Typhoon Doksuri (No.2305) caused an extremely rare torrential rainfall over Putian City, Fujian Province. Based on multi-source observational data, including surface meteorological observational data of Fujian Province, radar and satellite data, as well as reanalysis data from ECMWF (European Centre for Medium-Range Weather Forecasts), the stages and intensity characteristics of the extreme rainfall induced by Typhoon Doksuri were analyzed. The main conclusions are as follows: The entire rainfall process was consisted of three seamlessly-linked stages. The first stage was the typhoon eyewall rainstorm, which had the characteristics of intense short-term rainfall and uniform spatial distribution. The second stage was the spiral rainband rainstorm, which was characterized by significant differences in hourly rainfall intensity and distinct rain peaks. The third stage was the monsoon-enhanced rainstorm, with the characteristics of a wide range of heavy rain and a long duration. The heavy rain in Putian caused by Typhoon Doksuri exhibits remarkable extremeness, with specific manifestations as follows: extremely intense heavy rainfall, a wide impact range of extremely heavy rainfall, large cumulative rainfall, high frequency of short-term heavy precipitation, and long duration. Among these, the 24-hour rainfall at Putian Station reached 561.7 mm, breaking the historical record of Fujian Province, and its extreme characteristics are particularly prominent. The continuous maintenance of typhoon warm shear line, low-level southerly jet and monsoon system is an important weather background for the three stages of rainstorm to achieve “seamless connection”. The uplift and contraction of the southerly jet caused by the terrain of Xinghua Plain “surrounded by mountains on three sides and opening to the south” is an important factor for the rainstorm center to be located in the Xinghua Plain to the northeast mountainous area.

Examine the relationship between tropical Pacific sea surface temperature (SST) and precipitation in China has scientific significance for improving China's climate prediction level. Based on the long-term monthly rain gauge data of 160 stations in China and the monthly SST index from Climate Prediction Center (CPC), USA, this paper explores the response characteristics of precipitation in China to tropical Pacific SST changes through a new method of lag cumulative correlation. The results are as follows: (1) This method is able to reveal the cumulative effect of previous abnormal SST on the precipitation effectively, so as to provide a basis for selecting the optimal predictive factors. (2) Among Ni?o1+2, Ni?o3, Ni?o4, and Ni?o3.4 SST indices, previous Nino1+2 index has the most significant relationship with China’s precipitation. More precisely, the positive correlation between Ni?o1+2 timeseries and the 4-month lagged precipitation, and the negative link between 2-month cumulative Ni?o1+2 time series and the the 9-month lagged precipitation in China are most significant. (3) The Ni?o1+2 SST can distinctly influence the precipitation in China's monsoon regions, with the strongest positive feedback are as primarily locate in the eastern part of the Qinghai-Tibet Plateau and Yunnan Province. (4) The linear fitting between the Ni?o1+2 time series and the average precipitation of China with a lag of 4 months shows that the fluctuation trend of fitted precipitation is consistent with that of the rain gauge data, with relative small fitting errors in winter and spring and larger errors in summer and autumn.

Drought is one of the most important meteorological disasters affecting vegetation in karst areas of Guangxi, and a reasonable remote sensing vegetation parameter can address the impact of drought on vegetation more objectively. To quantify the response of vegetation to drought, fractional vegetation cover (FVC) and net primary productivity (NPP) were selected to analyze the responses to standardized precipitation evapotranspiration index (SPEI) under different topography conditions and forest species. The results are as follows: (1) The responses of FVC and NPP to SPEI were significantly different in karst areas of Guangxi. The response of FVC and NPP to SPEI showed the highest consistency in spring, followed by summer and then autumn. (2) The difference of the response of different forest species to SPEI was small on an annual scale, but was large on a seasonal scale. At annual time scale, the response sensitivity for FVC to SPEI from large to small was economic forest, eucalyptus forest, pine forest, broad-leaved forest, Chinese fir forest, shrub forest, bamboo forest, and for NPP was economic forest, pine forest, eucalyptus forest, broad-leaved forest, Chinese fir forest, shrub forest, bamboo forest. The economic forest was most sensitive to SPEI and the bamboo forest was least. At the seasonal time scale, the sensitivity of FVC and NPP of eucalyptus forest in summer and broad-leaved forest in autumn to SPEI was lowest, and that of eucalyptus forest was highest in winter. (3) The response of vegetation under different terrain conditions to SPEI was also different, but it was smaller than that of different forest species. At annual time scale, the sensitivity of FVC to SPEI from large to small was plain, mountain region, alpine, and for NPP was plain, alpine, mountain region. The response sensitivity to SPEI was highest in the plain area for both FVC and NPP. At seasonal time scale, the response sensitivity of FVC and NPP to SPEI in different terrain conditions was only different in summer and winter. For FVC, its response to SPEI in summer was greater in plain than in mountain region and in winter was greater in plain than in alpine, and for NPP was opposite.

By using the realtime data from wind profile radars and the Lband sounding system, the characteristics of vertical wind profile during persistent heavy fog processes at Urumqi airport from 2014 to 2016 were analyzed. The results are as follows: (1) There were four upper air circulation patterns during persistent heavy fog processes at Urumqi airport, including frontridge pattern, ridge pattern, westerly wind fluctuation pattern and horizontal trough pattern. (2) The major forms of vertical wind profile were identified as TypeⅠ(WNW wind layer and boundary layer wind field) and TypeⅡ (WNW wind layer, SE wind layer and boundary layer wind field). (3) The bottom of the WNW wind layer was lowest under the circumstances of frontridge and horizontal trough pattern. The SE wind layer was thickest under the circumstances of westerly wind fluctuation pattern. (4) The evolution of the vertical wind field had a time advance of 1-2 h, and the regularity played a certain role in the prediction of persistent heavy fog weather.

