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31 December 2016, Volume 32 Issue 6 Previous Issue    Next Issue

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Validation on numerical forecast products during the “8.16” severe torrential rain in Liaoning province LIANG Han, CHEN Chuan-lei, NIE An-qi, TIAN Li, HE Hui, HUANG Ge 2016, 32 (6):  1-9.  doi: 10.3969/j.issn.1673-503X.2016.06.001 Abstract ( 318 )   PDF (3900KB) ( 465 )   Save Based on observational data from surface meteorological stations and radiosonde data,the forecast products,such as precipitation,geopotential height field at 500 hPa,subtropical high index,from different numerical models for the severe torrential rain event on August 16,2013 were validated and comparatively analyzed.The results show that general precipitation forecast accuracy of the the T639 model is better than that of the the EC model,and the mean forecast accuracy of rainstorm from the EC model is slightly better than that from the T639 model.The spatial distribution pattern of positive and negative precipitation anomaly of the T639 is similar to that of the EC.The precipitation predicted by different numerical models is all significantly smaller than observations during the main precipitation period (11:00-23:00 on August 16) at Qingyuan station,and the 3-h maximum precipitation predicted by the WRF model is much larger than the real precipitation.The precipitation grades predicted by the T639 and the EC are both smaller than the real grades.The 72-h precipitation area and the center position of strong precipitation predicted by the EC and an ensemble model are relatively stable.The 15-d moving averaged validating results have some referential meaning to the precipitation forecast.The consistency of 72-h characteristics line predicted by the EC is better than that predicted by the T639,and the dispersion of precipitation predicted by the EC over the most regions of Liaoning province as well as upper trough in the upstream region is smaller than that predicted by the T639. References | Related Articles | Metrics

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Verification and modification to spring air quality forecasted by CUACE system in Shenyang LI Xiao-lan, MA Yan-jun, WANG Yang-feng, ZHAO Hu-jia, LIU Hong-li 2016, 32 (6):  10-18.  doi: 10.3969/j.issn.1673-503X.2016.06.002 Abstract ( 252 )   PDF (1034KB) ( 339 )   Save The performance of the CUACE system for spring air quality forecasts in Shenyang was verified and modified using the atmospheric environment observational data during April and May 2015.The results indicate that its forecasting for the mass concentrations of six pollutants,i.e.,PM10,PM2.5,NO2,O3,SO2,and CO,is generally smaller than the observed values,especially for the PM10 concentration that is significantly underestimated.The PM2.5 is daily primary pollutant in spring in Shenyang predicted by the CUACE system,while the observations show that there is comparable number of days when PM10 and PM2.5 both are the primary pollutants.Meanwhile,there is a large difference in the air pollution grades forecasted by the CUACE system and determined by the observations.The results forecasted by the CUACE system are modified using a linear fitting formula based on the forecasting and observed pollutants' concentrations.Through this modification,the forecasting results on the primary pollutants are principally consistent with the observed ones.Furthermore,the forecasting accuracy on the air pollution grade is improved by about 50% to 80%. References | Related Articles | Metrics

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Effect and possible mechanism of diabatic heating on evolution of cold vortex over Northeast China in June LI Yong-sheng, LIU Bo-qi, WANG Ying, LI Fei 2016, 32 (6):  19-26.  doi: 10.3969/j.issn.1673-503X.2016.06.003 Abstract ( 273 )   PDF (4765KB) ( 555 )   Save Based on the ERA-Interim reanalysis data and the theory of isentropic potential vorticity (IPV) and using methods of composite technology and dynamical diagnosis,climatic characteristics of cold vortexes over Northeast China in June as well as the important effects of diabatic heating on their formation and evolution were analyzed.The results show that climatic mean cold vortex over Northeast China forms in the upper troposphere at the middle latitudes,characterized by IPV strengthening from upward to downward and from the west to the east,which is closely related to variation of the atmospheric diabatic heating.Before cold vortex forms,diabatic heating at the upper levels is evidently strengthened,while as it forms,the local diabatic heating in the middle and lower troposphere rapidly enhances.Consequently,diabatic heating in the upper troposphere greatly determines the formation and development of cold vortex over Northeast China,and diabatic heating in the middle troposphere is the major reason to the delay of cold vortex over Northeast China. References | Related Articles | Metrics

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Analysis of differences of rainfall between urban and rural regions in Nanjing CHEN Sheng-jie, YIN Dong-ping, LI Yu-tao, SUN Yan, LI Chao 2016, 32 (6):  27-33.  doi: 10.3969/j.issn.1673-503X.2016.06.004 Abstract ( 257 )   PDF (1682KB) ( 374 )   Save The differences of rainfall between urban and rural regions in Nanjing from 2009 to 2013 were analyzed based on the hourly rainfall observation data from 71 intensive automatic stations.The results indicate that there is an obvious seasonal difference for the rain-island effect in the urban region.The urban rain-island effect mainly occurs in June to August,especially in July and August.There is no significant difference in rainfall amounts between urban and rural regions in the other seasons.The rainfall amounts for light,moderate and heavy rains also have no apparent differences between both of the regions,However,there are evident differences in rainstorm and short-time heavy rainfall during June to August in Nanjing due to the urbanization.The rainstorm frequency and intensity and the frequency of the short-time heavy rainfall in the urban region are higher than those in the rural region.So,it is easy to form an urban flood disaster.The urbanization has little impact on the differences in general rainfall between urban and rural regions,while it significantly makes the disaster rainfall events,such as summer rainstorm and the short-time heavy rainfall intensification. References | Related Articles | Metrics

