Current Issue

• Inprovement Study on Snow Scheme in LSM Scheme of NCAR CCM3 Model(Ⅱ): The GCM Simulation Experiment Analyses
• WU Tong-wen;QIAN Zheng-an;CAI Ying
• 2004 Vol. 23 (5): 569-579. 
• Abstract ( ) PDF (45KB) ( )
• To further test the simulation performance of the forementioned new LSM scheme, the snow scheme has been also incorporated into NCAR CCM3, a nearly two year integrals with the new LSM (hereafter NCCM3) and the old LSM snow scheme (OCCM3) have been run respectively, utilizing at 00GMT on December 16 as the initial time and the well-adjusted simulated atmospheric forcing, the soil tempetature and humidity, as well as the snow thickness at the time as the initial condition.The intercomparisons among the circulation, precipitation, and variety of snow variables simulated by NCCM3 and OCCM3 and observed show: (1) After introducing the new LSM snow scheme, the circulation, air temperature and SLP simulated by NCCM3 are somewhat better than those by OCCM3.(2) The snow mass and snow depth simulated by NCCM3 are a little larger than those by OCCM3.But the formers are closer to their observed values.The NCCM3 better simulate the main seasonal change features of the total snow mass over Eurasia, North America.The NCCM3 simulation also well reproduce well the February mean snow cover distribution features over Northern Hemisphere inthemostsnowy period, especially over North America.(3) In contrast to the OCCM3 simulation, the NCCM3 simulation also has better behavior in the surface temperature, surface sensible flux, and precipitation.

• Numerical Simulation of the Effect of Soil Drought on Short-Term Climate in North China
• WANG An-yu;FONG Soi-kun;TONG Tin-ngai;WU Chi-sheng;FANG Qi;MONG Wei-guang;HOU Er-pan;LI Jiang-nan
• 2004 Vol. 23 (5): 580-586. 
• Abstract ( ) PDF (629KB) ( )
• Using the PSU NCAR fifth-generation mesoscale model (MM5) couple with an advanced land surface model(OSULSM), a numerical experiment of the effect of the decreased soil moisture on the short-term climate have been performed in order to better understand the influence of soil drought on the short-term climate in North China.The results from the experiment indicate: With the decrease of the soil moisture, the monthly mean rainfall (MMR) of the whole experimental domain is only slightly changed.But it results in the large MMR negative anomalies for the large MMR regions and the small MMR positive anomalies for the middle and small MMR regions.This is because the decreased soil moisture may produce a large, shallow anomaly depression due to the increase of surface sensible heat flux and surface skin temperature and the decrease of surface latent heat flux for the continent region.This anomaly depression with anomaly ascent flow in the lower troposphere and anomaly descent flow in the middle troposphere weakens the intense precipitation systems and intensifies the weak systems.

• Observation Studies of Atmosphere Boundary Layer Characteristic over Dunhuang Gobi in Early Summer
• ZHANG Qiang;WEI Guo-an;HOU Ping
• 2004 Vol. 23 (5): 587-597. 
• Abstract ( ) PDF (407KB) ( )
• Using the sonding data of wind, temperature and humidity in Dunhuang meteorological station during the intensive period of "Land-atmosphere interaction field experiment over arid region of Northwest China from end of May to early June 2000, the structure characteristics and change laws of the atmosphere boundary layer over arid region of Dunhuang are analyzed.The results show that the mean value of the atmosphere boundary layer thickness is obviously more higher than usually.The biggest depth of the convective boundary layer exceeds 4000 m, the stable boundary layer depth is 1000 m or so.The turning height of wind direction is at about 3000 m high.The wind was blowing easterly in lower layers and west in upper layers.There is some diurnal variation in the turning height, and the diurnal variation of all nine days is mainly identical.The velocity shear is the bigger in boundary layer.In most time the low-level east jet appears, its intensity is close to 20 m·s ^-1 and its height is about 500 m.The humidity inversion is below about 500 m and it appears mainly in the evening.

