Vol.4, NO.2, 1993

Display Method:
Ozone Measurement with the Solar and Skylight Spectrophotometer
Xue Qingyu Guo Song Niu Jianguo
1993, 4(2): 138-144.
Ozone has intensive absorption in the UV band. By taking in the condition of direct sun, moon, and twilight zenith sky, the UV absorption spectrum is measured with a self–made Solar and Skylight Spectrophotometer. The vertical and slant column amount of ozone is computed by using the method of band absorption. The procedure of measuring and calculating ozone amount is introduced in the paper. Also the preliminary result of ozone under the clear weather condition in Beijing is given here
A Technique of Tangential Remove for Doppler Velocity Ambiguity
Tao Zuyu
1993, 4(2): 145-153.
According to the characteristics of the ambiguous Doppler velocity in the velocity-azimuth profile, a technique of tangential remove for ambiguous velocities is proposed in the paper. The process of removing the ambiguous velocities contains four major steps: Dividing the velocity-azimuth profile into zero segment (data gap), unambiguous segment, and ambiguous segment by removing the isolated points on the profile. Using the unambiguous segment with opposite signs at two ends as reference to determine the ambiguous segments and using the continuity of velocity distribution to remove the ambiguous velocity segments on the profile. Using the simulated harmonic curve of profile as reference to determine and remove the ambiguous points on the profile. Using one of the ambiguous velocity removed profile in a distance range as reference to remove ambiguous velocity according to the radial continuity of velocity distribution. The ration of the amplititude of simulated harmonic curve of profile to the average of the absolute value of Doppler velocity is used to check whether the ambiguous velocities are removed on a velocity-azimuth profile.
A Comprehensive Evaluation of the Effect of Artificial Precipitation in Gutian Reservior Area
Zhen Guangping Wu Minglin Lin Changcheng Liu Xiangming
1993, 4(2): 154-161.
Artificial experiments were performed in the Gutian reservoir region during April to June of 1975–1986. The statistical analyses from 244 experiments indicate that the effect of precipitation enhancement can reach about 20% by seeding. Meanwhile, the various cloud physics observations, including the concentration of ice nuclei, the Ag+ content in rain water, the features of radar echoes and the raindrop size distribution, and numerical simulations have been conducted. The results provide a preliminary physical explanation for the statistical conclusions
The Application of Physical Initialization to the Numerical Prediction for Typhoons
Yan Jinghua Xue Jishan
1993, 4(2): 162-168.
Several experiments of the physical initialization in the numerical prediction of typhoons, by using P.R. Julian’s scheme (1984) with the operational tropical limited area operational NWP model, are conducted. The results show that not only the initial state (stream and rainfall rate) in the areas of the typhoon, the monsoon depression or the subtropic high, but also the predictions of the strength and the track of the typhoon can be largely improved by the use of physical initialization, which proved to be a effective and feasible method in the tropical NWPs.
Construction of the Preliminary Fields of Meteorological Elements Within a Region Without Data or Conventional Data
Chen Mingyue Liao Dongxian
1993, 4(2): 169-176.
Based upon Stokes’ theorem and Gauss’s theorem, a method to evaluate the preliminary values of meteorological elements within a region without data or conventional data is proposed, which is different from that by using the recent instant forecasted values and favourable to improving the quality of objective analysis.
The Influences of Atmosphere Regimes on Vegetation Indexes
Zhao Gaoxiang Wang Hongqi
1993, 4(2): 177-184.
Based upon the simulations of radiative transfer, the influences of atmosphere regimes on the vegetation indexes are investigated, and two kinds of surface vegetation indexes which can reflect the inherent radiative properties of different types of vegetation are presented. The calculated results show that the vegetation indexes are more suitable for global vegetation monitoring
A Theoretical Analysis of Electrostatic Field Change Waveshape Caused Lightning Leader
Zhang Yijun Yan Muhong Liu Xingsheng
1993, 4(2): 185-191.
By analyzing theoretically the electrostatic field change of a CG lightning leader process, it is indicated that temporal variation rate of electrostatic field dE/dt caused by leader development is better than net field change △E for characterizing the leader propagation. Starting position of the leader, velocity of leader propagation near the ground and leader instant current when leader reached the ground could be determined by using the time-varying curve of dE/dt. Meawhile, the features of inclination or flexion of lightning channel can be infered from the distribution of extreme value point by the curve of dE/dt versus time.
The Special Property of Kinetic Energy of 30—50 Day Oscillation and Its Relationship to the Barotropic Instability of Basic Flow
Xu Jianjun Zhu Gang
1993, 4(2): 192-197.
By using ECMWF day–to–day grid data, the distribution of vector E, the special property of kinetic energy and the features of the barotropic instability for 30–50 day oscillation are analyzed. It is found that the energy propagation of 30–50 day disturbance is closely related to the location of the west wind jet. The wave energy propagates zonally at the place where the west wind is stronger but meridionally at the place where that is weaker. Due to the stronger conversion of barotropic energy, the disturbance with low—frequency can get energy from basic flow, which causes the greatest kinetic energy of these disturbances in the jet exit region. The vertical distributions of kinetic energy here show us the fairly barotropic characteristics which strongly contrasted to the baroclinic over area of low latitudes
Multi—step Prediction Model of Time Series for Precipitation
Cao Hongxing Wei Fengying
1993, 4(2): 198-204.