Based on retrieved soil volumetric moisture content of CLDAS (land data assimilation system of China Meterological Administration), extracted field capacity of HWSD (harmonized world soil database) from FAO and Vienna International Apply System Institute and ten-daily soil relative moisture observation data at 15 agro-meterological stations of Guangxi, the soil relative humidity of CLDAS was calculated and tested. Combined with the statistics data of drought disaster, the drought in sugarcane planting area of Guangxi from summer to fall in 2011 was monitored and evaluated by using the agricultural drought grades and sugarcane drought levels classification standards. And on this basis, the sugarcane drought monitoring indicators of CLDAS were adjusted, and it was applied in the monitoring of drought. The results show that the retrieved soil relative humidity of CLDAS was better consistent with ground observation data from agro-meterological stations. The correlation coefficients were from 0.62 to 0.87, and RMSE was from 7.9% to 16.7%. The classification standards of agricultural drought grades and sugarcane drought levels underestimated the drought in 2011 in Guangxi, especially for agricultural drought grades, while the adjusted monitoring index of CLDAS could reflect the drought and its evolution process in sugarcane planting area well, and the percentage of absolute error with statistical drought disaster area was less than 8%.

Based on the hourly precipitation data of 50 automatic meteorological stations in Jinan area from March to November during 2008-2017, the temporal and spatial variation characteristics of precipitation with rainfall intensity over 10.0, 20.0, 30.0 mm·h-1 were studied. The results show that the hourly heavy precipitation in Jinan was affected by urbanization, topography and prevailing winds. There were more precipitation in Jinan urban area, southern mountainous area, Shanghe county and piedmont region in Changqing district, while there were relatively less precipitation in the downwind area of the suburbs, Zhangqiu district, Jiyang district and Pingyin county. Hourly heavy precipitation occurred most in July and August, monthly average precipitation with rain intensity equal to or more than 20.0 mm·h-1 was over 40.0 mm and its contribution rate was over 25.0%. The diurnal variation of heavy precipitation was characterized by double peaks and double valleys. The minimum precipitation period was around 11:00 and 23:00, and the maximum precipitation period was 04:00-05:00 and 14:00-21:00. Most sites had peak precipitation from midnight to early morning and from afternoon to evening.

Based on the data of 64 meteorological stations from 1971 to 2017 in Karst region of Guangxi Zhuang Autonomous Region, standardized precipitation evapotranspiration index (SPEI) was adopted as a drought evaluation index to analyze the spatial-temporal evolution rules of drought in this region. The results show that in the study area, the annual droughts generally occurred once every two years and their frequency increased from the middle part to the east and west, which were mainly light drought or moderate drought. By contrast, the seasonal drought was mainly concentrated in autumn, followed by winter drought, with low frequency of spring drought and summer drought. Besides, spring drought occurred every 3 to 4 years, and the frequency decreased from southwest to northeast. Summer drought also appeared every 3 to 4 years, but its frequency showed a weakening trend from east to west. The autumn drought occurred almost every year and its frequency was higher in central and eastern part than that in western part, with more severe drought and extreme drought than other seasons. The frequency of winter drought was similar to the autumn drought, but it was higher in the northwest and decreased from west to east. From 1971 to 2017, the winter drought and summer drought of studying area showed a fluctuating and weakening trend, while the spring drought and autumn drought showed an increasing trend. On the time scale of 15 to 20 years, there was an obvious dry-wet cycle in annual and seasonal drought, and the drought cycle below 5 years oscillated more frequently. The significant positive correlation between SPEI and soil moisture made it possible to use SPEI objectively to reflect the drought situation in the region.

The multi-factor integrated correlation probability method and the multi-parameter dot pitch line method are used to analyze 160 hailstorm cases occurred in the plain region of Ningxia in flood season from 2003 to 2008. The quantitative comprehensive forecast index of severe convection weather in the plain region of Ningxia discriminated by Doppler Radar was found. The result shows that the success rate of identification of hail, heavy rain and other severe convective weather could reach to 87.1% while the comprehensive forecast index reaches 2.8

 Using the new generation weather radar(CINRAD) data including echo intensity, velocity, composite reflectivity, hail index profile, storm tracing information, VIL and meso-cyclone 12 severe cnnvective weather events nccnrred  in 2003 and 2004 in Ningxia were studied. According to image characteristics, radial velocity products were classified as 3 types, and  were analyzed respectively form meso-scale   SynOptlC  pTlnClple.  RPSL11tS  S110W  that  the  pTOdL1CtS  Of  CINRAD  are  L1Sefl11  t0  fnreeaSt  SPVPTe  COriVPCt1Ve  eVentS,eSpeC1811y hall. 1VIeanWhlle, the COmpaTlSOn analySlS  WaS g1Ven 8150 hetWPen CINRAD and TOlltlne  Weather radar In th1S paper.

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weather has been gained with statistics. By using the forecasting products of Ningxia meso一、tale model MMS, a simulative analysis
has been done on it's related physical quantities, which has gained a valuable results.