Abstract:A framework of dynamic useroriented interactive forecast system is proposed. The newgeneration forecast system contains an initial userend module for configuring the dynamic forecast target, the physical predictive, downscaling components, userend professional models, and a useroriented assessing module in association with decisionmaking at the userend. A case study involving application of current global ensemble forecasts (TIGGE) of rainfall for hydrological users in Linyi, a region rich in rivers and reservoirs in eastern China, is conducted in order to highlight interactive involvement of the userend information during forecast process. An iteratively selfimproving forecast system, involving changing decisionmaking information throughout a flood season, a changing threshold for floodleading rainfall depending on previous weather and concurrent hydrological conditions, and a dynamic useroriented assessing process of concurrent skill and uncertainty of the prediction, is built up. It is demonstrated how a forecast of floodleading rainfall leads to a better warning signal for the user with interactive involvement of the userend than without.

Abstract:In this paper, the dynamic characteristics of typhoon Goni, the No.9 typhoon of 2009, were analyzed with the threedimentional grid reflectivity generated by Cinrad Mosaic System developed by the State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences and the wind field retrieved by a twostep variational method proposed by Qiu［27］. The main results show that: (1) Horizontal component of wind retrieved by the twostep variational method demonstrated the vortex structure of typhoon Goni very well. The tangential component of wind was of unsymmetrical distribution with wavenumber 1; (2) Within the radius of maximum wind (RMW), the mean tangential component of wind increased linearly according to the increasing distance away from the center of Goni at the height of 4 km, and quite nearly the famous Rankine vortex model［31］; (3) The inflows did not run into the center of Goni at all azimuths at low levels and at upper levels the outflows did not run out of the center of Goni in all directions, either.

Abstract:With data of hail days at 755 stations, NCEP/NCAR monthly reanalysis and atmospheric circulation characteristics from 1958 to 2007, we have investigated the interdecadal change of hail events in China. The results indicate that the overall trend of hail events has declined remarkably since the 1980s. Most of China has a descending tendency especially in the Northeast China, North China, Northwest China and EastCentral Tibetan Plateau. According to the analysis of relation between hail events and wind fields, height fields, subtropical high, polar vortex and temperature fields, we have found that the hail event has declined significantly in northern China, which is related to the southward shift of the 200 hPa westerly jet stream, the upward elevating of the 850 hPa height field, the weakening of the subtropical high, the strengthening of the polar vortex and the shortening of the distance between 0 ℃ and -20 ℃.

Abstract:Several cold airflow snowstorms emerging in northern coast of Shandong Peninsula from 3 to 7 December 2005 and from 4 to 6 December 2008 were analyzed with Doppler radar data from Yantai and conventional observational data. The results show that the northeast cold vortex in mid troposphere influenced the Shandong Peninsula before and during the snowfall, respectively. Frequently strong cold air in the lower troposphere causes a great airsea temperature difference which is the main reason to induce thermal instability of atmosphere. The water vapor was transported to the snowfall area from the Bohai Sea and northern Huanghai Sea in the lower troposphere and boundary layer. Snowstorms occurred in updraft area with convergence in low troposphere and divergence in mid troposphere. Updraft layer is much more lower than summer heavy rain. The forming and maintaining of mesoscale coastal front along coast line of northern Shandong Peninsula played an important role in the genesis of snowstorms. Echo top and strong echo (above 30 dBz) height have good corresponding relationship with the lowlevel divergence, 0-2 km wind shear and airsea temperature difference. The strong convergence at 850 and 925 hPa, high 0-2 km shear and large lowlevel temperature difference were conducive to echo development. Doppler radar products show that the initial echo generated in southern Bohai Strait and the heavy snow band extended from Bohai Strait toward Shandong Peninsula, the composite reflectivity was about 25 to 35 dBz, echo top was about 3 km. In the velocity field, the coastal front along coast line of northern Shandong Peninsula was very obvious during the heavy snowfall. The swing of coastal front determines the heavy snowfall region which would be in the middle part of northern coast of Shandong Peninsula when the coastal front closes to the coast line, and would be in the east of northern coast of Shandong Peninsula when the coastal front is distant from the coast line.

Abstract:Based on lightning location data corresponding to hail, gale, shortlived severe precipitation and continuous rainstorm of northern Fujian Province in 2005-2009， the lightning data show different characters in the different kinds of weather. Some useful conclusions can be obtained from the electric field meter of the different weather types in October 2008-April 2010. The results can help forecasters understand these data and offer more forecasting references. The nowcasting monitoring and discrimination on the severe convective weather by utilizing the lightning and electric field meter have advantages of good qualitative analysis and objectiveness, thus it can play a practical role in operational use.

