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30 April 2017, Volume 33 Issue 2 Previous Issue    Next Issue

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Validation of forecasting regional rainstorms from multi-models over Jiangxi province during the flood season in 2015 SUN Su-qin, ZHENG Jing, JIN Mi-na, WU Jing, LI Wei 2017, 33 (2):  1-7.  doi: 10.3969/j.issn.1673-503X.2017.02.001 Abstract ( 258 )   PDF (898KB) ( 419 )   Save 24-hour precipitation and weather patterns observations data,model products of weather patterns from ECMWF and precipitation from ECMWF,JMA and T639 were used to analyze the spatial-temporal distributions of 15 regional rainstorm events over Jiangxi province during the flood season (from early April to early July) in 2015.Short-range validation was carried on for the forecasting synoptic systems and precipitation to evaluate the forecasting skills of weather patterns by the ECMWF model and the precipitations by three other models.The results show that ECMWF has certain capacities to forecast the adjustment and evolution of weather patterns,e.g.subtropical high and Southwest Jet over Jiangxi province during the flood season,though the errors increase with a length of forecasting time.Although the accuracy of ECMWF 24-hour forecasts is relatively high,the 48-hour and 72-hour intensities of subtropical high from the ECMWF model are significantly weaker than those of observations.The ridge location of subtropical high predicted by the ECMWF model is located more eastward and the intensities of subtropical high appear weaker with seasonal change.The high-level troughs and shear lines are rather accurately forecasted by ECMWF,except for a little slower in the movement of 72-hour shear lines forecasting.ECMWF tends to predict weaker Southwest Jets at 700 hPa,stronger ones at 850 hPa and 925 hPa,and higher relative humidities at lower levels as well.Each of the three models has significant capacity to regulate the forecast for regional rainstorms over Jiangxi province.The forecast skill of JMA ranks the number one,showing the best skill for precipitation distribution forecast despite the values seem smaller.Although the locations are generally northward,the precipitation intensity from ECMWF is well predicted.The main precipitation belts from T639 are broader than observations.All three models have deficiencies of missing forecasts of precipitation from extreme heavier rainstorm events. References | Related Articles | Metrics

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Analysis of the evolution of convective clouds during a rainstorm in 2015 over Hubei province ZHANG Duan-yu, CUI Chun-guang, XU Ming, WANG Jing-yu, HU Chang-qiong 2017, 33 (2):  8-17.  doi: 10.3969/j.issn.1673-503X.2017.02.002 Abstract ( 352 )   PDF (2955KB) ( 554 )   Save Conventional and intensive observation data,hourly rainfall data,FNL reanalysis data,as well as the Temperature of Black Body (TBB) observed by FY-2G satellite were used to analyze the environmental conditions and affecting mechanisms of convective clouds during a Meiyu rainstorm on July 14 to 15,2015 over Hubei province.The results show that the favorable conditions for the evolution of convective clouds are convective clouds located in front of the trough at 500 hPa,wind converging and small dew point depression at 850 hPa and warm advection maintaining between 500-850 hPa.When synoptic scale Warm Conveyor Belt (WCB) clouds develop from western Jiangnan area to the middle reaches of Yangtze River,and low-level warm shear lines appear over Hubei province,the precipitation will increase significantly.When WCB clouds obviously move eastward,rainstorm over Hubei province will terminate.When WCB is located over Hubei province,large positive items of both advection and convection of equivalent potential temperature will appear at 850 hPa,and the areas with large convection items will appear to the south of those with large advection items.Short-time heavy precipitation occurs predominantly in the rain-prevailing period,which is important to local rainstorms.There are four mechanisms influencing short-time rainstorms over Hubei province,including the western borders of convective clouds,center areas of deep convective clouds,"train effect" of convective cells and mergence of convective clouds.The number of rainstorms affected by the western borders of convective clouds and convective cells is relatively more,and the precipitation affected by center areas and mergence of convective clouds is relatively larger. References | Related Articles | Metrics

