Current Issue

• Study on the Effects of Volcanic Eruption and Solar Activity on Climate in China in Recent 50 Years
• JIA Peng-qun;SHI Guang-yu
• 2001 Vol. 20 (3): 225-233. 
• Abstract ( ) PDF (377KB) ( )
• The climatic signals of volcanic eruption and solar activity in China surface temperature and precipitation records in recent50 years were revealed by using a mixture of principal component analysis(PCA), superposed epoch analysis(SEA) andspectral analysis. Large explosive volcanic eruption resulted in a decrease in surface temperature over almost all parts of China, which hada time lag of about one year and continued for about half year. Besides this mainsignal, a complex pattern for temperature variation was expected over Qinghai-Xizang Plateau, southeastern coastal area and northeast region. While the spectral linkage between temperature variation and solar activity was more obvious, there was a weak volcanic signal in precipitation records, which indicateda positive anomaly in rainfall over South China in the following autumn and winter after the eruption. No significant signal hadbeen found in the records of snow cover and deep soil temperature over Qinghai-Xizang Plateau.

• Observation and Analysis on Elemental Composition of Atmospheric Aerosols over Mount Qomolangma Region
• ZHANG Ren-jian;ZOU Han;WANG Ming-xing;ZHOU Li-bo;ZHU Guang-hua
• 2001 Vol. 20 (3): 234-238. 
• Abstract ( ) PDF (290KB) ( )
• Chemical composition of atmospheric aerosols over mount Qomolangma region were observed by cascade and analyzed by using PIXE method. The results show that crustal elements such as Al, Ca, Si, K, Fe are the main composition of atmospheric aerosols over mount Qomolangma region and account for more than82% of the total elemental concentration. The concentrations of polluted elements such as S, Pb which are related to human activities are very low, as observed in Greenland Island. Observed elemental concentrations of S and Pb are91.64 ng·m ^-3 and2.93 ng·m ^-3 respectively. The enrich factors of crustal elements are a bit lower than that in Beijing, while enrich factors of element As and Pb over mount Qomolangma region are also much lower than that over Beijing. It shows that Mount Qomolangma region is much cleaner than Beijing and is rarely influenced by human activities.

• The Variation of Surface Heating Field over Northern Qinghai-Tibet Plateau and Its Effect on Climate
• JI Guo-liang;SHI Xing-he;GAO Wu-xiang
• 2001 Vol. 20 (3): 239-244. 
• Abstract ( ) PDF (272KB) ( )
• The relationship between surface heating fields and atmosphere general circulation in the corresponding period are analyzed by using the surface energy budget observed at Wudaoliang over Northern Qinghai-Tibet Plateau. The results show that the variation of surface heating fields in Northern Plateau are similar to the variation in Western Plateau, but it is different to thevariation in Eastern Plateau. The processes of surface snow cover in November have important significance to decide the properties of surface heating fields. The anomaly of surface heating field in winter cause the anomaly of surface heating field in summer may be one of reasons to cause the anomaly of atmosphere general circulation. Therefore, monitoring surface heating fields could provide basis for the climatic forecast of short period.

• Features of Atmospheric Ozone Interannual Variation in Spring of Northern Hemisphere and Its Effect on Temperature and Circulation
• GUO Pin wen;ZHU Qian-gen;LIU Xuan-fei
• 2001 Vol. 20 (3): 245-251. 
• Abstract ( ) PDF (372KB) ( )
• The spring total O ₃ in the atmosphere exhibited substantial interannual change over northern extratropics, which exerted crucial influence on atmospheric temperature and circulation characteristics. During the intense(weak) years of total ozone, for most of these latitudes, especially in Asia, the positive(negative) anomaly of the quantity was related to the negative(positive) anomaly mean temperature and geopotential height in troposphere and vice versa for in stratosphere, and instead, negative(positive) anomaly of the gas happened over the belt stretching from the Hudson Bay to the northern North Atlantic to West Europe and was in association with the positive(negative) anomaly of tropospheric(stratospheric) mean temperature and geopotential height(but the latter took place only in most cases). Obviously, the opposite features of the total ozone anomaly at extratropics over Asia and the northern North Atlantic represents an innegligible indicator of the impact of ozone, the negative(positive) and positive(negative) anomaly occoured in troposphreic mean temperature over North/East China and West/South China, respectively, just in opposition to the condition in the stratosphere.

