Table of Content

28 February 2019, Volume 35 Issue 1 Previous Issue    Next Issue

ARTICLES

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Simulation and improvement on structural characteristics of a squall line based on convection-allowing ensemble forecast MA Shen-jia, HE Hong-rang, CHEN Chao-hui, WU Dan, CHEN Sheng-jie 2019, 35 (1):  1-9.  doi: 10.3969/j.issn.1673-503X.2019.01.001 Abstract ( 237 )   PDF (6736KB) ( 196 )   Save The convection-allowing ensemble forecast is a new direction for studying strong convective weather,such as squall lines.The current research on the structural characteristics of squall systems is mainly based on the high-resolution deterministic forecast combined with the satellite and radar data.In this paper,the structure of the squall line was analyzed from the perspective of ensemble forecast technology.A convection-allowing ensemble forecast experiment based on the Weather Research and Forecasting (WRF) model was conducted for a strong squall line in eastern China on July 30,2014.The probability matched mean (PMM) method was used to analyze synthetically the modelling results and verify the ability to simulate structural characteristics of the squall line.The results indicated that the convection-allowing ensemble forecast is able to simulate the basic structural characteristics of the squall line system.Compared with control prediction,the ensemble mean (EM) and PMM methods can improve significantly the structure of echo,a thermal field,dynamic field and microphysical field for the squall line.The modelling results also reflect the interaction between the near-surface cold pool and the vertical wind shear in the squall line system,which is consistent with the RKW theory.The echo intensity obtained from the PMM method is more close to the observations than that by the EM method,which means that it has a guiding significance to use the PMM method to study extreme weather events in the convection-allowing ensemble forecast. References | Related Articles | Metrics

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Analysis of heavy rainfall distribution difference among three typical hollow typhoons landing in Fujian province LIN Xiao-hong, WU Jian-cheng, LIU Tong-yi, HAN Mei, GUO Hong, KE Xiao-qing 2019, 35 (1):  10-17.  doi: 10.3969/j.issn.1673-503X.2019.01.002 Abstract ( 211 )   PDF (6119KB) ( 258 )   Save Base on conventional meteorological observations and the National Centers for Environmental Prediction (NCEP) reanalysis data,the heavy rainfall distribution differences among three typical hollow typhoons (1710 “Haitang” on July 31,2017,1307 “Soulik” on July 13,2013,and 0709 “Sepat” on August 19,2007) landing in Fujian province were diagnostically analyzed.The results show that the divergence channels at high altitudes of the three typhoons are significantly different;typhoons of “Haitang” and “Sepat” both exhibit anticyclone outflows,while “Soulik” only has a single outflow channel.Vertical wind shear direction is useful to predict heavy rainfall area of typhoons “Haitang” and “Soulik”.The front zone of moisture and the intruding location of dry tongue greatly influence the formation of hollow structures and the difference in distributions of strong precipitation.The moist potential vorticity of the three typhoons is negative at low altitudes and positive at high altitudes,indicating a convectively unstable condition of the atmosphere at low altitudes.Wet positive pressure term provides major unstable conditions for the development of mesoscale convective systems (MCS) of “Haitang” and “Sepat”,while the wet positive pressure term and the wet baroclinic term both strengthen the development of MCS of “Soulik”,and the former term plays an important role in the formation of an asymmetric distribution of MCS. References | Related Articles | Metrics

