Table of Content

30 October 2019, Volume 35 Issue 5 Previous Issue    Next Issue

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Mechanism analysis of thunderstorm gale in Hefei area on May 14,2017 SHAN Nai-chao, ZHOU Hou-fu, CHU Bao-liang, ZHAO Qian 2019, 35 (5):  1-9.  doi: 10.3969/j.issn.1673-503X.2019.05.001 Abstract ( 384 )   PDF (8739KB) ( 218 )   Save Using the data from conventional meteorological observations,intensive automatic weather stations,radiosonde,airport automated weather observing system,Doppler radar and so on,the environmental conditions and influencing systems for a thunderstorm gale in Hefei airport and its surrounding areas on May 14,2017,were analyzed.Focused on Doppler radar data,the causes for the formation of the thunderstorm process were discussed.Results can be described as followings.Two convective storms in the northwestern part of the airport were merged at the levels of 3-6 km.A factor nucleus with strong reflectivity was formed at the level of 5 km.It quickly dropped to 4 km within 10 minutes.A strong cold pool was formed on the ground when the downdraft within the storm sinks.Its rapid movement led to the formation of strong winds at the airport.The initial cause of the downdraft formation is due to the drop and drag effects of the precipitation particles.The effect of inhalation,increasing of negative buoyancy between hydrate and the environment,downward momentum transmission,and the compensatory airflow are the important reasons for the downdraft formation.The gale belt in the southwestern part of the airport was resulted by the transiting of a thunderstorm outflow boundary.The extinction of super-refraction is a sign of cold air intrusion in the boundary layer.The continued cold air replenishment at the back of the storm and the continuous updraft in front of the storm maintains a steady vertical circulation.The continuous redeeming downdraft causes the gale in the eastern part of the airport to last for a long time. References | Related Articles | Metrics

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Evaluation on forecasting effect of 2 m temperature based on the WRF model in Shandong province XIA Fan, YANG Xiao-xia, LIU Shi-jun, XIAO Ming-jing 2019, 35 (5):  10-17.  doi: 10.3969/j.issn.1673-503X.2019.05.002 Abstract ( 298 )   PDF (2694KB) ( 219 )   Save The observation data of 123 stations in Shandong province from November 2017 to February 2018 was used to verify 2 m temperature forecast starting at 08:00 and 20:00,respectively based on the Weather Forecast and Research (WRF) model.The forecasting effects of hourly temperature at 2 m and the daily minimum and maximum temperatures were evaluated.The reasons for the large error at some stations were analyzed.The result shows that the accuracy of 2 m temperature forecasted from the WRF model starting at 08:00 is higher than that forecasted starting at 20:00.The forecasting effect in day-time is better than that at the night.The prediction effect in the northwest and peninsula region is better than that in the other region in Shandong province.The negative error rate of most stations is larger than the positive one.The forecasting effect of the daily maximum temperature is better than that of the daily minimum one.The terrain height error in the model is the main factor that makes a large positive error of 2 m forecasting temperature at Mountain Tai station.Two schemes based on temperature gradient are used to correct 2 m forecasting temperature at Mountain Tai station.After correction,the mean absolute error decreases generally.However,there is a negative effect in the correction in some forecasting cases when a single temperature gradient is used.The forecasting effect is more stable when using the temperature gradient changing with the forecasting time.Affected by the terrain height error in the model,the foehn cannot be simulated by the WRF model.When the foehn occurs in Taian station,very large negative errors of 2 m forecasting temperature occur.The difference of land type between the model and real situation is one of the most important reasons that make a large negative error of 2 m forecasting temperature at Xuecheng station at the night. References | Related Articles | Metrics

