Table of Content

31 October 2018, Volume 34 Issue 5 Previous Issue    Next Issue

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Analysis of extreme precipitation forecast deviation in a warm region of Hubei province in 2016 ZHANG Ping-ping, SUN Jun, DONG Liang-peng, CHEN Xuan, CHE Qin, ZHONG Min, ZHANG Meng-meng, ZHANG Ning 2018, 34 (5):  1-8.  doi: 10.3969/j.issn.1673-503X.2018.05.001 Abstract ( 284 )   PDF (8221KB) ( 202 )   Save Based on reanalysis data from a global numerical model of National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR),data from European Centre for Medium-Range Weather Forecasts (EC) and Shanghai Meteorological Bureau-WRF ADAS Rapid Refresh System (SMB-WARMS),and other conventional meteorological observational data,the forecast deviation of extreme precipitation event for a warm-region in Hubei province on July 5-6,2016 was analyzed.The results showed that the low-level wind field predicted by the EC model moves westward faster than the real situation,resulting in westward biases in the predicted heavy precipitation area.The forecast deviation in precipitation intensity and falling area during this event is mainly due to lack of awareness of the dynamic triggering effect of the shear line at 925 hPa and its influence on the dry layer in the upper troposphere,the rapid increase of water vapor and its extremity,and the evolution of Mesoscale Convective System (MCS).Although there is a deviation between the 72 h,48 h,and 24 h precipitation forecast and the real precipitation,the 12 h precipitation area in the SMB-WARMS model can be adjusted in advance,which can be used as a good indicator to the modification of precipitation prediction. References | Related Articles | Metrics

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Diagnostic analysis of a heavy rainfall event due to an eastward-moving northwest vortex HOU Shu-xun, ZHANG Wan-ying, CHEN Zhen, WANG Guan, YUAN Yuan 2018, 34 (5):  9-15.  doi: 10.3969/j.issn.1673-503X.2018.05.002 Abstract ( 191 )   PDF (4361KB) ( 192 )   Save Based on the conventional high-level and surface observational data and the FNL data with spatial resolution of 1°×1° from the National Centers for Environmental Prediction/National Center (NECP),the heavy rainfall event caused by an eastward-moving northwest vortex on August 17-18,2016 was diagnostically analyzed.The evolution of the northwest vortex and the physical mechanism of this heavy rainfall event were discussed in this study.The results showed that the northwest vortex is the direct system influencing on the heavy rainfall event.The intensity of this northwest vortex increases and decreases twice during its eastward movement,and the two peaks correspond to two heavy rainfall centers.The long-range transport of water vapor and energy from the typhoon "Dianmu" is an important reason for the enhancement of northwest vortex for the initial phase,and its second phase enhancement is due to the declination of isentropic surface as the northwest vortex moves from the Inner Mongolia plateau to the North China Plain,which leads to the development of slantwise vorticity after the increase in vertical wind shear and wet baroclinic zone.The low-level vortex shifts down the Yanshan Mountain,which is favorable for the enhancement of vertical vorticity.The zonal northwest vortex can trigger heavy rainfall in Hebei region under specific conditions. References | Related Articles | Metrics

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Characteristics of water vapor transport in precipitation difference between two landing typhoons of “Jelawat” and “Haiku” DAI Zhu-jun, WU Hai-ying, JIANG You-shan, XIA Min-jie, ZHU Xin-jun, QING Tao 2018, 34 (5):  16-24.  doi: 10.3969/j.issn.1673-503X.2018.05.003 Abstract ( 191 )   PDF (2886KB) ( 279 )   Save Based on the reanalysis data with a spatial resolution of 1.0°×1.0° from the National Centers for Environmental Prediction (NCEP),the atmospheric circulation data of 2.5°×2.5° from the National Oceanic and Atmospheric Administration (NOAA) and the assimilation data of 1.0°×1.0° from the Global Data Assimilation System (GDAS),and using the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) Model,the characteristics of water vapor transport were analyzed for two landing typhoons "Jelawat" and "Haikui" that had similar tracks but large difference in precipitation distributions and the effect of water vapor on increase of heavy rainfall after landing weakness of the "Haikui" typhoon was discussed.The results showed that the maintenance duration and precipitation of "Haikui" after landing are stronger than those of "Jelawat" after landing.Water vapor transported from the inland (59.9%) plays an important role for "Jelawat".Without water supplement from the ocean,"Jelawat" declines rapidly and the precipitation intensity decreases.After the landing of "Haikui",water vapor is mostly transported from the South China Sea and Yellow Sea,which can come from two paths,one from the eastern ocean surface that travels directly into the rainfall area and the other from the southern region related to the tropical cyclone (TC) circulations.Water vapor during the first heavy precipitation event after the landing of "Haikui" is mainly coming from the ocean in the east of Japan (61.2%),and water vapor transported from the South China Sea contributes the enhancement of the second heavy precipitation event to a certain extent.Water vapor during precipitation in the southern region of Jiangsu province is mainly from the East China Sea and East China (46.3%).Water vapor and energy in the East China are both smaller than those from the southern warm ocean,and water vapor decreases gradually during long distance transportation,which probably results in the weak precipitation in the southern region of Jiangsu province. References | Related Articles | Metrics