• Statistical Characteristics of Atmospheric Turbulence in Different Underlying Surface Conditions
• ZHANG Hong-sheng;LI Fu-yu;CHEN Jia-yi
• 2004 Vol. 23 (5): 598-604. 
• Abstract ( ) PDF (525KB) ( )
• A comprehensive study of integral statistics characteristics of atmospheric turbulence in the Gobi desert, grassland, and suburban and urban, outskirts of underlying surface conditions have been carried out.The turbulent data are collected by the same personnel, sound instrumentation, turbulent data acquisition system and turbulent processing system.The results shown that the normalized standard deviation of μ and v over rolling terrain is systematical smaller, in spite of the surface roughness the normalized standard deviation of w and temperature θ, humidity q are very close between each other.It is interesting, that the curves of the normalized temperature and humidity standard deviation vs. z/L are overlapping with each other in humid region.The humidity characteristics are similar with temperature in humid region.

• An Integral Calculation for Application to Estimation of Heterogeneous Surface Flux
• WANG Ji-jun;LIU Jing-miao;DING Yu-guo
• 2004 Vol. 23 (5): 605-611. 
• Abstract ( ) PDF (303KB) ( )
• On the basis of reference, the calculated scheme of soil moisture flux presented by Giorgi(1996) is further spread to be the simplified form of asymmetrical distribution, so as to obtained the mean flux of heterogeneous surface region.Taking the degree of soil moisture saturation for example, it is solved for the analytical solution of mathematics about regional mean value of soil moisture flux.Asymmetrical simplified probability density function (PDF) distribution is studied, and the cases for calculations of soil moisture flux over the heterogeneous land surface are verified by using the simplified PDF.

• Modeling Sulfate Aerosol and Its Radiative Forcing over China
• GAO Li-jie;WANG Ti-jian;XU Yong-fu;MIN Jin-zhong
• 2004 Vol. 23 (5): 612-619. 
• Abstract ( ) PDF (291KB) ( )
• Based on SO ₂ emission data of China in 2000, the meso-scale meteorological model and Eulerian transport model were applied to simulate the distribution of sulphate aerosol.The direct and indirect radiative forcing of sulphate aerosol were further estimated.The results show that the column concentrations of sulfate aerosol have significant spatial and seasonal variations.The sulfate aerosol is mainly distributed over Central, East and Southwest China, so do the direct and indirect radiative forcing.The direct forcing is strong in winter and spring, and weak in summer and autumn.The annual mean value reaches -0.71 W·m ^-2.For indirect forcing, it is strong in summer and autumn and weak in winter and spring.The annual mean value is -0.48 W·m ^-2.

• Numerical Simulation of High Resolution PBL Scheme in An η Model and Its Influence on Precipitation
• WANG Kang-kang;ZHANG Wei-huan;QIN Kai-bing
• 2004 Vol. 23 (5): 620-628. 
• Abstract ( ) PDF (456KB) ( )
• Using the 16-layer mesoscale ETA model with defferent interval layers, the high resolution PBL scheme is introduced into this paper, and the vertical layer numbers have been increased to 21.Experiments show that the improved model can simulate the daily variation and the structure of the boundary layer more finely.The numerical simulation of heavy rain shows that the improved model to TS grade of precipitation is obviously higher than the former model, especially in the TS grade of heavy rain.The mechanism about PBL process influencing on heavy rain is simply discussed.The numerical experiments show that the integrating of surface flux formed horizontal transfer of lower tropospheric jet is one main reason of the severe precipitation with shear line or quasi-stationary front in summer.

• The Role of Upper and Lower Tropospheric Jet in Yunnan Rainstorm Occurrence and Their Common Characteristics
• HE Hua;SUN Ji-hua
• 2004 Vol. 23 (5): 629-634. 
• Abstract ( ) PDF (383KB) ( )
• Through classification of 46 times heavy rain occurred in Yunnan province during the period of 1980_1990, it is found that the main impact systems of Yunnan rainstorm were resulted using the reanalysis data of NCEP/NCAR from 1989_1991, we discussed 11 times province wide cold front-shear line type rainstorm cases which most occurred in Yunnan by means of composite analysis.The results indicated the development characteristics of the atmosphere circulation, upper and lower jet or high wind line in troposphere before and after large-scale rainstorm occurred in Yunnan with cold front-shear line type circulation, the relationship between the development characteristics and the large-scale rainstorm, their commonness were found out in this work, we summarized the strong signal resulted in rainstorm in Yunnan for heavy rain storm forecast.