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Spatial and temporal characteristics of summer precipitation extremes in Liaoning province LU Jing-long, YAN Qi, JIA Xu-xuan, ZHU Xian-long, TIAN Li 2016, 32 (6):  34-42.  doi: 10.3969/j.issn.1673-503X.2016.06.005 Abstract ( 361 )   PDF (5735KB) ( 496 )   Save Based on the precipitation data from 54 meteorological stations in Liaoning province from 1981 to 2015,the spatial and temporal characteristics of summer precipitation extremes were analyzed using climatic trend coefficient,Morlet wavelet analysis and Mann-Kendall sudden change analysis and other climatic statistical methods.The results show that the larger values of the threshold of summer precipitation extremes occur in the coastal areas in the southwestern part of Liaoning province,the northern parts of the Bohai Sea and the Yellow Sea and in Dalian urban district.The smaller values occur in the western and eastern mountain areas of Liaoning province.The spatial distribution characteristics of extreme precipitation intensity are similar to those of the precipitation threshold.Basically,the distribution characteristics of extreme precipitation frequencies for different precipitation durations are same.There is not a clear trend in the long-term change of it.It mainly shows an inter-annual variation,with 3,5 and 8 years' change periods.The frequency of extreme precipitation is higher in the eastern mountain areas and lower in the coastal area of the Bohai and Chaoyang city.The spatial distribution of precipitation amount extremes within 24 h,12 h,6 h,3 h and 1 h in summer is particularly uneven,and the corresponding ratios of the maximum to minimum of extreme values are 1.2,1.6,1.6,2.4 and 1.8,respectively.The maximum length of extreme wet period occurs in Xinbin area and lasts about 11.3 days,and that of extreme dry period occurs in the Dashiqiao area and is persistent 24.3 days. References | Related Articles | Metrics

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Analysis on environmental parameters in potential forecast of severe convective weather in Shenyang LI Chong, JI Cao-xiang, XIA Chuan-dong, ZHANG Zhi, LI Dian, MENG Peng, BAN Wei-long, LIANG Hong 2016, 32 (6):  43-51.  doi: 10.3969/j.issn.1673-503X.2016.06.006 Abstract ( 458 )   PDF (2423KB) ( 488 )   Save Based on conventional radiosonde observations and analysis data of Weather Research and Forecast (WRF) model,the climatic background characteristics,evolutional feature and diurnal variation of severe convective weather in Shenyang from 2005 to 2014 were investigated.Severe convective weather was classified into four types,including hailstorm,thunderstorm and strong wind (≥17.2 m·s-1),short-time strong rainfall (≥20 mm·h-1),and the mixture of all.The function of the radiosonde data in the potential forecast of severe convective weather was analyzed,particularly that at 14:00 (02:00) in the short-term potential forecast of severe convective weather in Shenyang.The results show that the short-time strong rainfall among severe convective weather types occur mostly in Shenyang from 2005 to 2014,followed by thunderstorm and strong wind,and hail ranks the last.Severe convective weather mostly occurs in the afternoon towards the evening.Analysis of profiles of air temperature and humidity in T-LogP diagrams indicates that the short-time strong rainfall events usually accompany with significant moisture area in the middle and lower atmosphere,which are very different from those of thunderstorm,strong wind and the hailstorm.The latter three types show a dry layer in the middle atmosphere from the most of T-LogP diagrams.The heights of layers of 0℃ and -20℃ for hail are obviously lower than those of the other convective weather types.Temperature difference between 700 hPa and 500 hPa (T700-T500) and that between 850 hPa and 500 hPa (T850-T500) of hail weather are significantly larger than those of short-time strong rainfall,thunderstorm and strong wind,and the value of T850-T500 has better referential meaning.The mean value of Showalter index (SI) for the four types of severe convective weather is positive,which means that SI has no meanings.The K-index value of short-time strong rainfall weather is significantly greater than that of hail weather,and the convective available potential energy (CAPE) of thunderstorm and strong wind is significantly smaller than that of the other types.The predicted T-LogP diagram from the WRF model has a certain reference for the forecast of severe convective weather in Shenyang. References | Related Articles | Metrics

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Temporal and spatial characteristics of PM10 in Liaoyang of Liaoning province from 2006 to 2012 AN Juan, WANG Peng, WU Zhen-dong, LU Xiao-tong, LU Zhuo-yi, LIU Chun-ming 2016, 32 (6):  52-57.  doi: 10.3969/j.issn.1673-503X.2016.06.007 Abstract ( 212 )   PDF (732KB) ( 378 )   Save In order to understand the spatiotemporal distribution of PM10 over Liaoyang of Liaoning province and provide a scientific basis for air pollution prediction and measure of prevention,the spatiotemporal variations of PM10 were analyzed using daily monitoring data of PM10 in Liaoyang of Liaoning province from 2006 to 2012.The results show that the annual mean PM10 concentration decreases significantly during this period.The PM10 concentration is the largest in winter,followed in spring,autumn,and summer.The monthly mean PM10 concentration exhibits a "U" type distribution,with the higher values in January,February and December and the lowest one in July.The highest PM10 concentration is observed in Yuanlinqu station (a residential area),followed by Gangguanchang station (an industrial area),201 Xuezhan station (a traffic area),and Liaohua station(a clean area).The PM10 concentration has been observed decreasing at all monitoring stations in the recent 7 years,except for the Gangguanchang station. References | Related Articles | Metrics

