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30 October 2017, Volume 33 Issue 5 Previous Issue    Next Issue

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Verification and analysis of rainfall forecasted by the ECMWF model in Anhui province ZHAI Zhen-fang, WEI Chun-xuan, DENG Bin, JI Yuan 2017, 33 (5):  1-9.  doi: 10.3969/j.issn.1673-503X.2017.05.001 Abstract ( 395 )   PDF (1368KB) ( 822 )   Save The rainfall field forecasted by the ECMWF (European Centre for Medium-range Weather Forecasts) model from January of 2012 to March of 2015 in Anhui province was tested using TS (Threat Score),forecasting bias (BIAS),ETS (Equitable Threat Score) after removing random events,and TSS (True Skill Statistic) score methods in order to understand the forecasting performance of the ECMWF model and improve the correction skills.The results show that,in general,the forecasting performance of the ECMWF model in Anhui province is stable and exhibits a little inter-annual variation.There is a spatial distribution feature with high in the south part and low in the north part of the ETS value.All amounts of rainfall in each meteorological station are forecasted excessively.Based on the classification test in the amount of rainfall prediction,it indicates that the forecasting score of sprinkle is significantly higher than that of the other rainfall,while the forecasting bias of sprinkle is higher and the excessive forecasting phenomenon is serious.The model forecasting ability for the rainstorm within 72 h is very limited and the model has no forecast score for the rainstorm beyond 72 h.The accuracy forecasting rate of clear or rain within 48 h in spring,autumn and winter are above 88% with a small room to correct.The rate of false-alarm for forecasting of rainfall in summer and in spring,autumn and winter beyond 168 h is above 60%,and this needs to be corrected accordingly.The rate of missing report of rainfall in autumn is higher than that in the other seasons,especially for the rainfall forecast beyond 120 h.The amount of rainfall in each season is forecasted excessively,especially in summer.The rate of false-alarm of rainfall within 0.1-0.7 mm to the grid prediction is higher.This false-alarm rate can be improved significantly after correction,but it increases the risk of missing report rate. References | Related Articles | Metrics

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Simulation and analysis of air pollution and its directing effect to operation of precipitation/snow enhancement during winter over Dalian city LI Hong-bin, FU Yu, ZHANG Jing-xuan, ZHAO Fan-sheng, GAI Xiao-bo, HE Yang 2017, 33 (5):  10-16.  doi: 10.3969/j.issn.1673-503X.2017.05.002 Abstract ( 253 )   PDF (1343KB) ( 295 )   Save The temporal and spatial distribution characteristics of meteorological elements and aerosol in Dalian in December of 2015 when some air pollution events occurred were analyzed using the conventional meteorological observation data and air pollution indices from the Ministry of Environmental Protection of China as well as the simulation results from the regional air quality WRF-CMAQ (Weather Research and Forecasting-Community Multi-scale Air Quality) model.Under the air pollution weather conditions,how to carry out precipitation/snow enhancement operation was discussed as well.The results show that there are five air pollution events during December of 2015 in Dalian city,with a persistent time of 13 days,which is 41.94% of the total number of days in this month.The daily mean lowest visibility is 2.27 km.When the air pollution events occur,the temperature near surface increases slightly,and the atmospheric stratification is stable.Thus,it is suitable to choose aircraft or rocket to carry out the precipitation/snow enhancement operations in order to guarantee the catalyst to be sowed to the nucleation layer with the temperature of -15℃~-10℃.A certain amount of fine particles can reach up to the height of more than 3.00 km under the air pollution weather conditions.Therefore,the amount of catalyst should be properly reduced on the basis of the normal level when operating on the cold cloud target.Based on the analysis of a serious air pollution cases occurring in Dalian in December,it reveals that nitrate,ammonium,and sulfate are the main pollutant components,and the percentage of nitrate is the highest among these components,reaching 51.27%;it suggests that,except industrial sources and coal emissions,car emissions are also responsible for the pollution in Dalian city. References | Related Articles | Metrics

