SiB2, forced by five meteorological variables, was adopted to model the energy budget and CO₂ flux during stem extension, tassel and mature period over rice field in Changshu country of Jiangsu Province, China. These meteorological variables are solar radiation, vapor pressure, air temperature, horizontal wind speed and precipitation from in situ observation. Result shows that the energy partitions over these periods are different, so do CO₂ fluxes. The related results are close to those of IREX96. The SiB2 was demonstrated with automatic weather station (AMS) data and cold be used to estimate the energy components, CO₂ flux, soil wetness and soil temperature profile.

A comparison of the GAME reanalysis data with the NCEP/NCAR reanalysis data is discussed, where the GAME reanalysis data includes the data observed by HUBEX. On the basis of the weather processes over the Huaihe basin from June to August in 1998, the difference and reliability of the two reanalysis data from the fields of basic element, derivative, precipitation and surface flux were studied by the diagnostic and statistical methods. The results show that the GAME reanalysis data is more reliable than NCEP/NCAP reanalysis data at the bottom and mid-high levels of troposphere, and at the precipitation and surface flux fields the case is just the same. In addition, it revealed that the GAME reanalysis data can show the evolution of the southwest vortex but the NCEP/NCAR reanalysis data cannot do so. Meanwhile, the main cause that the GAME reanalysis data is better than the NCEP/NCAR reanalysis data tends to be the GAME reanalysis data including the sonde intensive observation of the GAME but not to the different assimilation modes of the two reanalysis data. Therefore it also indicates that the HUBEX as the Eastern Asia part of the GAME is necessary to continue, and increasing the temporal and spatial resolution of meteorological elements observed is important to improve our forecasting accuracy of the weather and climate.

In order to study the characteristics of errors associated with the lateral boundary conditions used in regional modeling, especially the regional climate modeling, based on the YH model, a regional model system nested with a spherical-belt type model is established and a set of error diagnosis tools are developed. By means of the software Excel, a series of comparative studies are carried out to analyze the spatial and temporal distribution of the errors due to the different lateral boundary conditions. The results show that the basic methodology for detecting the errors associated with lateral boundary conditions in regional modeling is rational, and the tools are quite useful. Moreover, it might also be applied to other studies, such as for diagnosing other types of errors in the model or developing some new schemes. The preliminary results indicated that the lateral boundary error of a regional model varies with the location in the model domain, and the spatial and temporal distribution of the error associated with different variables is rather different. Relatively, the errors of mass and potential vorticity fields are smaller in the YH model. The errors of kinetic energy and water vapor field are found mainly in the influent part of upper layers in the near-boundary region, while the error of sensitive heat field was in the upper layers of near-boundary region. The fixed lateral boundary conditions cause more serious errors than the nested ones, and the time interval updating the lateral boundary also has some impact on the error. It is interesting to mention that the errors of upper layers in the fine mesh regional model where the long wave motion dominates are larger than the errors found in the coarse mesh spherical-belt one. On the other hand, the errors of lower layers in the same fine mesh regional model where the short wave motion dominates are smaller than the errors found in the coarse mesh spherical-belt one.The impact of phase velocity error on lateral boundary errors is more significant in the lower layer, which is related to when the ratio of grid lengths of fine-mesh vis-à-vis coarse-mesh. The errors became much more serious when the diurnal variation cycle is turned off in the regional model.

Based on many kinds of observations, including conventional data, cloud image, Doppler radar data and wind profiler data, a squall happened in the Yangtze River Delta on 24 August 2002 is analyzed. It is found that this squall was caused by a mesoscale convective system (MCS). Cold front, water vapor transportation beside the subtropical high and a 500 hPa trough made the MCS arise and enhance. The fading and moving southward of the subtropical high and the local advantaged dynamic and air-layer conditions caused the MCS expand to be a squall, and the squall moved rapidly southward and eastward and brought wind and thunderstorm. The squall’s echo and wind structure are well figured out by Doppler radar, auto-station and wind profiler data .

The GPS signal ray’s perigee from the top of neutral atmosphere to the ground drifts largely in horizontal at an occultation event. The occultation event is simulated using the ray-tracking technique on the situation of the specified atmospheric refractive index model and the GPS constellation. The effect of atmospheric refractive index profile, LEO satellite’s height and inclination on the horizontal drift of the perigee studied. The results indicate that the difference between the average horizontal drift on day and that at night is about 20 km, the minimum of the average horizontal drift appears at some inclination 130° and the average horizontal drift increases from inclination 130° to 0° or 180° for a LED satellite which is at an altitude of 735 km above ground, and the average horizontal drift decreases from 400 km to 1500 km above ground for a LEO satellite at inclination 70°.

The meteorological elements such as temperature, precipitation, relative humidity, wind speed, cloud cover and visibility are predicted for the whole China by using the equations derived from the MOS (model output statistics) technique. The routine operational forecasts are made once daily for approximately 2230 sites. The qualities of objective element forecasts are affected by the data processing of predictors and predictands, the choice of parameters before making equation and also the choice of predictors. Therefore tremendous and careful efforts are needed. The results of the forecast verification indicate that the shortrange forecasts of max/min temperature and max/min relative humidity are reliable in most cases, but still need improvement. However, the forecast of precipitation is far from satisfaction. Its improvement requires the proper selection of predictors and full incorporations of various information obtained from different observation chances.