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Quantitative study on the effect of haze-fog events on solar radiation in Tianjin CHEN Yue-hao, XIONG Ming-ming, CAO Jing-fu, YANG Yan-juan 2018, 34 (5):  25-30.  doi: 10.3969/j.issn.1673-503X.2018.05.004 Abstract ( 229 )   PDF (726KB) ( 235 )   Save Based on the observational data from 13 surface meteorological stations in Tianjin from 2005 to 2016,the spatial distribution of haze-fog events in Tianjin was analyzed and its effect on the solar radiation was quantitatively studied using observational data of solar radiation at Xiqing station.The results showed that haze-fog events in Tianjin occur more frequently in north than in south,with a greater number of haze-fog day observed in Baodi and Jizhou and a smaller number of haze-fog day observed in the southern area of Binhai New District.The number of haze-fog day in Tianjin increases initially from 2005 and decreases later.Temperature inversion occurs frequently in autumn and winter,and the adverse diffusion conditions result in the frequent occurrence of haze-fog events.Therefore,the prevention and treatment of haze-fog events in autumn and winter are very important.The greatest influence rate of haze-fog events on solar radiation occurs in winter during the recent 12 years.With increasing duration of haze-fog events,the occurrence of haze-fog events in Tianjin decreases in a form of the power function.However,the decline of solar radiation due to haze-fog events in Tianjin becomes stronger.The solar radiation decreased by 57.14% compared with the background solar radiation in a 6-d persistent haze-fog event.The occurrence and persistence of haze-fog events have great effect on the production of facility agriculture and solar power generation in the northern region of China during winter,and some proper strategies should be taken in order to minimize disaster losses. References | Related Articles | Metrics

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Seasonal characteristics of haze events with different intensity in Ningbo area HU Xiao, XU Lu, JIANG Fei-yan, YU Ke-ai 2018, 34 (5):  31-38.  doi: 10.3969/j.issn.1673-503X.2018.05.005 Abstract ( 352 )   PDF (2035KB) ( 204 )   Save Characteristics of haze in Ningbo were analyzed using the hourly meteorological data and concentration of pollutants in Zhenhai from 2014 to 2016.The result shows that the hourly frequency of haze is 28.8%,and the ratio of damp haze is 61.0%.The frequency of haze has decreased during the recent three years.Haze occurred more frequently from November to January and less in summer.The diurnal variation of haze has double peaks which appear at 09:00 and 20:00-23:00 respectively.When the haze is heavy,the particulate concentrations of PM2.5 and PM10 were 2.13 times and 1.92 times as high as those during light haze days.The concentration of particulate matter of dry haze was higher than that of damp haze.The composition of particulate was relatively stable in Ningbo,and the value of PM2.5/PM10 was around 0.7.The correlation of particle concentration with wind speed and precipitation is good.Wind speed and PM2.5 is higher in spring and summer,while PM10 is higher in autumn and winter.The correlation between precipitation and PM10 is higher than PM2.5.The low ground wind speed with stable weather can easily cause an increase in the accumulation of fine particulate matter concentrations.Wind from the northwest and northeast in winter is the main conveying path that results in the change of PM2.5 concentrations in the Ningbo area.When the wind direction changes to the northwest,PM10 concentration in winter and spring will increase significantly. References | Related Articles | Metrics