• Application of TRMM Precipitation Radar Data to Meso-Scale Model MM5
• XU Zhi-fang;GE Wen-zhong;DANG Ren-qing;LANG Xu-xing;Toshio Iguchi
• 2004 Vol. 23 (5): 635-642. 
• Abstract ( ) PDF (345KB) ( )
• Numerical simulations of two heavy rain cases in the Changjiang-Huaihe river basin have been carried out with TRMM/PR (Tropical Rainfall Measuring Mission/Precipitation Radar) data incorporating into the PSU/NCAR meso-scale model MM5.First, rainwater mixing ratio qr is obtained from different Z-qr relations variating with height.Then, while specific humidity q'v in the model is replace with qv, where q'v= qv+ qr.Based on the above idea, TRMM/PR data is used to modify humidity obtained by conventional radiosound data.Simulation are performed and compared with the control run.The results show that both the heavy rainfall distribution and its heavy rain core amounts in sensitivity run are better than in control one.

• Spectrum Characteristic Analysis of Dust Storm and Dust Identified Using NOAA Satellites Data
• GUO Ni;Qing Ji-zu
• 2004 Vol. 23 (5): 643-647. 
• Abstract ( ) PDF (411KB) ( )
• Spectrum characteristics of several regions such as dust storm, cloud, desert, Gebi desert, snow, soil and vegetation were analyzed using NOAA/AVHRR data during the years from 2000 to 2002.The characteristics of dust storm in NOAA/AVHRR-2 are that: The reflectances of channel 1 and 2 are higher than the desert and lower than the clouds;the brightness temperature of channel 4 and 5 are lower than the regions in where are clear, and higher than clouds.The brightness temperature of dust storm in channel 3 is unusual, the temperature is the highest in all of the regions.It is show that there is more trace of dust in channel 3.It is disadvantage to monitor dust storm when AVHRR-2 have been replaced by AVHRR-3.Two dust identified indexes, which identify dust quantificational from AVHRR, were put forward.The dust had been identified successfully in many dust storm cases using the dust identified indexes.The results show that dust storm could be identified effectively by the dust identified indexes which are composed of multi-channel value.

• Calculation of Dust Emission by Wind Erosion in Dunhuang Gobi Surface
• SHEN Yan-bo;SHEN Zhi-bao;DU Ming-yuan;WANG Wan-fu
• 2004 Vol. 23 (5): 648-653. 
• Abstract ( ) PDF (683KB) ( )
• Using the observational data of Dunhuang, the dust emission (vertical dust flux) by wind erosion in Gobi surface on April 8, 2002 is calculated through three different schemes in this paper.The results indicate that the values of three schemes are very approximate, and the magnitude of downwind sand flux and vertical dust flux are m ^-4kg·m~(-1)·s ^-1and m ^-8kg·m ^-2·s ^-1 respectively when it is serious dusty weather.Comparing with the calculated and observed results and the physical mechanism of dust emission by wind erosion, the strongpoints and limitations of the three schemes are discussed.

• The Spectrum Distributions of Dust Aerosol over Tengger Desert Retrieved by Extinction Method
• XIN Jin-yuan;ZHANG Wen-yu;YUAN Jiu-yi;LIU Li-chao
• 2004 Vol. 23 (5): 654-659. 
• Abstract ( ) PDF (263KB) ( )
• The optical remote sensing observation of the atmosphere aerosol over Tengger Desert from April to September are analyzed.The results show that the extinction factor isn't very sensitive to extinction effect of huge dust particle, so that extinction method just retrieve better the spectrum distribution characteristics of aerosols ranging from 0.1 to 5 μm, especial the result of retrieve (0.1< r< 1 μm).The aerosol size distribution was very similar to a Junge distribution.The spectrum distribution in the dust weather was quite different from that of in the clean weather.In the dust weather, big dust particles (0.1< r< 1.0 μm) and huge dust particles ( r >1.0 μm) remarkably increased, and its aerosol number concentration was larger than several magnitude that of in the clean weather in quantum.In the clean weather, the aerosol size distribution over Tengger Desert was steady, consistent and similar to a Junge distribution, huge dust particle ( r >1.0 μm) concentration was very little, and there was an obvious peak value in the size distribution (0.4< r< 1.0 μm).

