Vol.3, NO.3, 1992

Display Method:
Satellite Image Analysis on the Natural Rain Clouds in Gutian, Fujian Province
1992, 3(3): 314-320.
The cloud and precipitation resources over the Gutian area from April to June by using IR cloud images data are statistically analysed. The results indicate that the best seedable weather system is frontal system, the best seeding period is in May, the best operational time is from midnight to early morning and the best target clouds are those with the top temperatures being –28℃ to –12℃.
Mesoscale Operational Forecast Experimental Model System
1992, 3(3): 257-265.
A 3-D mesoscale operational numerical model system (MOMS) is developed on a microcomputer PC-386 according to the requirements of real-time operational forecast and data availability. The system including data input, objective analysis, forecast processing and results output is run automatically. It can provide prognosis and precipitation forecast at any given interval within 24-hour period. The results are displayed on terminal with color graphics. The system was in operation in the summer experiments of Beijing-Tianjing-Hebei mesoscale experimental base during 1989 to 1990, and provided numerical forecast product services during the period of 11th Asian Games. The experimental operational forecast with this system was also carried out in weather forecast stations of Inner Mongolia Autonomous Region and Hebei Province in 1990. The results show that the model system operates steadily and can meet, with regard to timelyness, the requirements of real-time operational forecast. The forecasts provided by the system contribute positively to making 12-24 hours short range forecast
The Error Characteristics of Meteorological Parameters Retrieved from Satellite Remote Sensing Measurements and the Error Simulation Tests
1992, 3(3): 266-272.
Based on the error analyses of meteorological satellite remote sensing retrieval system, the error characteristics of meteorological parameters retrieved from satellite remote sensing measurements are described. Under the guidance of the error analyses, a series of simulation tests on the retrieval error are carried out and the error characteristics are revealed quantitatively. These analyses and simulation tests can used as a guidance for designing meteorological satellite remote sensing systems and for improving retrieval accuracy
A Study on the Numerical Prediction of Tropical Cyclone Track Tendency
1992, 3(3): 273-280.
A one-way nested barotropic model used for predicting tropical cyclone track tendency is developed. The so-called “relay forecasting” time integral method is suggested. That is the grid data supplied by ECMWF through GTS are used not only for determining the boundary value of fine-mesh forecasting domain, but also for updating large scale circulation during integral time. Five different “relay forecasting” schemes are designed and are all tested on tropical cyclones No. 8507 and No. 8509. After comparing and analyzing the results obtained from various forecasting schemes, the main factors which caused the forecast errors are identified. The experimental results show that “relay forecasting” method has great capability for predicting tropical cyclone track tendency. It may forecast not only the normal tracks more accurately than the operational models, but also the anomalous tracks and erratic paths of tropical cyclones. The longer the integral time is, the more obvious the superiority of this method is. This shows that the “ relay forecasting” method has not only suggested a new possible way for predicting tropical cyclone track tendency, but also has made a first encouraging step to develop a mediumrange forecasting method of tropical cyclone tracks. Furthermore, the results from various forecast schemes indicate that they can be used to facilitate the operational forecast.
Numerical Study of Mid-Range Weather Forecast Using Corrected FGGE-III b Data over Qinghai-Xizang Plateau
1992, 3(3): 281-288.
Five numerical tests were performed by using a northern hemispheric spectrum model with two different resolutions, T21L5 and T42L9, for 00 GMT 15—20 June, 1979. The initial fields used are the FGGE-III b data at 00 GMT over the Qinghai-Xizang Plateau. The results show that there are certain errors on FGGE-III b data at 00 the Plateau, and the errors in the upper troposphere are larger than those is lower troposphere. The correction of initial data over the Plateau has a remarkable effect on numerical forecast results, especially on the results of the model with higher resolution. The corrected initial fields affect not only the forecast over the Plateau, but also the east of China and Japan through energy dispersion, even Alaska and Northern America in about five days
A Study on Parameterization of Turbulent Characteristic Amounts at Near Surface Layer
1992, 3(3): 289-298.
On the basis of the surface energy buget equation, the surface turbulent fluxes are estimated from routine meteorological data. The inputs required by the model are surface wind speed, temperature and total amount of cloud. The outputs of the model are turbulent characteristic parameters and parameterized surface fluxes. The boundary layer data of the Wangara Experiment are used to verify the parameterization model. The calculated results are in good agreement with the observed values
The Characters of Viscous Barotropic Atmosphere on Sphere
1992, 3(3): 299-305.
The characters of nonlinear disturbance of viscous barotropic atmosphere on sphere is discussed. It shows that the envelop of disturbance is controlled by a simple equation because of the reactions of weak nonlinear interaction between waves. The simple equation changes into nonlinear Schr?dinger equation when viscous effect is died away. The result also shows that two factors, one is the effect of curvature of the sphere and the other is the shear of the basic wind field, are very important for the formation of the equation. The paper is also pointed out that the viscous effect may act as dispersion to enhance the energy of the envelop and it may be unfavourable for the formation of this statistical solitary wave (Schr?dinger wave)
A Diagnostic Study of the Transition of the 30 hPa Circulation in Northern Spring
1992, 3(3): 306-313.
Based on the northern 30 hPa daily altitude and temperature data for 1965—1986 and monthly mean ozone observations for 1958—1976, studies are conducted on the natural transitional process of the circulation from winter to spring by means of dynamic approach and statistical diagnostic analysis. Results are obtained as follows: (1) the first day on which the E index of eddy variance of the height field in the polar-cap area north of 50 oN is smaller than 4×104 (dagpm) 2 can be taken as an approximate measure of the beginning of spring for the natural season; (2) the circulation in the period from late winter to early spring experiences significant changes in the pressure, temperature, and zonal-meridional wind fields; (3) stationary and transcient vortex momentum, heat flux and flux convergence (divergence) undergo remarkable temporal-spatial variations; (4) in both the early and late transitions into spring, the heat source—ozone in the polar stratosphere shows zonal, meridional and vertical anomalies
An Analysis on Control Factors of Drought/Flood in the Changjiang Valley
1992, 3(3): 321-327.