Abstract:Using a statistical downscaling method （SDSM） we simulated and evaluated the changes of minimum and maximum temperatures, as well as precipitation during 47 years (1961-2007) in Beijing, and on this basis, we predicted the weather during the 2008 Beijing Olympic Games and during the 2009 National Day. The results show that, the SDSM has the ability of simulating temperature and precipitation. From the point of interannual simulation variability, the SDSM simulated temperature is better than precipitation, in which the simulated mean minimum (maximum) temperature is better than the simulated lowest (highest) temperature extremes. Meanwhile, the simulated annual maximum (minimum) temperatures are overall lower than the observed indicating there are systematic errors which show less ability to simulate extreme temperatures. The SDSMsimulated precipitation on the whole is less than the measured values, and the large values in the simulation of precipitation are even more serious. Weather forecasts during the Beijing Olympic Games and the National Day indicated that the predicted values for maximum and minimum temperatures, and precipitation are lower than the actual values, but the heating and cooling processes can be accurately predicted by the SDSM.

Abstract:By using temperature, humidity, wind speed, wet bulb globe temperature (WBGT), and solar radiation data during May to September 2008 and May to July 2009 obtained from Tianjin boundary layer observation stations, through correlation analysis and multiple regression, a WBGT simplified calculation method is established. At the same time, by using Rayman model, based on the cloud cover the average radiation temperature is calculated, achieving the weather forecasting factors, combining with GB/T 172441998 and ISO 7243 standard systems, further using WBGT forecast products and giving a proposal about labor time arrangements in the next 6 hours, so as to reduce the injury from high temperature outdoor working. The results show that, the WBGT is highly related with drybulb temperature and solar radiation. Based on conventional meteorological data and average radiation temperature, the WBGT simplified calculation methods are practical and feasible. If the WBGT prediction products are applied to the future work schedule arrangements, there will be a better guide effect.

Abstract:One severe freezing precipitation occurred over southern China in the early 2008. Using the Cloudsat products (ECMWF and radar reflectivity), from the cloud physics perspective, the main characteristics of cloud structure are studied based on sounding data and surface observations. The results indicate that there exists an obvious inversion layer, but it is not the only reason for freezing precipitation. Within a 10° latitude band from the Cloudsat orbit, there is a transition region, in the form of rain, freezing rain, ice pellets and snow, which is partially a consequence of sizedependent differences in melting layer and lowlevel subfreezing region. Combining with the vertical distribution of humidity, it shows that there exists abundant water vapor in the inversion layer. Compared with the soundings of Changsha station which is located at the Cloudsat orbit, the temperature of European Centre for MediumRange Weather Forecasting (ECMWF) is proved to be more correct than humidity. The radar reflectivity shows that there exists obvious signature of bright band during this freezing precipitation, which is just under the upper limit of 0 ℃ isotherm. The formation mechanism of “classical” melting process is demonstrated as the cause for freezing precipitation has been shown visually.

Abstract:Based on the experiment of solid precipitation weighingtype instrument at meteorological observation station of Altay in Xinjiang, the instrument of ZQZBH solid precipitation can measure solid precipitation in winter, and then can determine the grade of precipitation, especially the grade of precipitation above 0.2 mm precipitation amounts.

Abstract:In order to take advantage of the melting layer information in radar data, an automated identification technology has been developed by analyzing the signatures of melting layer in the reflectivity and linear depolarization ratio (LDR) parameters of millimeter wave cloud radar. Radar and radiosonde data during May to October 2010 in Hangzhou are used to compare and analyze the identification results and sensitivity of the parameters in the algorithm. Results show that this technology can identify the existence of melting layer. The difference between the top boundary average heights of melting layer obtained by this technology and the measured zero level height by radiosonde is less than 100 m. Parameter sensitivity analysis shows that melting layer signatures in reflectivity and LDR are different, and the thickness of melting layer is between 600 m and 1500 m. The causes of the little difference in this identification technology are the high range resolution of millimeter wave cloud radar, LDR sensitive to melting layer and the use of reflectivity and LDR dual constraints.

Abstract:A shared platform for the dynamic effect evaluation of precipitation enhancement， based on the model of Browser/Server (B/S)， is developed by using API, the second development platform of Google Earth. The system is based on “.NET” platform with C# as the main program language. The location of local rocket launchers and the flying track of aircraft are merged on the Google Map. Areas of the operated regions are affected by rocket seedings and/or aircraft seedings and the contrast regions can be promptly sketched and calculated dynamically. Databases of precipitation enhancement， meteorological observation and automatic raingauge can be browsed via Internet, and the reports of effect evaluation of precipitation enhancement can be exported by the system. The unification of regional effect evaluation of precipitation enhancement is realized. The system contains plenty of digital geography information from Google Earth. It is interactive and easily operated with friendly interface. A shared system for the regional effect evaluation of precipitation enhancement is realized.

