Abstract:The recent progress and development of Numerical Weather Prediction (NWP) in the USA was summarized. A general discussion about the development of operational NWP systems in China was given in the last section.

Abstract:①The variation of the mean grain yield per unit area amounts to two thirds of change of the total grian yield,and plays a decisive role. ② Since the 1950s,percentages of wheat and maize yield in the total grain yield have been individually tending to increase,rice to relatively stable,but that of soybean etc. to decrease.③ So far as the principal grain crop yields per unit area are concerned,the yield of single rice harvest is the highest,the increase of wheat yield is the fastest. The relationships between bumper or poor harvest of the mean grain crops per unit area and weather condition suggests that the connections between precipitation of Northwest and Northeast regions,and accumulated tempertatue of North China and good or bad harvest of the grain crops are intimate. The accuracy of this model established by these factors for assessing good or bad harvest of the grain crops is over 85 Percent.

Abstract:The correlational coefficient between the number of the equivalent torrential rain day and the total rainfall at June～August of this century in Beijing is 0.97. The correlational coefficient between the regional average number of the equivalent torrential rain day and the regional average total rainfall is 0.94. The linear correlation between the number of the equivalent torrential rain day and the total rainfall is given by the regression equation and the scatter diagram. The root mean square error of the total rainfall calculated by the regression equation is near 10 percent. The method of the total rainfall calculated by the number of the equivalent torrential rain day can be applied to the operational use.

Abstract:The data of single station lightning detection and ranging system and 713 radar echoes achieved from 4 cold vortex hailstorm events from 1996 to 1997 are analyzed. The results show that the number of times of lightning have a brewing and leaping procedure before the hail begins to drop 5 minutes,it reaches the maximum when the hail begins to drop and after the hail dropping it descends slowly. The distribution of cloud discharge and total lightning frequency corresponds with this phenomenon better. Comparing the ground area hitted by lightnings and the ground place of hails dropping on,it is found that the area coincides with the place well. Put the lightnings' place and the intensity data on top of the radar echoes picture,it is found that the place where lightnings appear frequently is just the place where the radar echoes are strong.

Abstract:A severe local storm in Guandong province during April 18~19,1996 was analysed with synoptic charts,satellite images and sounding. It is shown that severe and convective weather events produced by the meso scale convective systems were accompanied by the continuous affects of cloud systems of the southern branch and middle latitude trough. The mechanism of this event was discussed.

Abstract:The method of composite analysis is used to diagnose the deference of the circulation characteristics between the more high temperature year and the less high temperature year for the previous period by using 500 hPa data from 1951 to 1996. The results show that the deference is clear. In the more high temperature year,there are persistent positive anomalies in south of Asia from Jan. to June and the teleconnection over the West Pacific during the winter,and in the less high temperature year,anomalies in south of Asia are negative and the teleconnection over the West Atlantic is obvious. In April,Aleutial low and Alaska high are strong in the more high temperature year and they are week in the less high temperature year. The relationship between high temperature and 74 circulation indexes is analyzed. The results show that there are well positive correlation with the areas of subtropical high in Indian in spring and the position of subtropical high in the northern hemisphere in March,and the negative correlation with indexes of Eurasia longitude correlation in April and of East Asia trough's strength in Jan. and Apr. is notable.

Abstract:It is discussed that the quality control of some common meteorological data as temperature,precipitation and sunshine duration in the climatic special data band is essential before used. The methods and steps for basic quality control,time consistency check and space quality control are also introduced.

Abstract:It is discussed that the quality control of some common meteorological data as temperature,precipitation and sunshine duration in the climatic special data band is essential before used. The methods and steps for basic quality control,time consistency check and space quality control are also introduced.

Abstract:By internetworking,the former meteorology professional system can be used with the application of the real time data from the satellite network,so the timeliness of the meteorological forecast was increased.

Abstract:The meteorological disaster as a kind of natural calamity restricts the development of agriculture in Yunnan. It endangers Yunnan agriculture by a few main severe weather events such as drought,flooding, chilling,etc. and their basic feature was analyzed emphatically. At the same time,it is extremely important that people recognize correctly the status of meteorological disaster research in the two respects of agriculture production and ecological system.

Abstract:The meteorological conditions for a heat balloon flying over the Taishan mountain and the effect of the mountain of a heat balloon flying were discussed. By using historical data from Sep. to Oct. during 1988 to 1995,the meteorological conditions fitting the operation of a heat balloon flying were analysed. According to the weather situation and the characteristic that a heat balloon flying over the Taishan mountain was effected by many elements,some factors of better relativity among the elements were selected,and the forecast equations were established respectively,and then the synthetic forecast was given.