The Northeast Plain in China ranks among the top five regions that have been significantly impacted by haze pollution.To effectively control pollution,it is crucial to accurately assess the effects of emission reducti...The Northeast Plain in China ranks among the top five regions that have been significantly impacted by haze pollution.To effectively control pollution,it is crucial to accurately assess the effects of emission reduction measures.In this study,we analyzed surveillance data and found substantial decreases(ranging from 19.0%to 50.1%)in average annual mass concentrations of key pollutants(such as CO,SO_(2),NO_(2),and PM_(2.5))in the Northeast Plain from 2016 to 2020.To precisely determine the contributions of meteorological conditions and emission reductions to the improvement of air quality in the Northeast Plain,we conducted three scenario simulations.By comparing source emissions in December 2016 and 2020 using the WRF-Chem model(except for SO_(2)),we observed significant reductions of 21.3%,8.8%,and 9.8%in mass concentrations of PM_(2.5),NO_(2),and CO,respectively,from 2016 to 2020.This highlights the essential role that meteorological conditions play in determining air quality in the Northeast Plain.Moreover,further reducing source emissions by 30%in December 2016 resulted in subsequent reductions of 25.3%,29.0%,4.5%,and 30.3%in mass concentrations of PM_(2.5),SO_(2),NO_(2),and CO,respectively,under the same meteorological conditions.Notably,source emission reduction was effective for PM_(2.5),SO_(2),and CO,but not for NO_(2).The improvement in air quality in the Northeast Plain from 2016 to 2020 can be attributed to the combined effects of improved meteorological conditions and reduced pollution sources.展开更多
We used observed concentrations of air pollutants,reanalyzed meteorological parameters,and results from the Goddard Earth Observing System Chemical Transport Model to examine the relationships between concentrations o...We used observed concentrations of air pollutants,reanalyzed meteorological parameters,and results from the Goddard Earth Observing System Chemical Transport Model to examine the relationships between concentrations of maximum daily 8-h average ozone(MDA8 O_(3)),PM_(2.5)(particulate matter with diameter of 2.5μm or less),and PM_(2.5)components and 2-m temperature(T2)or relative humidity(RH),as well as the effectiveness of precursor emission reductions on the control of O_(3) and PM_(2.5) in Beijing–Tianjin–Hebei(BTH)under different summertime temperature and humidity conditions.Both observed(simulated)MDA8 O_(3) and PM_(2.5) concentrations increased as T2 went up,with linear trends of 4.8(3.2)ppb℃^(−1) and 1.9(1.5)μg m^(−3)℃^(−1),respectively.Model results showed that the decreases in MDA8 O_(3) from precursor emission reductions were more sensitive to T2 than to RH.Reducing a larger proportion of volatile organic compound(VOC)emissions at higher T2 was more effective for the control of summertime O_(3) in BTH.For the control of summertime PM_(2.5) in BTH,reducing nitrogen oxides(NOx)combined with a small proportion of VOCs was the best measure.The magnitude of reduction in PM_(2.5) from reducing precursor emissions was more sensitive to RH than to T2,with the best efficiency at high RH.Results from this study are helpful for formulating effective policies to tackle O_(3) and PM_(2.5) pollution in BTH.展开更多
In order to take advantage of the climate resources more effectively ac- cording to the local circumstances and to plan and develop the citrus industry in Southern Shaanxi more reasonably. On the basis of the investig...In order to take advantage of the climate resources more effectively ac- cording to the local circumstances and to plan and develop the citrus industry in Southern Shaanxi more reasonably. On the basis of the investigation of freeze dam- age to citrus occurring in Southern Shaanxi in the winter of 2010, the climatic back- ground for the formation of this freeze damage was analyzed. In combination with the freeze damage indicators during the overwintering period and the harmful accu- mulated cold during the cold wave, indexes for grading the freeze damage in southern Shaanxi were analyzed and verified, and the perspective of grading the freeze damage using the harmful accumulated cold during the cold wave was also presented. Through analyzing the extremely lowest temperature and the harmful ac- cumulated cold in the winter of 2010 and in history at 12 citrus growing counties （districts） in Ankang area and Hanzhong area, the reasons why the freeze damage to citrus during the overwintering period was severer in the west than in the east of Southern Shaanxi were discussed, and the results obtained were basically consistent with the actual situation observed from investigation. Finally, defensive countermea- sures against the freeze damage to citrus during the overwintering period were put forward from several aspects.展开更多
By comparative analysis on the meteorological conditions and occurrences of rice planthoppers in Guilin of Guangxi during recent 5 years,the temperature,precipitation,wind direction,wind velocity,humidity were chosen ...By comparative analysis on the meteorological conditions and occurrences of rice planthoppers in Guilin of Guangxi during recent 5 years,the temperature,precipitation,wind direction,wind velocity,humidity were chosen as the factors that affected the migration of rice planthopper in Guilin.Thinking of meteorological conditions and injurious number in early period,regression analysis method was used to establish the work system for grade forecast of meteorological conditions that affected the migration of rice planthopper.The forecast factors and targets were divided as 5 grades in the work system.Using one-week's weather forecast conclusion that local observatory had published,whether the meteorological conditions and injurious number were favorable or not was analyzed synthetically.The meteorological conditions grades that affected the migration of rice planthopper for each day in future 1-7 days were predicted.This is a practical forecast work system and the forecast accuracy for each day is larger than 70%.The work system has positive function in the manufacture practice.展开更多
