Abstract:During recent 50 years, the global climate change is mostly caused by increasing atmospheric concentration of greenhouse gases，while air pollution is mainly produced by atmospheric aerosol particles suspended in the air. They are both emitted by burning of fossil fuels. Recent studies have shown that the atm ospheric aerosols also have significant climate effects: (1) they can reduce sol ar radiation reaching the surface through scattering and absorbing the sunlight, thus leading to cooling; and (2) they can modify microphysical processes and pr ecipitation nature as cloud condensation nuclei, thus leading to change in hydro logical cycle in the atmosphere. Atmospheric aerosols may exert important impact s in many aspects, such as on agriculture, water resources, human health, urbani zation，and so on. Due to common causes between air pollution and climate change to a greater e xtent a unified action should be taken for abatement and control of air pollutio n and mitigation of emission of greenhouse gases, based on the formulation of a winwin efficient strategy.

Abstract:Distribution and variation characteristics of mesoscale precipitation of tropical cyclones landed in Hainan during 1996-2005 are studied with the dat a of hourly precipitation from satellite and surface observation. Based on the d ifferent moving pathways, the landing cyclones can be divided into four major ca tegories. The analysis of four different types in seven cases indicates that the re is a distinct variation of mesoscale precipitation distribution before and af ter tropical cyclones landfall. The results show that the mesoscale precipitatio n distributes quasisymmetrically near the center of tropical cyclones in 10 hou rs before landfall，but after 10 hours mesoscale precipitation distributes asymmetrically near the center of tropical cyclones or far a way center of tropical cyclones. The intensity variation of maximal precipitation center is obvious during the la ndfall course.

Abstract:Three local heavy rain events have similar location of rainfall, which occurred in Xiangshan, Shijingshan and Mentougou area in the west of Beijing fr om the end of June to early August of 2006. Product of Doppler radar exploration is used to do fine analysis and research. The result shows that development and evolvement of radar echoes in these three events are different thoughsimilar l ocation of rainfall. The influence of vertical wind profile of westerly in bound ary layer on location of torrential rain is consistent under the action of topog raphy. The south-east wind from the plain in surface layer is almost vertical to the mountain lasting about 6 hours and strengthens temperature and humidity con dition in surface layer in the front of mountain. Convergence and lifting in sur face layer in the front of mountain form under obstruction of mountain in the we st of Beijing. Westerly winds in boundary layer around top of the mountain provi de beneficial factor for divergence in boundary layer by lifting in atmospheric surface layer. Studies also indicate that development and evolution of mesosca l e and microscale systems such as thunderstorm cell around location of rainfall and mesocyclone are key factors that decide the location of torrential rain.

Abstract:Using the conventional weather data, WSR88D Doppler weather radar dat a, SAFIR 3000 total lightning data, intensified sounding and automatic surface w eather observations, a severe pulse thunderstorm which caused four grandstands d estroyed and one blew away about 20 meters in the Shanghai F1 Circuit on August 3, 2007 is analyzed. The case analysis shows the interaction of boundary layer c onvergence lines, sea breezing front, and the cold outflow of previousthunderstorms triggered the initiation of some pulse storms in local area. The p ulse storm which caused the wind disaster in F1 Circuit was triggered by the col lision between the cold outflow of previous thunderstorms and the earlier bounda ry layer convergence lines. Due to the high atmospheric instability energy, suff icient ambient moisture, and convergence in the low and middle levels, the pulse storm intensified significantly in the cool pool of the previous thunderstorms and resulted in a damaging wind gust of 40.6 m/s and heavy rainfall in F1 Circui t. Furthermore, the sudden increase of total lightning flash rate of the storm i ndicated the eruption of the storm with a strong downdraft and the beginning of its declining phase.