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Statistics and possible sources of low-level turbulence below 3000 m and its meteorological condition in Beijing JIN Chen-xi, GUO Wen-li, GAN Lu, WANG Chun-ling 2019, 35 (5):  18-26.  doi: 10.3969/j.issn.1673-503X.2019.05.003 Abstract ( 172 )   PDF (3776KB) ( 56 )   Save The turbulence of aircraft is a leading cause of injuries to the passengers and crew.The characteristics of low-level (below 3000 m) turbulence in Beijing during 2016 were investigated using the pilot reports accumulated by the Beijing Meteorological Center of Civil Aviation Administration of China.The frequency of turbulence in winter is the highest,and that in summer is the lowest due to the seasonal variations of wind speed.To examine the possible sources of the low-level turbulence in Beijing,the wind profiler radar data with a 120 m vertical and 6 min temporal resolution were used.The results show that the major meteorological factors and their thresholds influencing the turbulence include the horizontal wind speed (18 m·s-1),vertical shear of horizontal wind (10 m·s-1·km-1),horizontal shear of horizontal wind (0.1 m·s-1·km-1),time shear of horizontal wind (10 m·s-1·h-1),and the vertical wind speed (2 m·s-1).This paper has reference value for forecasting the low-level turbulence. References | Related Articles | Metrics

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Characteristics of GPS precipitable water vapor during three snowfall events from 2017 to 2018 in Liaoning province XU Shuang, HU Peng-yu, LIANG Hong, WU Yu-tong, LI Dian, ZHANG Shuai 2019, 35 (5):  27-36.  doi: 10.3969/j.issn.1673-503X.2019.05.004 Abstract ( 218 )   PDF (5429KB) ( 77 )   Save Using the ECMWF (European Center for Medium-Range Weather Forecasts) ERA-interim reanalysis data,convention observation data and GPS (Global Position System) precipitable water vapor (PWV) observations,the variations of PWV during the three snow-falling processes occurring in Liaoning province were analyzed.The results indicate that the variations of PWV present a single-peak structure during the snowfalls.There is a good correlation between the variations of PWV and the hourly amounts of snowfall.The occurrence of snowfall corresponds to the high value of PWV.The PWV has increased rapidly since the snowfall occurred six to fifteen hours ago.The total increasing amount of PWV is positively correlated with the intensity of snowfall. References | Related Articles | Metrics

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Analysis on the characteristics of heavy rainfall in Ningbo indirect caused by three landing typhoons QIAN Yan-zhen, PAN Ling-jie, DUAN Jing-jing, GUO Yu-guang, ZHU Xian-chun 2019, 35 (5):  37-45.  doi: 10.3969/j.issn.1673-503X.2019.05.005 Abstract ( 275 )   PDF (7220KB) ( 62 )   Save Based on the data from the conventional and intensive observations,satellite,radar,and the NCEP (National Centers for Environmental Prediction) re-analysis,the typhoons affected Ningbo,which landed in Fujian province but not in Zhejiang province,were investigated.The possible causes of heavy rainfall-induced by Typhoon Fitow,Dujuan,and Meranti in Ningbo were discussed.The results indicate that 43.9% of eighty-two typhoons selected from 1949 to 2016 results in local rainstorms in Ningbo,9.8% results in local large rainstorms,and 4.9% causes a city-wide large rainstorm.75% of these typhoons occur after 2013.It is found that after the weakening of a small scale typhoon coming from far-distance,the interactions of cloud diffusion with cold air,subtropical high and other typhoons facilitate to the formation of jet current and continuous heavy rain in Ningbo.However,the extension and degree of its influence are difficult to grasp.The increase or decrease of low-level water vapor supply is 6-12 hours ahead of the beginning time of rainfall increasing or decreasing.The strengthening or weakening of negative non-geostrophic wet Q-vector divergence may indicate the beginning or weakening of heavy rain with 6 hours in advance. References | Related Articles | Metrics