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Comparison analysis of three heavy pollution events in He'nan province DONG Zhen-hua, QI Yi-ling, KONG Hai-jiang 2019, 35 (1):  18-25.  doi: 10.3969/j.issn.1673-503X.2019.01.003 Abstract ( 275 )   PDF (4226KB) ( 178 )   Save Based on meteorological observation data,Europe Center (EC)-Interim reanalysis data,L-band radar sounding data and air quality monitoring data,the three heavy pollution events that occurred in He'nan province from November 27 to December 25 were comparatively analyzed,from the perspective of the pollution scope,time,intensity and primary pollutants as well as meteorological conditions.The results show that smooth circulation,weak pressure gradient,high humidity,small wind speed,and temperature inversion are all beneficial to the formation of heavy pollution.He'nan province is controlled by a weak ridge at 500 hPa during the most heavily polluted days in the event I and II and controlled by the northwesterly flows behind a trough in the event III.Northerly winds are favorable to transport pollutants from the north to the south and result in a large area of heavy pollution.All the three events end up with the westerly cold air flows.PM2.5 concentration has a lead-lag correlation with wind speed,humidity,24-h temperature variation,and 24-h pressure variation,with the best correlation of 4-h forward for wind speed,1-h forward for humidity,10-h forward for temperature variation and 19-h forward for pressure variation.Temperature inversion exists in the boundary layer during the three events.A temperature inversion occurs both near the surface and in the upper levels during the most period in the event I,while it occurs only near the surface in the event II and III.The air is relatively dry at high altitudes and moist at low altitudes in the event I;such characteristics are not observed in the event II and III.The pollutants are removed from in the middle and western regions at first,followed by the northern region,Nanyang area,and the eastern region in the event II and III,while in the event I,air pollutants in the northern region are removed firstly. References | Related Articles | Metrics

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Formation analysis of a heavy dust pollution event in the Yangtze River Delta in May 2017 HUO Yan-feng, DENG Xue-liang, GONG Zhong-qiang, YANG Guan-ying, SUN Qiang, ZHAI Jing, YU Cai-xia 2019, 35 (1):  26-34.  doi: 10.3969/j.issn.1673-503X.2019.01.004 Abstract ( 203 )   PDF (9374KB) ( 182 )   Save Based on surface air pollutant monitoring data,conventional meteorological data,the Europe Center for Medium Range Weather Forecast (ECMWF) reanalysis data and the L-band radiosonde observations,a heavy dust pollution event occurred in the Yangtze River Delta on May 5-7,2017 was analyzed in the combination of using a backward trajectory model.The results show that this dust pollution event is influenced by the weather system,surface meteorological factors,and boundary layer conditions.The eastward movement of East Asian rough,the southward movement of cold air,as well as the development of high pressure at surface lead to the occurrence of dust weather in the Hexi Corridor region,most of Ningxia Hui Autonomous Region and the western Inner Mongolia,which provide dust source for dust transport to the Yangtze River Delta region.Strong winds at 850 hPa favor the transport of dust particles from the upstream dust source region to downstream region.The descending movement of air at the high-pressure center and the enhancing convection in the daytime provide dynamic conditions for the effect of dust at high altitudes to the surface.As dust particles arrive in the Yangtze River Delta,cold air becomes weak and the near-surface layer remains stable,which is unfavorable for the pollutant dispersion and results in the heavy pollution event. References | Related Articles | Metrics

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Characteristics of spatiotemporal variation clustering of PM2.5 and its meteorological influence in cities of Liaoning province XIANG Cheng-cheng, CHAI Man 2019, 35 (1):  35-44.  doi: 10.3969/j.issn.1673-503X.2019.01.005 Abstract ( 208 )   PDF (3329KB) ( 311 )   Save Based on the ambient air quality monitoring data and meteorological observations in 14 cities in Liaoning province from November 2015 to October 2016,the spatiotemporal characteristics of particulate matter and the influence by meteorological factors were systematically analyzed and then a clustering partition was made.The results show that PM2.5 concentration in cities of Liaoning province has obviously seasonal variation,with the highest value in winter,followed by spring,summer,and fall.The spatial distribution of PM2.5 concentration in Liaoning province is characterized by the highest in the central plain area,lower in hills at two side regions and the lowest in the east coastal region.According to the scatter plots of PM2.5 concentration against meteorological parameters as well as the Spearman correlation coefficient,the cities in Liaoning province can be divided into four types,i.e.,Liaodong Peninsula type (Type I,including Dandong,Dalian,Panjin,and Yingkou),western Liaoning mountain type (Type II,including Huludao,Jinzhou,Chaoyang,and Fuxin),eastern Liaoning mountain type (Type III,Benxi and Fushun) and middle Liaoning plain type (Type IV,Tieling,Shenyang,Liaoyang and Anshan).PM2.5 concentration increases in cities from Type I to Type IV,which is most obvious in winter.Positive correlations between PM2.5 concentration and meteorological parameters such as air temperature,water vapor pressure and relative humidity at all cities are observed only in winter,but also observed in spring at cities of Type I and II,and in spring and summer for Type IV.PM2.5 concentration has a negative correlation with wind speed in all cities in winter and no obvious correlation with air pressure. References | Related Articles | Metrics

