Table of Content

30 April 2018, Volume 34 Issue 2 Previous Issue    Next Issue

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Dynamical climate downscaling over Liaoning area using nudging methods based on WRF model YI Xue, LI De-qin, ZHAO Chun-yu, ZHOU Xiao-yu, CUI Yan, HOU Yi-ling 2018, 34 (2):  1-10.  doi: 10.3969/j.issn.1673-503X.2018.02.001 Abstract ( 212 )   PDF (2593KB) ( 346 )   Save Dynamical downscaling is widely applied in regional climate downscaling to generate regional climate fields with high spatial-temporal resolution.Using the nudging techniques based on the Weather Research and Fore-casting (WRF) model,Climate Forecast System Reanalysis (CFSR) data were dynamically downscaled over Liaoning province.The observational data from automatic weather stations were assimilated based on the observation nudging method and the large-scale reanalysis data were assimilated based on the analysis nudging method.Meteorological elements determined by different downscaling methods were compared with the observations in Liaoning province during July and October to test the accuracy of each method.The results indicated that the modelling capability of temperature at 2 m height,wind speed at 10 m height,and relative humidity at 2 m height is significantly improved using nudging methods in the regional climate downscaling process.The simulation performance be-comes even better after assimilating automatic weather station data and the large-scale reanalysis data based on the nudging methods,with the average root-mean-square error of temperature,wind speed,and relative humidity in July and October decreasing by 25%,39%,and 30% respectively. References | Related Articles | Metrics

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Formation analysis of a severe air pollution event in Taiyuan LI Yi-yu, YANG Hong-ru, WANG Nan, LI Jun-xia, YAO Jia-lin 2018, 34 (2):  11-18.  doi: 10.3969/j.issn.1673-503X.2018.02.002 Abstract ( 304 )   PDF (1758KB) ( 495 )   Save Based on the conventional synoptic analysis and using emission inventories of SO2,PM2.5,and PM10,as well as the back trajectory model,the formation and causes of a severe air pollution event in Taiyuan,Shanxi province were analyzed.The results showed that the air pollution event has a long duration and lasted nearly 5 days.Many pollutant concentrations extremely exceed their standards,and fine particles play an important role in the pollution process.The large-scale atmosphere circulation provides Taiyuan with weak cold air and plenty of water vapor,and the persistent steady cold high pressure and weak winds near surface favor to form a large area and a long time period of stable weather condition.Air flows from the northwest and the west mainly controlled the Taiyuan area during the pollution episode,and the pollutant concentrations transported along the northwesterly flow are significantly lower than that along with other three trajectories.The height of pollutant transportation probably resulted in the difference between pollutant concentrations along different trajectories.In a combination of distribution of pollution emission,this pollution event is influenced by the local emission and long/short range transportation of air pollutants.The local emission is the primary contribution. References | Related Articles | Metrics

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Analysis of a typical regional sand-dust event over the eastern Tarim Basin QIU Hui-min, ZHOU Cheng-long, YANG Fan, MA Kai, YE Xiao-ting, ZHOU Xue-ying 2018, 34 (2):  19-27.  doi: 10.3969/j.issn.1673-503X.2018.02.003 Abstract ( 231 )   PDF (3014KB) ( 274 )   Save A typical regional sand-dust weather event over the eastern margin of the Tarim Basin was analyzed and the reason of dust hover and transport characteristics were also explored using the surface meteorological data,sounding observations,and National Centers for Environmental Prediction (NCEP) reanalysis data.The results showed that the intense development of a thermal depression in the southern Xinjiang Basin and abnormal high temperature provide dynamic and thermodynamic conditions for the occurrence of sand-dust event.During the maintenance of floating dusty weather,the near-surface layer in the Tarim Basin is characterized by stable stratification and weak vertical turbulence.The temperature difference of the inversion layer has a good correspondence with visibility,and the thickness of the inversion layer varied little.During the strong sand-dust weather,the temperature gradient in the inversion layer increases and the subsidence of floating dust particles occurs as the thickness of surface inversion layer becomes thinner,which leads to a higher visibility.When the dust storm turns to floating dusty weather,the temperature difference and thickness of the inversion layer increases significantly.When the dust storm moving path passes through two key regions including the southwest and the southeast regions of Korla,it probably affects the dust weather over the Korla region,while the particles moving along the eastern path will reduce the floating dust over the Korla region.Due to the effect of the geographical environment of Ruoqiang area,the northeast,southwest,or west paths can cause sand-dust weather over the Ruoqiang area. References | Related Articles | Metrics

