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30 August 2016, Volume 32 Issue 4 Previous Issue    Next Issue

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Characteristics of mesoscale convective system during two heavy rainstorms in the northeast region of Hubei province WANG Xiao-ling, WANG Yan-jie, CHEN Sai-nan, LI Yin-e, ZHONG Min 2016, 32 (4):  1-11.  doi: 10.3969/j.issn.1673-503X.2016.04.001 Abstract ( 215 )   PDF (6494KB) ( 411 )   Save Based on data from the Local Analysis and Prediction System(LAPS),as well as observations from satellite,radar,GPS,and automatic meteorological stations,characteristics of a mesoscale convective system(MCS)were comparatively analyzed during two heavy rainstorms in the northeast region of Hubei province on July 12-13,2012.The results indicate that forcing mechanisms of the two heavy rainstorms are distinctly different.One is forced by warm advection due to thermodynamic factors and the other is forced by the front due to dynamic factors.For the first heavy rainstorm,convective cloud has an asymmetric structure.Intensive echoes extend to the high altitudes.Its strong precipitation mainly locates in the areas with great gradients of TBB(Temperature of Black Body)accompanying with thunder and lightning.While for the second one,convective cloud has a symmetric structure.Intensive echoes only reach the lower altitudes.Its heavy precipitation mainly occurs in the center with a large-TBB value,indicating warm cloud precipitation.Two heavy rainstorms last for a long period of time.One reason is that the cold outflows from cool pool in the boundary layer converge with the southerly inflows in the rear of convective system and form a backward propagation that offsets the movement of heavy rain cells,which favors the maintenance of convective systems.The other one is that the convection system moves to the same direction with the steering flows.Heavy rain cells pass the same place successively,resulting in a strong cumulative precipitation. References | Related Articles | Metrics

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Study on physical mechanism of precipitation anomaly in Liaoning province in July of 2013 GAO Song-ying, ZHAO Ting-ting, SONG Li-li, YANG Qing, HAN Wei-dong, LUO Jian-yu, BAI Hua 2016, 32 (4):  12-22.  doi: 10.3969/j.issn.1673-503X.2016.04.002 Abstract ( 217 )   PDF (5483KB) ( 313 )   Save Based on the conventional observations and the NCEP (National Centers for Environmental Prediction) reanalysis data,physical mechanism of precipitation anomaly in Liaoning province in July of 2013 was analyzed.The results show that the anomalous high precipitation in Liaoning province in July of 2013 occurs under the background of anomalous atmospheric circulation.The intensities of Ural Mountain ridge and Baikal Lake trough are stronger.The activity of cold air enhances,and it moves along a southward path.There is a longitudinal strong front along the zone of 40°-50°N in the East Asia regions,which favors the formation and development of a cyclone system.The location of the subtropical high ridge line shifts about 2° further north compared with its normal location.There are warm moist air flows at the northwest side of the subtropical high.In July,when the cold air over the middle and high latitudes travels southward and invades to the 40°N region,it meets with the warm and moist air coming from the low and middle latitudes there,leading warm moist air ascending and resulting in rainstorms.There are mainly three influencing systems,i.e.,the North China cyclone,the Mongolia cyclone cold front and the shear line in the west side of the subtropical high.The physical mechanism of rainstorm is different among these systems.The water vapor sources of the North China cyclone are the most abundant among the three rainstorm events.They are generally from the western Pacific Ocean,the South China Sea,the East China Sea,the Yellow Sea,as well as the Bay of Bengal.The water vapor in the rainstorm region is mainly transported northward by the southwesterly and southerly winds along outside of the subtropical high.The strongest regions for water vapor convergence and transport are located in the northern part of the East China Sea and the Yellow Sea.The high-level air jet is influenced by intensity of Baikal Lake trough.Under different influence systems,the evolution and intensity of high-level jet,the distribution and intensity of low-level jet,as well as the locations of the high-level divergence and low-level convergence zones to the axis of high- and low-level jets are different.The strong water vapor convergence resulting from the coupling development of high- and low-level jets and the intense vertical upward movements bringing by the overlapping effect between high-level divergence and low-level convergence,make the top of the water vapor convergence of the North China cyclone rainstorm reaching 850 hPa,and those of the Mongolia cyclone cold front and the shear line in the west side of subtropical high pressure rainstorms reaching near 900 hPa or lower.The thermal analysis indicates that dry and cold air invades into the middle layer of the environmental atmosphere during the three rainstorm events,which increases the convective instability in precipitation. References | Related Articles | Metrics