• Tendency and Interdecadal Changes of Spring Dust Storm in China
• DING Rui-qiang;WANG Shi-gong;SHANG Ke-zheng;YANG De-bao
• 2004 Vol. 23 (5): 660-666. 
• Abstract ( ) PDF (258KB) ( )
• Singular spectrum analysis was used to study the trend and period of spring dust storm in seven regions in china where dust storm occurred frequently from 1960 to 2000.The results were as follows: From the beginning of 1960s, the dust storm days in spring appear a downward trend in six regions, except for North Xinjiang region, that is, the dust storm days were more in 1960s and 1970s, but less in 1980s, and the least in 1990s.This might respond to abrupt change of atmospheric circulation in the late 1970s.Its quasi-period for Tibetan region was 7.7 years, in other six regions there were main quasi-biennial and 5~6 years periods.

• Spatial and Temporal Distributions of NO _X Produced by Lightning in East Asian Region
• ZHOU Yun-jun;QIE Xiu-shu;YUAN Tie
• 2004 Vol. 23 (5): 667-672. 
• Abstract ( ) PDF (283KB) ( )
• The spatial and temporal distributions of NO _X produced by lightning(LNO _X) in East Asia Region have been analyzed by using satellite-based lightning data of NASA.The results show that the average annual total production of LNO _X in East Asia is about 2.30 Tg.Seven peak value centers are found to be within the 3 peak value groups which are located in south, middle, and north.The maximum values for the three groups are 16.4, 12.7, and 5.46 Bg/grid/yr, respectively.Compared with the total NO(X) emissions excluded lightning, it is found that the LNO _X distributes in larger regions, although its annual production value is only 23% of total NO _X emissions excluded lightning.The production of LNO _Xin summer is the highest.The regional characteristics of LNO _Xare obvious.The numerous lightning activity in some geographical location with special topography characteristics in middle latitude area contributegreatly to the total NO(X) production, in particularly in the boundary area of India and south of Chinese Tibet.The difference of the ground surface features is one of the major reasons for the inhomogeneous distribution of LNO _X in longitude.The increase contribution of LNO _X in the months corresponding to the climatic transition between warm and cold season is remarkable.The monthly LNO _X is characterized by a year cycle with two peaks structure.

• Temporal and Spatial Distributions of Lightning Activities along Qinghai-Xizang Railway
• ZHANG Ting-long;QIE Xiu-shu;YUAN Tie;ZHANG Tong
• 2004 Vol. 23 (5): 673-677. 
• Abstract ( ) PDF (293KB) ( )
• The temporal and spatial distributions of lightning activities along the Qinghai-Xizang railway are analyzed by using 8-year satellite-based data.The result indicates that the lightning activity along the Qinghai-Xizang railway hasobvious seasonal and diurnal variations.The lightning activities mainly occur from April to September, but disappear in October, and the most active month for different places is from May to July.The diurnal variationof lightning activities shows that the lightning along the Qinghai-Xizang railway more frequently occur between 12:00~16:00 (local time).The value of the flash density is the highest in Naqu, and decreases gradually southward and northward along the Qinghai-Xizang railway.In addition, the data analysis result from ground-based observation indicates the lightning activities showing a sencond peak at 19:00 in Naqu.

• The Effect of Environment Temperature and Humidity Stratification on Charge Structure in Thunderstorms
• GUO Feng-xia;ZHANG Yi-jun;YAN Mu-hong;DONG Wan-sheng
• 2004 Vol. 23 (5): 678-683. 
• Abstract ( ) PDF (231KB) ( )
• The reversal temperature affect charge structure in non-inductive electrification mechanism and it is a function of LWC (liquid water content).LWC depends on the arrangement of average relatively humidity and convective instability in initial field.In order to get different initial fields, we change the average relatively humidity of middle atmosphere and CAPE (convective available potential energy) and the instability factors of K and SI change together.Using 3D dynamics-electrification coupled model, the influence of temperature and humidity stratification on charge structure were researched.The results indicate that the electrical action is weak and charge structure is quasi reverted dipole and no relation to middle atmosphere average relation humidity when CAPE is small.When CAPE is big, bigger or smaller, the average humidity will induce strong electrical action and dipole charge structure.When the coexistent region between graupel and ice is out of updraft, it can form reverted dipole structure.On the same CAPE, increasing the middle average relative humidity will help convection development and form dipole structure and decreasing the average relative humidity will tend to form weak convection quasi reverted dipole structure.

