Current Issue

• RADIATIVE CHARACTERISTICS OF CIRRUS IN SOLAR RADIATIVE WAVELENGTH BAND
• Yang Ping;Cai Qiming;Jiang Xingan
• 1992 Vol. 11 (3): 223-234. 
• Abstract ( ) PDF (757KB) ( )
• The ice crystals in cirrus cloud layers are predominantly in the form of hexagonal columns and plates; and according to the investigation of Heymsfield, the size-distribution of the ice particles may be described in terms of Junge's formula with the parameters depending on ambient temperature. The presented studies focus on the albedo and transmissivity of cirrus with different optical depth under ambient temperature of -20-25℃ at four solar radiative wavelength. With the corresponding size distribution, the single scattering of ice crystals are solved by ray-tracing method proposed by the authors previously. Next, a discretely mathematical expression of doubling principle is presented and used to compute the radiative transfer through cirrus layers. Moreover, in the radiative transfer calculation, the strong forward-peaks of scattering phase function of the ice particles are truncated by taking away the diffraction part in single scattering, and the corresponding parameters of single scattering are adjusted according to Delta-M "equivalent" method. Finally, to evaluate the impacts of size-distribution of the ice particles under different ambient temperature, the radiative transfer computation is also carried out for the cirrus with ambient temperature of-55--60℃.

• SIMULATION AND DISCUSSION OF CORRECTING MICROWAVE ATTENUATION WITHIN RAIN AREA FOR DUAL LINEAR POLARIZATION RADAR
• Liu Liping;Xu Baoxiang
• 1992 Vol. 11 (3): 235-240. 
• Abstract ( ) PDF (389KB) ( )
• The critical problem in measuring rainfall rate and distinguishing the phase of hydrometeors by dual linear polarization radar is the data accuracy, and the microwave attenuation is very important to measuring error. In this paper, we have given the relations between the extinction coefficients K _{H, v} and Z _H, Z _DR for different raindrop size distributions(DSD) at 5.6 cm wavelength. We have simulated and discussed the effects of variation of temperature, DSD , smoothing of data and radar's system errors on the results of correcting attenuation. The results show that the attenuation makes Z _H, Z _DR becoming less, if the measuring errors of Z _H, Z _DR is not large, and other elements have not more effects on correcting results. Attenuation correcting could improve the measuring accuracy significantly, but measuring errors of Z _H, Z _DR is very important for correcting problem.

• OBSERVATION ANALYSIS OF THE MICROSTRUCTURES OF PRECIPITATION SHEET CLOUDS IN SUMMER OVER NINGXIA
• Niu Shengjie;Ma Tiehan;Guan Yuee;Lu Yulian
• 1992 Vol. 11 (3): 241-248. 
• Abstract ( ) PDF (475KB) ( )
• In this paper, the in situ measure data of As cloud during the artificial precipitation enhancement in 1988-1989 are analysed. The conclusions are as following:(1) The drop size distributions of As clouds are fitted by using XP aH-Ma formula for three main precipitation weather systems. The distribution parameter ais from 0.898 to 20.018, and bis from 0.427 to 0.598. The correlation coefficients are better than 0.86.(2) The vertical profiles of particle size distribution parameters are got.(3) There are single peak and double peak features in snow crystal spectra.(4) The mean liquid water content of As clouds for three weather patterns are 0.11, 0.08 and 0.05g/m ³, respectively.

• GEOGRAPHIC DISTRIBUTION CHARACTERISTICS OF THE SOLAR SPECTRAL RADIATION IN THE WEST KUNLUN MOUNTAIN REGION
• Wei Yaohong;Lin Zhenyao
• 1992 Vol. 11 (3): 249-258. 
• Abstract ( ) PDF (623KB) ( )
• The solar spectral radiations are observed in the west. Kunlun Mountain region during the summer of 1989. In this paper, the spectral radiation distribution, their daily and annual variations are discussed. The results are as follows: The energy of the spectral radiation is very strong in the west Kunlun Mountain region, in which the ultraviolet radiation is particularly large also. The instantaneous maximum of the ultraviolet radiation reaches to 99W/m ², and the ratio of the ultraviolet radiation to global radiation is very large too, reaches to 8.86%. There is a lines relationship very well among the flux of every wave-band of solar radiation and the direct solar radiation, sky diffuse radiation. The correlation coefficients are exceed to 0.99. The distribution of annual radiation have relation to sunshine. The solar radiations on each wave-band in the summer (June, July, August) close to 40%.

• LONGWAVE CLOUD RADIATIVE FORCING OVER THE QINGHAI-XIZANG PLATEAU
• Wang Keli;Zhong Qiang
• 1992 Vol. 11 (3): 259-266. 
• Abstract ( ) PDF (507KB) ( )
• In this paper, the diurnally-averaged longwave cloud-radiative forcing over Qinghai-Xizang Plateau is analyzed by the physical method developed by Ardanuy et al.(1989) based on NOAA-7 daily OLR and planetary albedo data during August 1982-July 1983. The results show that cloud cover is a major factor modulating OLR. The longwave cloud forcing reaches maximum in Spring. The annual mean cloud cover is found to be 47%. The regionally averaged longwave cloud radiative forcing is 29W/m ². The difference of spatial distribution of longwave cloud forcing is very large with season.

