Current Issue

• SOME ACHIEVEMENTS IN SCIENTIFIC RESEARCH DURING HEIFE
• Hu Yinqiao;Gao Youxi;Wang Jiemin;Ji Guoliang;Shen Zhibao;Cheng Linsheng;Cheng Jiayi;Li Shouqian
• 1994 Vol. 13 (3): 225-236. 
• Abstract ( ) PDF (428KB) ( )
• In this paper, the conditions of carrying out HEIFE are reviewed and the main achievements in scientific research are sumed up Through analysis, the results for the surface parameters of land surface process, characteristics of surface energy budget and the parameterization of turbulent flux are gained as well as the difference of physical mechanism of land sarface process between the arid and humid region are also gained These results bring to light the complete pictuse for the interaction between oasis and desert enviroment.

• THE NATURE GEOGRAPHY STATE AND CLIMATE BACKGROUND IN THE HEIHE EXPERIMENTAL REGION
• Tang Maocang;Zheng Guang
• 1994 Vol. 13 (3): 237-245. 
• Abstract ( ) PDF (329KB) ( )
• By using the climatic data more than 40 years, an analysis of mean streamline field, pressure pattern, precipitation field and the daily variation of climate in summer and winter over this rigion have been made It pointed out:this region was the rise of the two turbulent wake zones which were formed by the planetary west wind flowed around and flowed up over the Qinghai-Xizang Plateau The late 40-year climatic change of the region might be divided into two phases(time intervals), i. e. "warm-high flow year" and "cold-low flow year", the former coincided with the phase of more earthquake, the earth rotation accelerated motion and the phase of temperature and precipitation appeared positive correlation, that is to say these four events were agreeable;the latter, on the contrary 1992 might be the end of the late "warm-high flow year", the "cold-low flow year" phase will begin very soon and will last ten years at least A detail analysis of the data of each meteorological observing station has been done during the duration of FOP (Aug 1990 to the end of 1991) It showed that the macroclimate was characterized by warm and dry climate in this region during the duration of FOP, but various daily variations phenomena were the same as secular mean conditions At last, the weather situation background of several heavy rain and heavy snow has been described briefly during the duration of FOP.

• SEASONAL VARIATION OF MICROCLIMATIC CHARACTERISTICS FOR OASIS AND GOBI IN HEIFE AND THEIR COMPARATIVE ANALYSIS
• Zuo Hongchao;Hu Yinqiao
• 1994 Vol. 13 (3): 246-256. 
• Abstract ( ) PDF (457KB) ( )
• In this paper, the microclimatic characteristics and their seasonal variation over Oasis and Gobi are analysed and compared by the data observed in HEIFE The results show that: (1) There are local wind and local influence in HEIFE area (2) In summer, the microclimatic characteristics over Oasis and Gobi are obviously different Some internal boundary layer phenomena observed over Oasis and Gobi There are a "cold island effect" over Oasis, and an"inverse humidity" over Gobi near Oasis in clear daytime The latent heat flux is dominant in energy balance in the surface layer in Oasis, but the sensible heat flux is dominant in Gobi (3) In winter, the microclimatic characteristics over Oasis and Gobi are almost same The sensible heat flux is dominant in energy balance in the surface layer both in Oasis and Gobi.

• ESTIMATION OF SURFACE DRAG COEFFICIENTS IN HEIHE REGION AND NUMERICAL EXPERIMENTS OF THEIR INFLUENCES
• Zhang Lisheng;Qian Zhengan;Chen Bomin
• 1994 Vol. 13 (3): 257-265. 
• Abstract ( ) PDF (321KB) ( )
• In this paper, firstly based on the hourly surface tower-stat observation data of Gobi and Desert covering 12-, 6-days respectively during the period of the Field Experiment on land-air interaction in Heihe region (HEIFE), and the results of sensible heat and friction velocity got by Hu's, the dtag coefficients of surface fluces in Heihe region are estimtaed by using inversion-calcuation method.Then the numerical expriments about the influences of boundary proesses on short-range weather prdiction have been carried out. The rsults show:the drag coefficients in Heihe region have a obvious daily variation;the daily mean values of drag coefficients estimated in Gobi and Desert underlying surface in Heihe region are fundamentally reasonable;except for over certain especially sensitive or prevailed local influence region, the boundary processes only have a little influencees on the short-range westher presses.

