1997, 23(4):1-2. DOI: 10.7519/j.issn.1000-0526.1997.4.014
Abstract:The Shanghai precipitation forecasts using JMA numerical weather prediction have been tested. The result shows that the forecast accuracy of Shanghai precipitation is 60% only,and its monthly change is obvious and not regular. The forecaster's experience,the other forecasting tools and the local current weather must be considered by means of the numerical weather prediction of JMA.
1997, 23(4):3-8. DOI: 10.7519/j.issn.1000-0526.1997.4.001
Abstract:It is found by calculation that good correlation existed between summer rainfall in Shandong Province and SST in equatorial eastern Pacific(EEP) and in North Pacific Current(NPC) areas. On the basis of the correlative analysis,the contemporary and antecedent SST anomaly features of rainy and dry summers and the relations with atmospheric circulations were discussed. The contemporary SST departure (rainy summer minus dry summer) is remarkable, and the negative SST anomaly in EEP area prior to those summers is closely related to negative WP_pattern, and the SST anomaly in NPC area is likely to be modulated by the anomaly of atmospheric circulations. The experiments using SST of Feb. —Apr. in high correlative areas and SSTA of Mar. in EEP area and of July in NPC area show that SST is of great reference value for long-term forecast of summer rainfall in Shandong Province.
1997, 23(4):9-12. DOI: 10.7519/j.issn.1000-0526.1997.04.002
Abstract:Using the improved characteristic coefficient method,the probability strength of maximum precipitation from a 2 hour period to 24 hour period in every county of Taian City are evaluated. Evaluation result shows that probability strength of the 24 hour maximum precipitation on a 50 years cycle,a 100 years cycle and a 200 years cycle in central region of Taian city are 159. 9mm, 175. 9mm and 191. 8mm respectively. The probability strength of the maximum precipitation is also evaluated from a 2 hour period to a 24 hour period on different cycles in other counties of Taian city.
1997, 23(4):13-16. DOI: 10.7519/j.issn.1000-0526.1997.4.003
Abstract:General circulation features over the northeren hemisphere in 1996 were analysed. It is shown that the 500hPa subtropical high over the West Pacific was weaker than last year. Its ridge line moved northward in early summer and its west ridge line moved southward in midsummer. Meridional circulation was developed in early spring, blocking pattern was stable at middle latitude in midsummer. 500hPa geopotential height was higher in Qingzang plateau, South westerly trough was weaker in summer. 100hPa South Asia high in summer was stronger and moved eastward. Its ridge line moved southward. The La-Nino was very weak and gone to normal in summer.
1997, 23(4):17-19. DOI: 10.7519/j.issn.1000-0526.1997.04.004
Abstract:In 1996,there was less precipitation in the most of China in winter and spring,the drought area was larger in the North. There was more precipitation in summer,the flood extent was large and the damage was heavy. There was obviously frequent rain in the Huaihe Valley in Autumn. The annual mean temperature was higher and lower in the North and in the South respectively. The annual sunshine level was lower, the snow and frozen damage occurred in some regions. Landed typhoon and tropical storms were normal but its damage was heavy. Some regions were hit by hailstorm and tornado.
1997, 23(4):20-23. DOI: 10.7519/j.issn.1000-0526.1997.04.005
Abstract:Global climate continued to be warmer than normal in 1996. During winter, Europe and North America were hit continuously by arctic cold waves. Serious floods occurred frequently over different regions of the world,especially in Asia. Activities of North Atlantic hurricanes were very busy during June—November in 1996. The above anomalious climate features are likely related to the tropical ocean-atmosphere conditions,which turned from warm phase into cold phase during 1995-1996.
1997, 23(4):24-27. DOI: 10.7519/j.issn.1000-0526.1997.4.006
Abstract:Two methods assessing the year's harvest of cotton are introduced. One is comprehensive element and another is analogous analysis. The first is that a assessing index is given by analysing historical comprehensive meteorological element, which is adequately established by using ten-days' mean temperature,ten-days' precipitation and sunshine hours of AB telex data,and bumper or poor harvest of cotton. In the second, typical year of failure or good harvest of cotton is firstly defined. Analogous analysis indexes were attained by using principle of similar analysis. It is shown that their accuracy can reach more than 90% on adjudging bumper or poor harvest of cotton by using these indexes.
1997, 23(4):28-30. DOI: 10.7519/j.issn.1000-0526.1997.04.007
Abstract:The crop production formation is a developing process with time,the climatic assessment of crop should be conducted by a dynamic model. The assessment method is developing a series of monthly dynamic model for crop growing season,using the climatic yield as a criterion and assessing quantitatively the meteorological condition of crop production formation in different phases.
1997, 23(4):31-35. DOI: 10.7519/j.issn.1000-0526.1997.4.008
Abstract:The comparison between the cold vortex with the large area hail shooting process on 13 June 1996 and that without hail shooting on 20 June 1996 was c(3nducted. In addition to obvious difference of upper air circulation at north of the vortex, the significant differences in between were manifested on low-level wind field,temperature field and stability. If the ridge of high at north of the cold vortex over north China is extending forward northeast, there will be a northeast flow entering the rear of vortex along the front of the ridge. Meanwhile in the low level there is a obvious east-west frontal zone around 40°N with deformation field of frontogenesis, which approaching to the potential unstability area in northwest of Shandong province,the cold vortex will cause a large area hail shooting. Otherwise if the upper cold vortex developed into a symmetrical and deep cyclone,no hail shooting will occur in Shandong at the south of the cold vortex.
1997, 23(4):36-38. DOI: 10.7519/j.issn.1000-0526.1997.04.009
Abstract:The specific squall weather over Lixia River in north of Jiangsu Province, which ocurred in the process associated with the warm surface shear moving northward, was analysed. The favourable condition for occurence of warm shear squall line in the surface and the satellite image features of squall line were given.
1997, 23(4):39-42. DOI: 10.7519/j.issn.1000-0526.1997.4.010
Abstract:Shaanxi province drought months in recent years were analysed by examining the atmosphere general circulation features, drought index S and the signal-to-noise ratio. The results show that the general circulation of Shaanxi drought can be divided into three patterns:the stabilization of East Asian long wave trough,the dominance of west pacific subtropical high and the persistence of Tibetan high. The drought associated with the East Asian long wave trough is the most serious.
1997, 23(4):43-47. DOI: 10.7519/j.issn.1000-0526.1997.4.011
Abstract:The raindrop size distribution was measured for four times during the period from April to June, 1993. The data of measurement were compared with the observation data of filter paper. Based on the two categories of data the basic parameters of raindrop size distribution were calculated and some statistical calculations were made. Using this method the usability of GBPP-100 raindrop disdrometer on field experiments was discussed. The results indicate that: (1) the GBPP-100 can be used on field observation instead of the filter paper during the period that the rainfall intensity slowly changes and is smaller than 160mm/h; (2)there are some obvious differences between the two categories of measurement when the rainfall intensity of shower rapidly changes.
1997, 23(4):48-50. DOI: 10.7519/j.issn.1000-0526.1997.4.012
Abstract:Based on the TC forecast experiences in the past, using the PP method of the numerical forecast product interpretation, the Jiangsu TC Heavy Rain Forecast system was developed. Its examination by T63 model products had proved the system to be practical and full of promise.
1997, 23(4):51-54. DOI: 10.7519/j.issn.1000-0526.1997.4.013
Abstract:The methods of drawing change curve of meteorological elements on the display with resolutions of EGA/VGA were studied. Some skills such as opening different display windows, imitating picture animation,partly magnification and quick switchover of different class window on the same screen were given.