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Temporal and spatial characteristics of visibility in Beijing from 2007 to 2015 JIANG Jiang, GUO Wen-li, WANG Chun-ling 2019, 35 (1):  45-52.  doi: 10.3969/j.issn.1673-503X.2019.01.006 Abstract ( 210 )   PDF (1170KB) ( 329 )   Save Using the data from Daxing observation station,twenty-eight road automatic stations and regional automatic stations from 2007 to 2015,the temporal and spatial characteristics of visibility in Beijing were analyzed.The results show that the highest value of visibility appears in spring and the lowest one appears in summer.The annual and summer visibility in Beijing has increased significantly for the last nine years.From 2011 to 2014,the increase in the particulate matters results in low visibility in winter.The visibility in the northwest part is significantly higher than that in the southeast part.The annual spatial distribution of visibility features decreasing gradually from the northwest to the southeast,which is the same as those in autumn and winter.The factors that are highly correlated with visibility are as follows,i.e.relative humid,particulate matters,wind direction,wind speed,and rainfall.However,the degree of the correlation of these factors with the visibility is different according to the different months,seasons and years.During this period,the numbers of days with occurrence of the fog,haze and dust weather phenomena are all increasing.The frequency of visibility less than 10 km mainly increases and that of visibility less than 1 km decreases in the whole area.As for the case study,when the wet haze events (7.13%) occur,the visibility in Beijing becomes worse than when the dry haze events (44.29%) occur. References | Related Articles | Metrics

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Characteristics of air quality and its relationship with meteorological factors in Harbin ZHU Hong-rui, LIU He-nan, ZHANG Hong-ling, YIN Chang-jiao 2019, 35 (1):  53-58.  doi: 10.3969/j.issn.1673-503X.2019.01.007 Abstract ( 268 )   PDF (449KB) ( 256 )   Save Based on the air quality index (AQI) and meteorological observation data from 2014 to 2016,the variations of air quality and main pollutants and the relationship between AQI and the main meteorological factors in Harbin were analyzed.The results show that the number of days reaching the good air quality level is the highest,accounting for 47%,that reaching the level of pollution accounts for 31% during this time.The air quality in 2016 is the best.The AQI index is lower in spring and summer,and significantly higher in autumn and winter.The best air quality is found in September and the worst time occurs in winter.PM2.5 is the major pollutant causing air pollution in Harbin,followed by PM10,NO2,and ozone for 8 hours.The correlation between AQI and air pressure is positive and reaches the most significant level in autumn and winter.Wind speed shows mainly negative correlation with AQI,especially in winter.The relationship between temperature and AQI is disturbed by the changes in building heating.It shows a negative correlation in the time scales of annual,autumn and winter.However,it shows a positive correlation in the monthly scales.It has a negative correlation with precipitation,a significant positive correlation with relative humidity in winter and a negative correlation with relative humidity from May to September. References | Related Articles | Metrics

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Analysis of the regional division of volume capture ratio of annual rainfall runoff and its spatial variation in sponge city construction in Liaoning province GU Zheng-qiang, GONG Qiang, CHAO Hua, ZHANG Hai-na, XU Hong, ZHU Ling, SHEN Li-du, LIN Na 2019, 35 (1):  59-65.  doi: 10.3969/j.issn.1673-503X.2019.01.008 Abstract ( 222 )   PDF (3049KB) ( 807 )   Save Based on the daily rainfall observation data from 60 meteorological stations in Liaoning province and the monthly global reanalysis data of the NCEP/NCAR (the National Centers for Environmental Prediction/National Center for Atmospheric Research) from 1986 to 2015,the regional division of volume capture ratio of annual rainfall runoff and its spatial variation in Liaoning province were analyzed.Results show that the volume capture ratio of annual rainfall runoff in Liaoning province can be divided into II division,III division IV division,and V division.There is one more division-the V division,than those in the“Sponge Urban Construction Technology Guide-Low Impact Development of Rainfall System to Build”,and the spatial distribution for the same division of these two studies differs apparently.The proportion of total rainstorm in total rainfall is closely related to the regional division of volume capture ratio of annual rainfall runoff.The characteristics of water vapor transportation and topography in Liaoning province are the internal causes for the regional distribution differences of the division of volume capture ratio of annual rainfall runoff. References | Related Articles | Metrics