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Analysis of low-frequency atmospheric disturbances over mid-lower reaches of the Yangtze River during heavy rainfall in 1998 LI Jin, DING Ting, SUN Lin-hai, QIAN Wei-hong 2016, 32 (4):  23-31.  doi: 10.3969/j.issn.1673-503X.2016.04.003 Abstract ( 275 )   PDF (4161KB) ( 807 )   Save The data of daily precipitation in the mid-lower reaches of the Yangtze River and the reanalysis data of NCEP/NCAR (National Centers for Environmental Prediction/National Center for Atmospheric Research) which have been treated with the physical decomposition on atmospheric variables were used to study the significant characteristics of the low-frequency atmospheric disturbances during heavy rainfall events in 1998 based on the methods of Morlet wavelet analysis and Lanczos band-pass filters.The results show that before August it is the precipitation high incidence period,especially for the rainstorms in the mid-lower reaches of the Yangtze River in 1998.There are two kinds of low-frequency oscillations during heavy rainfall events;the 12-24 days low-frequency oscillations (LFO) mainly occur from January to April,and the 30-60 days LFO usually occur from June to August.Heavy rainfall events during January to April in this region are related to the 12-24 days low-frequency disturbed cyclones (or anticyclones) at 850 hPa that move eastward from the Sichuan Basin vicinity in the east side of the Tibetan Plateau,while the heavy rainfall events during May to August are related to the 30-36 days low-frequency disturbed cyclones (or anticyclones) that move westward from the sea surface of the south of the Japan main island.The geopotential height field of the 12-24 days low-frequency disturbances shows a vertical baroclinic structure,and its central axis tilts towards the west,which is different from that of the 30-60 days low-frequency disturbances characterized by barotropicity.The strongest signals of 12-24 days low-frequency disturbances that cause the heavy rainfall from January to April in this region are located around 925-850 hPa and originate from the east side of the Tibetan Plateau and the mid-high latitudes,respectively.However,the strongest signals of 30-60 days low-frequency disturbances are mostly located around 850-500 hPa and are generated from the eastern and central parts of the Pacific Ocean and the near place of the equator,respectively. References | Related Articles | Metrics

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Synoptic characteristics and prediction index of short-time strong precipitation in Dalian WANG Jian-jian, HUANG Zhen, ZOU Shan-yong, LIU Xiao-chu 2016, 32 (4):  32-38.  doi: 10.3969/j.issn.1673-503X.2016.04.004 Abstract ( 247 )   PDF (875KB) ( 423 )   Save Using hourly precipitation and conventional meteorological observation data from seven major stations and 249 automatic weather stations from 2004 to 2013,the spatial-temporal distribution and climate characteristics,evolution trend and circulation background of short-time strong precipitation in Dalian were analyzed.The weather prediction indexes of strong precipitation were established as well.The results indicate that regional short-time strong precipitation events occur normally 2.2-2.3 times per year.This number tends to increase slightly in the southern and eastern parts,remains stable in the central and northwestern parts,while decreases slightly in the north-central parts.It usually occurs during April to October,especially during July to August,generally happening from 02:00 to 10:00.The number of times that short-time strong precipitation occurs shows a clear spatial distribution feature,i.e.,increasing from the eastern to the western and central parts.The highest number occurs in the east-northern part,following by the southern part,and the lowest is in Wafangdian of the west-northern part.In July,the highest number of short-time strong precipitation appears in the northern part,and in August,it is in the eastern part.In other months,it shows strong spatial dispersion characteristics.The thresholds,including mean specific humidity between 925 hPa and 850 hPa,depression of dew-point temperature at 700 hPa,average difference in temperature between 500 hPa and 850 hPa,mean K index,mean height of 0℃ layer,and average thickness of warm clouds,can be used to forecast the short-time strong precipitation in real operation.This paper provides a reference for forecasting the strong precipitation in Dalian. References | Related Articles | Metrics