• ISENTROPIC POTENTIAL VORTICITY ANALYSIS OF A PRECIPITATION PROCESS OVER THE NORTHERN PART OF QINGHAI-XIZANG PLATEAU
• Li Li
• 1992 Vol. 11 (3): 267-274. 
• Abstract ( ) PDF (547KB) ( )
• In this paper, isentropic potential vorticity (IPV) theory is used to investigate a precipitation process in summer, which occured in Xinjiang of the Northern Qinghai-Xizang Plateau. The structure of atmospheric dynamic process associatted with precipitation is discussed. The results show that with the development of synoptic system, gradient of sloping to the north of isentropic surface in this region increassed, updraft enhanced here, so precipitation was influenced. The positive advection of IPV in IPV peak area make sense to forecast region in which it would be rain. The influencing system at surface mainly caused by frictional effects in planetary boundary layer frequently are high pressure ridges.

• THE STUDIES OF THE RELATIVITY OF THE 13 ANOMALY CHARACTERISTIC PATTERNS AT 50 hPa AND ITS SEASONAL, ANNUAL VARIATIONS
• Wang Yupei;Pan Tao;Li weijing
• 1992 Vol. 11 (3): 275-284. 
• Abstract ( ) PDF (654KB) ( )
• In this paper, the self-correlation coefficients chart(for 288 points) of the 13 anomaly characteristic patterns at 50 hPa and the point-correlation coefficients chart for the 288 points at 500 hPa and the 6 points in the sensitive regions have been drawn up and analysed. The three charts are very similar each other. This means that the stratosphere and troposphere are close related. The self-correlation chart at 50 hPa shows the evolution of the ultra-longwave system for wave number 1-3 all the year, while the point-correlation charts at 500 hPa show the evolutions of wave number 3 in autumn and wave number 2 in winter and summer. This sufficiently explains that the 13 anomaly characteristic patterns show the main atmospheric circulation characteristics in the stratosphere. Besides, we discovered that there are some evident evolutional rules in the seasonal and annual variations for each correlation and they are stable for a long period. These are very important on foreasting all kinds of the catastrophic weather and climatic processes.

• CHARACTERISTICS OF NET RADIATION OVER WEST PACIFIC AND ITS SURROUNDING SEA AREA IN 1986
• Cai Ying;Yao Lanchang
• 1992 Vol. 11 (3): 294-304. 
• Abstract ( ) PDF (788KB) ( )
• In the paper, we have computed in detail the net radiation by using the ocean data from January to December 1986 over west Pacific and its surrounding sea area. The results show that:(1) The equatorial and tropical sea areas in the Pacific act as a strong heat source, whatever in winter or in summer. The nonuniformity of distribution of net radiation in the eastern and western of Pacific indicates that thermal difference is very evident at ocean surface.(2) The seasonal variations of net radiation are evident and there are two heat increasing processes in each sea area.(3) Variation of net radiation intensity is very attractive, especially net radiation intensity over west Pacific in EI Nino period is evident different compared with normal conditions.

• Net radiation;West Pacific;EI Nino
• Gao Xiaoqing;Tang Maocang
• 1992 Vol. 11 (3): 305-311. 
• Abstract ( ) PDF (436KB) ( )
• Qinghai Lake level(QLL) dropped at a rate of 10 cm/year according to formal records since 1958. More and more people are concerned about it. In this paper, a preliminary study on inter-monthly variation of QLL has been done. In addition, by using water balance equation, a simple simulation of inter-monthly variation of QLL has been given.

• CLIMATOLOGICAL ANALYSES OF ANOMALY OF SOIL TEMPERATURE
• Liu Xiaodong;Wei Zhigang
• 1992 Vol. 11 (3): 312-320. 
• Abstract ( ) PDF (586KB) ( )
• Climatological characteristics about temporal and spatial variations of anomalies of 31 stations' soil temperature at depth 1.6m in China from 1974 to 1976 have been analysed. The results show that there is strong persistence in anomaly field of soil temperature. The more range of soil temperature anomaly changes large, the more the anomaly persists long. Meanwhile, it has been found that there is obvious quasi-semiannual rhythm in the seasonal transition of the anomaly field of soil temperature from winter to summer. Otherwise, accumulative absolute value of the anomalies of month's soil temperature in winter-half-year is large(or small), then the rainfall variability is high(or low) next year(and its flood season).

• THE RELATIONSHIP BETWEEN QBO AND DROUGHT AND FLOODING ON NORTHEAST SIDE OF THE QINGHAI-XIZANG PLATEAU
• Tian Rongxiang
• 1992 Vol. 11 (3): 321-327. 
• Abstract ( ) PDF (440KB) ( )
• In this paper, analyed results show that there is a period of quasi-biennial oscillation for rainfall on northeast side of the Qinghai-Xizang Plateau. It is well correspond to zonal wind oscillation on low layer of the stratosphere over Equator. When zonal wind is westerly phase, there is more rainfall on northeast side of the Qinghai-Xizang Plateau, and appears easily flooding; when it is easterly phase, there is less rainfall there, and appears easily drought. When El Nino event is happened, rainfall is decreased on northeast side of the Plateau.

• A PERIOD ANALYSIS ON THE COLD WAVE PERSIS TENT SNOWS IN SPRING IN NORTH OF ABA AREA
• Gao Qingyun
• 1992 Vol. 11 (3): 328-329. 
• Abstract ( ) PDF (133KB) ( )

• CONTRAST EXPERIMENTS OF TS-2A TETHERSONDE SYSTEMS
• Zhang Wenyu;Chen Changhe
• 1992 Vol. 11 (3): 330-334. 
• Abstract ( ) PDF (266KB) ( )
• In this paper field observational data of several TS-2A tethersonde systems were compared. The results show that the actual precision of the system is reduced compared with the designed precision. But it is still a fairly good radiosonde system for atmospheric boundary layer. The paper can be used as a reference for users of the system and data analyses.