• Cloud Cover over Qinghai-Xizang Plateau:Comparison among Meteorological Station Observations, ISCCP-C2, and NCEP Reanalysis Data
• WANG Ke-li;JIANG Hao;CHEN Shi-qiang
• 2001 Vol. 20 (3): 252-257. 
• Abstract ( ) PDF (270KB) ( )
• Temporal and spatial characteristics of cloud cover over Qinghai-Xizang Plateau are compared and analyzed based on data of the meteorological observing stations, the ISCCP-C2, and the NCEP-NCAR reanalysis during1984-1990. Results show that there is good correlation of cloud cover between the ISCCP-C2 and the stations, spatial distribution over Qinghai-Xizang Plateau about both of them is similar, annual and interannual variation trends about both of them are roughly same. For the Plateau climate studies, the reanalysis cloud cover data have connatural limitation.

• Estimation of the Direct Radiative Forcing Due to Anthropogenic Sulfate over Eastern Asia
• WANG Xi hong;SHI Guang yu
• 2001 Vol. 20 (3): 258-263. 
• Abstract ( ) PDF (292KB) ( )
• A three-dimensional regional Eulerian model of sulfur transport is used to simulate anthropogenic sulfate column burden over Eastern Asia during mid-1990s. Furthermore, a simple multiple reflective radiation model are used to assess the direct radiative forcing(DRF) due to anthropogenic sulfate over Eastern Asia. The geographic distributions and seasonal variations of DRF are also analyzed. The simulated results indicate the regional annual mean DRF due to anthropogenic sulfate is-0.7W·m ^-2. The DRF appears to be obvious geographical and seasonal patterns. Those geographical and seasonal cycles of DRF are mainly depending on the geographical and seasonal variations of sulfate loadings.

• The Influence of Cloud Layer and Aerosol on Absorption of Solar Radiation
• HU Li qin;LIU Chang sheng
• 2001 Vol. 20 (3): 264-270. 
• Abstract ( ) PDF (336KB) ( )
• Clouds is the major contributor to modulating the energy balance of the earth atmosphere system, thereby it plays a key role in the weather, climate and globe changes. Studies on the interaction of clouds with radiation are important. In the investigations, a recent debate about the anomalous absorption of solar radiation in the cloudy atmosphere aroused widely interest. The problem relating to this is the basic knowledge of absorption in cloud and cloudy atmosphere is still inadequate. In this paper, a radiative transfer code--DISORT is employed to calculate the absorptivity of cloudy atmosphere. After taking account of the affection of the molecular scattering, absorption and emission, the aerosol absorption and scattering and the cloud partical absorption and scattering, the impact of the cloud on radiation at different solar spectrum bands, solar zenith angles, cloud heights and underlying surfaces are considered. Some radiative properties of cloudy atmosphere in the solar radiation wave bands are shown.

• Simplified Calculation of Radiative Forcing with Adjusted Stratosphere Temperature
• YU Xiu-lan;SHI Guang-yu
• 2001 Vol. 20 (3): 271-274. 
• Abstract ( ) PDF (181KB) ( )
• Adjusted radiative forcing due to greenhouse gases is calculated in this paper using Shi(1991)'s1-RCM. The1-D radiation-convection model results can be expressed with simple empirical formula, which is fast and has reasonable precision. It is to be special noted that the formulae in IPCC(1990) and Shi(1992) were given in IPCC(1994). However, both of them are calculations based on IRF, so it's necessary to find the simplified calculation equations for ARF. Moreover, the simplified empirical equations are given out for ARF results refer to those of IRF given by Shi in1991. And the comparison with the results calculated with1-RCM shows that our simplified formulae could provide good accuracy.

• Numerical Simulations of Effects of Ozone Variation over Polar Regions on Climate of China
• XU Guo-qiang;ZHU Qian-gen;LIU Xuan-fei
• 2001 Vol. 20 (3): 275-282. 
• Abstract ( ) PDF (369KB) ( )
• By using the TOMS data, the atmospheric ozone season variations over Arctic and Antarctic firstly is investigated. The results indicate that both Arctic and Antarctic ozone decline are the most noticeable in spring.And then, with numerical experiments, we can conclude that polar regions ozone decline will bring roughly reverse to difference distribution of high and low level temperature and make changes of general circulation pattern as well as rainfall distribution feature. In the different areas of China, meteorological elements have the different variation features.

• Analyses on Aerosol Scattering Optical Depth in the Arid Region of North-West China
• LI Gang;JI Guo-liang
• 2001 Vol. 20 (3): 283-290. 
• Abstract ( ) PDF (331KB) ( )
• A method for estimating aerosol scattering optical depth in the atmospheric column in clear sky with the daily total of solar radiation(include global radiation and diffuse radiation) in operation whole-spectral(0.3~4 μm) measured at meteorological stations is described, based on the sensitivity of global radiation and diffuse radiation to aerosol physical optical properties. The method is established based on the comparison between observed data and model calculation. The550 nm aerosol scattering optical depth can be estimated with the method without consulting sounding data about water vapor, ozone and information of cloud condition. The seasonal and inter-annual variations of aerosol scattering optical depth in the atmospheric column in clear sky are analyzed by using the data observed at6 meteorological stations(Lanzhou, Dunhuang, Minqing, Geermu, Wulumuqi, Kashi) in the arid region of North-West China during the period from1986 to1992. Some interesting results will be revealed. The results are as flows:(1) Aerosol scattering optical depth have maximum values on the spring1992, this may be the effects of Pinatubo volcanic eruption;(2) Aerosol scattering optical depth at other5 stations have Minimum values in autumn or winter, whereas it happens in summer in Lanzhou;(3) Aerosol scattering optical depth are large in winter in Lanzhou, Wulumuqi and Kashi, these may be the effects of geography and city industrialization.

