Abstract:Applying the nonlinear barotropic vorticity equation to the flow of moving waves, an ordinary differential equation with single degree offreedom of the autonomous dynamic system is derived. Based on the qual-itative and geometric analyses of the differential equation, the geometrictopological structure of the integral curve is investigated in the neighbor-hood of the balance points on the phase-plane. Barotropic instability criterion is established for two balance points respectively. Overall char-acteristics of the motion on the phase-plane and the relation of balancestates to the parameters are analysed and criteria similar to the above-stated are thus found in a more intuitive way.

Abstract:Based on the oblique model scheme provided in the Appendix analysisis made of the teleconnectional structure (TCS) of the January 500 hPacontour field over the Northern Hemisphere, resulting in a series of telecon-nectional patterns representative of the main features of the TCS. Amongthem, the WPAA (Western Pacific/Asia/America) pattern is found forthe first time to be closely related to the circulation over East Asia. Control analysis indicates that the TCS is highly sensitive to the march ofseasons. This suggests that examination of the TCS of the Northern Hemi-spheric circulation on a month-to-month basis may be valuable.

Abstract:The Berland’s formula for calculating effective radiation is revised forpractical purposes over China. The revised formula offers clear physicalmeaning, high accuracy and wide application. If computer facilities andradiosonde data are available, it can be successfully used for climatological calculation of effective ground radiation.

Abstract:It is demonstrated that sampling distribution of correlation coefficientdeforms when there is autocorrelation in time series. In correlations ofsamples to the population, effects of autocorrelation and the time-lag cross-correlation are found to be superimposed on the sampling variances. Asshown both in theory and practice, correlations calculated for a series ofan arbitrary time period do not conform with those of random samples.Thus the correlation coefficients calculated for series with autocorrelationin current practices would contain higher variances than for the real ran-dom samples. It is also found that when the correlation coefficients ofsliding samples display a sine wave pattern, a U-shape probability distri-bution results, which again demonstrates the effect of autocorrelation. Animproved sampling procedure is suggested to obviate the effect of autocor-relation.

Abstract:Using a two-layer model and mean temperature and pressure data from1954 through 1963, the authors analyse the atmospheric heat source andsink for January, April, July and October over the Northern Hemisphere.It is found that both the extent and intensity of the source and sink aregreater in winter than in summer. The strongest winter source is locatedon the Eurasian coast and a noticeable sink over the North American con-tinent, both becoming weaker in summer and the positions reversed. Situ-ations in spring and autumn are transitional with the autumnal patternmore similar to that of winter. Annual variation along 60°N and 40°N ismost prominent and least over the equatorial area and along 50°N. Data for1976 have been singled out for a seperate analysis and the trend is foundto be analogous to the long term mean with the exception that both sourceand sink’ show somewhat stronger intensity in July and October. It is also indicated that the dynamically computed source and sinkmatch quite well with the upper-air circulation, with the sources corre-sponding to troughs and sinks to ridges; the situation is reversed in sum-mer and deviation in location greater. The north-south shift of positionsof the source and sink is a significant factor in the seasonal change of thegeneral circulation.

Abstract:A processor for meteorological satellite cloud pictures is developed.Grey-scale extension, line enhencement and quantified enhencement arepreformed on the incoming signals so that electrochemical paper instead ofphotopaper may be used to display the cloud pictures. Meteorological information shown on the displayed picture is multifarious and clear enoughfor operational application and the processor is already used in the firstChinese Antarctic expedition with positive results.

Abstract:After thorough examination of the Agricultural Meteorological Measuring System (AgMMS) of the Japanese EKO Instruments Trading Co., its application software is developed and expanded to incorporated the measurement of atmospheric pressure and the function of processing is extended.The revised system may now print out automatically weather reports inconformity with the regulations laid down in GD-01-Ⅱ published by theState Weather Bureau. Thus the improved system constitutes a fully auto-matic wired telemetric device for surface observation with such functionsas element sensing, parameters collection, data processing and weather report compiling and printing.

Abstract:A digital transmission system of weather radar images is developed forsignal digitization, video integration and coordinates transformation. Ordi-nary telephone line is used for transmission. The output consists of color display, disc recording and digital printout. Its construction, principle and characteristic features are discribed and the design idea and problems encountered discussed.