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Spatiotemporal characteristics of the short-term rainstorm and heavy rainstorm events in Liaoning province XIAO Guang-liang, CHEN Chuan-lei, LONG Xiao-hui, CHEN Guang-hui, CAI Kui-zhi, CHENG Pan, JI Yong-ming, LI Shu-ting 2019, 35 (5):  46-52.  doi: 10.3969/j.issn.1673-503X.2019.05.006 Abstract ( 382 )   PDF (5936KB) ( 141 )   Save Based on hourly precipitation data at 1587 automatic weather stations in Liaoning province from May to October during 2010-2018,we identified short-term rainstorm and heavy rainstorm events according to the standards of orange and red rainstorm warning signals issued by China Meteorological Administration.The spatial distribution and multi-scale temporal variations of the short-term rainstorm and heavy rainstorm were analyzed to obtain high-incidence areas and periods after synoptic analysis.The results showed that high-incidence areas of short-term heavy rainstorm events are distributed in the southeastern coastland of Liaoning province.The mutual effects of weather systems such as cold vortex in Northeast China,cyclone moving to the north,and subtropical high in the western Pacific probably result in the frequent occurrence of heavy and persistent rainstorm events over wide areas.The ten-day variations of day numbers of the short-term rainstorm and heavy rainstorm exhibit a "convex" shape,with a single peak between early May to early October.The occurrence frequency of heavy rainstorm significantly increase after early July and decrease sharply after late August.The diurnal variations of rainstorm and heavy rainstorm events exhibit the "two peaks and one valley" pattern.Rainstorm events mostly occur at night,which is probably due to the strengthening of southwestern jets.The highest occurrence frequency of short-term rainstorm occurs from 00:00 to 08:00 Local Standard Time (LST),especially in areas of Fuxin-Chaoyang,Fushun-Panjin-Huludao,and the southeastern Liaoning province.The high-incidence areas of short-term heavy rainstorm between 00:00 and 08:00 LST include the western,eastern and southeastern parts of Liaoning province. References | Related Articles | Metrics

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Characteristics of air quality index and its correlation with meteorological parameters in Shanghai ZHENG Qing-feng, SHI Jun, DONG Guang-tao, HUANG Wen-juan, XU Wei-zhong, WANG Quan-yuan 2019, 35 (5):  53-62.  doi: 10.3969/j.issn.1673-503X.2019.05.007 Abstract ( 269 )   PDF (3875KB) ( 324 )   Save Based on the daily individual air quality index (IAQI) of PM2.5,PM10,CO,O3,SO2,and NO2,observations of meteorological parameters (including wind speed,precipitation,temperature,relative humidity,total cloud cover,and low cloud cover),temperature inversion and upper-level atmospheric circulation data from 2012 to 2016,we analyzed the temporal variation of air quality index and the impact of climatic elements on air quality in Shanghai.We also compared the differences in atmospheric circulation during PM2.5 and O3 pollution events and clean days nearby.The results showed that the PM2.5,PM10,and NO2 pollution events occur frequently in winter,with day numbers of 31.4 d,10.0 d and 14.8 d,respectively,while O3 pollution events occur most frequently in summer (18.8 d).Wind speed and low cloud cover greatly affect PM2.5 pollution,with the correlation coefficient of -0.313 and -0.261,respectively.O3 pollution is closely related to air temperature and sunshine duration,with the correlation coefficient of 0.449 and 0.363,respectively.The formation of PM2.5 and O3 pollution also have a high correlation with a temperature inversion on the day and the former day.During PM2.5 pollution events,Shanghai is located ahead of a high behind a trough,accompanied by strong northwesterly winds at 850 hPa,while for clean days,Shanghai is behind a high and the southeasterly flows are dominated at 850 hPa.For O3 pollution events and clean days,the anomaly of outgoing longwave radiation (OLR) over eastern China is positive and negative,respectively.O3 pollution is easy to occur under a clear sky and low cloud cover conditions due to the subtropical high,and it hardly occurs in the presence of high cloud cover in Shanghai. References | Related Articles | Metrics