• THE INFLUENCE OF ATMOSPHERIC AND SURFACE PROPERTIES ON RADIATIVE HEATING FIELD IN THE ARID AREA
• Yang Wen;Ji Guoliang
• 1994 Vol. 13 (3): 266-273. 
• Abstract ( ) PDF (293KB) ( )
• A parameterized radiation and cloud model developed by the University of Utah U S A has been used to compute the atmospheric radiative properties in Zhangye area in January, April, August and October, 1991 during HEIFE period For cloudless atmosphere, the effects of atmospheric condition, surface albedo and emissivity on the solar radiation budget, solar heating and IR cooling rates of the earth-atmosphere system are discussed;the properties of atmospheric reflection, transmission and absorption in different seasons are revealed, respectively;in order to recognize the influence of atmosphere on radiation, the contribution of main absorbers to solar heating and IR cooling rates is analysed At the same time, the influence of the vertical layers in the model on the solar heating and IR cooling rates is also discussed simply.

• A NUMERICAL SIMULATION EXPERIMENT FOR THE GROWTH OF MIXED-LAYER DEPTH
• Pan Tao;Hu Yinqiao;Niu Guoyao
• 1994 Vol. 13 (3): 274-281. 
• Abstract ( ) PDF (353KB) ( )
• A numerical simulation experiment for the growth of Mixed-Layer depth was taken on In the numerical simulation experiment, the data collected in Gobi area of the HEIFE and a zero-order jump model that was governed by the thermodynamic and dynamic forcing on the ground surface and the effect of the downdraft are used The results show that the growth of Mixed-Layer depth was retained by the cold downdraft from Qilian Mountain, and the time of the maxmum Mixed-Layer depth is early, but the simulation height is agreed with the height got by echo intensity of Doppler Sodar.

• NEAR SURFACE LAYER EXPERIMENT AT FARAWAY OASIS DESERT STATION
• Nai Kang;Hu Yinqiao
• 1994 Vol. 13 (3): 282-290. 
• Abstract ( ) PDF (307KB) ( )
• Through comparison of the near surface data observed at two desert stations, which one is faraway oasis and the other is near oasis, we find that, the inverse specific humidity profile in the near oasis area is mainly interferened by oasis The energy exchange between earth and atmosphere is controled by sensible heat flux, it can be ignored the latent heat flux The sensible heat flux at faraway oasis desert station is closely to the one's at near oasis desert station The energy budget of Gobi or Desert in HEIFE can basically represent the characteristic of arid region.

• ATMOSPHERIC TURBULENCE STRUCTURE IN THE SURFACE LAYER OVER THE OASIS FOREST SHELTER-BELT AND THE GOBI DESERT AREAS
• Zhang Aichen;Chen Jiayi;Lin Xuelan;Cui Yan
• 1994 Vol. 13 (3): 291-298. 
• Abstract ( ) PDF (282KB) ( )
• The paper analyses two sets of the turbulence structure data, which collected from the Oasis forest shelter-belt and Gobi desert areas near the Linze County The instruments were installed at the height of 40 m over the Oasis, and 7.8 m over the Gobi Through the intercomparison between these two sets of the data, following interesting results have been shown: (1) Under the close stability conditions, the spectral curves over the Oasis attenuate faster than the Gobi's at low frequency portion (2) The values of φ _ε over the forest shelter-belt are smaller than the Gobi's, it approximates to 0.5 under the neutral condition If the flux divergence term and pressure term are neglected from the turbulent kinetic energy equation, we could write as φ _ε= φ _m- Z/ L. The results over the Gobi show a good fitting with the formula If we take half of the ordinary φ _m values under the various Z/ L, the estimated φ _ε shows a reliable fitting with above formula, except the extreme stable and extreme unstable conditions.

• SOME CHARACTERISTICS OF STRUCTURE OF PLANETARY BOUNDARY LAYER OVER HEIFE AREA
• Wang Junqin;Hu Yinqiao;Chen Jiayi;Zhang Aichen;Wang Qiang
• 1994 Vol. 13 (3): 299-306. 
• Abstract ( ) PDF (314KB) ( )
• The observations about the structure of planetary boundary layer over three kinds of underlying surface (Oasis, Gobi, Desert) in HEIFE area are carried out on Aug and Oct 1991 The results show, the temperature of the oasis surrounded by wide Gobi and Desert is obviously lower than that of enviroment and humidity of oasis is higher than that of the enviroment in the boundary layer under 200 300 m on whole day The "cold island effect" is so obvious and its affection altitude can get to 200 m The characteristic of diurnal variation of wind is evident in HEIFE area.