• A Numerical Simulation of Optical Characteristics for Atmospheric Dust Aerosols in Northwest China
• CHENG Tian tao;SHEN Zhi bao
• 2001 Vol. 20 (3): 291-297. 
• Abstract ( ) PDF (289KB) ( )
• By using of the data of atmospheric turbidity and surface radiation observed at Zhangye(oasis) and Desert stations in HEIFE area during the period from the third decade of February to the second decade of May in1991, together with the data obtained from NOAA-11 satellite overpassing this area at the same time, we estimate single scattering albedo(ω ₀) and fraction of optical depth[ k(τ _λ=8~10/τ _λ=0.55)] of atmospheric dust aerosols, by employed the radiative model(CRM) in NCAR CCM3. The results show that ω ₀ and k(τ _λ=8~10/τ _λ=0.55) is 0.94 in desert and 0.1 in oasis in clear day respectively, but in dusty day(ω ₀) is 0.90 in oasis and 0.84 in desert, k(τ _λ=8~10/τ _λ=0.55) is 0.3 in oasis and 0.4 in desert. In the climatic model, for dust source region in northwest China,(ω ₀) and k(τ _λ=8~10/τ _λ=0.55) will be 0.88 and 0.3, respectively.

• Researches on Optical Properties of Atmospheric Aerosol in Helan Mountain Area
• NIU Sheng jie;SUN Ji ming
• 2001 Vol. 20 (3): 298-301. 
• Abstract ( ) PDF (240KB) ( )
• According to the observation data of spectrosolar radiation by means of M-120 sunphotometer, optical properties of atmospheric aerosol in Helan mountain area have been analysed, and also the variation rule of aerosol optical depth and Angstrom turbidity parameter β, even wave exponent α under different weather conditions have been discussed. In addition, the relationships between the number concentration of ground aerosol and Angstrom turbidity parameter β, partical diameter of aerosol and wave exponent α have also been discussed.

• Simulation of Influence of Climate Change on Water Resource over Luanhe River Valley Using a Hydrological Model(Ⅱ):Simulated Result Analyses
• FAN Guang-zhou;Lü Shi-hua;CHENG Guo-dong
• 2001 Vol. 20 (3): 302-310. 
• Abstract ( ) PDF (358KB) ( )
• The influence of the climate change on the water resource of the different season in rainy year and drought year over Luanhe river valley was studied by using the precipitation-runoff modeling system. The results show that the air temperature mostly effect the evaporation of Luanhe river valley. And the influence of precipitation on the evaporation is comparatively less. The change absolute value of evaporation in humid season is greater, and its change percentage in arid season is greater. But the surface runoff, subsurface runoff, ground water and runoff are mostly effected by precipitation. The temperature influence on them is comparative less. And it is more sensitive in humid season than in arid season.

• A Study about Urbanization Effect on the Indoor and Outdoor Air Temperature of City on Low-Latitude Plateau
• ZHANG Yi-ping;PENG Gui-fen;LI You-rong;LIU Yu-hong;MA You-xin;WANG Jin-xing
• 2001 Vol. 20 (3): 311-317. 
• Abstract ( ) PDF (286KB) ( )
• The data roots in theobservation of air temperature that have been effected by city expansion in Kunming city weather station and that haven't been effected by urbanization in Taihua mountain station. The results indicate that the average air temperature increased 0.5℃/30a or so due to the global climatic warming; with Kunming city area expanding, the indoor and outdoor air temperature will rises, the range ability of indoor air temperature go beyond outdoor, dry season exceeded rain season. However, whether dry season or rain season, the correlativity between effection of city temperature increasing and urban area and urban population is considerable. Urban area increased has considerable effect on the average air temperature; while urban population increased obviously affects average air temperature of indoor. With urban area increasing1 km ², the annual average indoor air temperature will rise 0.0054℃, annual average air temperature will rise 0.012℃. On the other hand, with urban population increasing10000, the annual average indoor air temperature will rise 0.0259℃, the annual average air temperature will rise 0.0098℃. This result will provide reference for studying fundamentals about urbanization effect on urban climate and city planning.