Abstract:Using the Yingkou Doppler weather radar data, a preliminary analysis is made on the tornado process which occurred in the six townships of Yingkou Sou theast at about 16:00 on 10 August 2005. the main weather situation is a trough at hight altitude led by a northeast vor tex. The dry and cold air along the contour line and the wet and warm air produc ed stratification with covective instability. The south branch of jet and the so uthwest jet at low altitude as well as the northwest wind at high altitude gener ated a strong vertical wind shear, which is favorable for the generation of torn ado weather. This super cell is a low centroid convective system, of which the r eflectivity of radar echo is above 45 dBz. The severe tornado is accompanied wit h heavy rain, but without hail. The analysis indicates that this tornado is main ly a mesocyclone displayed on the velocity map. This case illustrates that the China new generation Doppler weather radar has the capability to detect tornado es.

Abstract:Using conventional survey, ground intensive observations, numerical pr ediction product T213 and FY-2c/2d infrared satellite cloud image, synoptic-dyna mical diagnosis and mesoscale analysis are carried on gale and strong sandstorm process initiated by squall line on May 2, 2008 in east of Hexi corridor. The re sults show that strong storm initiated by squall line produced the strong sandst orm. East of Hexi Corridor is in instable atmosphere stratification. Large scale circulation background is provided by stepped short wave trough of 500 hPa for squall line. Deformation field of 700 hPa is triggering system of squall line. G radient of pressure and temperature before and after cold front is enlarged by d evelopment of ground thermal low pressure, by whichthermal energy stability condition is provided for convection development. Upper air jet stream has vital role for production and development of squall line.

Abstract:The timedomain analysis on waveform change of lightning electric field and the identification of discharge types are one of the most important works in the st udy of lightning detection system. The risetime, falltime, pulsewidth and a series of timedomain features of return strokes and narrow bipolar events we re given through analyzing the fast electric filed change data our system acquir ed. The risetime of the negative returnstroke fields had an average of 2.9μ s, its falltime and pulsewidth were 89μs, 15.4μs on average.The average risetime value of the narrow bipolar events was 1.7μs. The mean of the fallt ime value and pulsewidth value of narrow bipolar events were 2.1μs and 2.4μs , respectively. Some of the results were consistent with other researcher’s, bu t some differences existed which is caused by the different equipment used. Neve rtheless all the waveform features we got was still valuable for the identificat ion. Based on these characteristics, a set of software which could distinguish r eturn strokes and narrow bipolar events automatically from all of the lightning radiations events was designed. The classification results were tested by manual selection of data, and it proved a 90% correctness of identifying negative retu rn strokes and a desired accuracy of identifying positive return strokes and nar row bipolar events. As a preliminary research of the waveform classification of lightning discharge events, this method already has a practical value. It can be used to distinguish cloudtoground lightning, cloudtocloud lightning and narrow bipolar events in the new lightning detection system.

Abstract:By using Jinan CINRAD/SA Doppler radar products, the weather proces s of squall line on July 5, 2006, evolution of echo and flow structure were anal yzed, the relations between the outflow boundary, sinking air currents and stron g wind were discussed，and the portfolio reflectivity factor, the vertical liqui d water content, the mesocyclone product characteristics were analyzed. The resu lts showed that two maxima of wind speed occurred during the squall line passing, one appeared in an outflow boundary impact sessions, another in strong echo si nking airstream affected periods. As the transverse trough moves southward, the inflow continuously added to the rear of squall line, the warm and wet air flow climbed along the rear of inflow, which constantly created new cells and maintai ned the development of storm. In the vertical flow structure, the warm air for t he front side was tilted upwards, and the main part tilled backwards. In the rea r there was the cold air injected and the downward flow formed. The sinking air near the ground diverged, together with the lateral inflow formed the lower gust front, which was the major factor causing the ground destruction. In the horizo ntal flow structure there was an upward motion of convergence at low level and a cyclone rotational flow at the middle level. At highlevel there was a diverge nce flow. In the dissipating period of squall line, MARC appeared at middle level , which brought strong winds and hail weather. The wind disaster with hail produ ced in the period when the squall line was the strongest and began to weaken. Wh en the echo intensity≥50dBz and vertical liquid water content ≥35 kg·m- 2, the mesocyclone is favorable for generating of hail and strong wind. The emerg ence of outflow border reflected that the strong sinking flow in the rear of stro ng echo is a precursor of the disastrous wind.