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Analysis of the epidemic characteristics of heat stroke and the influence of heat wave on it in Ningbo city from 2012 to 2016 SUN Shi-qiang, LU Wen-han, GUO Jian-min, QIAN Yan-zhen, LU Jing-jing 2019, 35 (1):  66-71.  doi: 10.3969/j.issn.1673-503X.2019.01.009 Abstract ( 212 )   PDF (900KB) ( 140 )   Save It has been a common understanding that urban heat wave events seriously affect human health and life safety.Based on the data of heat stroke cases in Ningbo city and the corresponding climate data from 2012 to 2016,a correlation analysis was made on the prevalence characteristics of heatstroke in summer and the impact of the heat wave on the heat stroke in Ningbo city.The results show that the number of heatstrokes is the highest in 2012 and 2013,and is concentrated in June to August,of which the percentage ratio is 55.3% in July.The incidence of heat stroke in males is significantly higher than that in females,and the degree of heat stroke is mainly concentrated in mild heat stroke.The proportion of heat stroke among people aged 31-60 is the highest,and the proportion of heat stroke in urban areas is higher than that in suburban areas.With two elements in combination with the heat index of temperature humidity and heat wave formula defined the Ningbo heat process,we find that the correlation coefficient of heat number and heat number is as high as 0.898.Seven heat processes were selected to calculate the heat stroke relative risk,it’s found that except 2013 the heat stroke relative risk index (RR) is under 10 in each year.The RR values corresponding to the three heat strokes in 2013 are 18.1,21.6 and 25.8,respectively,which are related to high frequency of heat wave in this year.Through comparing the relative risk of heat stroke before and after the seven heat wave events,no significant heat lag effect is found. References | Related Articles | Metrics

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Simulation and projection of temperature and precipitation by CCSM4 model in Northeast China ZHANG Hai-na, HOU Yi-ling, ZHAO Chun-yu, LIU Ming-yan, WANG Tao, ZHOU Xiao-yu, CUI Yan, AO Xue, YI Xue 2019, 35 (1):  72-78.  doi: 10.3969/j.issn.1673-503X.2019.01.010 Abstract ( 196 )   PDF (1948KB) ( 197 )   Save The monthly temperature and precipitation data from 162 meteorological observation stations were used to evaluate the simulation performance of the CCSM4 model and predict the climate change scenario in Northeast China from 2021 to 2050.Results show that monthly mean temperature and precipitation values simulated by the long-term historical climate CCSM4 mode simulation experiment from 1961 to 2005 can reproduce the Northeast regional annual average temperature,rainfall spatial distribution form.However,the temperature simulation values are lower than those of observations.The temperature error in 91.4% stations is within 1.5 ℃.The precipitation center is slightly shifted to the north compared with the observations.There is a positive bias of 35.18 mm of average precipitation for the whole region.For 2021-2050,the annual average temperature in Northeast China increases.The amplitude of increased temperature in the high latitude is larger than that in the low latitudes.Compared with the benchmark year,the temperature increasing amplitudes under RCP2.6,RCP4.5 and RCP8.5 scenarios are 6.00 ℃,5.86 ℃ and 6.42 ℃,respectively.The annual precipitation distribution presents a pattern of decreasing from southeast to northwest.The high-value center in precipitation appears at the southeast part of the junction zone of Jilin and Liaoning provinces.Under RCP2.6,RCP4.5 and RCP8.5 scenarios,the increasing percentage in precipitation is 15.2%,3.1%,and 2.0%,respectively for the whole research area. References | Related Articles | Metrics

