Abstract:Looking back the sixty years of glorious history, the World Meteorological Organisation (WMO) was established with confidence in its contribution to human security and welfare. Over the past 60 years, WMO and its Members have created and evolved standardized global observing networks, together with free and unrestricted exchange of data and products policy and capability, laid the solid foundation for WMO Members to meet the evergrowing challenges and requirements of an increasingly complex society. Global observations strongly rely on international cooperation, which has been the hallmark of WMO. World Weather Watch, itself a unique product of international cooperation and networking, touched every nation and enabled the global standardized observations and exchange of real time data across frontiers. The paper firstly reviews the evolvement of the World Weather Watch Global Observing System (GOS), a testament to WMO and its Members that the unique global system for which they have been responsible has so significantly contributed to the understanding of our world and its environment. The second section describes the Rolling Review of the Requirements process, i.e. how WMO observing capability can meet the user requirements, which gives excellent guidance for the observing system development. The third section gives the description of the Vision for the GOS in 2025, explaining the key development components of the future GOS. The fourth section elaborate the WMO new initiative: WMO Integrated Global Observing System (WIGOS), an integrated, comprehensive and coordinated observing system to satisfy in a costeffective and sustained manner the evolving observing requirements of WMO Members and programmes for their weather, climate, water and related environmental services and will enhance coordination of WMO observing systems with those of partner organizations for the benefit of society.

Abstract:Potential vorticity (PV) is one of the important concepts in advanced synoptic and dynamic meteorology. This paper is a brief introduction to the theory of potential vorticity, including the concept of PV, the conservation and invertibility of PV, PV thinking, moist PV (MPV), and the application of PV theory.

Abstract:By dividing Beijing into three plates indicating different urbanization levels according to the urbanization degrees, effects of Beijing urbanization on land surface temperature (LST) are analyzed with routine meteorological data and remote sensing products. (1) Impacts of urbanization on such features of LST as mean value of year, season, day, night, maximum and minimum are analyzed with the combination of meteorological data and the three plates. The results present that LST in three plates is all increasing from 1978 to 2006. In most conditions, mean LST calculated from the first plat is the biggest, and this from the third plat is smallest. (2) MOD13 and MOD11 products of 2001 and 2006 are used to study the effect of change in surface on LST during urbanization of Beijing. The results show that NDVI in 2006 is decreased by 51.3% compared to this in 2001 while day LST is increased by 73.74% and night LST is increased by 90.92%. （3） According to NDVI difference and day/night LST difference between 2006 and 2001 in Beijing, nine classes are extracted to present the change of LST with the change of NDVI. The classification result of NDVI difference and day LST difference shows that the percentages of the class presenting NDVI decreased while day LST increased in the three plates are 54.29%, 40.95% and 34% respectively. And the summary of the percentages of NDVI increased while day LST decreased and NDVI decreased while day LST increased is bigger than 50% in all three plates. The classification result of NDVI difference and night LST difference shows that the percentages of the class presenting NDVI decreased while night LST increased in the three plates are 51.67%、44.2% and 42.46%, which well explains the impact of surface change on LST during urbanization.

Abstract:According to the monthly precipitation data of 120 meteorological stations in Chongqing and Sichuan during 1960-2006, the precipitation distribution in these areas was analyzed. At the same time, by correlation analysis, crosswavelet transform, the relationship between the precipitation over Chongqing and Sichuan and SST in Nino3 and its stability were also analyzed. The main results are as follows: the consistent anomaly distribution is the main spatial model of precipitation variation in Chongqing and Sichuan. The first mode time series of EOF had good relationship with SST in Nino3. This relationship manifested that in the warm phase of SST in Nino3, the precipitation in Chongqing and Sichuan was less, while, in the cold phase, more. The precipitation in Chongqing and Sichuan had good relationship with SST in Nino3 in quasi2 a, 4-6 a periodic changes, but this relationship was not stable. There were good positive and negative correlations during 1960-1986 and 1987-2006 respectively.