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Characteristics of temporal and spatial distribution and influencing weather systems of extreme long duration rainstorms in Liaoning province CHEN Chuan-lei, GUAN Zhao-yong, XIAO Guang-liang, CHENG Pan, YANG Lei, HUANG Hai-liang 2018, 34 (2):  28-34.  doi: 10.3969/j.issn.1673-503X.2018.02.004 Abstract ( 235 )   PDF (1392KB) ( 372 )   Save Based on hourly precipitation data observed by automatic weather stations of Liaoning province and NCEP grid reanalysis data with resolution of 1°×1° from 2005 to 2015,the characteristics of spatial and temporal distribution and influencing weather systems of extreme long duration rainstorms and the distribution of precipitati-on influenced by different systems were analyzed in this paper.The resluts show that the long duration rainstorms in Liaoning province are widely distributed and can be roughly divided into four easy-occurrence areas.The dura-tion of rain with intensity ≥ 10 mm ·h-1 is dominated by 6-8 hours which the maximum duration is up to 14 hours and the maximum rainfall intensity is up to 91 mm ·h-1.Moreover,the total precipitation is up to 150-200 mm for which duration is 6-7 hours and up to 250-350 mm for which duration is 8-10 hours.The number of rainstorms varies significantly from year to year.July and August is a period with high occurrence.The numbers of rainstorms are great in July,while the ranges are narrow.The number of rainstorms is less in August,while the ranges are wide.This rainstorm occurs frequently at 15:00-17:00 and 22:00-02:00.In high weather systems,it is the widest distribution and greatest intensity as well as longest duration for rainfall caused by Okhotsk Sea blocking high,and they are scattered distribution caused by zonal circulation and centralized distribution caused by Baikal Lake bloc-king high,respectively.Among them,the number of the Okhotsk Sea blocking high is the greatest.In surface weather systems,the Northwestern side of high pressure appears frequently,and it can cause rainfall with the greatest intensity.It is the wide distribution for rainfall caused by Huabei cyclone,centralized distribution caused by the Northwestern side of high pressure and typhoon and Jianghuai cyclone,and scattered distribution caused by Mongolia cyclone and Huabei cyclone. References | Related Articles | Metrics

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Variations of temperature and precipitation from 1963 to 2012 in Nanchang city HE Zhi-ming, DENG Shi-ru, WU Qiong, LI Lei 2018, 34 (2):  35-43.  doi: 10.3969/j.issn.1673-503X.2018.02.005 Abstract ( 428 )   PDF (1983KB) ( 529 )   Save The influence of urbanization on the local climate of Nanchang city during the past 50 years was analyzed in conjunction with the urban development data.The results show that the increasing amplitude of the aver-age temperature in the urban area Nanchang city during the past 50 years is about 1.07℃.The increasing rate in temperature is about 0.21℃ per decade.In the suburban area,the increasing amplitude and increasing rate of aver-age temperature is about 0.54℃ and 0.11℃ per decade,respectively.From the 1960s,the heat island intensity in Nanchang city has been showing an upward trend.The heat island intensity is 1.0℃,and the increasing rate is 0.11℃ per decade.There are some high temperature centers in Nanchang city.It represents a multi-center distribution of the heat island phenomenon.The global warming and urban development play a significant impact on the minimum temperature in Nanchang city.In the past 50 years,the average minimum temperature in urban areas is 1.83℃ higher than that in the suburbs.The annual amount of rainfall in both urban and suburban areas shows an upward trend,with an increasing rate of 28.67 mm and 6.99 mm per decade,respectively.The monthly average a-mount of precipitation in the urban area is higher than that in the suburbs in the first half of the year.There is a"rain island"effect extend to a certain extent in this city.The rainfall-center and spatial distribution in different sea-sons are different. References | Related Articles | Metrics