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Climatic data reconstruction of haze days and its temporal-spatial characteristics in Bengbu area from 1970 to 2015 TIAN Lei, PEI Lin, CHEN Yu-gang, XIA Jiang-jiang, WANG Xiang 2018, 34 (5):  39-46.  doi: 10.3969/j.issn.1673-503X.2018.05.006 Abstract ( 219 )   PDF (893KB) ( 390 )   Save Based on the observational data four times a day at four meteorological stations in Bengbu from 1970 to 2015,including relative humidity,visibility,weather record,etc,and using an objective method to identify haze events,the climatic time series of haze days in recent 64 years were reconstructed and its spatiotemporal characteristics and relationship with criteria meteorological parameters were analyzed.The results showed that haze days series reconstructed from the daily mean value method can reasonably represent the long-term characteristics of haze events,which is well consistent with the haze days series obtained from the weather records,showing a significant correlation between them.The haze days number varied largely at different meteorological stations in Bengbu from 1970 to 2015,with larger value in south and smaller value in north.The largest total haze days number occurs at Bengbu station.The number of haze days in Bengbu is large in autumn and winter and small in summer,and it exhibits obvious decadal variation in the past 46 years.The number of haze days increases generally.After 2000,its increasing rate reaches 4.8 d·a-1.However,it decreases slightly in the period from the late 1980s to the early 1990s.The favorable meteorological conditions for the formation and development of haze events in Bengbu include the easterly wind in the near surface layer,high relative humidity,shallow mixing layer height,and the existence of temperature inversion.The relationship between haze days number and air temperature and pressure is not significant. References | Related Articles | Metrics

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Climatic variation of winter fog and its causes in Chongqing area GUO Qu, LI Rui, RUAN Ding-lun, ZHANG Tian-yn 2018, 34 (5):  47-56.  doi: 10.3969/j.issn.1673-503X.2018.05.007 Abstract ( 502 )   PDF (3182KB) ( 360 )   Save Based on meteorological observational data from 34 stations in Chongqing area from 1973 to 2015,the spatiotemporal characteristics and causes of fog events in Chongqing were analyzed using methods of conventional statistics and trend analysis.The results showed that the occurrence frequency of fog events during winter in Chongqing has distinct decadal variability,with an increasing trend from 1973 to 1989,turning to a decreasing trend around the 1990s,and then decreasing gradually.The spatial distribution of fog days number varies largely with the topography and landforms in Chongqing,with a larger number of fog days in the middle and western regions and smaller in the southeastern and northeastern regions.During the early 1990s and under the background of global climate warming,the decreasing trend of fog events during winter in Chongqing is mainly due to the transition phase of Pacific Decadal Oscillation (PDO) from warm to cold in preceding autumn (from September to November),increasing intensity of the Siberian High,increasing temperature and saturation specific humidity and decreasing relative humidity in the near-surface layer.In addition,the rapid development of urbanization in Chongqing and the increase of Aerosol Optical Depth (AOD) during winter also have an impact on the decrease in fog event. References | Related Articles | Metrics

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Extended range forecasting of low-frequency precipitation under different background circulations QU Jin-hua, WANG Yi-shu, TAN Gui-rong 2018, 34 (5):  57-65.  doi: 10.3969/j.issn.1673-503X.2018.05.008 Abstract ( 169 )   PDF (5508KB) ( 213 )   Save Based on daily precipitation observations from the national meteorological observatories,daily outgoing longwave radiation data from NOAA,and reanalysis data from the NCEP (National Centers for Environmental Prediction),an extended range forecasting for the low-frequency precipitation over south of the Yangtze River during April,May,and June (AMJ) from 1979 to 2013 was carried out under different background circulations.The atmospheric circulations over tropic or mid-high latitude,which are significantly correlated with the 10-30 d low-frequency precipitation,were selected as the influencing factors.The results show that the 10-30 d component of the AMJ precipitation over south of the Yangtze River is the most significant.The precipitation anomalies are significantly related to the tropical convection locates over the eastern Indian Ocean and Indonesia,as well as the atmospheric circulation anomalies over the high latitude of Europe and Siberia.They can be selected as the predictors for the extended range precipitation.When the geopotential height anomalies over the high latitude of Europe and Siberia areas appear to be suppressive,while over North America and west to the Lake Baikal appears to be active,moreover,the tropical convective appears to be suppressive,the rainfall over south of the Yangtze River turns scarce.The center of the rainfall anomaly locates in the middle and lower reaches of the Yangtze River.Based on the spatial distributions of geopotential height anomalies at the period longer than 30 days at 500 hPa,the low-frequency background of daily precipitation is divided into three categories.The correlation in -30 lag days between low-frequency precipitation and predictors exhibits their individual features in each background.The 500 hPa low-frequency circulation at the period longer than 30 days provides the stable background state for the 10-30 d extended range variations.The correlation between low-frequency precipitation and predictors turns out to be more significant and the lag days of correlation becomes longer,considering different backgrounds. References | Related Articles | Metrics