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Comparative verification and analysis of environmental meteorology operational numerical prediction models in China LIU Hui, RAO Xiao-qin, ZHANG Heng-de, LI Ming, ZHANG Zhi-gang 2017, 33 (5):  17-24.  doi: 10.3969/j.issn.1673-503X.2017.05.003 Abstract ( 319 )   PDF (868KB) ( 384 )   Save Based on the visibility and air quality results from January to March in 2015 forecasted by four environmental meteorology operational numerical models from the North China,East China and South China Regional Meteorological Centers and the National Meteorological Center,respectively,their forecasting quality was verified.The results show that with the decrease of visibility,these models' forecasting quality gradually reduces.When the visibility is less than 1 km,only models from the North China Regional Meteorological Center and the national fog and haze numerical forecasting operational system-CUACE (CMA Unified Atmospheric Chemistry Environment) exhibit a certain forecasting skill;the TS to 24 h visibility prediction in Beijing are 0.20 and 0.10,respectively.Generally speaking,the visibility prediction error of the CUACE model is larger than those of regional meteorological centers' models,and the correlation coefficient of observations with the predictions is less than 0.6.Similarly,with the decrease of air quality,these models' prediction quality to AQI (Air Quality Index) gradually reduces.When the AQI is at the excellent rank,the TS are higher;and due to the good air condition in South China,its TS score for AQI prediction is the highest.In general,for the 24 h AQI prediction,the forecasting qualities of the regional centers' models are superior to that of the CUACE model,and for the 48 h and 72 h ones,the situation is opposite.The values of PM2.5 concentration forecasted by these models are normally lower than those of observations.The error of 24 h PM2.5 concentration forecasted by the South China Regional Meteorological Center's model is relatively small,and those forecasted by the North China and East China Regional Meteorological Center's models are comparatively larger.For the prediction of PM2.5 concentration,the performance of the CUACE model is the worst among these models,with a lower correlation coefficient between the predictions and observations. References | Related Articles | Metrics

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Application of high-frequency ground wave radar in early warning of sea gale in Liaoning province CHENG Pan, SUN Hong-yu, CHEN Chuan-lei, CAI Kui-zhi, WANG Shu-yao, XIAO Guang-liang, LIU Jing, CHENG Hang, WANG Yi-wen 2017, 33 (5):  25-34.  doi: 10.3969/j.issn.1673-503X.2017.05.004 Abstract ( 271 )   PDF (1079KB) ( 437 )   Save Using the sea gale data detected by the high-frequency ground wave radar (HFGWR) in Dalian and Panjin cities and the wind data from the automatic meteorological stations along the coastal regions in Liaoning province,the retrieval results of HFGWR were evaluated based on analyzing the numbers of effective samples,acquisition rates,usability,average deviation,and standard deviation indices.The working situations of HFGWR were judged by the continuous detecting time and grading level of wind force.The results show that the overall performance of HFGWR in Dalian is better than that in Panjin.The acquisition abilities to wind direction and wind speed data in Dalian are equal,and basically satisfy the needs of operation and application.The radar data acquisition rate in Panjin is mainly in agreement with that in Dalian,but the usability of these data is relatively low;there is a certain gap from the real sea situation.Under a weak wind condition with wind speed less than 6 m·s-1,the wind fields detected by HFGWR in Dalian and Panjin both demonstrate a larger deviation from the real wind fields.When the wind speed is more than 6 m·s-1,the detecting ability of radar in Dalian is significantly improved and the detecting result generally reflects the actual wind change situation,while that in Panjin is not good enough.When the wind speed is more than 10 m·s-1,the detecting ability of radar in Dalian can be further improved. References | Related Articles | Metrics