• THE MEAN MOISTURE TRANSFERING IN AIR OVER NORTHWEST ARID REGION
• Gao Xiaoqing
• 1994 Vol. 13 (3): 307-313. 
• Abstract ( ) PDF (254KB) ( )
• The moisture transfering in air over northwest arid area was analyzed in this paper The results show that: (1) on an average, the maximum moisture transfering is at 600 700 hPa, but a few are near the ground for local effect in this area (2) The moisture transfering in summer is twice that in winter in this area (3) The loss of moisture in air in this region is supplied by evaporation of surface run off flowing in this region.

• THE RADIATIVE ENERGY BUDGET ON THE GROUND SURFACE OVER DESERT AND OASIS IN HEIFE AREA
• Shen Zhibao;Zou Jiling
• 1994 Vol. 13 (3): 314-322. 
• Abstract ( ) PDF (313KB) ( )
• The characteristics of the surface radiation balance over desert and oasis in HEIFE area were analysed and compared by using the data observed at Desert and Zhangye stations.The results show that ground surface plays an important role on surface radiative energy budget, the non-uniform ground surface leads up to remarkable special variation of surface net radiation in HEIFE atea.Under clear-sky condition, the incoming short-wave and long-wave radiations are nearly equal and have the same diurnal variations over desert and oasis in summer and winter.In summer the differences of net radiation between desert and oasis are caused by the differences of surface albedo and upward long-wave radiation determined by the ground surface and their thermodynamic natures, but in winter the thermodynamic cinditions of ground surface in HEIFE area are nearly the same, so the difference of the surface net radiation betweem desert and oasis is caused by the difference of albedo.Finally, the method for calculating surface net radiation over whole HEIFE area, and the effects of the difference of net radiation between desert and oasis on the micro-climate in HEIFE area are discussed.

• THE SEASONAL VARIATION OF SOLAR RADIATION BUDGET OVER OASES AND DESERT IN ARID REGION
• Ji Guoliang;Zou Jiling
• 1994 Vol. 13 (3): 323-329. 
• Abstract ( ) PDF (314KB) ( )
• In this paper, the characteristics of seasonal variation of solar radiation budget over two types underlying surface are analysed by using the data observed in oases(Zhangye) and desert in HEIFE in 1991 The results show that: in HEIFE region, the surface albedo is smaller in oases than in desert and its seasonal variation is obvious The effective radiation is also smaller in oases than in desert, its seasonal variation is obvious in desert and is not obvious in oases The surface net radiation is larger in oases than in desert and the surface heating fields act as a heat source whether in oases or desert for whole year.

• THE ATMOSPHERIC TURBIDITY AND THE INFLUENCE OF THE DUST ATMOSPHERE ON THE SURFACE RADIATION BALANCE IN DESERT IN REGION SPRING
• Shen Zhibao;Wen Jun
• 1994 Vol. 13 (3): 330-338. 
• Abstract ( ) PDF (314KB) ( )
• By using of the observed data at desert station of HFIFE in 1991, the characteristics of the atmospheric turbidity and the effect of the dust atmosphere on the surface radiative energy budget over desert region of Heihe River basin in spring were analysed In spring (March May), the mean atmospheric turbidity is high affected by the dust storm Most of the dust caused by the dust storm are held in the atmosphere for a long time About one week after dust storm the atmospheric turbidity return to normal The size distribution of the atmospheric dust is identical with Junge distribution The optical depth of the atmospheric dust is high and has good relationship with the atmospheric turbidity coefficient In case of very turbid condition the global radiation decreases, the incoming IR radiation decerases, the outgoing IR radiation decerases in the daytime and increases in the night, for the surface radiative energy budget, the net gain of the radiative energy on the ground surface decreases in the daytime, and the net lose of it decreases in the night.

• A PRELIMINARY ANALYSIS OF THE ATMOSPHERIC TURBIDITY OVER HEIFE REGION
• Wen Jun;Ji Guoliang;Lü Lanzhi
• 1994 Vol. 13 (3): 339-345. 
• Abstract ( ) PDF (253KB) ( )
• In this paper, the atmospheric turbidity characteristics at Linze, Zhangye and Desert stations have been analyed by using the atmospheric turbidity data observed by the MS-120 Sunphotometer in HEIFE in 1991 The diural variation, the inter-monthly variation and the frequency-distribution of the atmospheric turbidity are discussed.