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Characteristics of air quality in Haikou from 2013 to 2016 and pollutant source analysis during typical pollution events ZHAO Lei, WU Kun-ti, CHEN Ming 2019, 35 (5):  63-69.  doi: 10.3969/j.issn.1673-503X.2019.05.008 Abstract ( 195 )   PDF (2933KB) ( 98 )   Save Based on the daily air pollution monitoring data at the Haikou station from 2013 to 2016 provided by the Hainan Provincial Academy of Environmental Sciences,we analyzed the air quality status in this region.We also explored the major transport paths and potential source areas of the primary air pollutants (PM2.5 and O3) throughout December in 2013 using the methods of HYSPLIT trajectory clustering analysis,potential sources contribution factors,and trajectory analysis of concentration weight,based on the upper- and lower-level atmospheric circulation,air quality index (AQI),and aerosol thickness blue images from the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite.The results showed that the change in wind direction during winter and summer monsoon is the most important meteorological cause of air pollution in Haikou.The primary air pollutant is PM2.5,followed by PM10 and O3.Air quality above the good level reaches a rate of 97.1% in Haikou.The AQI exhibits a decreasing trend year after year,while O3 increases steadily.Air pollutant concentrations are affectedc by pollutant emissions and circulation fields.In Haikou,air pollution mainly occurs in the presence of three synoptic types,including the cold and high pressure,warming ridges,and typhoon peripheral descending airflow.The long-range transport of air pollutants is the main reason for the occurrence of a typical air pollution event.During this event,the potential source areas of primary air pollutant PM2.5 are distributed at the junctions of Hu'nan and Jiangxi provinces,coastlands in Guangdong province,the northern part of Guangxi province,the junctions of Jiangxi and Fujian provinces,and the center of Zhejiang province.Air masses from these potential source regions are transported to Haikou along the trajectories 1,2,and 4.The major contribution regions of O3 mass concentrations are concentrated in the junction of Hu'nan and Jiangxi provinces and the western part and Guangdong province.The pollutants are transported to Haikou from the inland along the trajectory 2. References | Related Articles | Metrics

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Effects of meteorological conditions on PM2.5 pollution in Shantou and the PM2.5 prediction DU Qin-bo, WU Xiao-yan, ZHENG Su-fan, LI Yue-ying, CHEN Huan-huan, ZHANG Yu-feng 2019, 35 (5):  70-77.  doi: 10.3969/j.issn.1673-503X.2019.05.009 Abstract ( 202 )   PDF (825KB) ( 122 )   Save Based on the daily concentration of PM2.5 data and the surface meteorological data from national meteorological observatory station in Shantou from 2014 to 2017,the variation characteristics of PM2.5 concentration in Shantou and the influences of meteorological conditions such as wind,mixed-layer thickness and precipitation on the concentration of PM2.5 were analyzed and the causes of pollutant concentration variation were investigated.On this basis,according to the climatic characteristics of Shantou,the models for predicting PM2.5 mass concentration in flood and non-flood season were respectively established with BP (Back-Propagation) artificial neural network method.The results show that the daily variation of PM2.5 concentration in Shantou is unimodal,which is different from most inland cities and is related to the geographic location.More specifically,Shantou is located in the coastal area affected by the land-sea breeze.The daily peak of PM2.5 concentration appears at around 8 o'clock,which is caused by the lower wind speed and the increase of pollutant emission in the morning.The average concentration of PM2.5 decreases with the increase of wind speed and is significantly correlated with the thickness of the mixed layer at 8 o'clock (the correlation coefficient is -0.143,p< 0.001).The concentration of PM2.5 in the non-flood period in Shantou city is higher than that in the flood season,which is related to the subtropical monsoon climate characteristics.In addition,there is no significant difference in the removal effect of PM2.5 among various magnitudes of precipitation in the flood season (except for rainstorms),while the precipitation during the non-flood period has an obvious effect in decreasing the concentration of PM2.5.The BP artificial neural network model shows a high hit rate in forecasting the grade of PM2.5 concentration.More specifically,Rank accuracy of PM2.5 are 100% and 90.3%,the accuracy coefficients are 87.7% and 89.9% in flood season and non-flood season,respectively.The number and amplitude of positive errors of the forecasted PM2.5 concentration by the model in different periods are larger than those of the negative errors.Furthermore,the prediction error of the model is larger when heavy rainfall occurs in flood season and cold air invades in non-flood season. References | Related Articles | Metrics