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Projected risk of drought and flood at Yangtze River Delta for the next 50 years YIN Xiao-dong, DONG Si-yan, HAN Zhen-yu, WANG Rong 2018, 34 (5):  66-75.  doi: 10.3969/j.issn.1673-503X.2018.05.009 Abstract ( 251 )   PDF (2325KB) ( 263 )   Save The Yangtze River Delta region has a dense population and high economic development.Under the background of global warming,the risk of future drought and flood in this region will change.Based on the results from 26 CMIP 5 (Coupled Model Inter-comparison Project Phase 5) global climate models,the drought and flood risk were quantitatively projected in the Yangtze River Delta region for the next 50 years (dividing two periods,2021-2040 and 2046-2065).The results show that the intensity of drought and flood risk reduces from north to south in the Yangtze River Delta region.According to the RCP (Representative Concentration Pathways) 2.6 to 8.5 scenarios,the flood risk in the northern part of the Yangtze River will gradually increase,while the drought risk shows a slightly different pattern.Under the RCP 8.5 scenario,the drought and flood risk is the most serious during the second period of the next 50 years among all scenarios and is higher than the area increment in the IV grade (including the IV grade) in the Yangtze River Delta region.The northern Jiangsu and northern Anhui province is the overlying region for the 5th-drought and the 4th-graded flood risks,while the southern Jiangsu province and Shanghai are that for the highest level of the 5th-grade of drought and flood risk. References | Related Articles | Metrics

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Influence of variation in precipitation on the construction of a low-impact-development rain-water system for sponge city in Liaoning province GU Zheng-qiang, ZHU Ling, GONG Qiang, ZHAO Chun-yu, SHEN Li-du, ZHANG Hai-na, SHAN Wei-wei, REN Zhi-yong 2018, 34 (5):  76-85.  doi: 10.3969/j.issn.1673-503X.2018.05.010 Abstract ( 167 )   PDF (5064KB) ( 145 )   Save Based on the historical daily precipitations at 50 national meteorological stations in Liaoning province from 1956 to 2016,the main control targets to the low-impact-development rain-water system for sponge city were investigated.The study includes the regional division of the detailed volume capture ratio to annual rainfall runoff and its relation with the precipitation,temporal variation of precipitation and its effects on the stability of the regional division of the detailed volume capture ratio to annual rainfall runoff.The results show that according to the regional division of detailed volume capture ratio of annual rainfall runoff in Liaoning province in 1956-2016,1956-1985 and 1987-2016,the western and northeastern Liaoning province belong to the second division,the eastern and coastal areas of Liaoning province are the third,the region around Donggang is the fifth,and the rest of the region is the fourth.The difference mainly occurs in the central and northeastern part of Liaoning province.A close relationship exists across rainstorm or moderate rain ratio,amount of rainstorm and the design rainfall for the regional division of detailed volume capture ratio of annual rainfall runoff,with the correlation coefficient test passing 0.01 of significance level,and 78% of the total measurement sites pass the test.No relationship is found with heavy rainfall.Changes of the regional division of detailed volume capture ratio of annual rainfall runoff exist due to the variation of precipitation.These regions mainly distribute in the central,western and northern parts of Liaoning province and southern Dandong (including Dandong and Donggang).Division revision to their historical highest level should be adopted in the areas with a number of divisional changes no less than 5 times.The regions with a number of divisional changes less than 5 times should choose the historical most frequent level.As the precipitation in Liaoning province has a 10-year periodical variation,a revision of sponge city master plan should be advised every 10-year in the construction of a low-impact-development rain-water system for sponge city,based on the design rainfall of detailed volume capture ratio of annual rainfall runoff. References | Related Articles | Metrics