• THE SOLAR ULTRAVIOLET RADIATION OVER OASIS REGION IN HEIFE
• Jiang Hao;Ji Guoliang;Lü Lanzhi
• 1994 Vol. 13 (3): 346-352. 
• Abstract ( ) PDF (255KB) ( )
• In this paper, the climatic characteristics of solar ultraviolet radiation over oasis region in HEIFE are analyed on the basis of the solar UV radiation data observed over Zhangye and Linze stations in HEIFE from Oct.1990 to Oct.1992.The results are as following:(1) The annual mean daily total of UV over oasis region in HEIFE is abour 0.48 MJ/m ², less than that over Qinghai-Xizang Plateau region and about half of that over Lhasa rehion.(2) The ratio of the UV to global radiation is littler than other tegion, the annual mean value is about 3%, there is two step change in annual variation caused by vapor and aerosol.(3) The reationship between the UV and global radiation in daily total is better than that in instantaneous value.(4) There is aregular variation of the tatio of the instantaneous UV to global radiation when global radiaion is strong, but the variation trend are different in summer and winter when global radiation is weak.(5) The ratio of the UV to global radiation is a quadratic function of daily total of global radiation.

• THE RADIATION BALANCE OBSERVATION DURING THE GROWING STAGES OF SPRING WHEATIN ZHANGYE AREA
• Zou Jiling;Ji Guoliang;Hou Xuhong
• 1994 Vol. 13 (3): 353-358. 
• Abstract ( ) PDF (270KB) ( )
• In this paper, the radiation balance properties during the different growing stages of spring wheat are analysed by using the observational data of radiation balance in Zhangye area from April to July 1991 in HEIFE The preliminaly results show: the albedos in spring wheat field are relatively stable in the whole growing stages, and the value range is between 15% and 19% The ratio of effective radiation to global radiation decreases rapidly along with the growing of wheat, and the range is between 33% and 17% On the contrary, the ratio of net radiation to global radiation increases along with the growing of wheat, and the ratio increases from 50% to 68%.

• THE INFLUENCE OF ENVIRONMENTAL FACTORS ON PHOTOSYNTHESIS AND TRANSPIRATION IN SPRING WHEAT FIELD OF HEIHE AREA
• Jia Li;Wang Jiemin;Liu Wei
• 1994 Vol. 13 (3): 359-368. 
• Abstract ( ) PDF (338KB) ( )
• The data measured by a LI-6200 portable photosynthetic system during the Biometeorological Intensive Observation Period (BIOP) of HEIFE in 1992 are used to study the influence of environmental factors on stomatal conduotance, photosynthetic rate and transpiration intensity of spring wheat in the arid Heihe River Basin The results show that photosynthetic rate and transpiration intensity are closely related to main environmental factors such as solar radiation, ambient temperature, vapour pressure deficit and soil moisture Meanwhile, a semi-empirical model, which describes the influence of photosynthetically active radiation, ambient temperature and vapour pressure deficit on stomatal conduatance, is developed in the light of Jarvis theory Furthermore, a funation evaluating single lear transpiration intensity of spring wheat is deduced from the stomatal model Then values calculated by this function and the modified Penman-Monteith equation with values measured are compared.

• HEIFE DATA BASE (HDB)
• Tao Zehong;Zuo Hongchao;Hu Yinqiao
• 1994 Vol. 13 (3): 369-376. 
• Abstract ( ) PDF (300KB) ( )
• In this paper, the making process and technique of HEIFE DATA BASE(HDB) are related, and scientific significance of the HDB are represented.It may be significance for using data of the HDB and making analogous data base.

• THE CHARACTERISTICS AND CALCULATIONAL METHOD OF THE EVAPORATION POWER FOR OASIS IN HEIHE RIVER BASIN IN HEXI REGION
• Wu Jingzhi;Wang Yaoqi;Gao Hongchun
• 1994 Vol. 13 (3): 377-381. 
• Abstract ( ) PDF (231KB) ( )
• A evaporation power was observed for different underlying surface during observational study on the interaction between earth and atmosphere in the Heihe River basin in Hexi region The evaporation power in oasis was only 44% 56% of that in Gebi and was not markedly greater than that in moist area The evaporation power at night is larger than that at day.It is a general phenomenon.The calculation error of evaporation power in arid area for few months in relatively high when the evaporation was computed with Penman's original-formula and modified formula It is optimum that the experience formula is obtained by air saturation difference fitting.