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Quantitative precipitation inversion algorithm based on the multi-radar mosaic II:scheme improvement and evaluation JI Yong-ming, CHEN Chuan-lei, JIANG Da-kai, REN Zhi-jie, MENG Ying, CAI Kui-zhi, ZHANG Shuo, HU Peng-yu 2019, 35 (1):  79-87.  doi: 10.3969/j.issn.1673-503X.2019.01.011 Abstract ( 214 )   PDF (2178KB) ( 291 )   Save In order to improve the accuracy of radar quantitative precipitation retrievals,combining Doppler multi-radar mosaic data and the gauge-observed hourly rainfall intensity data,the radar quantitative precipitation retrieval scheme was optimized in Liaoning province based on the established Z-I relationship using the optimization method.The results show that the evaluation indexes of the two optimization schemes for quantitative precipitation retrieval are improved.Overall,the two optimization schemes reduce the errors of radar quantitative precipitation retrieval effectively.The capability of precipitation retrieval is further improved.The precipitation retrieval results for Fushun “8.16” typical strong precipitation indicate that the spatial distribution of the radar quantitative precipitation retrieval using the two optimization retrieval schemes showed high accuracy compared to the surface precipitation data.In particular,the problems that the precipitation zone above 20.0 mm·h-1 is smaller than actually happening and the magnitude of the short-time strong precipitation above 40.0 mm·h-1 is underestimated are largely corrected.After using the optimization scheme,all the evaluation indexes are significantly improved and the uncertainties and dispersions in the radar quantitative precipitation retrieval are smaller than before.Precipitation retrieval results have better stability and reliability,which provide a quantitative reference for short-term forecasting and early warning of heavy rainfall events. References | Related Articles | Metrics

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Study on characteristics of seasonal drought composite index in the Qilian Mountain area from 1961 to 2016 GUO Xiao-qin, LUO Yong-zhong 2019, 35 (1):  88-93.  doi: 10.3969/j.issn.1673-503X.2019.01.012 Abstract ( 156 )   PDF (1109KB) ( 167 )   Save Based on Z index and entropy weight theory,the seasonal drought composite index was constructed to evaluate the drought intensity.Taken the Qilian Mountain area as an example,the characteristics and spatial distribution of seasonal drought were evaluated.The results show that drought intensity becomes weak from 1961 to 2016.The intensity of drought in spring and autumn is significantly weakened.The intensity of drought in summer is also weakened though it does not pass the significant test.In general,seasonal droughts are frequent and severe in the 1960s,1970s,and 1990s.However,the summer drought and winter drought become frequently since 2000,which should require to pay more attention.The drought intensity of four seasons sorted from severe to mild is winter,summer,spring,and autumn.In terms of drought variability,autumn is the strongest,followed by winter.Spring is the weakest.The south of the Qilian Mountains area is drier than the north in spring,summer and autumn,and vice versa in winter.Drought in winter is widespread,especially severe in the north of the Qilian Mountain area where Jiuquan is the center of this region.During the study period,the drought intensity becomes weak gradually in both north and south of the Qilian Mountain area.The drought intensity in the south becomes milder than that in the north.Drought intensity during the period of no-grass decreased significantly.This study provides a reference for the evaluation of drought in the Qilian Mountain area. References | Related Articles | Metrics

SCIENTIFIC NOTES

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Distribution characteristics and speciation analysis of heavy metal in Taizi River flowing through Benxi urban area WANG Jian, MA Bo-jian, YU Ying-tan, LU Bing, WANG Shou-peng, LIU Lin, ZHANG Xue, ZHANG Chao-xing 2019, 35 (1):  94-100.  doi: 10.3969/j.issn.1673-503X.2019.01.013 Abstract ( 196 )   PDF (924KB) ( 134 )   Save In order to investigate the distribution characteristics and speciation of heavy metals in Taizi River flowing through Benxi urban area,the concentration and distribution of heavy metals including Zn, Pb, Cd, Cu, Mn, Cr, Se in the river were analyzed.At the same time,the speciations of heavy metals were simulated using PHREEQ software.The results show that Mn and Cr are more serious pollutants relative to the other five kinds of heavy metals due to their average concentrations exceeding the national surface water environmental quality standards IV(GB 3838-2002).Multivariate statistical analysis shows that the seven heavy metals can be classified into two principal components.More specifically,the first principal component i.e.PC-I including Mn, Cd and Se is mainly affected by anthropogenic pollution factors,while the second principal component i.e.PC-II containing Zn is mainly influenced by natural geological background factors.Heavy metal pollution index (HPI) ranges from 28.49 to 473.76,which indicates that the degrees of heavy metals pollution in some parts of the sampling area go beyond the acceptable level.The speciation analysis results show that the seven heavy metals in water exist mainly in the forms of colloform (Cu(OH)2) or precipitate (ZnCO3,PbCO3,MnCO3,et al) and the concentrations of dissolved forms are lower.The research conclusion can provide references for the water pollution control and river restoration in the Taizi River flowing through Benxi urban area. References | Related Articles | Metrics