Abstract:Study on climate characteristics of Chinese freezing weather is important to forecast, preassessment and disaster prevention. The 48year averaged rime days and freezing rain days were computed to reflect the frequency and spatial distribution of freezing weather. The observed wire ice load was transformed into standard ice load to analyze the maximum ice load distribution. The spatial and temporal variations of freezing weather were analyzed by EOF expansion. Trends of Chinese yearly maximum ice load were studied. Results show that freezing weather appeared in most parts of China. Rime mainly appeared in northern China while freezing rain appeared in southern China. Yearly freezing days increase with elevation while less over height of 3100 m. Under the global warming background, the frequency of freezing weather decreased while the strength was stronger in most parts of China.

Abstract:Based on the JRA-25 (1.25°×1.25°) reanalysis datasets, the circulation features and moist conditions of the persistence rainy days from February to March 2009 are investigated. The results show that: (a) at the middlehigh latitudes, the blocking situations are stable over the Eurasia, and at the middlelow latitudes, the West Pacific subtropical high (WPSH) is intensified over the Philippine Sea. Under these stable circulations, the colddry air from the north contacts the warmwet airflows from the south over the middlelower reaches of Yangtze River for a long time, which forms a stationary front. (b) In the upper troposphere, the axis of the subtropical westerly jet stays around 35°N, enhancing the divergence above the stationary front. The divergence matches the cyclonic convergence north of the southwester lies on the low levels, which forms a favorable rainproducting dynamic structure. (c) The anticyclonic circulation anomaly, according to the intensified WPSH, results in a moisture transport anomaly from the West Pacific and the South China Sea to southern China. The meridional transport anomaly contributes the most of the moist convergence in the rainy area, having significant impacts on the development and persistence of the precipitation.

Abstract:By using observation data of mesoscale automatic station in Anhui and statistic data, the influence of Jiuhua Mountain underlying surface on the distribution and intensity of precipitation has been discussed， and the role played by underlying surface physical processes in the precipitation has been analyzed. The results show that the heat and humid conditions and its unstable energy in mountainous area are stronger than in surrounding areas. The thermodynamic effects of nonuniform underlying surface and the mountainous topography 〖HJ〗lead to ground wind field convergence， and the resulting vertical ascending motion strengthens lowlevel jet, which affects the formation of strong convective weather and development. The topography in mountainous area has an obvious effect on the rainfall distribution. The mean annual precipitation, precipitation days and intensity are significantly stronger than others in the peripheral hilly area. Precipitation is significantly enhanced at the windward slope and greater at higher mountains. The study on automatic weather station data gives a good indication of nowcasting for the formation, development and decay phases of a rainfall event in mountain.

Abstract:The typhoon No. 0716 (Krosa) landed on the vicinity region between Zhejiang Province and Fujian Province at 1530 BT 7 October 2007 for the third time. An outer spiral rainband passed through the dualDoppler radar observation domain that was composed of Ningbo and Zhoushan Doppler radars. Three dimensional wind field was retrieved by the dualDoppler radar data. The mesoscale structure of the spiral rainband was investigated by the 3D wind. It shows that there were some strong reflectivity areas in the low level of the rainband region. The inflow in the upstream of the rainband outside was weak. On the other hand, the inflow in the downstream of the rainband outside was strong. There was outflow in the inside of the rainband at the low level. In the vertical crosssection, there was inflow in the low level of the outside rainband. The inflow entered the rainband at low level (z<2 km) from the outside rainband. On the contrary, there was outflow in the inner side of the rainband. These flows converged at the low level of the rainband central region. The tangential component of the wind decreased with height and the maximum wind region was at 2 km level.

Abstract:A severe convective case, occurring in Shanghai on 30 July 2005, is examined with the composite datasets from WSR88D Doppler radar, automatic weather stations and mesoscale numerical model WRF. It is found that the occurrence of mesoscale convergence lines was mainly induced by the southward intrusion of weak cold front and the preexisted local mesoscale baroclinic instability. The growth of these mesoscale boundary layer disturbances within the convergence lines was favored by the dynamical cooperation among high gradient of moisture, strong vertical wind shear, and energy front within the lower troposphere, resulting in the abrupt growth of the convection. Mechanisms for the simultaneous occurrence of hail, heavy rainfall and gale during this severe convection are also analyzed.