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Application of assimilated GPS/PWV data to the rainstorms forecast over Anhui province HE Zhi-xin, JIANG Yang, ZHANG Su, YAO Ye-qing, QIU Xue-xing 2017, 33 (2):  18-27.  doi: 10.3969/j.issn.1673-503X.2017.02.003 Abstract ( 334 )   PDF (3377KB) ( 552 )   Save GPS/PWV (Precipitable Water Vapor) data,sounding and surface data are assimilated into the WRF model together with a 3DVar assimilation system to investigate their effects on a regional rainstorm on May 10 and a local one on May 24,2015,respectively,over Anhui province.The results show that GPS/PWV data assimilated to WRF can improve the relative humidities in an initial field,but have little influence on wind.However,sounding and surface data assimilation can improve both relative humilities and wind,with a slightly worse result than that of GPS/PWV for the humidities.The forecast capacities of rainstorm locations and intensities may be enhanced with the assimilated GPS/PWV data only,superior to those with sounding and surface data.If all these data were assimilated to the WRF,the rainstorm locations and intensities can be significantly improved and closer to the observations,leading to higher TS scores and lower false-alarm rates. References | Related Articles | Metrics

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Comparison research on the causes and warnings of two severe convection events over Shanghai LIU Fei, XIAO Peng, HUANG Ning-li, FANG Zhe-qing, XIE Xiao 2017, 33 (2):  28-36.  doi: 10.3969/j.issn.1673-503X.2017.02.004 Abstract ( 359 )   PDF (2574KB) ( 805 )   Save Comparison analysis were carried on using large-scale circulation,dynamic and vapor condition,instability stratification,and radar data to evaluate the formation reasons of the two severe convection events on August 24 and September 1,2014 over Shanghai,and a further warning research was conducted as well.The results show that the two events happened at the edge of subtropical high with obvious low-level jets.The events start times in forecasting were earlier than real conditions.As for the differences,severe convection appeared in front of the trough,accompanied by squall line and mesoscale gust front,causing the thunderstorm on August 24,while the deep moist tongue appeared in severe convection due to low-level vortex moving eastward,causing the long-time rainstorm on September 1,2014.Vertical wind shear is a fine indicator to the maintenance and development of a thunderstorm.The convection in front of the trough coupled with severe vertical shear tends to cause regional thunderstorm,but the convection due to low-level vortex moving eastward coupled with weak vertical shear tends to cause a regional convective rainstorm.Since the affecting time of convection system in front of trough is short,it is necessary to analyze the development of mesoscale and small-scale low pressure convergence.The start time of the convective rainstorm due to low-level vortex moving eastward is related to the warm-zone convective rainstorm. References | Related Articles | Metrics

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Climate characteristics of flood season rainstorms from 1960 to 2014 in Liaoning province WU Qiong, ZHAO Chun-yu, NIU Dan, CHAO Hua, ZHANG Zhi-heng, WANG Da-jun, XU Fang-shu 2017, 33 (2):  37-43.  doi: 10.3969/j.issn.1673-503X.2017.02.005 Abstract ( 301 )   PDF (1775KB) ( 436 )   Save Daily precipitation data at 54 national weather stations from 1960 to 2014 in Liaoning were used to analyze the temporal-spatial variation characteristics of the rainstorms and their intensities during the flood seasons (from June to September).The results show that most rainstorms appear in flood seasons based on data from 55 years,especially in July and August during which the number of rainstorms takes up 72% of the annual total.The number of rainstorm days decreases from the southeast to the northwest of Liaoning province and the rainstorm intensities decrease from coastal regions to inland regions.The lifetime for most rainstorms lasts about two days,and the number of occurring times at different regions is very different.The days,intensities and ranges of rainstorms vary little during the 55 years,with a 12-year variation period of rainstorm days and intensities and a 2-year significant period in 1990s. References | Related Articles | Metrics

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Modeling method of hourly meteorological data based on piecewise cubic spline function ZHU Ye-yu, SONG Li-li, JI Xing-jie, MENG Han-dong, LI Feng-xiu, LUO Xuan 2017, 33 (2):  44-52.  doi: 10.3969/j.issn.1673-503X.2017.02.006 Abstract ( 324 )   PDF (1003KB) ( 674 )   Save Fine hourly meteorological data are the basic for the studying climate feasibility.Based on the four times a day of observational data and daily maximum and minimum air temperature data at five meteorological stations in He'nan province,the hourly air temperature was calculated using a cubic spline interpolation method,and the differences between observed and simulated air temperature were analyzed based on the observations of Zhengzhou meteorological station from 2006 to 2015.The results show that the cubic spline interpolation method can effectively represent the variation of the actual air temperature.Through considering the daily maximum and minimum air temperature,the "six-point" interpolation model is better than the "four-point" interpolation model.The simulated and observed values of air temperature have a significantly high correlation (R2=0.99,n=730 40).The cubic spline interpolation method can effectively convert the four times observation data into hourly data,especially as temperature values do not have continuous jumps.This method can also be used to simulate hourly variations of other continuously changeable parameters,such as water vapor pressure,relative humidity,wind speed and their simulations are hardly limited by territory.The deviation and variation between the simulated and observed air temperature at the Zhengzhou meteorological station prove that the simulation results can meet the requirements of time accuracy of meteorological elements and climate application service. References | Related Articles | Metrics