Abstract:The maintenance process of typhoon Winnie (1997) after landfall was reappeared by using the MM5 model. The numerical simulations cover the entire process inclu ding initial weakening, extratropical transition and redeveloping. The adiabatic and diabatic effect on the local change of potential vorticity (PV) at lower tr oposphere was analyzed, during the entire process using Ertel potential vorticit y budget equation on isentropic surface. The results show that the PV increases in the west and north of tropical cyclone at lower troposphere and the location of core is not the same to the typhoon. Because of the existence of friction a nd diabatic heating, the PV changed at lower troposphere. The local change is mainly decided by the horizontal advection ofPV (conservation term), vertical advection of PV, vertical differential of heati ng (nonconservation terms). With the happening of extratropical transition, th e PV at lower troposphere changed further and the positive effect of diabatic te rms especially vertical differential of heating on the local increase of PV domi nated.

Abstract:Accuracy on measurements and computational results of wind energy reso urce is one of the key factors for successful investment in wind power projects. Meanwhile, the precision of measurements and calculation of the wind energy res ource are primarily dependent on the terrain topography around the wind power fa cilities, distribution of the wind observing stations in the field, performance of observational instruments, and installation of these instruments.  Based on field measurements and analyses of a number of wind power faci lities, in particular over complex terrains, several major measures are proposed on t he quality control of observation data and computational precision. They include 5 principles on distribution of wind measurement stations over complex terra in, reasonable selection and appropriate parameter setting of instruments. Furthermore, quantitative estimations proceeded on systematic errors inherent i n the anemometers, and computational errors possibly arisen from interpolation o f data series for data void points. The computational results based on large qua ntity of field measurements show that: (1) the relative deviations of the import e d anemometers currently in common use are contained between 1.6% and 5.25%, a nd therefore it may produce over 5%, with maximum 13.8%, of the power density er ror of annual mean wind near the top of wind mill. (2) In the zones with monsoon climate, complex topography and significant annual variation of winds, the data observed in the same season or under the same dominant wind direction should be chosen as base data for interpolation, correction of the data void points , and/or for extrapolation of the time series of the data. Otherwise, the relati ve error of the power density of the mean winds may reach as large as 20%～50%.

Abstract:The relationship between the Arctic sea-ice concentration (ASIC) and s ummer mean maximum air temperature (MMT) in China is analyzed by using Singular Value Decomposition(SVD), ASIC data and MMT data of 160 stations in China from 1 951 to 2002. The results show that ASIC reduced significantly in 1978/1979 and s till kept the low value after 1979. The response of MMT to the abnormal of SIC has 9 -13 months lag. The response patterns are opposite phase for South China or Nort h China, and same phase for central China areas. It is necessary to focus more a ttention on the Arctic sea-ice extent in the mechanism and prediction of summer MMT variation in China.

Abstract:In recent years, the Inner Mongolia Autonomous Region has established 6 sand sto rm inspection stations. A series of quantitative data, such as the instrumentm easured visibility, PM10, TSP was obtained from the continuously quantitat ive observation in the sand dust weather. It provides the basic requirement for the sand storm quantitative analysis and forecast. Ten strong sand storm process es in Inner Mongolian during 2004-2007 are chosen, and the instrument measured data of 6 sand storm inspection stations combining with the observati ons are analyzed. The analysis indicates that the instrumentmeasured data has superiority i n continuation, stability and quantification. But it is different from the view of point of the present sand weather service standard. The new grading standard is needed. Under the existing data condition, A sand dust weather grading standa rds is determined initially based on the instrumentmeasured visibilityand PM10. The quantitative condition and the mechanism of the sand storm formation are discussed. The instrumentmeasured visibility, PM10 sand sto rm quantitative prognostic equation is established on the predictor of sand dust composite index, the friction speed and so on. This sand storm forecast method is used in quantitative sand forecast in 2008 and obtained good effect.