Abstract:By using the data of FY series satellites, Doppler radar, lightning detection, automatic weather stations, etc., a primary observation and synoptic analysis were made to a lightning stroke casualty event occurring at Kaixian County of Chongqing Municipality on May 23, 2007. The main results show that this event was related to a rapidly developing MαCS which formed in northeastern Sichuan Province in the morning. The lightning stroke event happened when the MαCS moved eastward, developed continually and entered northern Chongqing in the late afternoon. The MαCS eventually developed into a MCC in the evening. The MαCS evolving process was monitored by the FY-2C, FY-2D satellites clearly, but not effectively by radar due to the limitation of detective range regardless of some information it revealed. The observation of the lightning location systems shows that more frequent positive cloud to ground (+CG) strokes were concentrated on the initial stage of MαCS, also the +CG strokes often occurred around the -CG stroke area during the developing stage, this distribution of CG flashes is maybe ralated to the newly developing cells. The southwest vortex and cold air and their interaction are the main triggering factors. The MαCS initiated and developed in weak convective unstable environments, but the middlelowertropospheric air is near saturated.

Abstract:The aim of this paper is to investigate spatialtemporal characteristics of the haze spanning 1971-2007 over Hebei Province of North China using the observations from 142 stations. Our study demonstrates that the haze frequency is changed with location and month, for example more haze appeared in piedmonts than in mountains or flat areas, while the haze was concentrated in winter (December and January) and least frequent in August and September. By using the observations about the 500 hPa height and the sea level pressure from 2004 to 2007, the conclusion can be drawn that the 500 hPa circulation patterns can be divided into 5 categories, including zonal circulation pattern, two troughs and one ridge pattern, mean height pattern, one trough and one ridge pattern and pattern of two ridges and one trough. A further analysis implies that the haze frequency also relies on local air pollution and regional circulation pattern dominant in addition to the terrain of surroundings. Above results are valuable to understand the forming mechanism and to establish a forecast system of haze over Hebei Province.

Abstract:It was carried out a comprehensive observation and analysis of a mixed convectivestratiform precipitation in Beijing on 30 June, 2007, by using IP/WVP3000 groundbased microwave radiometer, Doppler radar, satellite data, ground gauge and other observational data. The results showed that, there was a marked increase in the total liquid water content detected by the groundbased microwave radiometer, before the start of precipitation. Precipitation lagged behind the emergence of liquid water content began to increase for some time. By use of that phenomenon, it may be early warning in the stage of the development of precipitation, and applied to artificial rainfall. It showed that the vertical distribution trends of radar reflectivity and liquid water content detected by groundbased microwave radiometer had a good relationship, when detecting at the same time and same location. In addition, the distribution of the cloud liquid water, especially the lowlevel liquid water, had a direct relationship with the ground rainfall.

Abstract:Geographic Information System (GIS) as an important information technology is attracting more and more attentions and widely used in meteorological field during the past years．This paper firstly gives an overview of academic trends and technical application of GIS in meteorology and climate, and then addresses some fundamental issues for GIS further available for meteorology and climate application, such as GIS data model and meteorological data sharing, GIS spatial analysis and meteorological application model, GIS visualization and meteorological information science visualization. Lastly, it proposes some general principles and methods for constructing meteorological information system based on GIS capabilities. In conclusion, some new trends of GIS, which will be applied in meteorology, are discussed.

Abstract:By using the extensive theory， the YunnanGuizhouSichuanChongqing region’s geological disaster forecast system was built up. The macroscale model of WRF provides the precipitation forecasting for geological disaster forecast system. The probability forecast of geological disaster was produced. The system forecasts the probability of disaster on the lattice and then releases it in grade. Some localized tests have been done. The results show that the macroscale numerical model WRF has some certain forecasting capability.The forecasting capability of WRF model for long duration and regional rainstorm is better， and then WRF can provide good application service for geological disaster forecast. During 2 to 5 July 2007, a series of geological disasters took place in eastern Sichuan Basin. The forecasting results showed that the geological disaster system could forecast the disasters well. Different types of rainfall, which caused the geological disasters, could be responded well and the prediction accuracy in July was better. The system has some certain effect.