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Characteristics of atmospheric particulate and their relationships with meteorological conditions in Yinchuan area GOU Xiao-hui, YAN Xiao-yu, LIU Yu-lan, SANG Jia-ren 2016, 32 (6):  58-68.  doi: 10.3969/j.issn.1673-503X.2016.06.008 Abstract ( 277 )   PDF (1594KB) ( 478 )   Save Using the atmospheric particulate matter concentration and meteorological data in Yinchuan from 2013 to 2014,the distribution characteristics of atmospheric particulate matter concentration and their relationships with meteorological conditions were analyzed.The results show that the mean annual concentrations of PM10,PM2.5 and PM1 are 167.3 μg·m-3,67.2 μg·m-3 and 45.0 μg·m-3,and the mean annual values of PM2.5/PM10,PM1/PM10 and PM1/PM2.5 are 45.0%,32.0% and 65.0%,respectively.The maximum concentration of PM10 occurs in March,and the minimum one in August.The maximum concentrations of PM2.5 and PM1 occur in January,and the minimum ones of PM2.5 and PM1 occur in August and May,respectively.From March to May,the lowest values of PM2.5/PM10,PM1/PM10 and PM1/PM2.5 occur in a year.For different weather conditions,the order of PM10 concentration from high to low is raising-sand/floating-dust,average of typical weathers,haze,fine day and fog.The situation for PM2.5 is raising-sand/floating-dust,haze,average of typical weathers,fine day and fog.The case for PM1 is haze,average of typical weathers,fine day,raising-sand/floating-dust.There is a positive correlation between wind speed and PM10 concentration,and negative correlations of wind speed with PM2.5 and PM1 concentrations.When the wind direction is north-west,the concentration of PM10 is higher.When it is south-west and north-east,the concentrations of PM2.5 and PM1 are higher.There are significant negative correlations of air temperature with the concentrations of PM10,PM2.5 and PM1.Relative humidity has a significant negative correlation with PM10 concentration,and a strong positive correlation with PM1 concentration,while a weak correlation with PM2.5 concentration.The influence of air pressure on the PM10 concentration is small,while there are positive correlations of it with the concentrations of PM2.5 and PM1.The cleaning effect of precipitation on PM10 is the strongest,followed in PM2.5,and it basically has no impact on PM1. References | Related Articles | Metrics

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Climatic characteristics and causes of heavy fog in Anshan area JIN Wei, QU Shu-lin, WANG Ye-xiu, SHEN Yu-min, DAI Ping, GAO Ling-yun, QU Yan, YUAN Jiu-song 2016, 32 (6):  69-76.  doi: 10.3969/j.issn.1673-503X.2016.06.009 Abstract ( 303 )   PDF (835KB) ( 470 )   Save Based on the observational data of heavy fog in Anshan area from 1951 to 2014,the spatial and temporal characteristics of heavy fog were analyzed using a linear trend method and a polynomial trend method.The results show that the annual and seasonal numbers of fog days from 1951 to 2014 are larger in the southeastern region of Anshan,but smaller in the northwestern and central regions.The heavy fog days in different regions have different seasonal variations.Heavy fog events occur frequently in summer and autumn (from June to October) in the southeastern mountainous region,while they occur mostly in late autumn and winter (from November to January) in the other regions.Heavy fog days have a decreasing trend in the central region of Anshan,a weakly increasing trend in the western region,and a clear increasing trend in the southeastern region.The longest duration time of regional heavy fog events in Anshan is 7 d.It is seldom to have a heavy fog occurring in the whole region.Such events occurred only eight times from the record.The heavy fog events in Anshan show distinct regional feature due to the topographic effect.It seldom occurs in the plain regions,but frequently appears in mountainous regions and lasts longer.The duration time of heavy fog events in Anshan is about 1-2 h,and their starting time is usually around 05:00-06:00,08:00,and 20:00,mostly lasting for 20-21 h.Due to the inter-decadal variability of heave fog days in Anshan from 1961 to 2010,the number of fog days increases in the southeastern mountainous region and decreases in the central region.Since 1990s,it has decreased significantly in the central region,but increased in the northeastern region,which shows great regional difference.Meanwhile,the feedback of human activities to climate and environment is probably another reason for the variation of heavy fogs in Anshan. References | Related Articles | Metrics

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Characteristics of fog days in Liaoning province from 1961 to 2014 ZHANG Wan-ying, SUN Xiu-bo, LI Lan, WU Kan, QIN Mei-ou, LI Xiao-lan 2016, 32 (6):  77-84.  doi: 10.3969/j.issn.1673-503X.2016.06.010 Abstract ( 248 )   PDF (1970KB) ( 367 )   Save Based on observational data of atmospheric visibility from 53 meteorological stations in Liaoning province from 1961 to 2014,the spatiotemporal distribution of the number of fog days was analyzed.The inter-annual and inter-decadal variations of fog days in different regions according to the rotated empirical orthogonal function (REOF) method were investigated for understanding the regional characteristics of fog days on multi-time scales.The results show that the number of fog days has a low-high-low-high zonal distribution from the west to the east in Liaoning province in recent 54 years.Annual mean number of fog days in Liaoning province can be divided into six regions,including the western-central region,the eastern mountainous region,the southern-central region,the western region,the southern coastal region,and the northern region.The annual number of fog days has an increasing trend in the southern coastal region,the western-central region and the northern region,while the number of fog days decreases in the eastern mountainous region and the southern-central region,however,the fog days in the western region do not change obviously.The variation of fog days is significantly different from different regions.The annual mean fog days in the western-central region,the eastern region,the southern-central region,the western region and the southern coastal region have very strong inter-decadal variability,however,those in the north region has obvious inter-annual variability.The inter-annual variability of annual mean fog days in the western-central region and the southern-central region has a declining trend,but that in the other four regions is in an increasing stage.The inter-decadal variability of annual mean fog days is in a decline stage in the western-central region,the eastern region and the western region,however,it is in an increasing stage in the other regions. References | Related Articles | Metrics