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Characteristics of water vapor and liquid water content retrieved by ground-based microwave radiometer in Ji'nan ZHANG Qiu-chen, GONG Dian-li, WANG Jun, ZHANG Hong-sheng 2017, 33 (5):  35-43.  doi: 10.3969/j.issn.1673-503X.2017.05.005 Abstract ( 277 )   PDF (1208KB) ( 372 )   Save Using integrated Water Vapor (IWV) and Liquid Water Path (LWP) data determined from 14-channel ground-based microwave radiometer named RPG-HATPRO-G3 during October of 2014 and September of 2015 in Ji'nan,seasonal,monthly,diurnal variation characteristics of IWV and LWP,as well as their variation tendencies in severe convective and spit weather were analyzed.The results show that IWV exhibited apparent monthly variation during the research period.The tendency of these variations had a relatively good correlation with the long-term monthly mean precipitations during 1981 and 2010,with the highest value in summer and the lowest value in winter.Diurnal variations of IWV were weak in all seasons,and the seasonal standard deviations were in the decreasing order of summer,autumn,spring,and winter.After counting the number of LWP data in spring,summer and autumn seasons,the number of available LWP data in cloudy days is the minimum in spring and the maximum in summer.The number of frequency the monthly LWP peaks between 0-200 g·m-2 and declines with the increase of LWP.The number of frequency of the monthly LWP more than 1000 g·m-2 gradually increases with the increasing precipitation in summer season.IWV and LWP increase significantly ahead of an intensive convective weather,and LWP above 1000 g·m-2 accounts for 53.41%.IWV increases in a wave pattern before a period of spit weather,while LWP increases significantly near the beginning of spit weather.Monthly LWP concentrated between 0-200 g·m-2 with the frequency of 86.56%. References | Related Articles | Metrics

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Analysis of weather type during period of heavy air pollution days in Chaoyang District,Beijing CHENG Yue-xing, DAI Jian, WANG Wei-qi, LI Yan 2017, 33 (5):  44-52.  doi: 10.3969/j.issn.1673-503X.2017.05.006 Abstract ( 352 )   PDF (1949KB) ( 370 )   Save Based on the meteorological observational data and PM2.5 concentration monitoring data in Chaoyang District,Beijing from 2011 to 2015,weather types during heavy air pollution were analyzed.The results show that three weather types can be generally identified under heavy pollution conditions,i.e.,uniform pressure field,low pressure with convergence,and high pressure.For uniform pressure field type when heavy air pollution occurs,atmospheric stratification is stable and surface wind speed is weak,which results in the accumulation of pollutants at a low level.Meanwhile,due to the local topography effect,the mountain-valley wind circulation becomes significant over the Chaoyang District.The weather type of low pressure with convergence is characterized by ascending motion in the front of the trough,which leads to the accumulation of pollutants in the center of low pressure and the formation of heavy air pollution.Under high-pressure type,Chaoyang District locates in the rear or bottom of surface high pressure and is influenced by the southerly or easterly flows,and then pollutant concentration increased due to strong regional pollutant transport.On the whole,when three weather types appear alternately,persistent and heavy pollution easily occurs in Chaoyang District. References | Related Articles | Metrics

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Weather pattern and case analysis of air heavy pollution days in Beijing MA Xiao-hui, LIAO Xiao-nong, TANG Yi-xi, SUN Zhao-bin, LI Zi-ming 2017, 33 (5):  53-60.  doi: 10.3969/j.issn.1673-503X.2017.05.007 Abstract ( 241 )   PDF (1446KB) ( 507 )   Save Using the upper-level and surface meteorological observational data and daily atmospheric component monitoring data from January of 2008 to December of 2014 in Beijing,we statistically analyzed the duration,upper-level circulation pattern at 500 hPa,surface pressure field,and boundary layer structure during heavy pollution days with daily air quality above the 5 levels.The results indicate that heavy air pollution is usually accompanied with zonal circulation at 500 hPa,which counts up 58.4% of the total heavy pollution days.Heavy air pollution occurs most frequently under the weather type of low surface pressure system with convergence,with an occurrence frequency of 38.3%,followed by the rear of the surface high-pressure system,with an occurrence frequency of 18.8%.When heavy air pollution occurs in Beijing,the zonal circulation dominates at 500 hPa and the southerly warm flow dominates at 850 hPa.In addition,the surface pressure patterns include low-pressure system with convergence,the rear and bottom of high-pressure system,weak air pressure,the front of high pressure,depression trough,weak high pressure,saddle pressure field,and topographic trough over the northern China.Under such weather situations,thermal inversion,weak wind speed at low level,and high relative humidity exist in the boundary layer for a long period.Based on the aforementioned weather characteristics,a conceptual model of heavy pollution is established. References | Related Articles | Metrics