• Analyses on Boundary Layer Characteristics and Catalysis Conditions of Silver Iodide on Ground in Upper Reach of Yellow River in Summer
• ZHANG Guo-qing;ZHANG Jia-kun;Deligeer
• 2004 Vol. 23 (5): 684-688. 
• Abstract ( ) PDF (266KB) ( )
• Based on the observed data of boundary layer at Waisi station of Henan county in the upper reach of Yellow River in July 1998, the distribution and changes of boundary layer wind field, wind shear and the development of low-level inversion are analyzed, the distribution of updraft at 10 m above the ground and change of turbulent diffusion are discussed as well.At last, we summed up the condition and opportunity of inflaming catalysis of silver iodide incinerator.

• Vapour Analysis of A Heavy Rain in West of China in Autumn
• YU Shu-hua
• 2004 Vol. 23 (5): 689-696. 
• Abstract ( ) PDF (218KB) ( )
• The vapour of the heavy rain process in the west of Sichuan Basin on 15~17 september 1998 was analysed.Some resluts are obtained as follows: (1) During the heavy rain, the main vapour source in lower level of troposphere is in South China sea, and secondly East China sea and Bay of Bengal.The vapour transportation in middle and upper parts of troposphere is transferred from Indian Ocean to Qinghai-Xizang Plateau and then extend to Sichun Basin.(2) The heavy rain happened under the condition of stronger vapour convergence in lower level of troposphere and thicker vapour layer from lower level to middle and upper parts of troposphere.(3) The heavy rain change is nearly connection with vapour transportation is transferred from Indian Ocean to Qinghai-Xizang Plateau in middle and upper parts of troposphere.The vapour transportation has indicative significance for heavy rain development.

• Characteristics of Internal Wall Surface Temperature with South-North Orientations in Urban Area
• HE Yun-ling;ZHANG Yi-ping;LIU Yu-hong;MA You-xin;LI You-rong;DOU Jun-xia;GUO Ping
• 2004 Vol. 23 (5): 697-703. 
• Abstract ( ) PDF (399KB) ( )
• The internal wall surface temperatures (Tws) in April, August and December in Kunming, a city located in low latitude plateau, were investigated.Results showed that internal Tws have different temporal and seasonal variations for different orientations houses.Internal Tws in April were of the highest, then August and December.Internal Tws differences among walls with different orientations were higher in December, and lower in April and August.For the south house, internal Tws is the highest on S-wall at night and is the lowest on E-wall in the daytime in December, but it is the highest on E-wall at night and is the lowest on S-wall in the daytime in April and August.For the north house, internal Tws is the highest on E-wall at night and is the lowest on N-wall in the daytime in December, April and August.The results can serve as a basis for further research on building microclimate and urban architecture designs.It gives also suggestions for similar studies in other area.

• Study on Climate Change in Southeast Guizhou in Recent 40 Years
• CHI Zai-xiang;BAI Hui
• 2004 Vol. 23 (5): 704-708. 
• Abstract ( ) PDF (325KB) ( )
• Based on the data of mean air temperature, total cloud cover, pressure, water-vapour pressure, ten-day precipitation and heavy rain from 18 stations in 1961_2000, the climate changes and their characteristics in Southeast Guizhou Province in recent 40 years, especially recent 10 years were comprehensively analyzed and studied.The results show that the precipitation in Southeast Guizhou in recent 40 years is increasing (6.75 mm/10a), and the temperature is dereasing (-0.25℃/10a).

• Effects of Micro-Terrain in Nanling Mountains on Fog Intension over Leeward Slopes
• WAN Qi-lin;WU Dui;YE Yan-qiang
• 2004 Vol. 23 (5): 709-713. 
• Abstract ( ) PDF (221KB) ( )
• The climatic character of 31-year fog in Lechang and Ruyuan is statistically analyzed.The results show that the fog is considerably influenced by local micro-topography, and the day numbers of lee fog occurrence obviously increase.At the same time, by means of CSU-RAMS model, the effect of local micro-topography on lee side fog is further studied.The simulated results show that the dynamic function of micro-topography to lee side fog has important action, and the forming and developing of the lee side fog are to gain some dynamic profits from local micro-topography.