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A comparative study of spatial interpolation data for temperature and precipitation over China WANG Jiang, LE Zhang-yan, LIAO Rong-wei, ZHANG Pei, JIA Li-hong, ZHANG Dong-bin 2016, 32 (6):  85-93.  doi: 10.3969/j.issn.1673-503X.2016.06.011 Abstract ( 282 )   PDF (17682KB) ( 259 )   Save The precision and time series of different spatial interpolation data for temperature and precipitation over the mainland of China were studied,using 1.0°×1.0° and 0.5°×0.5° gridded,monthly temperature and precipitation data based on the optimal interpolation (OI),ANUSPLIN V2.0 (Australian National University's thin plate Smoothing SPLINe,AV 2.0) interpolation,and ordinary kriging (OK) approaches from the China National Meteorological Information Center and the GHCN (Global Historical Climatology Network) 5.0°×5.0° gridded,monthly precipitation data from the U.S.NCDC (National Climatic Data Center) from 1961 to 2004.The results show that under an average climatic state from 1961 to 2004,there are consistent spatial distributions and annual cycle change in temperature and precipitation in China using different interpolation approaches.The absolute errors of precipitation fields in the whole mainland,the eastern and western China determined using the OI and AV 2.0 approaches are 2.15 mm,1.28 mm and 0.00 mm,respectively.The absolute errors of temperature fields for these regions using the OK and AV 2.0 approaches are 0.20℃,0.05℃ and 0.45℃,respectively.For time series of precipitation field in China,there is a relatively consistent seasonal variation obtained from AV 2.0,OI and GHCN approaches,with a larger difference occurring in summer and a smaller one in winter.The correlation coefficient of precipitation fields between AV 2.0 and OI approaches ranges from 0.22 to 0.98 from 1961 to 2004,with a high correlation occurring in winter and spring,and a low one in summer and autumn.The difference of precipitation amount is larger in some individual autumn and winter,with a maximum value of 3.08 mm.The difference of mean precipitation amount from 1961 to 2004 is 0.64 mm.The difference of mean annual temperature obtained from AV 2.0 and OK approaches is less than 0.54℃,and most of time,the change trends of temperature from the two approaches are consistent. References | Related Articles | Metrics

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Integration and preliminary quality control of global surface hourly temperature and precipitation data YU Yang, ZHU Chen, ZHAO Qi, XU Wen-hui, YANG Su, JIANG Hui, LI Qing-xiang, SHEN Qiu-yu 2016, 32 (6):  94-101.  doi: 10.3969/j.issn.1673-503X.2016.06.012 Abstract ( 195 )   PDF (1028KB) ( 652 )   Save Global surface temperature and precipitation data are the foundation of research on climate change,and the hourly observational data are the important basis of climate monitoring.Based on two kinds of global surface data products such as the Integrated Surface Hourly Database (ISD)and the Global Transmission System (GTS)from U.S.National Climatic Data Center,the hourly temperature and precipitation data were integrated in real time.The integrated data were processed with preliminary quality control using methods of spatial consistency checks,internal consistency checks,boundary climate checks,and extreme climate checks,and eventually formed a real-time updated datasets of global surface hourly temperature and precipitation.The results show that the integrated surface temperature and precipitation data since 2015 contain hourly data from 11,990 stations on global that almost cover the whole world.Compared to the original data without integration,the density of stations and the amount of meteorological elements in all regions from the integrated dataset increase significantly,especially in regions of Asia,Europe,and North America.The accuracy and suspected error rate of integrated data is 94.4% and 5.6%,respectively.The data with suspected error mainly exist in the regions of northeast Europe,Asia,and China,and the internal consistency conflict and beyond the climate boundary limit value are main reasons for suspect error of data. References | Related Articles | Metrics

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Study on the relationships between land use and land surface temperature in Shenyang urban districts ZHAO Zi-qi, LI Li-guang, WANG Hong-bo, ZHAO Xian-li, JIANG Peng, WEN Ri-hong, DING Kang-kang, ZHAO Hu-jia, ZHAO Miao 2016, 32 (6):  102-108.  doi: 10.3969/j.issn.1673-503X.2016.06.013 Abstract ( 276 )   PDF (1032KB) ( 432 )   Save The relationships of land surface temperature (LST) with the land use types were analyzed in Shenyang urban districts.The analyzing processes are as follows.First,the LSTs of Shenyang urban districts and within the third ring road were calculated using Landsat TM data in August 2010.Then,the land use of the studying area were classified as building land,green land,farmland,abandoned land,road and water body six types using visual interpretation and supervised classification methods.Finally,the city center was regarded as an origin point,and the relationships between the land use types and the LSTs at different circles distancing from the origin point in the city were analyzed using multivariate linear regression and partial least-square regression methods.The corresponding modeling results were verified as well.The results show that the mean LSTs of building land,green land,farmland,and road and the central urban district decrease with the increasing of the distance from the city center origin point.At the same level within buffering zones,the LSTs of building land and road are higher,and that of water body is the lowest.The "booth pie" developing in a city makes that the percentage of building land and road areas gradually reduced with the increasing of the distance from the city center origin point.Both of building land and road enhance the heat island effect.The main land use types are building land in the studying area,followed by road.Both of multivariate linear regression and partial least square regression methods perform very well in predicting LST.Comparatively,the partial least square regression method is more ideal to analyze the relationships between land use and LST in Shenyang. References | Related Articles | Metrics