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Distribution characteristics of wind and pollutant concentration fields in a parallel urban block ZHAN Long-fei, SHU Jiong, CHEN Liang 2017, 33 (5):  61-67.  doi: 10.3969/j.issn.1673-503X.2017.05.008 Abstract ( 263 )   PDF (2939KB) ( 468 )   Save In order to study the characteristics of wind field and pollutant transportation in a block,the wind field and pollutant concentration were simulated based on the computational fluid dynamics (CFD) software FLUENT using the RNG κ-ε turbulence model.A non-isolated three-dimensional (3-D) parallel block with a linear pollution source in the center of the street was taken as the research object,which was close to the real.The numerical scheme was validated by a wind-tunnel experiment,and then the distribution characteristics of flow field and pollutant concentration in the inner and downstream areas of the 3-D block on a micro scale were analyzed and demonstrated.The results show that the blocking effect of building group results in vortex area with low wind speed in the downwind direction and leads to high loads of pollutants from the inner block.The area of maximum wind speed exists nearby the entrances of two main roads due to the narrow tunnel effect,corresponding to the lowest pollutant concentration.A clockwise-rotated vortex appears in the street canyon with a ratio of height to width of 1:1,and pollutants mostly accumulates in the bottom of leeward,which is consistent with previous studies.The diffusion of pollutants is closely related to turbulence intensity and wind speed.Low pollutant concentration usually appears at the windward with intense turbulence and strong wind speed,while high pollutant concentration exists at the leeward.This work can provide a scientific basis for the city planning and alleviate the air pollution in populated urban areas using natural wind. References | Related Articles | Metrics

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Spatiotemporal characteristics of geological hazard in Liaoning province CHEN Chuan-lei, GUAN Zhao-yong, CHENG Pan, XIAO Guang-liang, SUN Hong-yu, KOU Ying-jie 2017, 33 (5):  68-75.  doi: 10.3969/j.issn.1673-503X.2017.05.009 Abstract ( 178 )   PDF (2998KB) ( 301 )   Save Based on the historical data of geological disaster investigation from 2005 to 2015 in Liaoning province,the composition and spatiotemporal characteristics of different categories of geological disasters such as debris flow,landslide,rockfall,ground subsidence,and the different levels (extra large,large,medium,and small) of geological disasters in Liaoning province were analyzed.The categories,intensity,hazard-prone areas and high incidence periods of geological disaster in Liaoning province were finally summarized.The results show that the geological hazard in Liaoning province is characterized by great variety,wide distribution,high frequency and large intensity.The types of geological hazards are mainly involved landslide and debris flow,and the level of geological hazards is usually small.Although geological disasters occur every year from 2005 to 2015,their annual occurrence numbers vary greatly.The period of high incidence concentrates from May to August,with the largest occurrence frequency and worst influence in August.Geological disasters occur mostly at the ravines on either side of the ridge and plains or hills in Liaoning province and occur most frequently in Dandong.Landslides and debris flow mainly occur in countries while rockfall and ground subsidence usually occur in urban areas.This work would be beneficial to understand the characteristics of geological disasters in Liaoning province and provide a reference for the meteorological risk early-warning of geological hazards. References | Related Articles | Metrics

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Effects of water controls at different levels on soil respiration characteristics of maize farmland in Northeast China LÜ Guo-hong, WEN Ri-hong, XIE Yan-bing, WANG Xiao-ying 2017, 33 (5):  76-81.  doi: 10.3969/j.issn.1673-503X.2017.05.010 Abstract ( 214 )   PDF (762KB) ( 199 )   Save Based on soil water controlling experiment conducted in Jinzhou in 2013,the effects of soil moisture and soil temperature on soil respiration of maize farmland in northeast China were investigated under three levels of soil relative water contents (SRW) of 86%,96%,and 105%,respectively.The results indicated that the intensity of soil respiration is influenced by soil moisture condition.Specifically,soil respiration rate decreases with the increasing SRW.Meanwhile,the diurnal pattern and the seasonal dynamic are not impacted by SRW and both show a variation trend of the one-peak curve.The daily and annual maximums of soil respiration rates appear at 11:00-14:00 and in August,respectively.The sensibility of soil respiration to soil temperature in maize farmland is affected by the different levels of soil water controls,which is represented as the daily dynamic of soil temperature at the soil depth of 10 cm lagging behind that of soil respiration and a 5-6 hour lagging of the daily maximum soil temperature relative to the daily maximum soil respiration in August and September.In addition,the positive correlations between soil temperature at the soil depth of 10 cm,15 cm,30 cm,45 cm and soil respiration are respectively significant or extremely significant under different soil moisture conditions and soil respiration has the highest correlation with soil temperature at the soil depth of 45 cm.Besides,under the SRW of 86%,96%,and 105%,soil respiration shows an exponential relationship with soil temperature at the soil depth of 45 cm and soil temperature sensibility indices i.e.Q10 are 1.92,2.20 and 1.72 in the studied area in 2013,respectively. References | Related Articles | Metrics