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Effects of water stress and supplement after sowing on emergence rates of maize ZHU Meng-yuan, ZHANG Hui, LI Shuang, ZHANG Bing-bing, CHANG Song, CAI Fu, ZHAO Jia, CAI Wen-bo 2019, 35 (1):  101-107.  doi: 10.3969/j.issn.1673-503X.2019.01.014 Abstract ( 211 )   PDF (633KB) ( 113 )   Save In order to investigate the effects of water stress and supplement during the period from sowing to seedling emergence on the emergence rates of maize,the amount and time of water supplying after sowing and soil relative water content on sowing date (wsowing) were analyzed based on pot experiment under different water supplying schemes.The results show that the emergence rate decreases with decreases of the soil moisture,the duration of drought prolonging and the amount of water supplying reducing.Under the condition without water supplement after sowing,the emergence rates of maize are 100%,77.8% to 66.7% and 0% corresponding to soil moisture from 70% to 60%,55% to 50% and 45% to 30%,respectively.Whereas,when wsowing ranges from 35% to 45% with water supplying of 20 mm for 5 to 20 days after drought,the emergence rates ranges from 66.7% to 100%.But if the water supplying drops to 10 mm,the emergence rates drop to 0 to 77.8%.When wsowing ranges from 35% to 45%,in order to ensure the ideal emergence rate,water supply must be conducted within 10-20 days and their amounts increase with soil moistures decreasing.The research can be used as references for determining the latest time and the minimal amount of water supplying in the areas where maize often suffer spring drought. References | Related Articles | Metrics

BULLETINS

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Study on temperature forecast method for villages and towns based on a numerical forecast model WU Chun-ying, LIU Duo-wen, ZHONG Bo, JIANG Ting-ting, YU Hui-jing, CHEN Jia-mei, GAO Yan 2019, 35 (1):  108-112.  doi: 10.3969/j.issn.1673-503X.2019.01.015 Abstract ( 210 )   PDF (698KB) ( 216 )   Save Using the observation data of daily maximum and minimum temperature in Changxing island and Jiaoliu island weather stations from August 2015 to July 2017,the 2 m fine ECMWF grid temperature forecast value,the Japanese FSFE02 (24 h ground situation forecast) and FSFE03 (36 h ground situation forecast) were verified.The results show that on the basis of the historical regression statistical test method,the forecasted 24 hours maximum and minimum temperatures at 2 m using the ECMWF fine grid model have significant forecast effects and pass the 0.05 confidence test.A close correlational relationship between the prediction and observation for each month is obtained.Making use of the difference of the 2 m temperature between the observation and the forecast value from ECMWF fine mesh the day before in Changxing island,integrating the statistical correction of the 2 m temperature forecast values from the ECMWF fine grid,the temperature for the next 24 hours at Changxing island stations is forecasted.The temperature forecast of Jiaoliu island station is produced based on that of Changxing island station.On the basis of the statistical analysis,the temperature difference between Jiaoliu island and Changxing island station is closely related to the ground situation and wind field.Based on the corrections of different ground conditions and wind field,the temperature at Jiaoliu island station is forecasted.Applying development function of the Matlab computer language to extract the maximal and minimal temperature at 2 m from the ECMWF fine mesh and to input their real values at Changxing and Jiaoliu island stations,the maximum and minimum temperatures in the next 24 hours are automatically forecasted.Besides,a visual forecast working platform is built to realize the automation of villages and towns temperature forecast. References | Related Articles | Metrics