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Study on features of road-surface temperature on Zhoushan Bridge over the sea and its statistic model in summer LIU Dan-ni, WU Yang, WANG Ying 2018, 34 (5):  86-92.  doi: 10.3969/j.issn.1673-503X.2018.05.011 Abstract ( 180 )   PDF (1333KB) ( 238 )   Save Based on datasets of Zhoushan Bridge over the sea,including air temperature and road-surface temperature,the features of maximum air temperature and maximum road-surface temperature in summer were discussed after the data undergone the quality control.According to different types of underlying surface,the statistic models of road-surface temperature were established using sunshine duration dataset of Zhoushan and a maximum air temperature of Zhoushan Bridge over the sea.The results show that the maximum air temperature decreases and then increases weakly from west to east,the transition zone appears on the Cezi island.Most of the stations' maximum road-surface temperature are directly related to the underlying surface type.The stations can be divided into two categories,i.e. over the sea and over the land.The maximum road-surface temperature at stations over the sea category is much higher than that at stations over the land category.The statistic models of road-surface temperature reflect that sunshine duration item contributes a larger portion at stations over the sea category than that at stations over the land.According to the evaluation results of the statistic models,it shows that models perform poorly,partly due to the flaw of the linear regression method.Meanwhile,the quality control approach adopted in this paper can sensitively reflect the wrong station data.At a certain extent,it avoids the disturbance of the wrong data on the results. References | Related Articles | Metrics

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Climatic characteristics of spatial-temporal variations of maximum and minimum temperature in Northeast China during 1961-2015 HOU Yi-ling, LIU Ming-yan, ZHANG Hai-na, ZHAO Chun-yu 2018, 34 (5):  93-99.  doi: 10.3969/j.issn.1673-503X.2018.05.012 Abstract ( 274 )   PDF (1490KB) ( 301 )   Save Using the daily data from 162 weather stations,the spatial and temporal variations of maximum and minimum surface air temperature in Northeast China were studied under the highest level of freedom condition for the period from 1961 to 2015.The results show that the distribution of annual mean maximum and minimum air temperature are significantly affected by topography.It has good spatial consistency.The spatial distribution of the maximum temperature shows significantly zonal characteristics,while that of the minimum temperature shows local characteristics.The temporal trend exhibits an initial increasing and then changes to decreasing trend,and the transition point appears in 1997.From 1980 to 1997,the temperature shows an increased trend over the entire region,representing the first spatial distribution pattern.From 1998 to 2015,the temperature shows an "increasing in the north and decreasing in the south" trend,representing the second spatial distribution pattern.The probability density curves of the maximum and minimum temperatures move to high-value areas after 1997.After 1990,the probability of extremely high temperature shows an increasing trend,while that of extremely low temperature is a decreasing trend. References | Related Articles | Metrics

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Analyses of wind similarity in onset of Asia tropic summer monsoon ZHANG Dong-ling, ZHAO Yan-ling, ZHANG Ming 2018, 34 (5):  100-107.  doi: 10.3969/j.issn.1673-503X.2018.05.013 Abstract ( 142 )   PDF (9504KB) ( 104 )   Save In this paper,the similarity of day-to-day wind during the period of onset of Asia tropic summer monsoon (ATSM) was analyzed using 30-year averaged daily wind data on standard isobaric surface with the spatial resolution of 2.5°×2.5° during 1968-1997 derived from NCAR/NCEP reanalysis dataset.The results show that the similarity can reflect the onset of the ATSM better.Specially,in the lower troposphere,the level grads of contour line of wind similarity are very large and regarded as "frontal zone of the similarity".The change of atmospheric circulation is larger relative to that in the middle troposphere when South China Sea monsoon (SCSM) and South Asia summer monsoon (SAM) set up.The monsoon moves along the normal of the grads.Climatic SCSM sets up early in most cases in western Pacific warm pool and then covers the whole South China Sea after several days,which is caused by saltation of lower atmospheric circulation.Climatic SAM sets up early in most cases in tropical Eastern and Western Indian Ocean and then covers the whole South Asian Subcontinent and its saltation is weaker than that of the SCSM.Besides monsoon area and its neighboring districts,dramatic adjustment and even abrupt changes in the atmospheric circulation occur in some areas in global when the ATSM starts to set up. References | Related Articles | Metrics