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Applicability analysis of air temperature data from regional automatic weather stations in Shijiazhuang YUE Yan-xia, ZHI Li-hui, WANG Lei, CAO Chun-li 2017, 33 (2):  53-62.  doi: 10.3969/j.issn.1673-503X.2017.02.007 Abstract ( 311 )   PDF (1636KB) ( 514 )   Save The similarities and differences of spatial distributions of hourly and daily air temperature observed at national and regional weather stations were crossly compared,which include observational data of hourly air temperature and daily maximum and minimum air temperature from 17 national weather stations and 61 regional weather stations in Shijiazhuang region from 2009 to 2015.The results show that observational environment has larger influence on daily maximum air temperature and smaller effect on daily minimum air temperature.The differences of air temperature among different regions in Shijiazhuang are the largest in winter,the smallest in summer,and moderate in spring and autumn.Effect of solar radiation can reduce the temperature difference between different regions.Temperature difference quickly reduces after sunrise and reaches the smallest as radiation is the strongest.The largest temperature differences occur after sunset and remain a high level until sunrise.The values of air temperature are low in the northwestern mountainous region of Shijiazhuang and are higher in the eastern plain region,and highest in the urban region.The usage of different weather stations under different observational environment has more effects on the statistical value of daily minimum air temperature than that on daily maximum air temperature.The seasonal variation of temperature differences observed at national stations from 23:00 to the next day 10:00 can represent the temperature variation in the entire region,however,such representativeness is worse at other hours and worst from 18:00 to 20:00.The urban heat island effect appears more obvious in the main urban region than in the surrounding area of Shijiazhuang during nighttime in winter,and the maximum air temperature in the mountainous region is smaller than that in the urban region in summer.The urban cold island effect is most obvious in county city than in villages and towns at daytime in winter and spring. References | Related Articles | Metrics

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Analysis of air pollution control measures and meteorological conditions in Hohhot during the APEC meeting SONG Gui-ying, JIANG Jing, DI Hui, CHEN Yun-gang 2017, 33 (2):  63-69.  doi: 10.3969/j.issn.1673-503X.2017.02.008 Abstract ( 246 )   PDF (911KB) ( 389 )   Save The effects of air pollution prevention and control and the role of meteorological conditions during the APEC meeting in Hohhot were analyzed,based on the upper and surface meteorological conventional observations over the Eurasian region,the NCEP (National Centers for Environmental Prediction) reanalysis data,and the monitoring data of pollutant concentration and daily AQI (Air Quality Index) from the environmental monitoring central station of Inner Mongolia Autonomous Region from October 14 to November 13,2014.The results show that before air pollution prevention and control measures were carried out in Inner Mongolia Autonomous Region,the number of days with the light and upper levels of air pollution in Hohhot during October 14-25,2014 is 37.5% higher than that during the same period of 2013.With the measures taken on October 26,the concentrations of contamination particulate matter decrease significantly,and the number of days with the light and upper levels of air pollution in Hohhot decreases by 100.0% in 2014 than that in the same period of 2013.There are four times of obvious cold air activities in North China during the period of air pollution prevention and control.Strong cold advection flows intrude to the ground from the middle and upper levels,and wind speed increases in Hohhot,resulting in favorable meteorological conditions for the diffusion of air pollutants.The four times of cold air activities all correspond to the smallest values of AQI in Hohhot.Therefore,the air quality in Hohhot achieved excellent level during the APEC meeting,which is probably due to the significant effects of government prevention and control measures based on meteorological conditions. References | Related Articles | Metrics