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Spatial-temporal variations of snow cover increment and days in Jilin province from 1961 to 2016 XU Shi-qi, FU Shuai, ZHANG Xiao-quan 2018, 34 (2):  44-51.  doi: 10.3969/j.issn.1673-503X.2018.02.006 Abstract ( 243 )   PDF (5882KB) ( 458 )   Save Using the daily snow depth observations at 45 meteorological stations in Jilin province from 1961 to 2016,the spatial and temporal characteristics of snow cover increment and the number of days were analyzed based on the empirical orthogonal function (EOF),ensemble empirical mode decomposition (EEMD) and linear fitting methods.The results show that there are significant differences in the spatial distributions of the snow cover increment and the number of days.The higher values of them mostly present around Changbai Mountain located in the eastern part of Jilin province.The lower ones present in the mid-west plain of Jilin province.The amount of snow cover tightly connects with the geographical location of observations.In the higher altitudes and lower latitudes regions,more of snow cover is observed;while less is observed in the lower altitudes and higher latitudes.From the 1960s to the end of 1980s,the amount of snow cover increases with time,but it decreases in the 1990s.After 2000,it increases rapidly.Three typical spatial patterns of snow cover increment and days are found.The first pattern is a consistently more or less than the normal one over the whole region.The second pattern is a reverse phase one be-tween the eastern and western parts,and the third pattern is a seesaw one between the central regions and other regions.Both of the traditional linear fitting and the EEMD non-linear trend methods illustrate an increasing tendency in the amounts snow cover increment and the number of the days,but the former amplifies the increasing rates. References | Related Articles | Metrics

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Relationships between air quality and meteorological conditions in Shanghai in 2015 MAO Zhuo-cheng, MA Jing-hui, QU Yuan-hao, YU Zhong-qi, ZHOU Guang-qiang, XU Jian-ming 2018, 34 (2):  52-60.  doi: 10.3969/j.issn.1673-503X.2018.02.007 Abstract ( 294 )   PDF (1770KB) ( 672 )   Save Using the air quality data from 2001 to 2015 and the meteorological data from 2014 to 2015,the air quality status,variation characteristics,and the corresponding meteorological factors in Shanghai in the context of strong El Niño atmospheric circulation in 2015 were analyzed.The results show that average annual concentrations of PM 10 and SO2 in 2015 in Shanghai reach the lowest values during the recent 15 years,and that of NO2 reaches its second lowest value.The air pollution situation in Shanghai has shifted from the traditional coal burning pollutants,such as sulfur,nitrogen,and PM10,to a compound pollution represented by PM2.5 and photochemical pollution represented by O3.Among the three firsttier cities,the excellent and good rate of air quality and average concentrations of PM2.5 and PM10 in 2015 in Shanghai are all between those in Beijing and Guangzhou.The average annual concentrations of NO 2 and O3 in Shanghai are the lowest,and that of SO2 in Shanghai is the highest.The concentration of PM2.5 in Shanghai in 2015 is higher than that in 2014.Compared with 2014,the concentration of PM2.5 in Shanghai decreases significantly in spring and summer in 2015,and those in the easily-polluted seasons including January,February,October,November and December increase significantly.This is mainly due to the lower wind speed,fewer times of continuous small winds,stronger in the inversion intensity,more times of inverse temperature,and increasing intensity in the west wind transport in the easily-polluted seasons in 2015.Influenced by the strong El Niño event,a weaker cold air activity is formed due to the polar vortex contraction in the northern hemisphere,strengthening in the Eurasian Zonal Circulation,and weakening and eastward in the East Asia Trough in the pollution season.It provides an atmospheric circulation background for the bad air quality condition in 2015 in Shanghai. References | Related Articles | Metrics

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Change characteristics and prediction model about concentration of anions in the Emei mountain scenic spot ZHANG Yong, CHEN Lan-ying, LIU Ting, XIAO Juan 2018, 34 (2):  61-68.  doi: 10.3969/j.issn.1673-503X.2018.02.008 Abstract ( 273 )   PDF (1324KB) ( 288 )   Save Based on the data of concentration of anions,air quality index (AQI),temperature,humidity and rainfall from September of 2015 to August of 2016 at the scenic spot of Emei mountain (Mt.Emei),the seasonal variation characteristics of concentration of anions and their relationship with meteorological factors were analyzed,and a prediction model for concentration of anions in the Mt.Emei was established.The results show that concentration of anions has an obvious seasonal variation.The highest values appear in autumn,followed by spring and summer,and the lowest one appears in winter.They all reach the SGFA (Standard Grades of Forestry Aeration) secondary standard.The AQI,temperature,rainfall are the key factors influencing the concentration of anions in the Mt.Emei.The reason of the highest concentration of anions appearing in autumn is due to the suitable temperature,abundant precipitation,wet air,large biomass,and so on.The falling leaves of the deciduous and mixed forest,reducing biomass,less rainfall and dry air are the reasons for the lowest concentration in winter.The prediction model based on the S model is as follows:y=exp (1.4552/x+7.5988).Its prediction accuracy is good.R-square of the three-dimensional model is excellent with 1.It can reflect the rules between the concentration of anions and the interpretation parameters in the Mt.Emei.The prediction model based on the S model can forecast the concentration of anions.The three-dimensional model builds an analysis-forecast system and is more suitable for forecasting the concentration of anions in the Mt.Emei. References | Related Articles | Metrics