Abstract:Mohe is in the most north in China, the clima tic character and change of its extreme low temperature and extreme high tempera ture in 1963-2000 are analyzed by using the correlation coefficient method and c ontrast analysis method. The result shows that Mohe is the coldest place in Chin a, not only creates the record of coldest extreme low temperature, -52.3℃, but a lso the extreme low temperature of every year is below -38℃. The annual extreme high temperature is 38℃. Its annual range of extreme temperature is large, with the lowest of 73.1℃ and the highest of 87℃. In 1980s the annual range of extre me temperature tended to decrease. The overall change in the extreme low temperatu re is not obvious, but in 1990s increased significantly, with an average increase of 1.6℃. The extreme high temperature changes in a flu ctuation way, with an obvious increase of 1.6℃ in 1970 s and decrease of 1.1℃ in 1980s. The annual extreme low temperature occurs in N ovember, December, January and February. The annual extreme high temperature occ urs in May, June, July and August, and most in July. The daily lowest temperatur e occurs at 4:00—7:00, and the daily highest temperature occurs at 14:00—1 6: 00. It is worth to mention that the temperature below zero all happened in the e xtreme low temperature of December-January in the period of 1963-2000.

Abstract:By adopting the methods of moving average, trend analysis, wavelet transform and MannKendall method, the characteristics of interannual and interdecadal c han ges of precipitation and temperature in the area from Sanmenxia to Huayuankou (h ereafter abbreviated to “Sanhuajian” area) in the middle reaches of Yellow Riv er are analyzed with precipitation and temperature data of 21 weather stations i n this area from 1955 to 2006. The results are as follows：Firstly， the interdecadal change of average temperature is getting warm in the recent 50 more years，the late 1950s to 1980s is a cold period，whereas after 1990s is a warm period，the transition from cold to warm occurred in 1994.The period fro m 2001 to now is the warmest；The annual and seasonal mean temperatures in winte r, spring and autumn all show the trend of increasing, and occurrence of warming begins especially early and remarkably in winter. Secondly，The interdecadal c hange of precipitation is that the late 1950s to 1960s and the years after 2001 are rainy periods, whereas 1970s to 1990s is a less rain period, and particularl y, the precipitation in 1990s is the least；Seasonal precipitations all show the trend of decreasing except winter, and it decreases especially remarkably in su mmer. Thirdly，the main trend of climate change in “Sanhuajian” area is becom i ng warm and dry，but the fact that more precipitation appears after 2003 may ind icates the possibility of warming and humidifying in the coming years.

Abstract:Combined the development of Beijing Olympic Games weather service information is suing system, several often used monitoring means in data transmission operational systems were comparatively analyzed. Regarding the running state of Olympic Games weather service information issuing system, a sol ution is proposed to exert secure, effective and convenient supervision. RBAC (Role-Based Access Control) technologies based on B/S structure , in implementation of distributed monitoring are also covered in the paper.

Abstract:In order to improve the ability to use the products of T639, some synoptic verif ication about its medium-range forecasting for 2008 autumn is made in comparison with the NWP of ECMWF and Japan models. The results show that the three models have good performances in the aspect of predicting the large-scale circulation e volution and adjustment in Asian middle and high latitude area, and they all sho w significant indication to forecast the transition and the weather disaster. As a whole, ECMWF model is better in forecasting key weather systems compared with the T639 and Japan models. Especially, T639 and Japan models have failed in pre dicting path and intensity of strong typhoon HAGUPIT, whereas ECMWF model are re latively accurate.