 Vol. 23 (3): 360-367. 
• Abstract ( ) PDF (356KB) ( )
• The differences between ground soil and air temperature ( T _s- T _a)are analyzed and studied by using the data of ground and air temperature of 55 stations in the arid region of Northwest China from 1961 to 2000, with EOF and REOF analyses and wavelet analysis methods.The results show that ( T _s- T _a) in the arid region of Northwest China have the biggest values in June and the smallest values in January;the values of ( T _s- T _a)is positive in spring, summer and autumn, but opposite in winter;the first three loading eigenvector reflect the main spatially-anomalous structure of ( T _s- T _a) in the arid region of Northwest China that contain the consistent positive or opposite pattern in all of their sub-regions, and the two spatially-opposite patterns in the North and the South and in the East and the West.( T _s- T _a) in the arid region of Northwest China show in the past 40 years there were the four patterns of time evolution including the parabola patterns with the maximum or minimum values, the patterns increasing or decreasing trends in monotonously;( T _s- T _a) have periodic variation about 3~6 years and 20 years.

• Model Computation and Analysis about Evolution of Mixed Layer Height in Atmosphere
• ZENG Zhi-hua
• 2004 Vol. 23 (3): 368-373. 
• Abstract ( ) PDF (247KB) ( )
• A set of equations, the slab model, governing the mean state of convectivly mixed layer are firstly designed and used then to simulate the evolution of the mean elements in mixed layer with time.Using the energy method and taking the factors of buoyancy, wind shear and downdraft into account, we have calculated the process of the mixed layer height varied with time.The results show that the model can be used in operational forecast.Meanwhile the calculation method of model is improved and the effects of the physical factors on the evolution of mixed layer height are discussed.

• Study on Intensity Standard of Regional Sandstorm in Gansu Province
• CHEN Xiao-guang;ZHANG Cun-jie;DONG An-xiang;LU Deng-rong
• 2004 Vol. 23 (3): 374-381. 
• Abstract ( ) PDF (324KB) ( )
• Using the daily data of sandstorm of 18 representative meteorological stations in Gansu Province from 1955 to 2000, the intensity standard of regional sandstorm and single station's sandstorm was studied.The sandstorm weather was divided into very strong, strong and general sandstorms by this standard at 80 meteorological stations in Gansu Province since 1955.The spatial and temporal distribution characteristics of sandstorm were also analyzed.

• Analyses on Duststorm Climatic Characteristics in Alashan, Inner Mongolia
• YOU Li;WANG Ge-li;WU Xue-hong;WANG Guo-qin
• 2004 Vol. 23 (3): 382-386. 
• Abstract ( ) PDF (216KB) ( )
• Based on the observed duststorm data in Alashan region of Inner Mongolia from 1961 to 2000, the climatic characteristics of duststorm in this region was analyzed, especially the geographical distribution and seasonal, interannual and interdecadal characteristics.The results showed that the duststorm day in Alashan region decreased in the period of the last 40 years, but the duststorm day were increasing as wave in northern Alashan in 1990's, the variation of the duststorm day numbers are responsive to some special climate variations, and the continued deterioration underlying surface condition is one of an important reason of increasing duststorm day numbers in this region.

• Application of Potential Vorticity Diagnoses in Yunnan Summer Heavy Rain Forecasting
• FAN Ke;JU Jian-hua
• 2004 Vol. 23 (3): 387-393. 
• Abstract ( ) PDF (376KB) ( )
• This is an approach to application of the potential vorticity diagnosis technique to Yunnan heavy rain forecasting through one of most often occurring strong precipitation cases so-called as "Yunnan-Guizhou convergence pattern" summer.The main results are as follows: Both the dry and moist potential vorticity(PV) can well present the features of the weather systems.The dry PV reflect both the cold and warm air flow activities.The upper tropospheric dry PV tends downward to the lower-levels and vice versa for the lower-level troposheric dry PV.It is favourable for causing the heavy rainstorm when the dry air in upper levels meets with the warm and wet air in the lower-levels along with the convergence conditions of low and shear line in lower-layers;but once the PV weakens in upper- and lower-levels the precipitation will be ended soon.The "Yunnan-Guizhou convergent pattern" rainstorms show usually there are a dry PV high value oriented belt in NE to SW or N to S in the mid-and lower-troposhere, and when the high value belt is broken, the process of heavy rain over Yunnan will end up.The moist potential vorticity (MPV)presents the cyclones on the 700 hPa much better than the dry PV.Commonly, the conditions MPV<0 and MPV>0 on 700 hPa occur during the heavy rain process in Yunnan.