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Study on the soil PAHs pollution characteristics of main parks in Shenyang LIU Wei-peng, LIU Wei, ZHANG Wen-juan, HOU Wei, LI Yue 2018, 34 (2):  69-74.  doi: 10.3969/j.issn.1673-503X.2018.02.009 Abstract ( 184 )   PDF (888KB) ( 140 )   Save Soil samples were collected from 7 major parks in Shenyang in March,2017.The concentrations of 15 Polycyclic Aromatic Hydrocarbons (PAHs) were analyzed with a High-Performance Liquid Chromatography (HPLC) method.Results show that the characteristics of PAHs pollution in the parks are different,that is,the main pollution components are obviously discrepant.The pollution level is the highest in Wanquan Park where the concentration of PAHs in soil samples is much higher than those in the other sample points.With the increase of soil depth,PAHs concentrations in the studied parks in Shenyang all show a decreasing trend.Analyzing the proportions of PAHs of different ring numbers in soil samples indicates that the content of middle and high ring pollutants is higher and derives from fuel combustion,while the low ring pollutants content is relatively low.Besides,further analysis based on the ratio method shows that the sources of PAHs in Shenyang parks are mainly the high-temperature combustion of fuel,i.e.the mixture of coal,petroleum,and biomass. References | Related Articles | Metrics

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Effect of drought stress on root growth during the key growth periods of spring maize in Northeast China CAI Fu, MING Hui-qing, XIE Yan-bing, MI Na, ZHAO Xian-li, ZHANG Yu-shu 2018, 34 (2):  75-81.  doi: 10.3969/j.issn.1673-503X.2018.02.010 Abstract ( 185 )   PDF (821KB) ( 216 )   Save Based on the large farmland soil moisture control experimental and root observational field in Jinzhou and minirhizotron method,water stress treatments were carried out during jointing and tasseling stages of maize with the way of continuous no-water complementing for a long time.Dynamics of root distributions at the soil depth of 40 cm,120 cm and 160 cm and their responses to drought stress (DS) were observed and investigated.Results show that the number of fine roots with the diameter below 1 mm is greater than that of thick roots and ac-counts for a large proportion at the soil depth of 40 cm.The proportions of thick roots at the soil depth of 120 cm and 160 cm increase compared with those at shallow soil layer.At the early stage of DS,root length density (RLD) at the soil depth of 40 cm is increasing with the aggravated DS and the DS promotes roots growing toward deep soil layer.In addition,after tasseling stages,the roots in the upper soil layer indicate premature and acceler-ated aging when suffering the DS in jointing stage.Moreover,the DS during tasseling stage of maize is able to prompt roots growing toward deep soil layer too,but the later DS results in the effect of DS on root growth weak-ened.Besides,a quick and compensatory growth of root is possibly caused by re-watering after maize suffering a long DS. References | Related Articles | Metrics

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Temporal and spatial distribution characteristics of spring maize agro-climatic resources suitability in Jilin province QIU Mei-juan, GUO Qiao, GUO Chun-ming, WANG Dong-ni, YUAN Fu-xiang, MU Chen-ying 2018, 34 (2):  82-91.  doi: 10.3969/j.issn.1673-503X.2018.02.011 Abstract ( 223 )   PDF (2559KB) ( 234 )   Save In order to understand the agricultural climate resources suitability of spring maize in Jilin province,temperature suitability (TS),precipitation suitability (PS),sunshine hour suitability (SS) and climate suitability (CS) models for the whole growing season,vegetative growth stage,and reproductive growth stage were established using a fuzzy mathematical method.Then the spatial and temporal distribution characteristics of TS,PS,SS,and CS were analyzed.The results show that,in recent 50 years,the TS for the whole growing season of spring maize in Jilin province is generally more than 0.70 with an increasing trend,which is suitable for maize growing as a whole.TS is higher in western Jilin and lower in eastern Jilin.The distributions of the TS at vegetative and reproductive growth stages are in consistent with that of the whole growing season.The SS at each growth stage of spring maize in Jilin province is higher with the value between 0.80 and 1.00.SS is higher in western Jilin and lower in western Jilin.The PS of spring maize at each growth stage is between 0.40 and 0.60,which has larger variation.CS for the whole growing season of spring maize is between 0.60 and 0.75.CS of vegetative growth stage,mostly above 0.70,is higher than that of the whole growing season.However,CS of reproductive growth stage,mostly below 0.70,is lower than that of the whole growing season.For CS of maize in Jilin province,there are no obvious differences between areas.CS of each growth stage shows a decreasing trend though they have not passed the significant test. References | Related Articles | Metrics