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Temporal and spatial distribution of gale in the coastal zone of Liaoning province and its reason during 1971-2015 AO Xue, ZHAI Qing-fei, CUI Yan, ZHOU Xiao-yu, GONG Qiang, ZHAO Chun-yu, ZHU Ling, SHEN Li-du 2018, 34 (5):  108-118.  doi: 10.3969/j.issn.1673-503X.2018.05.014 Abstract ( 252 )   PDF (2764KB) ( 185 )   Save Based on the daily maximum wind speed and wind direction data of coastal zone weather stations in Liaoning province from 1971 to 2015,the temporal and spatial distribution characteristics of gale days and its variation were analyzed.The results show that the number of gale days is highest in spring and followed by winter and summer.The monthly variation of the number of gale days is a bimodal type in the northern part of Bohai Sea and Bohai Strait with a peak value in April.The northerly and southerly winds dominate in the coastal zone and the east and west winds occur infrequently.The number of gale days in most of weather stations of coastal zone shows a decreasing trend except the Gai county.The decreasing trend in the Bohai strait is most significant with a rate of 19.3 d/10 a,followed by the northern part of the Bohai Sea.The decrease rate in the northern part of the Yellow Sea is relatively smaller.In addition,the number of gale days in the northern part of Bohai Sea and the Bohai Strait show a main cycle of about 7 years,and a decreasing climate abrupt change occurs in the 1980s.Besides an 11-year cycle occurs in the northern part of the Yellow Sea and an abrupt decreasing appears after the 1970s.There are three high-value centers including Lüshunkou-Dalian,Changhai and Jinzhou-Panshan and three low-value centers such as Donggang,Suizhong and Pulandian area for the averaged annual gale days in the coastal zone of Liaoning province in recent 45 years.The high and low incidence areas demonstrate a cross-distribution.The zonal index enhancement leads to a weakening of meridional circulation,which is not favorable to the exchange between cold and warm air.The Asia polar Vortex Area Index and the Northern Hemisphere Polar Vortex Area Index decrease significantly and the polar vortex central position is northward propelling,implying that the intensity and frequency of the cold air activity are reducing.The weakening Siberia high intensity cuts down the pressure gradient in the east-west direction.As a result,the decreasing frequencies of cold wave and strong cold air and the daily range of temperature may be the important reason for decreasing the number of gale days in the coastal zone. References | Related Articles | Metrics

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The verification of northeast regional numerical model products in operational weather forecast services SAI Han, LI Yan, LIU Shuo, QUAN Mei-lan, SUN Yue-cheng 2018, 34 (5):  119-127.  doi: 10.3969/j.issn.1673-503X.2018.05.015 Abstract ( 220 )   PDF (1116KB) ( 194 )   Save Based on the ground temperature,precipitation,wind direction and speed,relative humidity data from seven main weather stations in Dalian area in 2015,the conventional weather elements predicted with the Northeast Regional Mesoscale Numerical Model (WRF) were analyzed for assessing the forecasting ability of WRF Model.This research will provide a technical reference for the revision of the model products in weather forecasting service.The results show that the forecast accuracy of temperature at 08:00 by WRF is higher than that at 20:00.The forecast value of minimum temperature is more accurate than that of the maximum temperature.WRF demonstrates a better performance in predicting the trend of warming and cooling.The forecast accuracy of precipitation by WRF is relatively high compared with other meteorological variables.The accuracy of the wind direction predicted by WRF is about 50% while that of wind speed can be 60% to 70%.The relative humidity predicted by WRF can be applied in the fog forecast. References | Related Articles | Metrics