In order to get a time series that represent the total characteristics of some regions, objective analysis and regional-averaged method are widely used to handle observation data. Barnes objective analysis method is a convergent weighted-averaging interpolation scheme which is most generally used in meteorological and ocean field. The characteristics of the elements such as soil temperature, air temperature (include max and min temperature), air pressure etc. On the Tibetan-Qinghai Plateau were analyzed by using these two methods. It is found that when data are not good in continuity, the influence caused by the different region of observe station must be removed in order to get a reliable conclusion, otherwise an erroneous conclusion is got, so this question should be paid attention to.

The examination of reconstruction for missing data and homogeneity for summer precipitation and temperature in China was completed. The experimental study is on the reconstruction for missing data for the period of 1~5 years using stepwise regression and stepwise discrimination. It is found that the stepwise discrimination is better than the stepwise regression in the validity of the reconstruction. The experimental studies about different methods of discriminate group show that the discrimination based on Gamma distribution is better with a good validity. The discrimination selected nearly stations have a good validity than the stepwise discrimination with F value. The experimental results also show that the reconstruction for missing with the little error in the six areas in China on reconstruction using discrimination selected nearly stations.

To evaluate the ravages of a drought, a farther modified Meteorological Drought Severity Model for China was developed based on the Palmer Drought Severity Model and the modified Palmer Drought Severity Model corrected by An Shunqing etc. The monthly temperature and precipitation data at Jinan, Zhengzhou and Taiyuan (1961—2000) were used as basic data and relevant data gained at other 21 stations (Harbin, Jiamusi, Hohhot, Shenyang, Beijing, Guyuan, Xian, Hanzhong, Qingdao, Dezhou, Yuncheng, Changsha, Wuhan, Nanchang, Hangzhou, Fuzhou, Guangzhou, Kunming, Nanning, Chengdu and Guiyang) to obtain the weighing coefficient. The potential evapotranspiration for an individual month was computed by the Penman-Monteith equation commended by FAO. The available soil moisture in both layers (0—20 cm, 20—100 cm) was determined by the soil moisture data and the soil characters. The monthly Palmer Drought Index was computed at 139 stations of North China from 1961 to 2000. Comparing the computed Palmer Drought Index with the situation of drought and waterlog recorded in some documents, it is found that the farther modified Palmer Drought Severity Model can reflect the severity of meteorological drought or waterlogging comparatively and is applicable for China.

The historic observation data of dry-hot wind of spring wheat in Yongning, Ningxia and the wheat yield recorded by Ningxia Statistics Bureau are analyzed with the aid of disaster data got from Civil Administration Department of Ningxia. The clustering analysis method sieving step by step and giving an original clustering kernel as well as a segregated method step by step of the spring wheat yields are used. The indexes for two types of dry-hot wind of spring wheat in the Ningxia irrigated areas are obtained. Then, the discriminate equations are established respectively in the different disaster grades. The yield losses of spring wheat suffered from dry-hot wind in the grouting stage are segregated by means of climate simulation before the flowering and tasselling stage. A synthetically checking table for different disaster grades is given to combining the influence between the yield loss and the disaster degrees suffered from dry-hot wind in the different wheat growth stages. An estimating yield loss model is established and the monitoring disaster and the estimating yield losses are available .

Beginning from the completeness and rationality of the data and standardization of the methods, the designed wind velocity (DWV) for the Shenzhen Bay Bridge is caculated. A 48-year series of yearly maximum 10-minute averaged wind velocity at the 10 m height above surface is obtained through several correcting steps to the original records of yearly maximum wind velocity (MWV) from 1954 to 2001 at Shenzhen Meteorological Station so that meets the requirement of the guidance or standard for the resistance of building structures against wind pressure. Reference wind velocitys (RWV) at different return periods of 200, 120, 100, 60, 50, 30 and 10 years are caculated by adopting the function of Extreme I. It is found that MWV at the automatic meteorological stations near the beach or the bridge is positive correlation with that at Shenzhen Meteorological Station and the averaged value of the former is 10% larger than the later. Further more, the wind velocity over the sea is 4.9% larger than that at the beach according to the standard. So, DWV can be got through enlarging the RWV by a times of 1.1×1.049 (1.154), which is out-extended to every 10-m interval layers under 150 m above the sea surface .

The lack of unanimous opinion in spectral correction of energy and carbon dioxide eddy covariance flux error caused the difficulties not only in intercomparison of results derived form the different experiments, but also in synthesis data for global models. Two kinds of spectral methods used to correct sensor error were introduced. The influence of two-dimension and triple–dimension air current on CO₂ flux was discussed. Meanwhile, Error encountered in processing data and problems of measurement CO₂ flux in nighttime were investigated.

The sandstorm weathers in spring from 1981 to 1997 in the northern China are analyzed synthetically. The dynamic clustering method is used to divide the weather types to the day in sandstorm. Three of typical types are chosen, i.e., the northwest cold front type, the western trough and ridge moving type and the northern path type. The large-scale circulation situation and main weather systems of three types are studied. The basic characteristics of sandstorm weather are revealed. It is concluded that the clustering result can reflect objectively the basic weather types of sandstorm, which provides a path for the weather modeling method driven by data. It is the match of circulation situation in the high and the low altitude that results in sandstorm outbreak.

Based on MHF wavelet transform during the past long years in Chongqing the variations of temperature were analyzed. Some multi-scale and jump features of variations were discovered. Results show that the variations of temperature in Chongqing contain obvious staggered features. The variation tendency of temperature is descend. It is opposite to the tendency of the variations of temperature of the global, northern hemisphere and China.