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Characteristics and influencing factors of ozone pollution in summer in Chengdu ZHENG Li-ying, XU Ting-ting, CHEN Zhi-an, WANG Huan-bo 2019, 35 (5):  78-84.  doi: 10.3969/j.issn.1673-503X.2019.05.010 Abstract ( 308 )   PDF (1782KB) ( 164 )   Save Based on the hourly O3,NO2,and PM2.5 concentrations at three national environmental monitoring sites (Jinquanhe,Junpingjie,and Liangjiaxiang) and surface meteorological parameters including temperature,relative humidity,wind speed and direction,solar radiation,and precipitation at the Wenjiang national weather station in Chengdu during summer of 2014,we analyzed the diurnal and monthly variations and spatial distributions of O3 concentrations and explored the effects of precursors and meteorological parameters on O3 concentration.The results showed that the averaged concentration of O3-8 h is 104.4 μg·m-3,and the proportion of days with O3 concentration exceeding the Chinese National Air Quality Standard ranges from 2.8% to 15.3% at different sites.The highest and lowest O3 concentration occur in June and August,respectively.The diurnal variation of O3 concentration exhibits a single peak at 15:00.O3 concentration has a negative correlation with NO2 concentration,with a correlation coefficient of -0.5,and has no significant correlation with PM2.5 concentration.High temperature,low relative humidity,and strong solar radiation are beneficial to the O3 formation.The higher O3 concentration usually occurs in the presence of southerly flows with wind speed between 2.5-3.0 m·s-1. References | Related Articles | Metrics

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Daily maximum mixing height and its effects on air quality in the Pearl River Delta region LIAO Zhi-heng, XU Xin-qi, XIE Jie-lan, ZHOU Xue-si, FAN Shao-jia 2019, 35 (5):  85-92.  doi: 10.3969/j.issn.1673-503X.2019.05.011 Abstract ( 193 )   PDF (2334KB) ( 179 )   Save Atmospheric mixing height is one of the main factors affecting vertical diffusion and plays an important role in the assessment of air quality and the storage and distribution of air pollutants.Based on 4-year (from April 2014 to March 2018) radiosonde measurements at Hong Kong (coastal) and Qingyuan (inland) stations,this study employs the dry adiabatic curve method to estimate the daily maximum mixing height (MMH) in the Pearl River Delta (PRD) region,then discusses the spatial differences of the MMHs in the coastal and inland areas,and finally analyzes the effects of the MMH on regional air pollution.The results show that the atmospheric mixing height has typical local characteristics.Specifically,the MMH in the coastal area is lower than that in the inland area and their average values are 982 m and 1198 m,respectively.The spatial differences of the MMH in the PRD region can be jointly explained by many factors,among which temperature diurnal range plays the most important role.The coastal area features a relatively smaller temperature diurnal range due to the modulation of seawater on air temperature,so the atmospheric mixed layer is relatively lower.Besides,there are great distinctions in the correlation between the air pollutants and the MMH in the PRD region.The primary pollutants (e.g.,CO) are negatively correlated with the MMH,while the secondary pollutants (e.g.,O3) are positively correlated with the MMH.In contrast,atmospheric particulate matters (e.g.,PM2.5) are weakly correlated with the MMH likely due to the complexity of their sources (including primary emission and secondary formation). References | Related Articles | Metrics