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The relationships between bush fire/burnning area and meteorological factors SUN Hong-yu, CHENG Pan, CHENG Jia-yue, ZHU Yi-ming, JIA Bin-ying, HUANG Ge, LU Zhong-yan 2018, 34 (5):  128-134.  doi: 10.3969/j.issn.1673-503X.2018.05.016 Abstract ( 228 )   PDF (480KB) ( 206 )   Save Based on the bush fire damage observations during 2002-2015,the hot point data from satellite observations from 2014 to 2016 and related upper weather chart,the characteristics of the bush fire and burned area and their relationships with solar terms were investigated using the statistical analyses,synoptic-meteorological techniques and grey correlation analysis method.At the same time,the meteorological factors affecting the occurrence phases of fire damage were quantitatively analyzed.The results indicate that March,April and May in spring are the dominant months during which the bush fire occurs frequently.Most bush fires occur during 10-15 o'clock(Beijing Time) (2-7 GMT) in these months.The Spring Equinox (4th solar term) is highly correlated to the date when the hot-point on satellite images occurs and therefore is regarded as the beginning time of the fire warning in Liaoning province.In addition,the first 10 day in April (Chinese bright and clear day,5th solar term) becomes the key period for fire protections in every year.The monthly mean air temperature and wind speed in April,the monthly mean air temperature and relative humidity in May and the monthly mean wind speed in March are the main factors causing the occurrences of fire damages.Base on the relationships between the meteorological factors and the occurrences of fire damage from the on-the-spot investigation data,the warning time of high-incidence of bush fire and the related warning meteorological indices are proposed to provide scientific basis to forest fire weather service. References | Related Articles | Metrics

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Applicability of cooling/heating degree days in evaluating building energy consumption of different climate zones SUN Mei-ling, LI Ming-cai, CAO Jing-fu, SUN Yue, LI Ji 2018, 34 (5):  135-141.  doi: 10.3969/j.issn.1673-503X.2018.05.017 Abstract ( 190 )   PDF (1117KB) ( 167 )   Save This study revealed the reliability of degree days for reflecting the office building energy consumption by simulating the energy consumption from 1961 to 2012 and then investigating the correlations between the heating and cooling energy consumption and degree days in four cities including Harbin,Tianjin,Shanghai and Guangzhou representing different climate zones in China.The results show that there are significantly linear positive correlations between the heating energy consumption and heating degree days in Harbin,Tianjin and Shanghai and degree days can explain up to 95% variations of heating energy consumption,implying that heating degree days can be efficiently used to reflect the characteristics of the heating energy consumption and therefore to study the impact of climate change on heating energy consumption.On the contrary,the cooling degree days are unable to accurately reflect the variations of cooling energy consumption.By analyzing the relationships between energy consumption and relevant climatic factors,the heating energy consumption is dominantly affected by the temperature in winter while the cooling energy consumption is related to various factors such as temperature,humidity and radiation in summer,especially in the cities of hot climate zone. References | Related Articles | Metrics

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Evaluating the effect of FY-3A MWHS data assimilation on atmospheric humidity field forecasting TANG Shu-min, MA Jie-liang, YIN Jia-yan, LU Qi-feng, GUAN Yuan-hong, CAI Xi, TANG Wei-yao, ZHU Liu-hua 2018, 34 (5):  142-148.  doi: 10.3969/j.issn.1673-503X.2018.05.018 Abstract ( 181 )   PDF (2727KB) ( 250 )   Save Feng-Yun 3A is the first satellite with microwave humidity sensor (MWHS),which can provide data for numerical weather forecasting on global and regional scales.This paper focused on assessing the effects of FY-3A MWHS data assimilation on relative humidity analysis and forecasting by using a 3D-Var data assimilation system coupling WRF model.The results show that the MWHS data assimilation improves relative humidity analysis,and obtains better relative humidity analysis compared to the NOAA AMSU-B data assimilation.In general,the method using the MWHS data assimilation improves the relative humidity forecasting accuracy compared with the method using the AMSU-B data assimilation.For 18 hour forecasting results,the humidity forecasting accuracies at 400 hPa,600 hPa and 800 hPa levels using the MWHS data assimilation method are higher than those using the AMSU-B data assimilation method.These results indicate that the FY-3A MWHS has a wide application prospect in numerical weather forecasting. References | Related Articles | Metrics