A time series model for the multi―step prediction is proposed in the paper. Having calculated mean generating functions of the time series and its difference and then screening all extending series of the mean generating functions with the couple score criterion, the model which is well available for both the fitting and the forecast is built. As an example, total precipitation during the period from June to August over the lower and middle reaches of the Yangtse river is modeled. It is shown that the model proposed here is useful for year―to―year climate prediction or month―to―month long―range weather forecast
The Transnormalized Regression Probability (TRP) Model and Its Application in Aeronautical Meteorological Service
Tian Junjie Pan Chunsheng Zhao Songhua
1993, 4(2): 205-211.
In the paper, an Equivalent Normal Deviate (END) statistical method is introduced in order to process relative data and establish corresponding transnormalized functions by using the climatological data at Nanjing and surrounding five locations and the data of LFM numerical products of NMC in 1986. TRP equations of low cloud cover and visibility at Nanjing are also developed using TRP model. Finally, the applications of TRP model in aeronautical meteorological service are discussed
The Atmospheric Transmissivity Measurement in Infrared Window Region
Zhang Guangshun Zhang Yuxiang Wu Chengquan Wang Guanghua Zhang Lijun Gao Erwei
1993, 4(2): 212-217.
This report mainly introduces the theory and facility for measuring solar infrared spectrum of window region. It also gives the method for calculating the atmospheric transmissivity within the range of 2390cm-1 to 3470cm-1 and 750cm-1 to 1300cm-1. The analysis results show that the data is helpful to the choice of infrared channels of remote sensing instruments of meteorological satellite, it is also useful to the retrieval of satellite data and so on.
Correction of the Exchange Coefficient on Air—sea Interface in the Tropical Western Pacific
Qu Weizheng Li Jiangbo
1993, 4(2): 218-225.
On calculating heat flux, latent flux and momentum flux, the errors of heat exchange coefficient cT, evaporation coefficient c E, and friction coefficient cv are brought about, owing to the different measure height of meteorological elements, respectively, which will affect the result to a certain extent, In the paper, a method of height correction is introduced in order to amend the coefficients. And, the method will improve the accuracy of calculation. The result shows the errors of coefficient corrected can reduce by a factor of 9% to 11%.
The Detection of Global Climate Warming and Its Causes
Wang Shaowu
1993, 4(2): 226-236.
The progress and advances in studies on the global climate warming are reviewed. The conclusions are as following: Earth surface temperature has increased by 0.5℃ during the last one hundred years. 1980’s became the warmest decade for that time interval. The warming is being in continuing in early 1990’s. 1990 was the warmest year, 1991 was the second warmer year since 1861. However, the warming of 0.5℃ is still in the range of natural variability. The temperatures in the Medieval Warm Period (900-1300) were probably comparable to that in the 20th century. The temperatures during the Little Ice Age (1550-1850) may be lower than that at present time by 1.0-1.5℃. Therefore, it is crucial to study systematically the impact of solar activity and volcanism on the climate for the last millennium. The warming in the warm scenario with doubled CO2 based on the time-dependent coupled GCM is 1.3-2.3℃, which is much less than the estimation of the balance simulation of AGCM. And, the cooling effect of the anthropogenic aerosol is emphasized, it could compensate partly the greenhouse effect.
A Review of the Development of Air-sea Coupled Model and the Experiment on Seasonal and Interannual Prediction
Tang Xu
1993, 4(2): 237-243.
The current status on the air-sea coupled models and prediction experiments is intruduced and reviewed by analysing the model intercomparisons as following: (1) treatment on climate drift and ENSO interannual variability, (2) influence of model resolution coupled pattern and parameterization on the interannual variation, (3) the relationship of ENSO-related interannual prediction to the initial time and data, and (4) the relationship of ENSO to moonson: air-sea-land coupled system. Finally, a suggestion on how to run the corresponding experiment in China is proposed.
Differential Absorption Measurements of Atmospheric Methane Concentration
Kong Qinxin Wang Gengchen Liu Guangren Gu Zhifang
1993, 4(2): 245-249.
The differential absorption method with two He-Ne lasers is discussed for the monitoring of methane in the ambient atmosphere. Absorption coefficients of methane at He-Ne laser emiting wavelengths are measured in the laboratory. By using a pair of 3.3922μm laser lines, the measurements of methane concentration are made in outdoors. The average methane concentration of 1.77ppm in the natural atmosphere near the ground is obtained
The Heating Effects of Irradiance on Rice Leaf Temperature and Its Influence on the Photosynthetic Rate
Li Linying Wu Yuanzhong Duan Xiangsuo
1993, 4(2): 250-255.
The variation of rice leaf temperature with ambient air temperature and irradiance intensity imposed on the leaf surface is discussed based on the experimental data in a controlled environment chamber. The heating effects of irradiance on leaf temperature will change the patterns of photosynthetic response to light intensity. According to the rectangular hyperbola photosynthetic model, the rice leaf photosynthetic character in different environment conditions is simulated. The results show that when the air temperature is less than the temperature suitable for photosynthetic physiological process, the heating effects raise the leaf temperature, thereby improving the photosynthetic capacity. Otherwise, the effects are contrary to the results above.