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Effect of future climate change on water resource in Honghu watershed based on SWAT model WANG Miao, LIU Min, XIA Zhi-hong, WANG Kai, XIANG Hua, QIN Peng-cheng, REN Yong-jian 2016, 32 (4):  39-47.  doi: 10.3969/j.issn.1673-503X.2016.04.005 Abstract ( 283 )   PDF (747KB) ( 706 )   Save Using the SWAT (Soil and Water Assessment Tool) model and data from the global climate model BCC-CSM 1.1 (Beijing Climate Center Climate System Model 1.1) adopted by the IPCC (Intergovernmental Panel on Climate Change) Fifth Assessment Report,the change of water resource in Honghu watershed under three future climate change scenarios,including RCP (Representative Concentration Pathway) 2.6,RCP 4.5 and RCP 8.5 emission ones,was simulated in this paper.The results indicate that the SWAT model is appropriate to simulate the change in water resource of Honghu watershed.Under the RCP 2.6,RCP 4.5 and RCP 8.5 emission scenarios,the temperature increments are 1.4℃,1.9℃ and 2.4℃,and the variation rates in precipitation are -3.20%,7.60% and 7.90%,respectively.With the increasing in temperature,the amount of evapotranspiration increases for all the three emission scenarios.The runoff is influenced significantly by precipitation.For the different scenarios,the responses of runoff to precipitation are different.Under the RCP 4.5 and RCP 8.5 scenarios,the amounts of surface and groundwater runoffs and flood-peak flow and the times of flood happening in different kinds of return periods all increase.The increasing amount in surface runoff is more remarkable for the RCP 8.5 scenario.Comparatively,the amounts for both of the surface and groundwater runoffs decrease under the RCP2.6 scenario.The variation coefficients of runoff under all these scenarios are bigger than that of the reference period.It means that the possibility of extreme meteorological evens (such as drought and flood) may increase,and the ability to utility and control of water resource in Hongdu watershed may decrease. References | Related Articles | Metrics

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Effect of fireworks forbidden on air quality during the Spring Festival in Nanjing YANG Feng, LI Wen-qing, XIE Fang-jian, LU Xiao-bo 2016, 32 (4):  48-54.  doi: 10.3969/j.issn.1673-503X.2016.04.006 Abstract ( 251 )   PDF (1064KB) ( 543 )   Save Based on monitoring data of main pollutant (PM10,PM2.5,SO2,and NO2) concentrations and meteorological data from urban and suburban areas in Nanjing during the Spring Festival of 2014 and 2015,the effects of fireworks forbidden on air quality were analyzed.The results indicate that fireworks forbidden during the Spring Festival of 2015 result in improving air quality effectively in Nanjing.Air quality index (AQI) decreases 20%-30% during the Spring Festival of 2015,comparing to that during the same period in 2014.Air quality remains in a good level from New Year's Eve to January 3,2015 according to the lunar calendar.During the Spring Festival of 2015,SO2 and NO2 concentrations vary relatively small and reach the secondary level according to Chinese air quality standard.However,PM10 and PM2.5 concentrations show an opposite variation with those in 2014 and have relatively larger range of variation,varying from 13 μg·m-3 to 234.5 μg·m-3 and from 17.5 μg·m-3 to 320.4 μg·m-3,respectively.The main pollutants that cause air pollution during the Spring Festival in Nanjing are primarily PM2.5,and then PM10.The maximum hourly mean concentrations of PM10 and PM2.5 during the Spring Festival of 2015 only take up 51% and 40% to that of 2014,respectively.In addition,PM2.5 concentrations in urban and suburban areas reduce obviously in the Spring Festival of 2015,but the difference between the two areas is small.Meteorological factors greatly influence pollutant diffusion during the Spring Festival in Nanjing;however,the fireworks prohibition has a dominant effect on the reduction of PM2.5 concentration. References | Related Articles | Metrics

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Correlation analysis of atmospheric visibility and meteorological parameters in Gaizhou of Liaoning province ZHU Yi-ming, ZHANG Jin-guang, YUAN Jian, ZHANG Xiu-yan, LI Yang, ZHANG Wei-quan, WAN Xu-jiang, LU Bing-hong 2016, 32 (4):  55-62.  doi: 10.3969/j.issn.1673-503X.2016.04.007 Abstract ( 271 )   PDF (665KB) ( 403 )   Save Based on the observational data of atmospheric visibility and some meteorological parameters (relative humidity,wind speed,air temperature,and atmospheric pressure) at ground from 2011 to 2012 in Gaizhou of Liaoning province,the monthly and daily variations of atmospheric visibility as well as its correlation with meteorological parameters were analyzed.The results show that the high visibility events usually occur in March and October in Gaizhou,and the low visibility ones mostly occur from June to August.The visibility in summer is the lowest during a whole year,and its largest visibility appears at 14:00,lower one at 08:00,and the lowest at 20:00 during a day.The correlation of atmospheric visibility with relative humidity is the best,and followed by wind speed,air temperature,and atmospheric pressure.As relative humidity is larger than 80.0%,the minimum atmospheric visibility is in the range of 10.4±3.2 km,and the correlation coefficients between visibility and atmospheric pressure,air temperature,and relative humidity are -0.52,0.51 and -0.52,respectively.Low visibility events (<10 km) in Gaizhou mainly result from higher air temperature and relative humidity,as well as smaller wind speed and atmospheric pressure. References | Related Articles | Metrics