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The effectiveness analysis of the artificial precipitation enhancement technique with the silver idoinde (AgI) flame bomb carried by a balloon SUN Li-de, GUAN Xin, LI Bao-gang, GAO Peng, SUN Zi-yuan, LIANG Zhi-bing, YANG Jin, JI He-cheng, DAI Li-da 2019, 35 (5):  93-99.  doi: 10.3969/j.issn.1673-503X.2019.05.012 Abstract ( 172 )   PDF (724KB) ( 24 )   Save In this paper,the effectiveness of the artificial precipitation enhancement technique by means of silver iodide (AgI) flame bomb carried by balloon in Kazuo of Chaoyang was analyzed on the basis of the experimental data from 2003 to 2017.The results show that the best effect is achieved under the three synoptic situations including Mongolia cyclone,short-wave trough,and cold-vertex.The experiments show that the optimal seeding heights of the flame bomb in the process of snow and rain enhancements are respectively 2000-4000 m and 3000-5000 m,especially for the St,Ns and As in the stable layer-form clouds.Under the condition of the temperature of -10℃,the average generative rate of ice nucleus is 6.3×1013 per gram.The average annual precipitation in Kazuo county is 505.87 mm and is 57.54 mm more than the other counties of the Chaoyang.The average annual amount of the increased rainfall is 129 million m3.Whereas,the increasing amount of annual rainfall from the artificial precipitation enhancement using the balloon flame bomb is 31.31 mm which is converted into the water of 7.007×107 m3.The ratio of the input to the output is 1:97.1.The above-mentioned precipitation enhancement method is able to provide the scientific reference and technical support for relevant businesses in other areas. References | Related Articles | Metrics

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Analysis of the seeding conditions and effects of an artificial precipitation enhancement operations on a serious forest fire fighting in Hu'nan province FAN Zhi-chao, LIU Fu-lai, XIAO Qing, DING Yue-qiang, LI Nou-zhou 2019, 35 (5):  100-107.  doi: 10.3969/j.issn.1673-503X.2019.05.013 Abstract ( 163 )   PDF (2852KB) ( 48 )   Save Artificial precipitation enhancement operation is an important scientific and technological means for extinguishing the forest bush fire.Forecasting operational conditions and grasping operational opportunity are the keys to the success or failure of the operation.Based on the condition of artificial precipitation enhancement operation on the serious forest fire disaster in Dacheng Mountain in Hu'nan province on August 10-16,2013,the operational conditions forecast and operational scheme design are analyzed by using various meteorological data,and then the effects of operation are evaluated by employing the radar echo parameter variation method before and after the operation and the radar echo tracking method of maximum correlation coefficient (TREC).The results show that the artificial precipitation enhancement operation on the serious forest fire disaster in Dacheng Mountain effectively enables the local precipitation to fell to the fire site where the location is relatively concentrated by capturing the cumulus cloud system that rapidly grows and dissipates at the periphery of the typhoon.As a result,the rain increases after 15 minutes of the 7th,8th artificial precipitation enhancement operations on August 15,which effectively suppresses the forest fire and saves the trapped persons in time.In addition,the 11th operation on August 16 plays an important role in extinguishing the forest fire.In general,it is easier to seize the operation opportunity by using rockets,artillery and other ground equipment for carrying out artificial precipitation enhancement operation for local cumulus clouds,while seeding by aircraft is more appropriate for a wide range of convective-stratiform mixed clouds.Besides,aircraft plays an important role in forest fire reconnaissance photographed and meteorological observation and so on. References | Related Articles | Metrics

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Quantitative evaluation index and risk analysis of continuous rainfall disaster during the growing stage of cotton in Hebei province DAI Li-qin, WANG Meng, LI Chun-qiang, YAO Shu-ran 2019, 35 (5):  108-114.  doi: 10.3969/j.issn.1673-503X.2019.05.014 Abstract ( 183 )   PDF (1195KB) ( 57 )   Save Based on the daily meteorological data of 40 weather stations and the observed cotton yield data of agro-meteorological station in cotton planting regions of Hebei province from 1981 to 2015,the characteristics and the impacts of continuous rainfall (CR) process on the cotton yield were analyzed,and the index of CR disaster was revised and optimized.Then,through the mathematical statistics,the yield loss rate caused by CR was calculated and the key disaster-causing factors of CR were filtered.Furthermore,using the weight coefficient of factors,the intensity indices of CR during the cotton growth stage were designed.Moreover,based on the relationship between the intensity index and yield loss rate,the evaluation model of yield loss was established.According to the analytical method of the ordered sample cluster,the disaster grade was ranked.Finally,based on risk analysis principle of disaster,the indices and characteristics of risk were established and analyzed.The results show that the intensity index of CR can objectively reflect the intensity of CR and the effect of yield loss evaluation model is satisfactory.The occurrence probability and the yield loss caused by CR during the seeding stage are both small and are 0.076 and 0.09%,respectively.The growth of cotton is mainly affected by the CR during squaring to boll opening stage and the orders of probability and the yield loss caused by CR changing from large to small are flower-boll stage (0.447,17.1%),squaring stage (0.394,11.7%) and boll opening stage (0.237,7.2%).In recent years,the amount of CR decreases during the squaring stage,and increase during the flower-boll and the boll opening stages,especially during the boll opening stage which is the most major stage when the cotton growth is affected by CR.The high-risk area of CR during the squaring stage distributes in the north of Baoding and its northward areas,while that during the flower-boll stage distributes in the north of Baoding and its northward areas as well as the west of three cities including Shijiazhuang,Xingtai and Handan.The above-mentioned areas are non-major cotton planting area.The high-risk area of CR during the boll opening stage distributes in the southwest of Baoding,the west of Hengshui,Shijiazhuang and its southward areas. References | Related Articles | Metrics