• Intercomparisons of GPSO ₃ and Vaisala ECC Ozone Sondes
• XUAN Yue-jian;MA Shu-qing;CHEN Hong-bin;WANG Geng-chen;KONG Qin-xin;ZHAO Qiong;WAN Xiao-wei
• 2004 Vol. 23 (3): 394-399. 
• Abstract ( ) PDF (262KB) ( )
• Ozone sonde is widely used for in situ measurements of atmospheric ozone profiles from ground to 35 km.In order to obtain the measured precision, sensitivity and reliability of Chinese ozone sonde named GPSO ₃, a series intercomparison with Vaisala ECC type ozone sonde has been carried, including the sensitivity and response time of ozone sensors, ozone measurements at ground in comparison with that by a standard ozone analyzer, the pump efficiency at low pressure, and balloon soundings with two sondes together.The results show that our GPSO ₃ ozone sensor has the capability similar to that of Vaisala ECC ozone sonde.

• The Change Characteristics of Surface Air Tempearture between Changjiang River and Nanling Mountain in Recent 50 Years
• HOU Wei-fen;WANG Qian-qian
• 2004 Vol. 23 (3): 400-406. 
• Abstract ( ) PDF (412KB) ( )
• Based on the surface air temperature data of 160 stations in China in the recent 50 year (in 1951-1999), and using the anomaly, weighted means of binocmial coefficient, maximum entropy spectrum and wavelet analysis methods, the interannual and inter-decadal change characteristis of surface air temperature over the region between Changjiang River and Nanling Mountain were analyzed.The results show that there are different tends about the change of air temperature over the region in four seasons in recent 50 years.The climatic tend coefficents in spring summer, autumn and winter are 0.16, -0.0 8, -0.02 and 0.29, respectively.The warming trend in winter is obvious and cooling trend in summer which have different periodics.The air temperature anomaly in summer exist 3.6 year dominant periods, and others are 2.5- and 5-years, but for winter, the main periods are 6.3- and 3.3- years.

• Climatic Characteristics of Heavy Fog in Shaanxi Province
• HE Hao;Lü Hong;XU Hong
• 2004 Vol. 23 (3): 407-411. 
• Abstract ( ) PDF (215KB) ( )
• Using the data of heavy fog at 17 stations in Shaanxi provience from 1970 to 2000, the climatic and regional characteristics of heavy fog are analyzed.There are three high and low frequeucy centers of mean fog days in Shaanxi provience from north to south.They are: Yijun-Luochuan, Shiquan-Hanzhong and Xi'an, along the ancient Great Wall in northern part of Shaanxi, and the east and west- enter (exit) regions in Guanzhong plain, respectively.Although the heavy fog can form in each month of a year, the occurring frequency of heavy fog in autumn and winter (September~December) is the most, and that of February and June is the least.The mean foggy days of Yijun, Shiquan and Xi'an exist obvious interannual change, about quasi-period of 6, 8 years.The variations of 30-year fog days in Xi'an and Xianyang is opposite, it is decreasing in Xi'an, increasing in Xianyang.

• Discussions about Study on the Boundary Layer Meteorology over Heterogenous Underlying Surface
• LIU Hong-nian;LIU Gang;JIANG Wei-mei;ZUO Hong-chao
• 2004 Vol. 23 (3): 412-416. 
• Abstract ( ) PDF (240KB) ( )
• The adversaria about the discussion on heterogenous boundary layer meteorology was gave in this paper, including the atmospheric layer experiment, the applying scope of M-O theory, the parameterization of physical processes the energy budget, city boundary layer, as well as the turbulent structure and characteristic of atmospheric boundary layer.It maybe can provide some useful clues for heterogenous boundary layer meteorological study.