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Change trends of meteorological factors during the maize growth period and their relationships with meteorological yield in Jinzhou during 1981-2010 XU Yu-xiu, JIANG Shan-shan, ZHOU Fu-ran, WEN Zhou, BAI Xue, SHI Hong-ting, HU Ming, ZHANG Cui-yan 2017, 33 (5):  82-90.  doi: 10.3969/j.issn.1673-503X.2017.05.011 Abstract ( 244 )   PDF (988KB) ( 418 )   Save Based on daily meteorological data including temperature,precipitation and sunshine duration and maize yield in Jinzhou from 1981 to 2010,using correlation analysis,running average and Mann-Kendall test methods,the change trends of meteorological factors and their relationships with maize meteorological yield were investigated.The results show that the daily maximum and minimum temperature,the active accumulated temperature ≥ 0℃ increase with a rate of 0.359℃/10 a,0.461℃/10 a,64.593 (℃·d)/10 a,while daily temperature difference and sunshine duration decrease with a rate of -0.102℃/10 a and -0.139 h/10 a and precipitation changes with a rate of 4.183 mm/10 a in Jinzhou during recent thirty years,respectively.Meanwhile,there is no obvious abrupt climate changes for temperature and precipitation,while the abrupt change points for sunshine duration appear in 1982,1985 and 1986.In addition,the daily maximum temperature and the active accumulated temperature ≥ 0℃ increase significantly after 2000 and 2001,respectively.Inversely,all of the other factors do not show significantly abrupt climate changes.Moreover,small bell and flare opening,as well as tasseling stage,are the key periods when maize meteorological yield is susceptible.The major meteorological factors affecting maize meteorological yield are the daily maximum temperature,active accumulated temperature ≥ 0℃ and sunshine duration and the next two are the daily minimum temperature and precipitation.The meteorological factors within a reasonable range promote the increase of the meteorological yields.On the contrary,they will be harmful to the growth and yield formation of maize when exceeding their corresponding threshold values. References | Related Articles | Metrics

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Comparative analysis of reflectivity factors measured with raindrop spectrometer and weather radar LI Yang, ZHANG Jin-guang, YUAN Jian, FANG Bin, CHEN Yu, SHAN Nan, ZHAI Qing-fei, ZHU Yi-ming, WAN Xu-jiang, CUI Yuan-hong 2017, 33 (5):  91-96.  doi: 10.3969/j.issn.1673-503X.2017.05.012 Abstract ( 273 )   PDF (1735KB) ( 379 )   Save A comparison observation between the Parsivel raindrop spectrometer and the new generation weather radar on a rainstorm occurring in Shenyang area in 2012 was conducted and the counted classifiable reflectivity factor ZP calculated with the raindrop spectrometer data was compared with the reflectivity factor Z calculated with the radar Range-Height Indicator data.The results show that for the rainstorm,the echo intensity of radar is underestimated and the reflectivity factor ZP is greater than Z.Based on the statistics of radar data at a single point and its 3-point average,the reflectivity factor Z is on average about 8.30 dBz and 8.64 dBz lower than the normal value respectively.The sampling range of observation instrument,temporal-spatial matching of data and the change of spectral width are the main reasons for causing the inconsistency between two kinds of reflectivity factors observed with the two devices. References | Related Articles | Metrics