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Study on high temperature disaster risk regionalization in Jiangsu-Zhejiang-Shanghai region FANG Xiao-yi, DU Wu-peng, QUAN Wei-jun, XUAN Chun-yi, GUO Wen-li 2016, 32 (6):  109-115.  doi: 10.3969/j.issn.1673-503X.2016.06.014 Abstract ( 238 )   PDF (2415KB) ( 434 )   Save In this study,the meteorological data from 144 stations (1961-2009) and the related socio-economic data (2008-2010) were used to analyze the high temperature disaster risk in Jiangsu-Zhejiang-Shanghai (JZS) region from the points of disaster factors' hazard,sensitivity of disaster environment,vulnerability of bearing body and resistant capacity.The results show that hazard of high temperature disaster factors is high in the southern area of JZS region and is relatively low in the northern JZS,and the dangerous index is significantly larger in Zhejiang province than in Jiangsu province and Shanghai.The sensitivity of disaster environment (SDE) value is higher in northern and central areas of JZS,while it is lower in southern JZS.The maximum value of SDE is distributed in Jiangsu,Shanghai,and the plain and seashore areas in northern Zhejiang.For those important developed large cities in Yangtze River Delta,their bearing bodies of high temperature disaster are of the highest vulnerability.Regions with low vulnerability,sub-low vulnerability or moderate vulnerability are distributed in northern Jiangsu and southern Zhejiang where it is relatively undeveloped.The regions with the strongest resistant capacity are distributed in the surrounding areas of Shanghai,Nanjing and Hangzhou,and the homologous risks in these areas are relatively low.The integrated risk of high temperature disaster in JZS region is high in central and southern JZS while is relatively low in northern JZS.The highest-risk and sub-highest-risk areas are distributed in Zhejiang,Shanghai and southern Jiangsu,and the low-risk and sub-low-risk areas are mostly distributed in the areas north to the Yangtze River and the coastal areas of Zhejiang province. References | Related Articles | Metrics

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Study on meteorological disaster risk division in Jinnan District of Tianjin based on RS and GIS LIANG Dong-po, SUN Zhi-gui, GUO Jun, GUO Yu-di, WANG Jing, XU Jun-de 2016, 32 (6):  116-121.  doi: 10.3969/j.issn.1673-503X.2016.06.015 Abstract ( 211 )   PDF (1162KB) ( 385 )   Save Based on the data of Landsat 8 in July 2014,the risk division of meteorological disasters in Jinnan District of Tianjin was carried out using RS (Remote Sensing) and GIS (Geographic Information System) technologies.The results show that the high precision land classification in Jinnan District of Tianjin based on RS technology provides important basic data for evaluating the meteorological disasters.The meteorological data and geographical environment as well as historical disaster information from 2004 to 2014 in Jinnan District of Tianjin are integrated using GIS technology.A two-rank evaluation index system is established using hierarchy analysis,risk index,integrated weighting,and other analysis methods.At the same time,a risk evaluation model is established to assess the different kinds of meteorological disasters in Jinnan District,in which four items,i.e.,the causing disaster factor,inducing disaster environment,carrying bodies' vulnerability and disaster prevention measurement are selected as the first-rank indexes.Furthermore,the division map of meteorological disaster comprehensive risk in Jinnan District of Tianjin is drawn as well.The high risk zones mainly concentrate at the regions with high population density and industrial concentration or low disaster prevention ability,such as urban and the large agricultural planting areas.In contrast,the regions with low population density and economic density are not sensitive to all kinds of meteorological disasters,and they belong to the low risk zones. References | Related Articles | Metrics

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Variation characteristics of ground temperature in Hu'nan Province from 1981 to 2013 LIAO Yu-fang, ZHANG Jian-ming, GUO Ling-yao 2016, 32 (6):  122-129.  doi: 10.3969/j.issn.1673-503X.2016.06.016 Abstract ( 338 )   PDF (2714KB) ( 536 )   Save Based on air temperature and ground temperature measured at 0-320 cm soil depths of nine meteorological observation stations in Hu'nan province from 1981 to 2013,the comparison of variation characteristics of ground temperature and air temperature was made using the relevant statistical methods.The results show that ground temperature of each depth exists two typical spatial structures,i.e.high in the southeast versus low in the northwest and high in the southeast versus low in the northeast and northwest.Under a certain depth,variation of monthly ground temperature is not synchronized with air temperature,and the transition layer is at 40 cm depth.The minimum monthly ground temperature for the layers between the surface and 40 cm depth occurs in January,and the maximum monthly ground temperature occurs in July,which are in accordance with the occurrence times of the minimum and maximum monthly air temperature.Along with increasing of soil depth (below 40 cm depth),the occurrence times of the minimum and maximum monthly ground temperature delay.The minimum ground temperature of 320 cm occurs in April,and the maximum occurs in October.The correlation coefficients of shallow ground temperature and air temperature are more than 0.97,which reduce along with the increasing of soil depth below 40 cm layer.Inter-annual variation of shallow ground temperature is large in winter,followed in spring.Inter-annual variation of deep ground temperature in winter and spring are obviously larger than that in summer and autumn.With increasing of soil depth,the ground temperature is gradually decreasing in spring and summer and increasing in autumn and winter.As a result,the deep ground temperature is significantly higher than air temperature in winter,and lower than air temperature in summer.The annual average ground temperature of different layers shows an increasing trend significantly.The increasing rates of ground temperature of different layers are slower than air temperature except for 0 cm ground temperature.The warming trends of ground temperature at different layers are consistent with air temperature in all seasons,and temperature increasing rate is the most rapid in spring,followed in autumn,not obvious in winter.Annual average ground temperature at different layers presented increasing abrupt during 1993-1995.Abrupt in winter are the earliest,followed in spring and autumn,late in summer.Quasi-oscillations of 2-3 years,3-4 years and 6-9 years are found for annual average ground temperature of different layers. References | Related Articles | Metrics