• Analysis on Characteristics of Interannual Variability of the South Asian Summer Monsoon
• WANG Ke-li;JIANG Hao;WU Hong
• 2001 Vol. 20 (3): 318-324. 
• Abstract ( ) PDF (371KB) ( )
• Characteristics of interannual variability of the South Asian summer monsoon are analyzed by using the NCEP-NCAR monthly mean reanalysis data from1958 to1997. The Results show that the zonal wind shear between850 and200 hPa represents the main characteristic of the South Asian summer monsoon activity, the summer monsoon duration is from June to September and the key region is in 0°~20°N,40°E~130°E. The analyses based on these show that unitary variation of the South Asian summer monsoon in the region is primary. The opposite variation of the west part from the east part, in which the line of demarcation appears about the80°E, is secondary and represents chiefly variation of the Southeast Asian summer monsoon in the east. Following above all, four main types are categorized. For the different types, precipitation rate patterns are obviously different.

• The Forming and Forecasting of Winter Snow-Disaster Weather in Easten Pastoral-Area of Qinghai-Xizang Plateau
• MA Lin;LI Xi-fu;ZHANG Qing-mei;ZHAO Chun-ning;MA Yuan-cang;WANG Wen-ying
• 2001 Vol. 20 (3): 325-331. 
• Abstract ( ) PDF (317KB) ( )
• The forming and forecasting analysis of winter snow disaster weather in the easten pastoral area of Qinghai-Xizang Plateau(1967-1996) has been made. The main conclusions are as follows:The forming of snow disaster weather situations over the Plateau is closely linked with the large-scale weather systems, e.g. the Arctic Ocean troughs, the Baikal lake low pressures, the deep troughs of East Asia and the South branch troughs. The two kinds of concept models are sumed up. The quantitative indexes of air unsteady-waving are mainly discussed in the Plateau, and some of the statistical relations of the low temperature and snowfall are found. Two actual examples of Yushu and Dari stations are provided that how snow disaster forecast are made. Finally, the constructive suggestions of winter snow-disaster forecast are presented in the area.

• The Vorticity, Heat, Moisture Budget Evolution of MCC over South China
• KANG Feng-qin;XIAO Wen-an
• 2001 Vol. 20 (3): 332-339. 
• Abstract ( ) PDF (332KB) ( )
• Using the technique of composite analysis, the MCC life-cycle of meso-α-scale convective complexes occurred over South China is divided into seven sub-periods, then the MCC vorticity, heat, moisture budget evolution are revealed in detail and the role of meso-scale and cumulus convection are stressed. The results are as follows:(1) It is an important factor that meso-scale and cumulus convective activity over the MCC life-cycle for vorticity residual term.(2) In the initial stages of the MCC life-cycle, meso-scale cumulus convection are active due to dissipating heat and water vapor and resulting in the apparent heat sink and the apparent moisture sink. In the mature stages, the meso-scale systems and cumulus convection are active due to the apparent heat source and the apparent moisture source which is the cause of MCC long life-cycle. In the later MCC life-cycle, due to the apparent heat sink and apparent moisture sink from the meso-scale systems and cumulus convection activities unfavorable large scale weather conditions, MCC is dissipating slowly.(3) Synoptic features control MCC genesis and growth, but once after MCC formed, the cumulus convection and mesoscale updrafts/downdrafts in the lower-and middle-troposphere have important role in MCC process. In the mature stages, the meso-scale systems and cumulus convection release heat and lead to MCC long-life. In the late stages of MCC, the large-scale weather condition is changed and also the meso-scale systems and cumulus convection elements are changed also, so the MCC is dissipating.(4) In the pre-MCC, the latent heat release is main heating factor. And after that time, the convective vertical transfer water vapor and heat is more important than the latent heat does.

• Analyses of Relationship between Anomalous Snow Cover over Qinghai-Xizang Plateau and Drought and Low Temperature Damage in Various Areas in Guizhou
• LUO Wen fang
• 2001 Vol. 20 (3): 340-344. 
• Abstract ( ) PDF (269KB) ( )
• The statistical relationship between anomalous snow cover over Qinghai-Xizang Plateau(QXP) and intensity of the drought and low temperature in spring-summer in various areas in Guizhou have been analysed by using of correlative data from1958 to1992. The results show that the correlation coefficient between anomalous snow cover over QXP and intensity of the drought and low temperature in spring-summer in various areas in Guizhou was found to be quite apparent. The drought in spring-summer in the various areas is stronger and the low temperature damage in spring is weak in Guizhou when the winter-spring snow cover over QXP is more than the average years.The drought in spring-summer in the various areas is slightly and the low temperature damage in spring is stronger in Guizhou when the winter-spring snow cover over QXP is less than the average years.