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Characteristics of air pollution and its relationship with meteorological parameters in typical representative cities of China ZHANG Ying, JIA Xu-wei, YANG Xu, WANG Shi-gong, CHENG Yi-fan, YANG Liu, XIAO Dan-hua 2017, 33 (2):  70-79.  doi: 10.3969/j.issn.1673-503X.2017.02.009 Abstract ( 414 )   PDF (1684KB) ( 872 )   Save Based on the daily air pollution monitoring data of 120 environmental protection key cities in China as well as surface meteorological data and sounding data from June of 2000 to August of 2013,the characteristics of air quality situation in typical representative cities of China and its relationship with meteorological parameters were analyzed.The results show that the spatial distribution of API (Air Pollution Index) in China has a trend of reducing from the north to the south.The seasonal distribution of API in northern cities presents a pattern of "winter high and summer low",and the amplitude of API variation in northern cities is significantly greater than that in southern cities.The temperature inversion layer thickness in northern cities is basically higher than that in southern cities,and temperature inversion layer thickness in representative cities shows a "U" pattern on an annual scale and has characteristics of strong in the winter half year and weak in the summer half year.The maximum mixing layer thickness and inversion layer thickness change in an inverse phase.The maximum thickness of mixing layer and its amplitude in high-altitude cities in the northern and southern regions are large,while those in low-altitude cities in the southern region are small.Meteorology parameters of air pollution have a close relation with API.Heavy pollution in northern cities during winter results from both of the increase of the pollutant emission due to heating and the reduction of diffusion capacity in the atmospheric boundary layer that can be reflected by the pollution meteorological parameters.It could provide a reference for the potential prediction of air pollution. References | Related Articles | Metrics

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Pollution characteristics of PM10 and its capacity calculation in the atmospheric environment over Hefei in winter SUN Wei, CHENG Xiao-quan, WANG Hui, LIU Cheng-xiao, HUANG Xiao 2017, 33 (2):  80-86.  doi: 10.3969/j.issn.1673-503X.2017.02.010 Abstract ( 272 )   PDF (1278KB) ( 610 )   Save The pollution characteristics of PM10 over Hefei were analyzed based on the data from 10 air quality auto-monitoring stations in winter (from October to December) of 2013.The PM10 atmospheric environment capacity for the pollution source in Hefei was estimated using a linear programming method.Before estimation of the environmental capacity,the related pretreatments included investigation of the main atmospheric pollution sources in Hefei,simulation of the PM10 mass concentration using the CALPUFF (CALifornia PUFF) model,and establishing a transfer matrix for atmospheric pollutants.The results show that the daily variation of the PM10 mass concentration demonstrates a typical bimodal distribution in winter,with the peaks appearing in the morning and evening,and the minimum values in the afternoon and midnight.The high values of PM10 mass concentration appear at the northeastern part and the low ones appear at the southwestern part of Hefei.The simulation results of the CALPUFF model are basically consistent with the observations,and can virtually reflect the spatial distribution of PM10 mass concentration in Hefei.When the area source emission reduces 705.233 t·a-1,the point source gets 12 935 t·a-1 of PM10 atmospheric environment capacity in Hefei. References | Related Articles | Metrics

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Climatic characteristics of haze weather during heating periods from 1980 to 2015 at Shenyang region XU Hong, CHEN Jun-qing, HE Dou-tai, CHENG Pan, WANG Wen, ZHU Ling, CHAO Hua, GU Zheng-qiang 2017, 33 (2):  87-94.  doi: 10.3969/j.issn.1673-503X.2017.01.011 Abstract ( 205 )   PDF (1077KB) ( 485 )   Save The annual and daily variation of haze weather during heating periods,and the variation of the corresponding meteorological elements were analyzed using the ground observation data in Shenyang from 1980 to 2015.The results show that the number of haze days during heating periods demonstrates a steady increasing trend from 1980 to 2015.The haze weather mainly appears from 07:00 to 11:00 a.m.,mostly disappears at night and in the afternoon.The duration of most of haze weathers is within 7 hours.When the haze weather happens during heating periods,the relative humidity on the ground is high and regularly in the range of 70%- 90%.The wind on the ground is often static,its speed is commonly less than 3.0 m·s-1,and its direction is mostly easterly.The height of mixing layer calculated by the surface observation data has a good indication effect to the different ranks of haze weathers.For the severe haze weather,the height of mixing layer is frequently within 0-400 m;for the moderate one,it is within 0-600 m;and for the mild one,it is within 200-600 m.To strengthen the monitoring and forecasting of weather conditions can help to effectively predict haze weathers and to take useful measures to reduce the haze influence. References | Related Articles | Metrics