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Evolution and characteristics of haze in Shijiazhuang region from 1970 to 2013 QIAN Wei-miao, CHEN Jing, WANG Xiao-min, YUE Hong 2016, 32 (4):  63-69.  doi: 10.3969/j.issn.1673-503X.2016.04.008 Abstract ( 227 )   PDF (4200KB) ( 392 )   Save Characteristics of spatial distribution of haze were analyzed using meteorological data at ground obtained from seventeen weather stations in Shijiazhuang region from 1970 to 2013.The results show that the reginal distribution of annual total haze days changes greatly from 1970 to 2013 in Shijiazhuang.The former distribution pattern is characterized by higher haze days appearing in the mid-eastern plain area and lower ones in the northwestern mountainous region.However,such distribution pattern gradually changes with higher haze days in the southwestern region and lower ones in the mid-eastern region.This kind of change becomes even more significant after 2010.With the rapid development of economy,the abundant mine resources in the western mountainous region have been exploited,which results in excessive emissions of pollutants such as SO2,NOX,and VOCS,and favors the conversion and formation of aerosols through photochemical reaction.In addition,pollutants can be transported from the southeastern region and accumulate at the mountain's front due to the block of the Taihang Mountains under a certain weather background condition.Therefore,besides the local pollutant emissions,regional transport of pollutants is another reason for severe pollution in the western mountainous region.The total number of days with the persistent haze events takes up more than 50% of the annual total number of the haze days.According to the classification of persistent haze event,when the duration of a haze event exceeds four (eight) days,it is defined as a medium (extreme) persistent haze event.The annual mean number of medium persistent haze events is 9.8,and that of extreme persistent haze events is 1.6.Taking the south-northeast railway line in Shijiazhuang as a boundary,extreme persistent haze events occur mostly in the mid-eastern and southern regions (Wuji,Zhengding,Gaocheng,Luancheng,and Zhaoxian),and less in the northwestern region (Pingshan,Xingtang,and Lingshou) and the eastern region (Jinzhou,Shenze,and Xinji).Medium persistent haze events occur typically in December and January and least from June to August,while extreme persistent haze events occur mostly from November to February,especially in January.The monthly mean occurrence number of extreme persistent haze event is the largest in January with 0.4 averaged from the study period,and less than 0.2 in other months,which means a small occurrence probability of haze in these months. References | Related Articles | Metrics

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Characteristics and causes of regional acid rain in Fujian province CHEN Bin-bin, WANG Hong, ZHENG Qiu-ping, YANG Kai 2016, 32 (4):  70-76.  doi: 10.3969/j.issn.1673-503X.2016.04.009 Abstract ( 395 )   PDF (1040KB) ( 475 )   Save Based on the monitoring data of acid rain obtained from four meteorological stations including Shaowu,Fuzhou,Yong'an,and Xiamen of Fujian province from 2007 to 2014,the temporal-spatial characteristics of acid rain in different regions and the variation of strong acid rain were analyzed,and the causes of acid rain formation were preliminarily explored.The results show that the annual mean pH in precipitation is between 4.64 and 4.97,which belongs to moderate acid rain.The pH value has an increasing trend,and the acidity in precipitation as well as the occurrence frequency of strong acid rain both show a decreasing trend.Acid rain occurs frequently in Shaowu and Fuzhou,and the strongest acidity in precipitation and the high occurrence frequency of acid rain as well as strong acid rain all appear in Shaowu.However,the acidity of precipitation is weaker and the strong acid rain occurrence frequency is lower in the two regions after 2011.Xiamen and Yong'an belong to the regions with weak acid rain,and strong acid rain rarely occurs in Yong'an during a whole year.However,the acidity in precipitation at these two regions increases after 2012,due to the increasing occurrence frequency of acid rain and the increasing cumulative amount of acid rain.Acid rain shows a certain regular monthly variation in Fuzhou,Xiamen,and Shaowu;acid rain pollution is heavy in winter and spring,but relatively weak in summer.However,such monthly acid rain changes oppositely in Yong'an,with an alkaline precipitation in autumn and winter,and weak acid rain pollution in spring.The probability of monthly mean precipitation pH less than 4.50 in Fujian province from 2007 to 2014 is 0.0% in Yong'an,4.2% in Xiamen,29.2% in Fuzhou,and 42.7% in Shaowu,respectively,and all show a decreasing trend.The regional acid rain pollution in Fujian province is caused by the emissions of urban acid pollutants,inter-provincial transport of acid substances,geographical environment,and weather conditions. References | Related Articles | Metrics