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Variation characteristics and forecasting models of the minimum temperature in solar greenhouse in Shenyang LI Shi, ZHANG Jing, ZHANG Shu-jie, SONG Xiao-wei, MU Chen-ying, XU Quan-hui, ZHENG Chuang, LIU Qing 2016, 32 (6):  130-136.  doi: 10.3969/j.issn.1673-503X.2016.06.017 Abstract ( 214 )   PDF (744KB) ( 599 )   Save Based on the meteorological observation data inside and outside solar greenhouse from 2013 to 2014 in Shenyang,variation characteristics and forecasting models of the minimum temperature (Tmin) in greenhouse were studied using methods of a correlation analysis and a stepwise regression analysis.The results show that Tmin inside the greenhouse is significantly correlated with the previous day's maximum and minimum temperature outside the greenhouse,Tmin outside the greenhouse of the day,and the previous day's maximum and minimum temperature inside the greenhouse.Tmin forecasting models for the greenhouse are different depending on different weather types of the four seasons.Forecasting accuracy of the greenhouse Tmin is the highest in winter,followed in spring and autumn,and the forecasting accuracy in summer is relatively worse.The differences between observed and simulated greenhouse Tmin less than 3℃ in winter,spring,autumn,and summer account for 91%,85%,81% and 79%,respectively of the total samples for test.Forecasting accuracy of greenhouse Tmin is the highest in snowy rain days,followed in overcast days and sunny days,and the forecasting accuracy in cloudy days is relatively worse.The model accuracies for the simulated greenhouse Tmin less than 3℃ in snowy rain days,overcast days,sunny days,cloudy days are 90%,87%,83% and 77%,respectively.The results suggest the performance of the greenhouse Tmin forecasting model is satisfied and the models have their practical applicability,which provides a reference for the greenhouse Tmin forecast in Shenyang. References | Related Articles | Metrics

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Diurnal variations characteristics of heat flux in cross-section of typical brick wall in solar greenhouse in Tianjin area LI Chun, XUE Qing-yu, GONG Zhi-hong, GUO Jing, DONG Chao-yang, LIU Shu-mei 2016, 32 (6):  137-141.  doi: 10.3969/j.issn.1673-503X.2016.06.018 Abstract ( 178 )   PDF (575KB) ( 322 )   Save In order to analyze the heat flux variation characteristics of solar greenhouse with brick wall,an experiment was carried out at Tianjin in winter of 2012 to measure the heat flux on ceiling,north wall,and soil.The results show that heat flux variations of the two monitoring points,situated at the north of soil and the top of the back wall,display a single-peak pattern.The heat fluxes of the two monitoring points,situated at the south of soil and the bottom of the back wall,are between 5.0 and 10.0 W·m-2 for a day.The diurnal variation characteristic of heat flux is especially distinct during the day with sunshine,while the amplitudes of heat flux during the continuous cloudy days is relatively small.The results suggest that soil and wall are the main areas for heat storage and heat release and the ceiling and the combine places of each enclosing structures are the areas for heat release.According to the variation rules of heat flux,the heat preservation performance of greenhouse could be improved for better greenhouse production. References | Related Articles | Metrics

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Contribution rate and beneficial evaluation of major meteorological disaster service for crops in Heilongjiang province WANG Qiu-jing, WANG Liang-liang, MA Guo-zhong, LI Shuai, JIANG Li-xia 2016, 32 (6):  142-147.  doi: 10.3969/j.issn.1673-503X.2016.06.019 Abstract ( 198 )   PDF (502KB) ( 287 )   Save Based on the assessing method of Delphy and grain yield data of 2009 and 2011,the benefit of meteorological service for meteorological disasters of the main crops was analyzed and evaluated in Heilongjiang province.The results show that beneficial contribution rates of meteorological service for main crops in 2009 and 2011 were 4.9% and 3.1%,respectively.The occurrences times of meteorological disaster in 2009 is more than that in 2011,which leads to beneficial contribution rate of meteorological service higher in 2009 than in 2011.Compared the beneficial contribution rates of meteorological service for three crops in Heilongjiang province,the rank of beneficial contribution rate is rice >corn >soybean.For maize and soybean,contribution rate of meteorological service is the highest during the period from sowing to emergence.For rice,contribution rate of meteorological service is the highest during the period from seeding to active growing season. References | Related Articles | Metrics