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The risk assessment of wind disaster of greenhouse in Shandong province based on information dissemination theory LI Nan, XUE Xiao-ping, LI Hong-yi 2018, 34 (5):  149-155.  doi: 10.3969/j.issn.1673-503X.2018.05.019 Abstract ( 157 )   PDF (1463KB) ( 399 )   Save Wind tunnel test was used to measure the surface wind pressure coefficient of solar greenhouse under different wind direction angles.The critical wind speed of each part of solar greenhouse leading to the occurrence of wind disaster was obtained and used to analyze wind disaster index.Using 120 auto-observed meteorological stations data of daily maximum wind speed,as well as the wind disaster index,the inter-annual variation and inter-monthly variation of occurring number of wind disaster from 2006 to 2015 were analyzed.Using ArcGIS spatial analysis module,spatial distribution of wind disaster was studied.Risk assessment of wind disaster of greenhouse in Shandong province was performed by calculating wind disaster risk probability of different levels for all regions based on information dissemination theory.The results show that the critical wind speed of solar greenhouse wind disaster is 18.9 m·s-1.The main type of solar greenhouse wind disaster in Shandong province is light-level wind disaster during 2006 to 2015.Spring is the season with more disasters.The spatial distribution characteristic of wind disaster shows that more disasters occur in the East (North) while less in the West (South) of Shandong province.The wind disaster occurs mainly in the peninsula of Shandong province,the most part of north-west of Shandong province,the middle part in east of Shandong province,and some parts of south-east of Shandong province.The risk probability of wind disaster of these regions is more than 80.1%.Our study provides some helpful scientific advices for protecting solar greenhouse production. References | Related Articles | Metrics

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Concentration distribution of flue gas discharged at washing process of natural draft cooling tower YANG Hong-bin, ZHANG Yun-hai, ZOU Xu-dong, WANG Hong-yu, LIU Hai-long, LIU Yu-che 2018, 34 (5):  156-162.  doi: 10.3969/j.issn.1673-503X.2018.05.020 Abstract ( 257 )   PDF (418KB) ( 135 )   Save Concentration of various pollutants discharged at washing process was simulated using washing module of AUSTAL2000 model and pollutant source data from a thermo power station which flue gas discharged from the natural draft cooling tower.The results show that different wind speeds and cooling tower geometrical parameters exert considerable influence on the simulated concentration of pollutants in the air and at the ground.The maximum concentration of pollutant in the air and at the ground decreases along with the increasing wind speed when the height of cooling tower is 110 m.Moreover,the height of the maximum pollutant concentration in the air and the horizontal distance from the cooling tower also decrease.There is no obvious variation of the pollutant concentration in the upper air and at the ground except the maximum concentration in the air and at the ground decreasing when the height of the cooling tower increases to 130 m with other parameters unchanged.When the inner diameter of cooling tower outlet increases from 50 m to 60 m with other parameters unchanged,the pollutant concentration in the air and at the ground varies slightly with the increasing wind speed,but the horizontal distance of the maximum pollutant concentration in the air and at the ground from cooling tower increases slightly. References | Related Articles | Metrics

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The study on impact of air humidifier on indoor air quality ZHU Yi-meng, GUO Zhen-dong 2018, 34 (5):  163-168.  doi: 10.3969/j.issn.1673-503X.2018.05.021 Abstract ( 213 )   PDF (1193KB) ( 197 )   Save In this study,ultra-pure water,mineral water and tap water were selected as humidifying water sources.One brand household ultrasonic humidifier was adopted to humidify on a closed office.By using intelligent flow PM2.5 sampler,FA-3 aerosol particle size sampler and wide-range particle size spectrometer (WPS),the indoor aerosol mass concentration,mass concentration spectrum,particle number size distribution were measured and water soluble ions in aerosol were measured by chromatograph analysis.The results show that indoor PM2.5 mass concentrations have obvious growth and dominant of water soluble ion after humidification by different types of water.The net increase by humidification of ultrapure water,mineral water and tap water in indoor PM2.5 were 16.9,46.0 and 428.2μg·m-3 respectively.The humidification is mainly to increase the mass concentration and ion concentration of the fine particle size range below 2.1μm.The increase of major ions (SO42-,NO3-,Cl-,Na+,Ca2+,K+) were directly related to the most significant ions in the types of water.WPS measurements show that indoor aerosol number concentration increases significantly with a peak at about 20 nm,after humidify by ultrapure water and mineral water.While humidification by tap water,number concentration increases with a peak at about 30 nm.All types of water humidification lead to the number concentration increment of more than one order of magnitude.The increase of mass concentration by WPS peaks in size range of 500-600 nm after humidification,which is in accord with the measurement by aerosol particle size sampler that the peak increment at 0.43-0.65μm.When the ultrasonic humidifier was used,the pure water is recommended for health safety. References | Related Articles | Metrics