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Characteristics of acid rain and its impact factors in Dandong YU Wen-ge, LIANG Tie-jun, SUN Ying, SONG Li-li, BAI Hua, ZHAO Ting-ting 2016, 32 (4):  77-82.  doi: 10.3969/j.issn.1673-503X.2016.04.010 Abstract ( 207 )   PDF (674KB) ( 325 )   Save Based on the observational data of acid rain and the surface and high-level meteorological data in Dandong from 2009 to 2013,the spatial and temporal characteristics of acid rain were analyzed,and the pH value in precipitation and frequency of acid rain under different weather conditions were investigated using a correlation analysis method.This study is aimed at providing a scientific basis for the evaluation and prediction of acid rain.The results show that the distribution of pH values of acid rain is uniform in Dandong.Both of the pH value in precipitation and the frequency of acid rain have an increasing trend during the study period,and the smallest pH value in precipitation and the largest frequency of acid rain occur in autumn.The pH value in precipitation is closely related to precipitation magnitude,and fog favors to enhance the precipitation acidity.The southerly winds prevail at ground when acid rain occurs in Dandong.There is an obvious difference in the effects of surface wind speed on the intensity of acid rain during the early stage and the middle stage of precipitation.The pH value in precipitation is mainly determined by the 24-h temperature deviation,the 12-h wind direction before precipitation,and wind speed at 850 hPa during precipitation.The southerly wind is dominant at 850 hPa during acid rain events.Temperature inversion and K index strongly influence the acid rain pollution. References | Related Articles | Metrics

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Characteristics and impact factors of acid rain in Zhenjiang of Jiangsu province SUN Cui-mei, KONG Qi-liang, GUO Yu, WU Qiong, QIAN Peng, ZHOU Qing 2016, 32 (4):  83-90.  doi: 10.3969/j.issn.1673-503X.2016.04.011 Abstract ( 202 )   PDF (1066KB) ( 379 )   Save The characteristics and variations of the intensity and occurrence frequency of acid rain at the annual,seasonal,and monthly scales as well as its meteorological impact factors were analyzed in this study,using the observational data of acid rain in Zhenjiang from January of 2008 to December of 2012.The results show that all the annual,seasonal,and monthly mean pH values of acid rain are relatively small,the intensity of acid rain is strong,and the occurrence frequency of acid rain is usually high in spring and autumn.Considering the effects of meteorological parameters such as precipitation,wind direction,temperature inversion,and the vertical transport of non-local pollutants,it is found out that both of the occurrence frequency of acid rain and its proportion to the total precipitation are large.More than half of the acid rain in Zhenjiang occurs under the northeasterly,southeasterly,and easterly wind conditions.Acid rain in Zhenjiang is also related to the pollutants transport from other regions,probably including the northern China region,the eastern China region,Hu'nan province,and Hubei province.The deep temperature inversion in the lower troposphere (at and below 925 hPa) usually favors the occurrence of acid rain,and the acid rain intensity is associated with the temperature inversion intensity,which means the temperature deviation in the inversion layer is larger,the pH values is smaller,and the acid rain intensity is larger. References | Related Articles | Metrics

