Abstract:A brief overview on progress and problems in studies of surface air temperature changes both in China and the world is given. It is suggested that more attention should be paid to the inhomogenization of temperature data and influence of urbanization on surface air temperature records in the future research.

Abstract:A heavy rain event near Gannan and Baicheng of Nenjiang valley during 9-11 August in 1998 is investigated. Diagnostic analysis, mesoscale filter analysis and numerical simulation have been conducted to inquire into the physical mechanism responsible for the above heavy rainfall. It shows that the existence of meso-β scale system is the direct reason of the event. A comparison of physical mechanism is made between Gannan and Baicheng. The results show that terrain elevation and latitudinal secondary circulation contribute to Ganan heavy rain, weak cold air and latitudinal secondary circulation and thermal effect in mid-low troposphere play important role in Baicheng heavy rainfall process. The MM5 model reproduces successfully the development of the two weather processes. Sensitive tests show that latent heat release acts a decisive role in the formation of the meso-β scale systems. Mesoscale terrain affects obviously the location and intensity of precipitation cell, and it makes Gannan precipitation increase. At the same time, it favors the maintenance and development of meso-β scale system. The effect caused by the variation of initial humidity field on simulation of rainfall area and intensity gradually decreases along with the increase of integration period. For Northeast China, the amount of water vapor which is necessary for the formation of precipitation is not only determined by the initial field, but also affected by the water vapor transportation from the tropical area to Northeast China.

Abstract:Based on dual-Doppler radar data, the tri-dimensional wind of the heavy rain on 22 July 2002 is retrieved with iterative technology and MUSCAT technology. The major characteristics of the event are the wind shear, meso-scale convergence line and the meso-scale cyclone at the low-level. The detailed feature of three-dimensional wind field from two methods are significantly different.

Abstract:Based on XDD03A lightning data in Beijing from 1999 to 2001, the lightning distribution characteristics of convection are given with hourly lightning frequency of thunderstorm combined reflectivity factors. And therefore, meso-scale convections could be deduced based on lightning tracks.

Abstract:The heavy rain process from July 28 to August 2, 2001 in Xinjiang is analyzed. It is shown that the heavy rain event is produced by the interaction and the adaptive configuration of the mult-scale systems of the higher, middle and lower layers under the anomaly change of the large-scale. Furthermore, the transportation path and its model of water vapor are given, and it is shown that water vapor of Arabian Sea and Bay of Bengal would influence South and East Xinjiang. Also the relationship between the energy front and heavy rain is discussed.

Abstract:Based on the climatic and water resources data in the last 50 years in North China, the situation of water resource and its exploration and utilization in this area are analyzed, as well as the features of climate change and impacts of climate on water resources and their relationship. Water resource assessment models are developed based on the above study and water resource condition of 2003 are pre-assessed quantitatively in advance through taking short term climatic forecast results into account.

Abstract:Based on the climatic data of ten years(1991─2000), the spatial-temporal characteristics of hailfall in North China are analyzed. The results show that: (1) The main hail zone appear in the shape of the letter T around the Yinshan mountain ranges and Taihang mountain ranges. (2)The annual variation appears a tri-peak form in the curve of dekad- or pentad-hail days evolution. (3) The daily variation of hailfall also has seasonal characteristics.

Abstract:Heavy rain event on September 11 2002 in Lingshi and Heshun, Jinzhong city, Shanxi province is diagnosed. The results show that the event is caused by active subtropical high, at the moment, there is also a uncertain cold front on the surface. The area where the heavy rain event lies to center of high energetic humid tongue. Low-layer humid tongue lags behind mid-layer humid tongue. In addition, local meteorological factors and local topography could be taken for factors of the reference to forecast local heavy rainfall.

Abstract:Referring to the methods of hydrological and meteorological observatories, the boundaries of Haihe and its 8 sub-valleys are objectively determined and the representative stations of each sub-valley are automatically selected. An ensemble forecast method is presented and its forecast results are verified. In addition, the relationship between area rainfall and the flux into Panjiakou reservoir is given.

Abstract:Based on grid data of forecasting fields (500hPa height, sea level pressure, 850hPa temperature) of T213L31 model and real-time objective analysis fields, prediction Natures on main affecting synoptic systems of eight strong cold wave processes in China during 2001/2002 winter are verified. The result benefited the interpretation of NWP products and operational forecast.

Abstract:By use of the T106 NWP products and the MOS method, the 1-5 days rainfall and temperature forecast equations of 81 stations in Guizhou province were established. It was proved working well by operational test, providing the effective objective forecast products for guidance in provincial forecasting opration. Furthermore, some proposal to improve the equations are given.

Abstract:With the application of satellite images and radar echoes to the best occasional choice,precipitation enhancement works are made by the airplane and the cannon in dry spell,June and July,2000. Practice showed that from above-mentioned data,water content,cloud top temperature,the intensity of clouds could be obtained,and then,the best time and area to precipitation enhancement could be chosen.

Abstract:The contrast observational results of ultraviolet solar radiation monitors (SUR-1) and the wide wave band ultraviolet radiation monitor (TUVR) are given. The results suggest that there is obvious difference between the two kinds of observations, that is, the former is lower than the latter, but there is a close relationship that the correlation coefficient is about 0 98.