Abstract:“Objective Analysis and Graphic System” is a populated twodimension meteorological plotting application with friendly graphic interface, which runs on Microsoft Windows. The updated software supports many new kinds of meteorological data interface, such as the geostationary satellite data, the new generation weather radar data, and the GRIdded Binary 2 (GRIB2) format data. Some new meteorological algorithms were developed in the new software, which are the isentropic analysis, the CTREC vector calculation, the TITAN convective storm tracking, lots of new kinds of graphs, the graphic clipping, and so on. The creation, drawing and editing of the contour, streamline, vector, post, geographic maps were improved in the new software. The data processing, the operation of user, and the output images were also bettered in the new software. However, the new software has also some shortages and need to be further improved in the future.

Abstract:The service processes of typhoon Fengshen are summarized when the performance of numerical weather prediction is disabled and the typhoon forecasting track is deviated to easterly. At that time, prompt revisions are made to typhoon forecasting track based on the nice changes of weather conditions. During the services, 1500 people working on maritime oil platforms are evacuated safely. Therefore, casualty and economic loss are avoided because of our high responsibility and good professional ethics. The results show that: (1) typhoon Fengshen turns westwards because of strong convection on the west side of Fengshen, negative pressure variety at the ground level, plus vorticity center at the middlelevel, and plus divergence at the highlevel . At the same time, the beltshaped blackbody area on the north side of “Fengshen” on cloud chart is also favourable to its turning westwards. (2) At 500 hPa, twice turnings northwards are caused by the low pressure circulation centre on the southwest side of typhoon and the high pressure belt on the northeast side successively.

Abstract:Weather service is called as the starting point and destination of the meteorological development. It is conducive to improving and perfecting the weather services and to promoting the meteorological development sustainably and rapidly in China so long as the evaluation on meteorological service benefits can be carried out scientifically and objectively. In this paper, the present situation and prospect of evaluation on meteorological service benefits, including in the basic theory and technology, are reviewed.

Abstract:The following are the main characteristics of the general atmospheric circulation in March 2011. There is a strong polar vortex centre in the Northern Hemisphere. The circulation presents a fourwave pattern in middlehigh latitudes. The south branch trough is slightly stronger than the normal, and the Northwestern Pacific subtropical high (NPSH) is slightly weaker. The regional averaged precipitation for whole China is 20.4 mm, and 27% less than the normal, which is the least in the past ten years. There are 7 main precipitation processes, which mainly occurred in the second and the last dekad, induced by cold surge, south branch trough, and NPSH. The monthly mean temperature is 2.4 ℃, and 0.8 ℃ lower than the normal, which is the lowest in the past 23 years. There are two cold surge processes affecting most areas of China, which result in the disasters, such as snow storm and sand slides in east of Gansu and east of Tibet, northwest of Yunnan, and west of Sichuan.

Abstract:In the past few years, rapid progress has been made in high performance computer capability building in South China Regional Meteorological Centre. The total capability exceeds 2 TFLOPS in theoretical peak performance now. In order to make the most of the computing resources invested, a finegrained computing resource management system is successfully designed and developed, which draws much from national meteorological high performance computer resource management software and takes into consideration the actual demands of South China Regional Meteorological Centre. The design idea of “resource accounts” and “resource credits” is adopted by the resource management system and thus, different kinds of users are provided with corresponding user organization solutions. Code implementation and deployment have been done with two leading high performance computer systems under management in South China Regional Meteorological Centre. Since it has been applied into operations, the resource management system produces satisfactory effects, implements balanced and full use of resources and becomes the right hand for system administration technicians.

Abstract:The paper uses the data of average air temperature, relative humidity and wind velocity from Yongshun Meteorological Station in every month from 1971 to 2000 as the factors of driftage comfortableness to evaluate the climate environment for Mengdong River tourism spots in Hunan which is a fourstar route as one of the only two driftage routes all over the country by means of fuzzy mathematics, and based on the model the forecast equations are set up. The results showed: (1) It is suitable for driftage from March to November in every year. The climate conditions are relatively comfortable from May to September, the most comfortable time is from June to August. July and August are the peak season for driftage. (2) The correlation degree is 0.859 between the judgment result of climate comfortableness and tourist traffic, showing that meteorological factors are the most important factors that affected tourist traffic. (3) Based on fuzzy evaluation the forecast equations were established for the comfortable level of meteorological conditions in the paper. In practice, it can provide guidance for the tourists drifting.