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An improved evaluation method to the meteorological grade of heatstroke in Ningbo LU Jing-jing, LV Jin-wen, QIAN Zheng 2016, 32 (4):  91-97.  doi: 10.3969/j.issn.1673-503X.2016.04.012 Abstract ( 241 )   PDF (740KB) ( 357 )   Save Based on the daily surface meteorological observation data from 1980 to 2014 and the cases of residents' heatstroke during June to August from 2011 to 2014 in Ningbo,a new meteorological grade of heatstroke was established using a quantile method according to the correlation between local meteorological factors and heatstroke cases.The 45th,70th and 85th quantiles were used to divide the maximum temperatures and heat indices into new division grades.The meteorological grades of heatstroke were improved by combining the heatstroke cases and the persistent days of the maximum temperature.The meteorological grades of heatstroke were classified as possible,easy,easier and extremely easy occurence.The results show that the improved meteorological grade of heatstroke is more suitable to Ningbo region.The heatstroke grade determined by the meteorological conditions and heatstroke cases are able to reflect the risk of heatstroke.This work provides a reference for predicting the real meteorological grades of heatstroke. References | Related Articles | Metrics

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Determination of low-temperature and frost damage indicators and construction of a temperature forecasting model for tomato in greenhouse ZHANG Shu-jie, SUN Li-de, MA Cheng-zhi, ZHANG Jing, CHEN Yan-qiu, LI Guang-xia, HAN Xiu-jun, WU Man-li, GUO Hai 2016, 32 (4):  98-105.  doi: 10.3969/j.issn.1673-503X.2016.04.013 Abstract ( 212 )   PDF (662KB) ( 451 )   Save Based on greenhouse microclimate observation data in two growing seasons from December 2012 to January 2013 and from December 2013 to January 2014,the occurrence of frost damage for tomatoes in greenhouse and their influencing factors were analyzed.The diurnal temperature difference index was constructed and taken as an indicator for the happening of low-temperature and frost damage during fruit enlargement period for tomato in greenhouse.Additionally,a temperature forecasting model was constructed through a regression analysis method.The results show that the occurrence of low-temperature and frost damage for tomato in greenhouse can be attributed to the combined effects of continuous low temperature,lack of sunshine and high humidity in greenhouse.Low-temperature and frost damage happens when the number of scant-sunshine days with rain or snow outside greenhouse is more than 3,the maximum temperature in greenhouse is less than 10℃,the minimum temperature is less than 5℃,and the duration of low temperature (less than 5℃) is more than 15 h.In this study,hourly temperature data inside and outside greenhouse are used to construct a temperature forecasting model on an hourly time step for greenhouse.The forecasting accuracy for hourly temperature with an absolute error ≤3℃ from 18:00 to 08:00 reaches more than 86%.Based on the low-temperature and frost damage indicators and the hourly temperature forecasting model,an early warning for occurrence of low-temperature and frost damages can be provided.It improves the disaster prevention and mitigation capabilities in a greenhouse. References | Related Articles | Metrics

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Applicability analysis of SMCR_N model for eggplant growing in alluvial region of Beijing DONG Yi-wei, LI Yu-zhong, ZHANG Ke-feng, XU Chun-ying, LI Qiao-zhen, FANG Fu-li, GUO Zhi-cheng 2016, 32 (4):  106-112.  doi: 10.3969/j.issn.1673-503X.2016.04.014 Abstract ( 203 )   PDF (701KB) ( 277 )   Save To provide a reference for regional application of SMCR_N (Simulation Model for Crop Response to Nitrogen fertilizer) model in alluvial region of Beijing,it has been used to simulate the yields of purple long- and round-eggplants as well as the amount of N uptake by round-eggplants using the location experiment,meteorological and cultivating management data in the eggplant field with alluvial soil in Beijing from 2009 to 2010.The parameters of the model were calibrated using data from this experiment.The performance of the model was evaluated with experimental data as well.The results show that the original eggplant parameters in SMCR_N model can be directly applied to simulate the yield of purple long-eggplants growing in alluvial region of Beijing.The simulating results indicate that RMSE (Root Mean Square Error),n-RMSE(normalized Root Mean Square Error),EF (model prediction Efficiency),E,d (fitting index),and R2 (determination coefficient) are 0.42 t·hm-2,0.06 t·hm-2,0.95,0.40,0.99,0.96,respectively.The cultivar of round-eggplant used in the location experiment is different from that in SMCR_N model.So,the corresponding parameters in SMCR_N model need to be adjusted.The sensitivity analyses show that simulation results are sensitive to crop growth parameter (K1).When K1 is adjusted to 1.4,the simulating result of dry weight is more accurate,with RMSE,n-RMSE,EF,E,d,R2 of 1.2 t·hm-2,0.12 t·hm-2,0.59,0.76,0.93,0.80,respectively.After calibrating model parameters,the SMCR_N model can be also used to simulate the N uptake by round-eggplants.The simulating results are satisfactory,with R2 of 0.85.In conclusion,the variations of total dry weight and N uptake by eggplants in alluvial region of Beijing can be well simulated through calibrating the parameters in SMCR_N model.The SMCR_N model can be applied to guide a reasonable fertilization for eggplant fields in alluvial region of Beijing. References | Related Articles | Metrics