SCIENTIFIC NOTES

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Effects of soil moisture on yield components of soybean in black soil area WANG Ping, YAN Ping, LI Xiu-fen, WANG Liang-liang, WANG Qiu-jing, GONG Li-juan 2019, 35 (5):  115-122.  doi: 10.3969/j.issn.1673-503X.2019.05.015 Abstract ( 126 )   PDF (657KB) ( 30 )   Save The purpose of this study is to analyze the effects of effective soil water content (ESWC) on soybean yield in the black soil region (Heilongjiang),so as to provide the scientific basis for disaster prevention and mitigation of soybean production.Based on the data of development period,soil water content and yield components during 1994-2017 in the main soybean producing areas of Heilongjiang province,the variation characteristics of ESWC in different development stages of soybean and the classification of drought grades based on the relative soil moisture index were investigated.Meanwhile,the effects of ESWC on soybean yield components in different development stages were analyzed.The results show that the average ESWC in different development stages of soybean is between 14 mm and 18 mm and there are 82 times of droughts including 77 times of mild droughts and 5 times of moderate droughts and there is not severe and special drought from 1994 to 2017.More specifically,the drought more frequently occurs during the period of flowering to pod setting and the period of pod setting to filling and its amount is decreasing year by year in the studied time.The meteorological yield of soybean and the kernels and grain weight per plant have little correlation with the ESWCs at different soil depths,while the hundred-grain weight has a significant correlation with the ESWC at the depth of 20-50 cm from three-leaf to flowering stage and at the depth of 0-20 cm from pod setting to filling stage.In addition,the stem weight indicates a positive correlation with the ESWC at the depth of 30-50 cm from sowing to seedling stage.The higher the ESWC is,especially in deep soil in a certain range from sowing to flowering,the more pods per plant are.Besides,there is a significant correlation between the percentage of empty chaff pods and the ESWCs at the depth of 0-20 cm and 30-40 cm from sowing to seedling and that at the depth of 30-40 cm from seeding and three-leaf stage. References | Related Articles | Metrics

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Observation study on lightning characteristics of hail cloud in central and western Guizhou ZENG Yong, ZOU Shu-ping, LI Li-li, CAO Shui, HUANG Yu, YANG Zhe 2019, 35 (5):  123-129.  doi: 10.3969/j.issn.1673-503X.2019.05.016 Abstract ( 168 )   PDF (1409KB) ( 129 )   Save The lightning characteristics of 13 hail weather cases in Central and Western Guizhou province were analyzed by using the data of the 3-D lightning monitoring network,a new generation of weather radar and ground observations.The results show that the whole life history of hailstorms is mainly caused by negative lightning and accompanies heavy rainfall.At the developing stage of the hailstorm cloud,the lightning frequency in hailstorm zone increased obviously.The lightning frequency appeared "sharp jumping" before hailstorm occurred.The lightning frequency in some hailstorm spots increased twice.At the hail cloud dissipation stage,the frequency of lightning decreased significantly.The total flashes and positive flashes of hailstorm clouds were higher than those of thunderstorm clouds.The lightning frequency per 5 minutes being more than 16 times and increasing more than 12 times per 5 minutes could be used as an index to identify hailstorm clouds.In addition,the hail zone is relatively overlapped with the center of lightning density.The position of lightning density center is slightly ahead of the hail position.The lightning distribution indicates the developing direction of hail cloud.The above characteristics can provide a reference for hail recognition,hailstone short-term warning,and artificial hail suppression. References | Related Articles | Metrics