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Insurance product design based on maize drought weather index: A case study in Jilin province QU Si-miao, WANG Dong-ni, GUO Chun-ming, YANG Xu, WANG Mei-yu, QIU Mei-juan 2018, 34 (2):  92-99.  doi: 10.3969/j.issn.1673-503X.2018.02.012 Abstract ( 189 )   PDF (1202KB) ( 314 )   Save The insurance product design based on maize drought weather index is a beneficial supplement to tradi-tional agriculture insurance,which is important for transferring drought risk and ensuring the development of Jilin province's economy.In order to establish the drought weather index insurance model of maize,the long sequential developmental phase data of maize,meteorological data and maize yield data from 1981 to 2014 were collected.Then pricing pure premium rate determined by the parametric yield risk analysis method based on Weibull distribu-tion model and its spatial distribution were analyzed in this paper.Finally,maize drought weather index model was established and the insurance product based on different deductible excesses was designed.The results show that maize yield risk distribution in Jilin province could be simulated using the Weibull distribution model.Besides,the Weibull distribution model could also be used for pricing pure premium rate.The western of Jilin province is the region with high pure premium rate and is suitable for the high deductible rate.Whereas,the southeast of Jilin Province is the region with low pure premium rate,and is suitable for the low deductible rate.The pricing of the maize drought pure premium rate is consistent with the reality of maize planting in Jilin province,which could reflect the regional differences in Jilin province.The insurance product based on maize drought weather index is designed with the different deductible excess rate.The compensation starting values of weather index are 14.25,30.15 and 46.06 when the deductible rates are 10%,15%,and 20%,respectively. References | Related Articles | Metrics

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Integration forecast experimentation for PM2.5 mass concentration in Shenyang based on BP artificial neural network LI Xiao-lan, LIU Yang, LUAN Jian, MA Yan-jun, WANG Yang-feng, ZHANG Wan-ying 2018, 34 (2):  100-106.  doi: 10.3969/j.issn.1673-503X.2018.02.013 Abstract ( 178 )   PDF (1296KB) ( 229 )   Save Based on the forecasting products of CUACE (CMA Unified Atmospheric Chemistry Environment) and CMAQ (Community Multiscale Air Quality) models,integration forecast models for PM2.5 at different positions in Shenyang under conditions of small wind speed and high relative humidity were developed and validated using an artificial neural network method with back-propagation (BP) algorithm.The results indicate that PM2.5 concentrations predicted by integration models are much closer to their observational values than those predicted by CUACE and CMAQ.The values of mean deviation and NMSE (Normalized Mean Square Error) of modelling results decrease significantly,and the values of FAC2 increase obviously.The PM2.5 forecast from integration models can better reflect the variation of high PM2.5 concentrations,and its development at surrounding urban areas of Shenyang is significant.The integration models based on BP artificial neural network are a kind of effective method for PM2.5 forecast,which can provide a reference to the real-time operational forecast of air quality. References | Related Articles | Metrics

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Application study on the atmospheric diffusion model system in Huludao LIU Hai-long, ZOU Xu-dong, YANG Hong-bin, ZHANG Yun-hai, WANG Hong-yu, LIU Yu-che 2018, 34 (2):  107-112.  doi: 10.3969/j.issn.1673-503X.2018.02.014 Abstract ( 179 )   PDF (540KB) ( 202 )   Save Using the AMS/EPA Regulatory Model (AERMOD) and information on the emission inventory and relevant parameters of pollutant sources in Huludao city during 2016,the surface SO2 and NO2 concentrations were simulated and the results were validated with the observational data from four atmospheric environmental monitoring stations in Huludao.The results show that the simulated mean concentrations of SO2 or NO2 are slightly smaller than observational values,and the major one among various reasons is that the emission inventory in the model is not perfect.The correlation between the simulated and observational concentrations of SO2 is relatively better than that of NO 2,with the mean value of correlation coefficient of 0.71 for SO2 and 0.64 for NO2.The relative er-ror of the simulated concentration of SO 2 averaged at four monitoring stations is -19.4% and that of NO2 is -25.6%.The correlation between the simulated and observational SO 2 in winter and spring is better than other sea-sons,with the correlation efficient of 0.79 in winter.While the correlation between the simulated and observational NO 2 in winter and autumn is better,with the correlation efficient of 0.69 in winter. References | Related Articles | Metrics