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A comparative study of microclimate characteristics between a reed wetland and a maize dry land in Liaoning province JIA Qing-yu, YU Wen-ying, XIE Yan-bing, LIANG Cheng-hua, LV Guo-hong, WANG Xiao-ying, WEN Ri-hong, LIU Jing-miao 2016, 32 (6):  148-154.  doi: 10.3969/j.issn.1673-503X.2016.06.020 Abstract ( 263 )   PDF (1306KB) ( 310 )   Save The interaction between wetland and atmosphere through the exchange of energy and mass forms unique regional microclimate characteristics.A comparative analysis of microclimate characteristics near the surface layer from 0 to 30 cm between Panjin reed wetland in the Liaohe River Delta and Jinzhou maize dry land located at the same latitude as at Panjin reed wetland was conducted in 2015 using the microclimate gradient method.The results show that the mean annual air temperature of Panjin wetland is 9.91℃ in 2015,which is 0.58℃ lower than that of Jinzhou maize dry land.The wetland plays a cooling effect in spring,summer and autumn,and a warming effect in winter.The daily variations of mean annual air temperature at Panjin wetland and Jinzhou maize dry land range from 7.50-12.92℃and 6.16-15.59℃,respectively.The amplitude of the mean temperature and temperature difference between the different vertical layers of the wetland are less than those of the dry land.The mean annual relative humidity at Panjin wetland is 64.58%,which is 7.97% higher than that of Jinzhou dry land.The monthly relative humidity of wetland is mainly affected by the hydrological factors and vegetation transpiration.The daily variations of mean annual relative humidity of wetland and dry land range from 51.78%-74.38% and 41.00%-73.00%, respectively.There are inversion humidity phenomena in both of wetland and dry land,while the occurring heights are different.The spring wind speed in Panjin wetland is 2 times higher than that in Jinzhou dry land.The wind speed of wetland increases exponentially with the height.During the growth season,Panjin reed wetland has a higher roughness.With the decrease of height,the wind speed decreases significantly.This kind of sheltering effect in wetland is much better than that in dry land.The land surface turbulent affected by the solar radiation is the main factor to influence the diurnal variation of wind speed in dry land,while that in Panjin wetland reflects the characteristics of thermal difference between land and water.Due to the water coverage on the land surface in wetland,there are higher evapotranspiration amount and leaf area index,which slows down the changing rates in temperature and relative humidity near the land surface layer,and can effectively reduce the wind speed.This kind of ecological functions to regulate the regional microclimate in wetland is better than that in dry land.This study provides a reference for the evaluation of the impact of wetland in the Liaohe River Delta on the regional climate and their ecological and environmental effects. References | Related Articles | Metrics

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Variation characteristics and regulation mechanisms of water vapor flux over a rain-fed maize farmland ecosystem in Jinzhou WAN Zhi-hong, LI Rong-ping, ZHOU Guang-sheng, WANG Ying, WANG Wan-zhao, ZHANG Xiao-yue 2016, 32 (6):  155-159.  doi: 10.3969/j.issn.1673-503X.2016.06.021 Abstract ( 251 )   PDF (586KB) ( 381 )   Save Based on the observation data of eddy covariance over a rain-fed maize farmland ecosystem in Jinzhou in 2014,the water vapor flux characteristics were analyzed and regulation mechanisms of the vapor flux were determined using the microclimate observational data.The results show that a single-peak curve is presented for diurnal variation of water vapor flux for each month.The daily average water vapor flux during growing season is 10 times as large as that during non-growing season.The maximum value of 30-min averaged water vapor flux appears in July with the value of 0.1202 g·m-2·s-1.The annual evapotranspiration of maize farmland in 2014 was 417.37 mm,and the total evapotranspiration during non-growing season was 49.57 mm which slightly higher than the precipitation during the same period.The proportions of evapotranspiration to precipitation in May and June (i.e.,early stage of the growing season) are 52.0% and 71.0%,respectively.The amount of evapotranspiration during July-September is greater than that of rainfall,and in July the evapotranspiration is 3 times as large as precipitation.Because it is the period of corn pollination in July,severe water deficit during this period would affect maize yield.The water vapor flux during the growing season is significantly positively correlated with the net radiation and is controlled by air temperature and saturation vapor pressure difference to some extent. References | Related Articles | Metrics

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Temporal-spatial distributions of bad-weather conditions along high-speed railway in Liaoning province MING Hui-qing, ZHANG Kai, HOU Ya-hong, GUAN Jian-hua, XI Tao, CAI Fu, ZHAO Miao, GUO Ning, WANG Yang 2016, 32 (6):  160-165.  doi: 10.3969/j.issn.1673-503X.2016.06.022 Abstract ( 236 )   PDF (1628KB) ( 506 )   Save Temporal-spatial distributions of bad-weather conditions including low temperature,snow cover,rainstorm,fog,wind,thunderstorm and hail,which can influence the High-speed Railway (HSR) operations,were investigated using methods of a spatial analysis and a time serial analysis.Observational data from 52 weather stations in Liaoning province from 1982 to 2012 were used to conduct this study.The results show that the most parts of Liaoning province belong to extremely cold region except for the Liaodong Peninsula and circum-Bohai sea areas where they belong to cold region.The maximum number of days with snow cover appears in January (13 days) from 1982 to 2002.The areas with snow depth more than 50 cm are distributed in the mid-north and eastern mountain of Liaoning province as well as Yingkou.Most rainstorms happen in May and June and the number of monthly-occurrence time is about 0.2 on average.The number of annual average rainstorm days with 2 days is relative high in western part and eastern mountain regions of Liaoning.Annual average frequency of thunderstorm ranges from 5 to 7 for recently 30 years and most thunderstorms happen from June to August.The areas with high frequency (more than 30 times per year) of thunderstorm are distributed in the mid-north of Liaoning and Chaoyang.Comparatively,the frequency of thunderstorm in other areas is 21-30 per year.According to the influence characteristics of severe weather on the periods and sections of HSR,crucial periods and sections of meteorological service for severe weather along the HSR in Liaoning province are provided.Finally,the further development trends and directions of meteorological service for the HSR are proposed. References | Related Articles | Metrics