BULLETINS

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Evaluation of typhoon disaster risk for Hevea brasiliensis in Hainan island HUANG Hai-jing, YANG Zai-qiang, WANG Chun-yi, ZHANG Jing-hong, ZHANG Ya-jie, ZHANG Ming-jie 2019, 35 (5):  130-136.  doi: 10.3969/j.issn.1673-503X.2019.05.017 Abstract ( 166 )   PDF (935KB) ( 62 )   Save Typhoon disaster is the most serious disaster for rubber planting in Hainan province.This study took Hainan island,a major natural rubber producing area in China,as the research object.Based on the disaster risk assessment theory,the risk,exposure and vulnerability assessment model of rubber typhoon disaster was established combining rubber typhoon disaster with social economy and meteorological data.The weighted comprehensive evaluation method was used to evaluate the risk of natural rubber forest disaster.Results show that the high-risk areas of rubber planting in Hainan province locate in the coastal cities and counties where frequent typhoons occur,among which,Qionghai,Wenchang,and Haikou are the areas with the highest risk of rubber disaster in Hainan island,and Lingshui,Wanning,Qiongzhong,Tunchang,and Dongfang are also the areas with higher risk of disaster.The areas with the lowest risk are in Wuzhishan,Baoting,Ledong,and Sanya.The evaluation results are consistent with the actual disaster and planting conditions.The evaluation results show that the dangerous of typhoon disaster is the main factor of risk,but it is not the single determinant,planting technology,cultivar improvement and other technical measures play an important role in reducing the vulnerability.The evaluation results can provide a basis for preventing disaster and planting layout of rubber forests. References | Related Articles | Metrics

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The effect of meteorological elements on adult asthma hospitalization in Shijiazhuang LIU Hua-yue, FU Gui-qin, WANG Jie 2019, 35 (5):  137-143.  doi: 10.3969/j.issn.1673-503X.2019.05.018 Abstract ( 170 )   PDF (745KB) ( 95 )   Save To investigate the impact of meteorological elements on adult asthma hospitalization,based on the adult asthma hospitalization records of Shijiazhuang Medical Insurance Center from January 1,2013 to December 31,2016,and the meteorological and environmental observations during the same periods,the generalized additive model (GAM) was used to analyze the exposure-response relationship between the meteorological elements and the number of adult asthma hospitalization after controlling the factors such as long-term trend,holiday effects,and air pollution.The results show that different elements have different impacts on the number of adult asthma hospitalization.With 1℃ increasing in daily mean air temperature (T),daily maximum temperature (Tmax),and daily minimum temperature (Tmin),the risk of adult asthma hospitalization decreased by 0.7%,0.6%,and 0.7%,respectively.The risk of adult asthma hospitalization increased by 0.6% with the increase of daily mean air pressure (P) by 1 hPa.The risk of adult asthma hospitalization decreased by 5.2% with 1 m·s-1 increasing in daily mean wind speed (Ws).When relative humidity (RH) was less than 24%,the risk of adult asthma hospitalization reduced by 3.4% with RH increasing 1%.The risk of adult asthma hospitalization increased by 12.5% with RH increasing 1% when RH was greater than or equal to 92%.The effect of T,P,and Ws on the number of adult asthma hospitalization was strongest on the same day or on the followed day.Impacting characteristics of meteorological elements can provide a basis for healthy weather forecasting services and public defenses. References | Related Articles | Metrics