Recently，frequent occurrence of extreme weather and climate events had caused serious impacts on people s production and livelihood，so the extended － range weather forecast attracted more and more attention． With the national spread and promotion of the low － frequency synoptic chart，extended － range synoptic processes forecast was developing vigorously throughout the country． To better satisfy the service need of synoptic processes forecast，an on － line displaying system associated with the extended － range synoptic processes forecast was developed in Zhejiang Climate Center． In this paper，the design philosophy，detailed structure，and the thoughts of future improvement and optimization were introduced extensively． The on － line displaying system included two columns，i． e． ，the heavy rainfall processes and the intensive air － temperature reduction processes based on different objects of forecast． The column of heavy rainfall processes consisted of the figure comparing between forecast and the actual state，forecast document，table of dynamic scores，table of brief description of the realistic observation，and table of detailed description of the realistic observation． The contents of intensive air － temperature reduction processes column were similar to that of the heavy rainfall processes，but the table of dynamic scores was omitted． In the future，the system will receive more improvement and optimization through designing more suitable indices and establishing the marking scheme for intensive air － temperature reduction processes and expanding the components of extended-range synoptic processes forecast．

Based on the routinemeteorological data and the Dopp ler radar date, the causes of a hail p rocess occurred on August 2, 2006 in Qingyang were analyzed from the synop tic environment, physical quantity field and the characteristics ofDopp ler radar echoes. Results show that itwas a typ ical northwest flow pattern at the level of 500 hPa, the lower air convergence and the upper air divergence,the coup ling of the positive vortex in themiddle troposphere led to the liftingmovement develop ing in the low level, and thiswas advantageous to the upward transportation of the local water vapor; the short wave trough at the north of Hetao area caused the cold air to move down and this became the main triggeringmechanism of this p rocess. The Dopp ler radar data analysis showed that the p rocess occurred after a strong convection cloud which created by a squall line, and there was a good corresponding relationship between the change of the cloud top temperature and the development of the convection cloud; the merge of the single cloud cluster was advantageous to the energy enhancement and easy to p roduce the hail.

The regional distribution features of daily mean net radiation，sensible heat flux，latent heat flux and soil heat flux density in summer over central Gansu were derived from the Surface Energy Balance A1gorithm for Land(SEBAL)using micrometeorological ob．servations over a wheat field at Dingxi station，solar radiation observations at Dingxi and Lanzhou stations．observations of 34 meteoro-logical。hydrological and rainfall stations over the Maxian Mountain region，combining with NOAA一16 AVHRR data，as well as the land surface reflectance an d vegetation coverage retrieyed from NOAA一16 AVHRR data．the efects of land surface process on precipi．tation were also analyzed in this paper．Th e results show that the regional distribution of annual mean precipitation corresponds well to vegetation coverage in summer。the correlation coeficient is 0．722．and the correlation coeficients of annual mean precipitation and soil heat flux ．1atent heat flux density are 一0．65 and 0．615．respectively．It is showed that the forest can not only increase net radia-tion but also decrease sensible and soil heat fluxes by decreasing surface reflectance and temperature．More solar energy can bere·ceived and mostly used for evapotranspiration over forest regions．which makes vapor content increased there．For this reason precipita—tion over forest regions is much more than that of semi—arid regions with sparse vegetation

Based on constant altitude p lane data of reflectivity factor from new generation weather radarwhich are interpolated with 3D - Barnes scheme, vertically integrated liquid water content (V IL) of hail cloud cell calculated with its theoreticalmodel, vertically integrated liquid water content density( V ILD) calculated by the ratio of V IL value to top height of hailcloud cell, the daily variation character, size distribution and the relations between the maximum diameter of hail on the ground (Rmax) and V ILmax, as well as V ILDmax of hailcloud cell during hail fall on the northeast of Tibetan Plateau are studied with statistic method. Results are as follows:(1)On the northeast part of Tibetan Plateau, hail fall was mainly in middle size hailstones ( diameter range: 5 - 20 mm) , and then smaller size hailstones ( diameter less than 5 mm) , larger hailstones ( diametermore than 20 mm) occurred less; (2) Local hail fall occurred mainly in the afternoon and evening, and there are two peak periodswhich are from 15: 00 to 16: 00 and from 20: 00 to 21: 00,and this result is accordant to the former research of Chen qian et al. on the whole but earlier in occurring period; ( 3) As a whole,there is a positive correlation between Rmax and V ILmax orV ILDmax, but the correlation between V ILDmax and Rmax is better; some difference exists in V ILDmax values of hail cloud cells corresponding to the same size hail but it is small and less than 0. 1 g. m - 3 ;( 4) The cone of silence for radar detecting, strong echo area leaning and echo overhanging of hail cloud cell are major factorswhich resulted in negative correlation between Rmax and V ILmax orV ILDmax.

The regional distribution features of daily mean net radiation，sensible heat flux，latent heat flux and soil heat flux density in summer over central Gansu were derived from the Surface Energy Balance A1gorithm for Land(SEBAL)using micrometeorological observations over a wheat field at Dingxi station，solar radiation observations at Dingxi and Lanzhou stations．observations of 34 meteoro-logical。hydrological and rainfall stations over the Maxian Mountain region，combining with NOAA一16 AVHRR data，as well as the land surface reflectance an d vegetation coverage retrieyed from NOAA一16 AVHRR data．the efects of land surface process on precipi．tation were also analyzed in this paper．Th e results show that the regional distribution of annual mean precipitation corresponds well to vegetation coverage in summer。the correlation coeficient is 0．722．and the correlation coeficients of annual mean precipitation and soil heat flux ．1atent heat flux density are 一0．65 and 0．615．respectively．It is showed that the forest can not only increase net radia-tion but also decrease sensible and soil heat fluxes by decreasing surface reflectance and temperature．More solar energy can be received and mostly used for evapotranspiration over forest regions．which makes vapor content increased there．For this reason precipitation over forest regions is much more than that of semi—arid regions with sparse vegetation

The contrast analysis of two strong cold wave and frost weather processes, which occurred on May 1-4 in 1994 and May 1-5 in 2004 in the middle of the Hexi corridor of Gansu province, was given from the aspects of the real weather state, the influence systems and numerical forecasting products. At the same time, the forecast points of this kind of weather process were given out also.