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Characteristics of freezing rain in Beijing from 1960 to 2013 YU Bo, DU Jia, ZHANG Lin-na 2016, 32 (4):  113-118.  doi: 10.3969/j.issn.1673-503X.2016.04.015 Abstract ( 281 )   PDF (1918KB) ( 395 )   Save Using the data from surface meteorological stations,observatory sounding and the NCEP/NCAR (National Centers for Environmental Prediction/National Center for Atmospheric Research) reanalysis,the characteristics of synoptic process and the occurrence conditions for freezing rain observed at 20 surface meteorological stations in Beijing from 1960 to 2013 were analyzed.The results show that the freezing rains mainly occur from November to April of the next year.The freezing rain phenomena normally appear in Daxing,Tongzhou and Changping districts.The conditions of abundant water vapor and uplifting at the low atmospheric level are favorable to the formation of freezing rain.The vertical structure of atmospheric stratification can be divided into two types,i.e.,the melting and non-melting layers.The occurrence frequency of freezing rain for both of them is equal.Based on the comparative analyses,it indicates that the warm advection between 700 hPa and 850 hPa plays a crucial role in the change of inversion temperature intensity.For the cases without melting layer,the height of cloud top is higher.The air temperature under the 700 hPa is from -10℃ to 0℃.The precipitation drops to the ground as supercooled water,and it happens to freeze and forms freezing rain.For the cases with melting layer,the wet layer is shallower,only existing under the 850 hPa.The warm moist air sliding on the cold air near the surface is one of the favorable conditions for the formation of this kind of freezing rain. References | Related Articles | Metrics

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Characteristics of lightning distribution in Beijing,Tianjin,and Hebei province from 2007 to 2015 YANG Min, YANG Xiao-liang 2016, 32 (4):  119-125.  doi: 10.3969/j.issn.1673-503X.2016.04.016 Abstract ( 220 )   PDF (1673KB) ( 393 )   Save Based on the data of CG (Cloud-to-Ground) lightning observed by a lightning localization system and thunderstorm observed from 2007 to 2015,the distribution characteristics of lightning in Beijing,Tianjin,and Hebei province were analyzed.The results indicate that the total number of the thunderstorms observed by meteorological observers is different from that of CG lightning observed by the lighting localization system,while the temporal distributions of them are consistent.The thunderstorm data observed by the observers at the surface can only be used to reflect the basic concept of the thunderstorm days due to the limitation of the observation technical standards.By contrast,the CG lightning data observed by the lightning location system are closer to the real lightning distribution.The percentage of the number of PCG (Positive Cloud-to-Ground) lightning to that of TCG (Total Cloud-to-Ground) lightning is 7.8% in Beijing,Tianjin,and Hebei province from 2007 to 2015.This percentage is different in different seasons and regions.Unlike those of TCG and NCG (Negative Cloud-to-Ground) lightnings,the distribution of monthly PCG lightning is relatively uniform.There are no significant differences in the daily variation among TCG,PCG and NCG lightnings.The CG lightning generally appears at the transition zones between mountains and plains and the joint regions of land and ocean in Beijing,Tianjin,and Hebei province. References | Related Articles | Metrics

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Characteristics analysis of lightning disaster in Beijing from 2005 to 2014 QIAN Mu-hui, LI Jing-xiao, LI Ru-jian, ZHANG Yu-long, LU Xi, JI Xiao-ming 2016, 32 (4):  126-131.  doi: 10.3969/j.issn.1673-503X.2016.04.017 Abstract ( 274 )   PDF (1003KB) ( 527 )   Save Using lightning disaster data from 2005 to 2014 and ADTD (Active Divectory Topology Diagrammer) lightning location data from 2008 to 2014 in Beijing,the characteristics of lightning disaster and lightning were analyzed based on statistic approaches.The results show that there are totally 532 cases of lightning disasters from 2005 to 2014,with an average of 53.2 cases per year in Beijing.The annual direct economic losses are more than three million yuan.The lightning disaster mainly occurs during June to August,especially in June,mostly happening at 17:00 to 23:00,especially at 19:00.The spatial distribution of lightning disaster demonstrates that there is a higher value in the urban and southern parts and lower in the suburb and northern parts.The lightning disaster primarily happens in the civilian,business,transportation,electric power,communication,petrochemical,finance,and tourism industries.The victims of lightning disaster generally include office (54.12%) and household (30.47%) electronic appliances.The lightning disasters usually focus on the living,office and production spaces.The temporal distribution of lightning disaster is basically consistent with that of the lightning,while the spatial density distributions of them are a little different. References | Related Articles | Metrics