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Application of field observation combined with CFD simulation method in evaluation of building wind energy XU Hui, ZHANG Liang 2016, 32 (6):  166-173.  doi: 10.3969/j.issn.1673-503X.2016.06.023 Abstract ( 194 )   PDF (1739KB) ( 466 )   Save The wind field between the two office buildings of Jilin Meteorological Office in 2012 was measured and the results were compared with the wind data observed at a meteorological station in Changchun.The results show that a tunneling effect exists between the two office buildings,which results in the convergence of wind.The wind field between the two office buildings simulated using the CFD technology (the Fluent software) is generally consistent with the real wind field.The annual average wind power density calculated from the simulated wind field is 139.0 W·m-2,with the largest wind speed area occurring at a 40 m height around the top wind exit between the two office buildings,which means the probability to explore wind power at this observational site.Meanwhile,it is feasible to evaluate wind power around buildings using both of real observations and CFD simulation. References | Related Articles | Metrics

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Characteristics of the first soaking rain in spring sowing season of Liaoning province and their relationships with Okhotsk blocking high LI Fei, ZHAO Chun-yu, LIN Rong, CHAO Hua 2016, 32 (6):  174-178.  doi: 10.3969/j.issn.1673-503X.2016.06.024 Abstract ( 237 )   PDF (1908KB) ( 330 )   Save Using daily precipitation data from 52 meteorological stations in Liaoning province and the NCEP/NCAR (National Centers for Environmental Prediction/National Center for Atmospheric Research) reanalysis datasets in April and May from 1961 to 2013,characteristics of the first soaking rain in spring sowing season of Liaoning province were analyzed.The impacts of the Okhotsk blocking high on it were discussed.The results show that the first soaking rains in the spring sowing season of Liaoning province occur from April 17 to May 3,and the average date is April 22 during 1961 to 2013.The occurring dates of the first soaking rain in the spring sowing season successively postpone from the southeastern to northwestern parts.The Okhotsk blocking high is the main circulation system that affects when the first soaking rain in the spring sowing season occurs.Due to the obstructing by the Okhotsk blocking high,the cold air piles up in the Baikal Lake,and the Okhotsk blocking high stimulates a cyclonic circulation at the low layer of the troposphere.As a result,the water vapor that transports from the Bay of Bengal to Liaoning through the central and eastern parts of China provides a necessary condition for the occurrence of the first soaking rain in the spring sowing season of Liaoning province. References | Related Articles | Metrics

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Vertical distribution of atmospheric particulate matter during a heavy fog-haze event in Beijing observed by an unmanned aerial vehicle LI Yang, MA Shu-qing, JIA Xiao-fang, ZHENG Yu, LU Sai, ZHAO Hu-jia 2016, 32 (6):  179-183.  doi: 10.3969/j.issn.1673-503X.2016.06.025 Abstract ( 249 )   PDF (781KB) ( 537 )   Save A severe fog-haze event occurred in late autumn and early winter in 2015 in North China.Vertical distribution of the mass and number concentrations of atmospheric particulate matter in Shunyi and Fangshan areas of Beijing during this event was analyzed using an Unmanned Aerial Vehicle (UAV) equipped with aerosol samplers and a laser particle counter.The results show that the number concentrations of aerosols with diameter less than 1.0 μm change little with the height,and those with diameter greater than 1.0 μm decrease slightly with the increasing height.This can explain that particle number concentration is relatively stable in the near-surface layer during heavy pollution events,with more submicron particles and smaller coarse particles in number concentration.The mass concentration is higher at the height of 50 m,with the maximum value of 700 μg·m-3. References | Related Articles | Metrics

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Extenics evaluation of lightning risk degree in Dalian region using an entropy weighting method ZOU Shan-yong, WANG Shu-yi, ZOU Hao-yu, WANG Hong-xiang 2016, 32 (6):  184-189.  doi: 10.3969/j.issn.1673-503X.2016.06.026 Abstract ( 194 )   PDF (578KB) ( 307 )   Save lightning risk degree is an integrated index to reflect the harmful level of lightning disasters.Based on data from ADTD (Active Divectory Topology Diagrammer) lightning location system,observation of annual thunderstorm days,investigation of lightning disaster,detection of 1679 lightning protection units,topography and geomorphology,the lightning risk degree in Dalian region was studied using an extenics comprehensive evaluation method.The result shows that the extenics comprehensive evaluation system of lightning risk degree is established based on field investigation data.There are 12 indexes in the evaluation system selected from 3 aspects which influence the degree of lightning risk,i.e.lightning activity characteristics,disaster prevention and reduction capabilities and the present situation to be evaluated.The classical and segment fields of lightning risk degree are determined using an associated function and the matter-element theory.In addition,the weighting coefficients of each evaluation index are defined based on the entropy weighting theory.The lightning risk degree in Dalian region is divided.Through typical example validation,it indicates that this method established in this paper is reasonable and practical. References | Related Articles | Metrics