Abstract:Using the research result for ENSO events and their intensity during the past century by Wang Shaowu,et al.,the statistical relation between ENSO events and drought/flood over the Beijing area in the past century was analyzed.It's shown that there is the perplexed relation between ENSO event and drought/flood in Beijing.The corresponding relationship between the nature (warm or cool),intensity,beginning season,length of ENSO events and drought/flood in Beijing are complicated.Based on the data of ENSO events and the equivalent trrential rain days in Beijing,some statistical results were given.

Abstract:Based on the precipitation and flow curve data during 1959—1997,the relationship between the precipitation and the flow curve in the upper reaches of the Huanghe river was analysed by using of the mathematical statistic forecasting methods of EOF,REOF,power spectrum,and trend analysis etc.The variation trend of precipitation over the upper reaches of the Huanghe river was also studied.The optimum assesment model of the flow curve prediction was established by means of the stepwise regression and optimum subset regression.

Abstract:Using the rainfall and hydrologcal data flood season in Hunan province 1998,the survey of rainwater conditions of heavy torrential rain and flood in Dongtinghu basin was analysed,and the essential feature of floods in Hunan in 1998 was provided.

Abstract:A real time testing result of precipitation forecast in 1998 flood period with a limited area nested grid model(LNGM) of η-coordinate was given.And it has indicated that this NWP with real-time initial field data of T106L19(the numerical weather forecast model of China)has a better TS forecast score of precipitation in the flood period in Hunan.In the second & third dekad of June and the third dekad of July in 1998 i.e.Hunan′s main flood period,the TS for precipitation forecast (24 hours) in the limited-area(hyetal region) with its center in Hunan,are 56.4%,33.9%,21.6% & 10.6% respectively to ≥1mm,≥10mm,≥25mm,≥50mm/24h,better than T106L19 and HLAFS(the mesoscale numerical weather forecast model of China),and the TS of precipitation ≥25mm/24h is 13.1% higher than HLAFS.

Abstract:Using the ocean temperature of Northwest Pacific and the precipitation in summer of Hunan,the interconnection between Kuro-shio from last autumn to last winter and the precipitation and flood in summer in the Dongtinghu area were analysed.The results show that the interconnection between the Kuro-shio in the period and the precipitation and flood in summer in the Dongtinghu area is very outstanding.The anomaly of Kuro-shio is an important background of climate that influences precipitation anomaly and flood in summer in the Dongtinghu area.

Abstract:The statistical analysis of influence of summer monsoon,the blocking patterns at high and middle latitudes,the west Pacific subtropical high and cross-equatorial flow on the heavy precipitation in the Yangtze river area was done.The results show that summer monsoon circulation is the result of northward progression of the summer monsoon and the Easterm Asia summer monsoon circulation in weak phase of ITCZ.Summer monsoon circulation and double blocking high with low-cyclone in high middle latitude made the large circulation of the continuous heavy rain gush.They provide south warm-moist current and north cold current separately.The current meets in the Yangtze Area.Rainfall areas were decided by the line of subtropical ridge and western points of the subtropical ridge.The cross-equatorical flow influences the Yangtze basin Area flood disaster mainly.On the one hand,it reinforces the low-level southwest jet,on the other hand,it has a low frequency vibration feature with 4—7 days.Undoubtedly,it provides a useful information for the medium-range forecast.

Abstract:Using the hourly precipitation data,surface wind filed,upper air data and radar echo data in Hunan province from 13 to 14 June in 1998, the evolution character of the mesoscale proess was analysed preliminarily.The mesoscale system——direct cause of the heavy rain and the corresponding connection for heavy rain with physical quantity,active of mesolow circulation were pointed out.The large scale circulation situation, mesoscale convergence line and orographic action provided advantage condition for local large heavy rain.

Abstract:Based on April～August surface weather observation data from 1982 to 1997 in Henan province and corresponding radar echo data,the characters of weather and rader echo parameters in 40 times regional hail process (neighboring stations≥3) were researched statistically.Some forecast criterions and image features of Doppler radar intensity field and velocity field with better correlation were obtained.These achievements provide scientific basis for making short term forecast,radar monitoring and hail suppression operation.

Abstract:By analyzing North Atlantic Ocean′s climate feature,combining with meteorological route choice discipline and route experiences across North Atlantic Ocean obtained from NMC/MRC recently years,the analyses of climate feature and weather pattern field may be provide a scientific basis for ships across North Atlantic Ocean.

Abstract:The temporal and spatial distribution of hail and thunderstorm in Wutai mountain and nearby plain region were discussed.Results show that it is in the Wutai mountain area that convective storms happened frequently.There were four possible cases of convective storms crossing over the mountain,e.g.① convective storms stagnate,decrease and disappear voer western Taihang Mountain;② the upper of convective cloud cluster across voer the mountain turns into medium and high cloud;③ the initial cloud cluster across over the mountain generates new convective cloud cluster;and ④ convective cloud cluster across over the mountain formates downslope storm.

Abstract:The key of forecast torrential rain area have gotten by analysing the feature of θ_(se) in “98.6” torrential rain process, point out θ_(se) analysis method superior to weather system situation.

Abstract:The collecting and processing system of the surface data at national and provincal levels was set up on the same platform with the same software after conducting telecommunication transmission. It is not only going to reduce some trouble, simplify operation and raise efficiency, but also going to raise systematicness and work quality as a whole through strengthening connection between national and provincial levels.