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Research progress of δD and δ18O in different water bodies in China LI Guang, ZHANG Xin-ping, SONG Song, YAO Tian-ci, XIANG Jie, DENG Xiao-jun 2016, 32 (4):  132-138.  doi: 10.3969/j.issn.1673-503X.2016.04.018 Abstract ( 272 )   PDF (569KB) ( 1099 )   Save The hydrogen and oxygen stable isotopes in water bodies are very sensitive to environmental changes.In the processes of water vapor evaporation and water vapor condensing into raindrop,the variations of δD and δ18O closely link with moisture sources and surrounding meteorological factors (e.g.temperature,precipitation and relative humidity,etc.).Studying on the temporal-spatial distributions of δD and δ18O in different water bodies can be beneficial to discussing the characteristics of atmospheric circulation and the mechanisms of global and local water cycles.Additionally,it can also provide a new basis for recovering and reconstructing the paleo-climate and paleo-environment.This paper summarizes the research progress of hydrogen and oxygen stable isotopes in different water bodies including its research contents and methods.Moreover,interdisciplinarity and application values of hydrogen and oxygen stable isotopes are discussed in this paper.Based on above discussions,some important directions are proposed for further research in order to provide some ideas for related studies. References | Related Articles | Metrics

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Application of bias correction to temperature forecast in winter in Liaoning province JIA Xu-xuan, TIAN Li, LU Jing-long, YANG Yang 2016, 32 (4):  139-143.  doi: 10.3969/j.issn.1673-503X.2016.04.019 Abstract ( 326 )   PDF (994KB) ( 471 )   Save The interpolation results of 2 m temperature forecast products produced by the meso-scale operational model in winter of 2014 in Liaoning province were corrected using methods of 7-day bias correction (7DBC) and running mean bias correction (RMBC).The correction results were compared to products of MOS (model output statistics) forecast.The forecast accuracy of the three methods,MOS forecast,7DBC and RMBC,were analyzed.The results show that forecast accuracy of the two bias correction methods is higher than that of NWP (numerical weather prediction) interpolation method.The RMBC method is better than the 7DBC method.As to 24 h maximum temperature forecast,the forecast accuracy of the RMBC method is the highest.For minimum temperature forecast,the forecast accuracy of RMBC is higher than that of NMC (National Meteorological Center) MOS forecast at 08:00,while less than MOS forecast at 20:00.The method of RMBC needs accumulated data of 1 to 15 days.Compared to MOS method,the method of RMBC needs less data and is easy to operate,which is more suitable for areas without long-term records to conduct numerical model revisions for temperature. References | Related Articles | Metrics

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Characteristics of heating degree days in the Changbai Mountains HU Yi-xin, LIU Yu-ying, ZHANG Chen-chen, YU Xiu-jing, WEI Xiao-li 2016, 32 (4):  144-149.  doi: 10.3969/j.issn.1673-503X.2016.04.020 Abstract ( 227 )   PDF (1188KB) ( 330 )   Save Based on the daily mean temperature data from 29 meteorological stations from 1961 to 2014 and RegCM4 (Regional Climate Model 4) model data from 2010 to 2059 in the Changbai Mountains,annual heating degree days were calculated,its spatio-temporal variation characteristics were analyzed,and the relationships between heating degree days and annual mean temperatures were investigated.The results show that the value of annual heating degree days in the Changbai Mountains is high and fluctuates in a range of 4311.8-5723.7℃·d.The value of annual heating degree days is higher in the northern part and lower in the southern part of the Changbai Mountains.The value of annual heating degree days tends to decrease since 1961,especially since 1989 to 2009.From 2010,it tends to increase slightly again.There is a clear negative relationship between the value of heating degree days and annual mean temperature.Under RCP (Representative Concentration Pathway) 4.5 and RCP 8.5 scenarios,it is expected that heating degree days would decrease with increasing in temperature from 2010 to 2059. References | Related Articles | Metrics