Abstract:The advances for more than 20 years' studies of methane emission from rice paddy fields in China are reviewed,including the study of methane emission models and estimated methane emission from rice fields; possible techniques for reducing methane emission. Numerical model is an effective method to estimate the total amount of methane emission from rice fields. Model study is now in the developing phase. Several primary models are introduced: physical process model and empirical Model. Estimated methane emission from rice fields is ranging from 6.79 to 41.4Tg/yr. The precision of estimated value has been improved with the development of science and technology and experiments as well. Mitigation methods are necessary to reducing methane emission,but the methods are still in the phase of study and the application of mitigation techniques is not mature.

Abstract:In the ages when NWP didn't come out,weather forecasts were made by the forecasters. With NWP's improvement,NWP took the place of synoptic forecasting in first step,and at present it even takes place of the part of weather elements. In the next two decades mesoscale NWP and ensembles will be improved very much,although objective forecasts may replace some part of forecasts made by forecasters,but forecasters will play an important role in weather forecasts. We need to analyze the combination between objective and subjective forecasts to improve weather forecast further.

Abstract:The heavy rain occurred in the northwestern area of Beijing on the night of June 24,2002 is a severe orographic rainfall.The heavy rain under the conditions there were two inverse temperature layers in the middle and low troposphere is affected by the reciprocity between mLLJ and Beijing terrain.The generation and development of mLLJ in boundary layer is caused by deflective east wind in the low layer,the inner boundary effect in the dry and wet process,the latent heat release of strong rainfall and the reciprocity of them.

Abstract:Based on grade data of drought and flood of Anhui for recent 554 years,the statistic analysis are made. The results show that the series are partial distribution,or floods are more than droughts,and the series have the feature of periodic variation,and the series also have the alternation between drought and flood. That turning points appeared in about 1723,1774 and 1913,that were tested by the analysis with moving-t method and Yamamoto method.

Abstract:With GMS-5 TBB data from 1980 to 1997 according to the appearing frequency of those TBB lower than -28℃,the synoptic and climatic features of the convection is investigated over the South China Sea and its ambient area.

Abstract:An analysis of spatial-temporal variation of precipitation in summer over Bayinguoleng,Xinjiang is made. The results show that (1) there are two basic distribution patterns over Bayinguoleng; (2) the summer rainfall has an increasing trend for the last 40 years and (3) there are the periods of about 5- and 2- year in the series of precipitation. Finally,a equation for summer rainfall forecast is developed.

Abstract:Based on two-year radar data of severe weather in Beijing,echo characteristics of severe storm are studied. The echo top of severe storms such as hailstorms and thunderstorms accompanied by gale is higher than that of heavy rain,the former is up to 12km. However,the latter is only 7km.Comparing with local heavy rain,the movement of radar echoes of hailstorms and thunderstorms is rapid. Based on analyzing the radial velocity,it is concluded that the dynamic structure of hailstorms and thunderstorms is quite different from that of the heavy rain. Moreover,the influence of topography is also very significant.

Abstract:The first heavy rain process during 2002 flood season of Hunan,with strong rainfall intensity and wide scope,occurred on 12—14,May 2002. Analyzing synthetically the process from several aspects,such as the general circulation,the physical factors,the satellite images,the radar echo,the numerical weather forecast products,etc.,it is shown that the key forecasting the heavy rain process succeeding and serving well is making best use of the above-mentioned products besides understanding the weather pattern deeply.

Abstract:Based on analysis of the characteristics of circulation background,physical mechanism and satellite cloud images of the rainstorm in southern Hami during 18-19 June 2002,cause of the rainstorm was described.

Abstract:Doppler radars have become one of the most important instruments for weather nowcasting,and for meso-scale weather research because of it's higher spatial and temporal resolutions. A dealing and graphic system for Doppler radar data was developed so as to providing a convenient tool for users. According to user's needs,many kinds of variables can be ploted and superimposed upon each other. Wind can be displayed such as contour,streamline and vector. It can be used very easily and conveniently.

Abstract:The temporal-spatial distribution of the rainfall,the surface runoff,the evaporation of various river systems in Huanggang,Hubei Province are analyzed. Under the various guaranteeing rate of industrial and agricultural production,and the demand for the water resource of the human lives,the distribution of water resource in the region is also analyzed. It is shown that the water resource is abundant in total amount,and potentiality of development and utilization is great. However,the uneven temporal-spatial distribution would cause the flood and drought events frequently.

Abstract:With the eco-climatic adaptability data,the growth laws and indexes of navel orange in Guangan,Sichan Province are studied. And the distribution model of climatic factors is established,i.e. y=f(h,Ψ,l,β).Then based on the GIS data of 1∶250000 and GIS technique,the climatic division of Guangan navel orange production is made. The result shows that climatic condition in some sub-area is not adaptive to the navel orange production.