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Comparative analysis of the thunderstorm characteristics of Liaoning inland and coastal cities GAO Ling-yun, LUAN Jian, WANG Di, MA Hong-xu, LUAN Lan 2017, 33 (2):  95-100.  doi: 10.3969/j.issn.1673-503X.2017.02.012 Abstract ( 252 )   PDF (3359KB) ( 408 )   Save Using the thunderstorm observation data from 1961 to 2012 from 59 meteorological stations in Liaoning province and the NCEP/NCAR (National Center for Environmental Prediction/National Center for Atmospheric Research) daily reanalysis data,the characteristics of thunderstorm activities and atmospheric circulation for inland and coastal cities were compared and analyzed based on the climate trend analysis and the synthesis of t-test methods.The results show that the annual mean number of thunderstorm days for inland cities decreases gradually from the east and the west mountain areas to the central hill and plain areas.The annual mean number of thunderstorm days for coastal cities decreases with the decreasing of latitudes and is generally less than that for inland cities.The annual mean number of thunderstorm days for inland and coastal cities both shows a decreasing trend with a time of year,and the decreasing speed for coastal cities is faster than that for inland cities.The thunderstorm activities for inland cities are related to the near-surface air temperature,Asian zonal and meridional circulations,and those for coastal cities are closely related to the wind and height fields at the lower and middle troposphere,and its inter-annual variation of thunderstorm activities is closely related to the ridge line location of the Western Pacific subtropical high. References | Related Articles | Metrics

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Influence of air temperature on the number of hospital admissions due to chronic obstructive pulmonary disease at Shijiazhuang region FU Gui-qin, LIU Hua-yue, JIA Jun-mei 2017, 33 (2):  101-106.  doi: 10.3969/j.issn.1673-503X.2017.02.013 Abstract ( 293 )   PDF (655KB) ( 414 )   Save Based on the medical records of chronic obstructive pulmonary disease (COPD) from January 1 to December 31 of 2013 and the meteorological observation and air pollution data in the same periods,the influence of air temperature on the number of hospital admissions due to chronic obstructive pulmonary disease at Shijiazhuang region was analyzed using the generalized additive model to control the confounding effect of time trend and air pollution.The results show that three indexes,i.e.,the variable temperature in 24 h (BT),3 d lagged minimum temperature (Tmin3) and 5 d lagged diurnal temperature range (Tc5)influence the number of the COPD hospital admissions at different extends.When BT is larger than -4.4 ℃ and equal or less than -0.7 ℃,Tmin3 is larger than-3.6 ℃,equal or less than 3.2 ℃ and larger than 20.5 ℃,and Tc5 is larger than 0.9 ℃ and equal or less than 8.6 ℃,the relative risk (RR) of the COPD hospital admissions is 1.0207 (95%CI (Confidence Interval): 1.0074-1.0342),1.0118 (95%CI:1.0015-1.0222) and 1.0069 (95%CI:1.0005-1.0133),respectively with every 1.0 ℃ increase in these three temperature indexes.The results provide guidance for the COPD meteorological forecasting services. References | Related Articles | Metrics

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Simulation and application of the field strength of high-altitude meteorological exploring radar SHEN Ye, ZENG Ming, ZHANG Fu-jian, YE Jing, YIN Min 2017, 33 (2):  107-111.  doi: 10.3969/j.issn.1673-503X.2017.02.014 Abstract ( 253 )   PDF (1562KB) ( 393 )   Save Based on the FEKO (Feldberechnung bei Korpern mit beliebiger Oberflache) products,the strength of the high-altitude meteorological radar field was simulated.The discrete values of its relative field strength were obtained.Five kinds of interpolation methods,including the bilinear interpolation method,the inverse distance weighted method with k=1 and 2,respectively,and the inverse distance weighted method based on an edge-smoothness with k=1 and 2,respectively,to calculate the relative field strength of high-altitude meteorological radar in any directions were compared.The results show that at any azimuth and zenith angles,the bilinear interpolation method performs the best results.Under the condition that the initial field strength is at intervals equal or less than 0.5 degree in the main lobe and equal or less than 0.1 in the side lobe,its simulation results can meet the needs of the meteorological radar to simulate a training system. References | Related Articles | Metrics