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Influence of extreme temperatures change on Ulmus pumila phenophase in Inner Mongolia area YANG Li-ping, FENG Xu-yu, YAN Wei-xiong, GUO Xiao-li, QIN Yan, JIA Cheng-zhen 2017, 33 (5):  97-102.  doi: 10.3969/j.issn.1673-503X.2017.05.013 Abstract ( 233 )   PDF (604KB) ( 270 )   Save Based on Ulmus pumila phenophase and simultaneous extreme temperatures data in Wuchuan and Ongniud area of inner Mongolia during 1985-2012,the change characteristics of Ulmus pumila phenophase and its response to extreme temperatures were investigated using linear tendency estimation and Pearson correlation coefficient methods.The study will play an important role in guiding forest productive practice.The results show that the extreme maximum temperature fluctuates inconspicuously in the two studied areas during 1985-2012.On the contrary,the extreme minimum temperature indicates a dramatic and different variation in the two areas.The extreme minimum temperature in Wuchuan increases with a tendency rate of 0.617℃/10 a and that in Ongniud decreases significantly with a tendency rate of -0.678℃/10 a,respectively.In addition,the Ulmus pumila florescences in the two areas show a starting earlier trend,but the end dates of leaf fall lag behind and bring forward significantly as well as the growth periods prolong relatively with a rate of 14.14 d/10 a and 2.37 d/10 a in Wuchuan and Ongniud,respectively,throughout the recent 28 years.In conclusion,the extreme maximum temperature is the key meteorological factor impacting the Ulmus pumila florescence while the end date of leaf fall of Ulmus pumila is more sensitive to the extreme minimum temperature. References | Related Articles | Metrics

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Seasonal selections of atmospheric scale and scope evaluation in the natural draft cooling tower project YANG Hong-bin, ZHANG Yun-hai, ZOU Xu-dong, WANG Hong-yu, LIU Hai-long, LIU Yu-che 2017, 33 (5):  103-107.  doi: 10.3969/j.issn.1673-503X.2017.05.014 Abstract ( 266 )   PDF (386KB) ( 198 )   Save The Guidelines for Environmental Impact Assessment of atmospheric environment (version 2008) has recommended SCREEN3 estimation model for the atmospheric evaluation scales and scopes.The model can be used for the estimation of atmospheric evaluation scales and scopes of point sources,area sources,line sources and body sources,but can't be used for the projects of natural draft cooling towers (NDCT).AUSTAL2000 model and meteorological observation data in 2016 were used to simulate the pollutant concentrations on various leeward axials under 1296 groups of meteorological conditions.Then the seasonal maximum ratios of ground concentrations (Pi) for different pollutants and the longest distance (D10%) corresponding to the 10% of the standard limit of the ground concentrations were selected to evaluate the seasonal atmospheric scales and scopes.The results show that the atmospheric evaluation scales of NDCT project are most second scale.The atmospheric evaluation scopes vary with the estimation of seasonal meteorological data,with the largest one in summer,the second largest ones in spring and autumn,and smallest one in winter. References | Related Articles | Metrics

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Study on forecast method of Cherry yield in Laoshan District of Qingdao LIU Chun-tao, MU Chen-ying, LI De-ping, GUO Can, ZHU Jun-han 2017, 33 (5):  108-112.  doi: 10.3969/j.issn.1673-503X.2017.05.015 Abstract ( 234 )   PDF (362KB) ( 272 )   Save Based on the meteorological and cherry yield data in Laoshan area of Qingdao from 2000 to 2016,the key meteorological factors affecting cherry yield were investigated and the cherry yield forecasting model was estimated using the operational system on agrometeorological yield forecasting(WAPFOS 2015.1.0).More specifically,based on the separated trend and meteorological yields from the cherry yield data in Laoshan area from 2000 to 2014,the trend and meteorological yield forecast model for cherry was established by using grey smoothing simulation,polynomials and stepwise regression methods and the prediction test of the model was carried out with the data from 2015 to 2016.The results show that the accuracies of the cherry yield forecast model are,on average 96.98% during 2000-2014,95.94% in 2015,and 96.80% in 2016,respectively.According to the established model,the determined key meteorological factors affecting cherry yield are the average minimum temperature in early to mid-March,the precipitations in mid-to-late March and in early April and the average minimum temperature in the middle April.Besides,the research indicates that the average minimum temperature in early to mid-March is below -5.0℃,precipitation in mid-to-late March and early April is respectively larger than 15.0 mm and less than 5.0 mm in lean year,while the average minimum temperature in early to mid-March is above -3.0℃,precipitation in mid-to-late March and early April is respectively less than 5.0 mm and larger than 15.0 mm in abundant year. References | Related Articles | Metrics