Abstract:The cubic spline interpolation method is applied to make TC （Tropical Cyclone） track and intensity forecasting based on ECMWF (European Center for Mediumrange Weather Forecasts) daily mean sea level pressure (SLP) fields from 2004 to 2007, and errors are calculated. Compared with subjective TC track forecasting by JTWC (Joint Typhoon Warning Center), JMA (Japan Meteorological Agency) and CMO (Central Meteorological Office), the JTWC outperforms the other three for leading time within 72 hours, followed by JMA, and ECMWF is left behind among the four centers, while ECMWF does better than JTWC for 96 h and 120 h TC track forecasting. ECMWF provides higher pressure values up to 15-20 hPa than the observed for 24-120 h forecasting. Results based on the 20 BT initial fields display no differences from those of the 08 BT initial fields for 24-48 h forecasting, but are better than those of 08 BT for 72-120 h forecasting.

Abstract:Research on water balance and evapotranspiration (ETa) process is an important part in water cycle research. Observation and assessment on ETa over land surface are of great significance for the understanding of water cycle and sustainable development of water resources under climate change conditions. However, traditional lysimeter is usually of simple function, limited precision, and is expensive in installation and daily operation. To observe ETa over land surface and understand the ‘evaporation paradox’, the authors designed this new lysimeter system, which is located in the Ecological Experiment Station of Nanchang County in Jiangxi Province, to study the impacts of climate change on water cycle and ETa over land surface. With many hitechs such as high resolution weighting system (0.01 mm), pfmeters (pf: 07) and observation GPRS loggers (24 bit, 512 k), ETa over land and its process are measured based on the observation of soil water potential (Matrix potential), lysimeter and groundwater level. Besides higher precision and frequency compared to traditional lysimeter, this new system can observe ETa process, the new loggers for soil moisture and water potential, which got the international patent in 2004 thus it is of high precision, observation frequency and wide adaption to environment, and therefore can be used to a wide range of application based on different targets and new version of design. 

Abstract:Ground weather monitoring specification has been changed in 1980. To well understand the effect of the change to the visibility data continuity, the visibility data in Nanning and Guilin from 1951 to 2006 are analyzed using the accumulated percentage method, Ridit method and “very good day” method. The results show that high values of visibility in Nanning and Guilin rapidly decrease in 1980 in contrast to 1979, which results in rapidly descending of Ridit average value and “very good day” number. The reason for rapid decrease is the change of ground weather monitoring specification in 1980. Therefore it is unreliable to use visibility high value, Ridit average value and “very good day” number to analyze visibility data around 1980.But visibility middle value and low value in Nanning and Guilin are not affected by the change of ground weather monitoring specification in 1980, which means it is reliable to use visibility middle value and low value to analyze visibility data around 1980.

Abstract:Based on Zhundong’s power load information and the forecast products of T213 from April to September in 2005-2006, the effective timeserial data of daily average are established. Correlations of power load and T213 main forecast factors are analyzed. 700 hPa water vaporflux, 850 hPa water vaporflux and precipitation are selected as those important forecast factors, and forecast equation of daily average power load variation is obtained. Testing forecast to year 2007, power load change tendency is consistent with reality, but there are some forecast errors sometimes when load makes fluctuate evidently. The reason is that T213 makes mistakes for forecasting rain weather. An improving scheme is combining T213 model with weather forecaster experience. The forecast equation is rebuilt by using T213 important forecast factors and new precipitation factors which are selected from weather observation elements. The forecast result is more accurate. After analyzing forecast errors from April to September in 2007, the conclusion is that the planed power load’s average error is 11.5%, T213 model’s is 8.2%, and the optimizing model’s is 6.4%. In rain days, the planed power load’s error is 22.3%, T213 model’s is 13.4%, and the optimizing model’s error is reduced to 8.9%.

Abstract:By analyzing current status and existent problems of automatic weather monitoring system, and based on the general packet radio service and network communication technology and data processing technology, a new, safe, reliable system was designed on the rapid data transmission and information concurrent processing of a large amount of automatic weather station. The system design thought, communication means, network architecture, transmission protocol, workflow, software design, technical characteristics were described in detail. It is a good system design method that is able to guide the development of other largescale, unattended, realtime data acquisition, data burst transfer application systems.