• How to Succeed in the Short-Term Climate Prediction
• TANG Mao-cang;LI Dong-liang;ZHANG Yong-jun
• 2004 Vol. 23 (5): 714-717. 
• Abstract ( ) PDF (252KB) ( )
• In the past 100 years, the weather forecast has passed three successful stages: Norway school, Rossby school and numerical model stage by Charney.But because the guidance thought that climate is the synthesization of weather is wrong, the short-term climate prediction is not so successful yet in the past 100 years.However there are also three stages, just followed each weather forecast stages: Grosswetterlage stage, ultra-long wave one and numerical climatic model one.The author proposed that the first successful stage of short-term climate prediction should materialized the climate system.The geothermal vortex etc may be the materialized climate system and the prediction map describing the ground temperature distribution may be equivalent to the weather map.

• The Variation and Relation of 500 hPa Height Field in China-Mongolia and Surface Temperature of North China in Winter in Recent 50 Years
• YAN Hua-sheng;WAN Yun-xia;LI Shao-juan
• 2004 Vol. 23 (5): 718-722. 
• Abstract ( ) PDF (176KB) ( )
• By analyzing the variations of 500 hPa height field and monthly mean surface air temperature of 160 stations in China, the reasons that winter surface air temperature appearing interdecadal change in North China are discussed.The results are as following: a) It is shown that the temperature in North China had positive trend and interdecadal change in winter.b) The positive trend of height of China and Mongolia was corresponding to the strong zonal circulation, weak meridional circulation and weak cold air activities;c) It is shown that the winter temperature in North China during the period of the past 51 years were closely related to the positive trend of 500 hPa height field in China and Mongolia.

• Variations and Trends of Temperature and Precipitation in the Mountain Drainage Basin of the Heihe River in Recent 50 Years
• LAN Yong-chao;DING Yong-jian;KANG Er-si
• 2004 Vol. 23 (5): 723-727. 
• Abstract ( ) PDF (248KB) ( )
• Based on precipitation observational data at the weather stations in the mountain drainage basin of the Heihe River and historical material and tree growth ring record in the recent 50 years, the variation characteristics, possible causes and trends on the multi-yearly mean precipitation in the region are analyzed.The results show the response of the precipitation in the region to global climate warming is obvious, so the precipitation in the region presents a little increasing trend.Because the subtropical high of west Pacific is closly related to the global air temperature change, and the strengthening and expanding of subtropical high of west Pacific is of advantage for East Asian summer monoon moving forward to north or even more, which will bring on the increase of precipitation in the mid-and-west parts of the Qilian mountain.Therefore, as a whole, the global climate warming is favourable for the increase of precipitation in the mountain drainage basin of Heihe river.The climate of the mountain drainage basin of the Heihe River is just in the fifth warm periods or the third warm-humid periods in the histrial data records at present and it began from 1980's.We forecast that the precipitation in the mountain drainage basin of Heihe river with the further warming of the global climate will continously maintain the slow increase in the future some years.

• Study on Characteristics of Atmospheric Boundary Layer over Naqu Region of Northern Tibetan Plateau
• LI Mao-shan;MA Yao-ming;HU Ze-yong;MA Wei-qiang;WANG Jie-min;OGINO Shin-ya
• 2004 Vol. 23 (5): 728-733. 
• Abstract ( ) PDF (219KB) ( )
• Using the observed data in the PIOP (pre-intensive observing period) of CAMP/Tibet (coordinated enhensive observation period (CEOP) Asian-Australian Monsoon Project (CAMP) in the Tibetan Plateau), the characteristics of daily change of equivalent potential temperature, specific humidity and wind speed, as well as that of the steady and convective boundary layers over Naqu region of northern Tibetan Plateau were analyzed.The results showed that the daily change of boundary layer over Naqu region of northern Tibetan Plateau is significant, the height of convective mixed layer can reach 1800 m, and time forming converctive boundary layer in rain day is later than that in cloudy and fine days.