The relationships between the probable control factors, such as the sea surface temperature (SST) in the equatorial Eastern Pacific and the subtropical high etc., and drought/flood in the Changjiang valley are studied by using the related moment analysis. The contribution of each factor to the formation of drought/flood is also discussed. The results show that the abnormal change of all factors in the earlier stage has influence, to a different degree, on the variation of precipitation in summer. The relationship is shown principally by the abnormal drought/flood years. The correlation of the SST, SOI and subtropical high with the drought/flood is persistent to a certain degree. The synthetical analysis of the factors indicate that SST, SOI, subtropical high and the temperature in the Changjiang valley area have greater contribution to the formation of drought/flood.
An Investigation for Computing Three-Dimensional Trajectory
1992, 3(3): 328-333.
A method for computing the trajectory is presented, and then a case study is made with the method by using a ten-level primitive equation model. Comparing the results obtained from the data with different time intervals ranging from 30 minutes to 12 hours, including the conventional observations only twice a day shows that using those data with the intervals equal to or less than 3 hours can lead to accurate trajectory computations while significant discrepancies are found with 12 hour interval.
Study on the Features of Radar Echo and Rainfall of Natural Cumulus in Summer and Autumn and the Estimation of Rainfall
1992, 3(3): 334-339.
The features of radar echo and rainfall of cumulus are analysed by using the field observational data obtained in Hunan Province in summer and autumn, 1979—1988. The regression relations of radar echo parameters with the rainfall amount of single station, depth of rainfall, total rainfall amount and rainfall density are then established. The test of such relations using the cumulus rainfall data in Hunan and Guangdong Provinces indicates that they are applicable, to a certain degree, in estimating cumulus rainfall in the vast areas of southern China.
Review on the Numerical Weather Prediction in the Past Decade and Its Prospects
1992, 3(3): 340-346.
The general development trend of NWP and its progress in operational forecasting, model design, physical processes, data assimilation, related mathematics and so on in the past decade are reviewed. At same time the existing problems in NWP are pointed out. Finally, its prospects in the near future are envisioned
Characteristics of Temperature and Rainfall Distribution in the Uninhabitable Area Kekexili, Qinghai Province
1992, 3(3): 347-352.
The preliminary analysis on the temperature and rainfall data collected in the Kekexili area of Qinghai Province by field investigation is made.This preliminary analysis may serve as part of the scientific supports for the construction of the Kekexili Natural Reserve.
A Method of Iteratively Reweighted Least Square and Its Application
1992, 3(3): 353-358.
The robust regression is obtained by using the method called the iteratively reweighted least squares (IRWLS). The comparison between robust regression and least squares (LS) regression is also made. The results point out that the procedure may lead to gradual reduction and convergence of the sum of absolute residuals. This procedure is also used to forecast the rainfall over the middle and lower reaches of the Changjiang River. The tests on dependent and independent sample data prove that the IRWLS is better than the LS
The Error Analysis of a Spherical Harmonic Expanding in Limited Regions
1992, 3(3): 359-362.
The numerical computation of expanding a meteorological element in terms of spherical harmonic functions for five regions is carried out by using 500 hPa height observations. The calculated results show that all root-mean-square errors (RMSE) of spherical harmonic expansion are less than 2.5 gpm (0.04%) and the maximums of absolute error are less than 14 gpm (0.23%) for four limited regions with the number of longitudinal arid points L=64, while the number of Gauss discrete points in the latitudinal direction is 32 and the wave number M=L/2=32. The RMSE of the spherical harmonic expansion for limited areas are 2—3 gpm less than that for the globe. This is principally due to the longitudinal gridlength is shorter for the limited areas than that for the globe.
The Relationship of Corn Storage and Transport with Climatological Conditions in Jilin Province
1992, 3(3): 363-366.
Based on the statistic analysis of observational and experimental data, the paper reveals that relationship between the vulnerability and air temperature and moisture. According to the climatic data of Jilin Province and all over China the optimum periods for purchase, storage and transport of corn with different water content are established and suitable destination areas in terms of climatic conditions for corn transport are identified
Comparison of AVHRR Channel 1 and 2 Albedo Data Between NOAA-9 and NOAA-10 and Its Calibration
1992, 3(3): 367-370.
The channel 1 and 2 of AVHRR on NOAA polar orbit satellites have no on-board calibration capabilities. Therefore, a methodology is developed to make comparison analysis on the data measured by NOAA-9 and NOAA-10 by using the earth surface with neglectable seasonal changes as the target area. A statistical method to normalize NOAA-9 data to those of NOAA-10 is presented.
Study on the Relation of Geogarphic Conditions Variation and Deviation of Climatic Analogue with the Adaptability of Rice Varieties Introduced
1992, 3(3): 371-375.
The rice yield variation due to different geographic elevation and latitude and the deviation of climatic analogue in target area of rice varieties introduction is analysed through statistic method. The standards and schemes for determining the adaptability of rice varieties introduced are presented.
An Algorism for Objective Analysis of Streamline
1992, 3(3): 376-382.
A simple and practical algorism for objective analysis of streamline is given. The principle of the algorism is to adopt a set of functions as wind vector tracer. The realization of the algorism is discussed in detail. The result of objective analysis agrees basicly with that of subjective one, although there are still a few discrepancies. This result is recognized by tropical weather forecasters.