Based on the data of 18 cases during the past 30 years from 1978 to 2007,the major meteorological conditions for outbreak of blue-green alga in Hongze Lake were analyzed.The results showed that the main meteorological...Based on the data of 18 cases during the past 30 years from 1978 to 2007,the major meteorological conditions for outbreak of blue-green alga in Hongze Lake were analyzed.The results showed that the main meteorological conditions that affected the production and outbreak of blue-green alga were unusual high monthly average temperature,less precipitation and more sunshine hours in ten days.Through the selection of 1 or 0 factors on the values of above meteorological conditions over the years,if the conditions were accorded with the outbreak of blue-green alga,the factor was signed as 1,or it would be signed as 0;if there was outbreak of blue-green alga within ten days,it was signed as 1,or it would be signed as 0;crossing interrelated and integrated prediction method was adopted to establish the prediction equation for outbreak of blue-green alga,the historical fitting rate was 87.5%,and the predicting accuracy rate in 2008-2009 was 87.5%.In addition to meteorological conditions,outbreak of blue-green alga was also influenced by industrial pollutions,etc.,which should be considered in the forecasting procedures.展开更多
Guilin sugar orange has advantages of good taste, harvest during the Spring Festival, marketable market, and it has got swift and violent development in recent years. Sugar orange yield and quality is closely related ...Guilin sugar orange has advantages of good taste, harvest during the Spring Festival, marketable market, and it has got swift and violent development in recent years. Sugar orange yield and quality is closely related to meteorological conditions, so in order to study the effect of meteorological conditions on the Guilin sugar orange, the local conditions of each orange-planting county in Guilin is analyzed, and study is also carried out on the severe weather and its defense measures. The suitable growth temperature for sugar orange is 23-29 ℃, and sugar orange is not tolerant to waterlogging and drought, like light, and has no resistance to ice cold. The main meteorological disasters include high temperature, low temperature, flood, drought, wind, hail, etc. Reasonable selection of orchard, scientific management, especially the management of plant diseases and insect pests, is the key to ensure high-quality high sand sugar orange.展开更多
The recent year's monitor results of Beijing indicated that the pollution level of fine particles PM 2.5 showed an increasing trend. To understand pollution characteristics of PM 2.5 and its relationship...The recent year's monitor results of Beijing indicated that the pollution level of fine particles PM 2.5 showed an increasing trend. To understand pollution characteristics of PM 2.5 and its relationship with the meteorological conditions in Beijing, a one-year monitoring of PM 2.5 mass concentration and correspondent meteorological parameters was performed in Beijing in 2001. The PM 2.5 levels in Beijing were very high, the annual average PM 2.5 concentration in 2001 was 7 times of the National Ambient Air Quality Standards proposed by US EPA. The major chemical compositions were organics, sulfate, crustals and nitrate. It was found that the mass concentrations of PM 2.5 were influenced by meteorological conditions. The correlation between the mass concentrations of PM 2.5 and the relative humidity was found. And the correlation became closer at higher relative humidity. And the mass concentrations of PM 2.5 were negtive-correlated to wind speeds, but the correlation between the mass concentration of PM 2.5 and wind speed was not good at stronger wind.展开更多
To guarantee the blue skies for the 2022 Winter Olympics held in Beijing and Zhangjiakou from February 4 to 20,Beijing and its surrounding areas adopted a series of emission control measures.This provides an opportuni...To guarantee the blue skies for the 2022 Winter Olympics held in Beijing and Zhangjiakou from February 4 to 20,Beijing and its surrounding areas adopted a series of emission control measures.This provides an opportunity to determine the impacts of large-scale temporary control measures on the air quality in Beijing during this special period.Here,we applied the WRF-CMAQ model to quantify the contributions of emission reduction measures and meteorological conditions.Results show that meteorological conditions in 2022 decreased PM_(2.5)in Beijing by 6.9 and 11.8μg/m^(3)relative to 2021 under the scenarios with and without emission reductions,respectively.Strict emission reduction measures implemented in Beijing and seven neighboring provinces resulted in an average decrease of 13.0μg/m^(3)(-41.2%)in PM_(2.5)in Beijing.Over the entire period,local emission reductions contributed more to good air quality in Beijing than nonlocal emission reductions.Under the emission reduction scenario,local,controlled regions,other regions,and boundary conditions contributed 47.7%,42.0%,5.3%,and 5.0%to the PM_(2.5)concentrations in Beijing,respectively.The results indicate that during the cleaning period with the air masses from the northwest,the abatements of PM_(2.5)were mainly caused by local emission reductions.However,during the potential pollution period with the air masses from the east-northeast and west-southwest,the abatements of PM_(2.5)were caused by both local and nonlocal emission reductions almost equally.This implies that regional coordinated prevention and control strategies need to be arranged scientifically and rationally when heavy pollution events are forecasted.展开更多
The impacts of the meteorological condition and emissions reduction on the aerosol concentration over the Beijing-Tianjin-Hebei(BTH) region during the COVID-19 lockdown were analyzed by conducting three numerical expe...The impacts of the meteorological condition and emissions reduction on the aerosol concentration over the Beijing-Tianjin-Hebei(BTH) region during the COVID-19 lockdown were analyzed by conducting three numerical experiments,including one with the meteorological field in 2019 and MEIC-2019(2019 monthly Multi-resolution Emissions Inventory for China),one with the meteorological field in 2020 and MEIC-2019,and one with the meteorological field in 2020 and MEIC-2020,via a WRF-Chem model.The numerical experiments were performed from 3 to 16 February in 2019 and in 2020,during which a severe fog-haze event(3-16 February 2020) occurred in the BTH region,with a simulated maximum daily PM2.5 of 245μg m-3 in Tangshan and 175μg m-3 in Beijing.The results indicate that the daily PM2.5 decreased by 5-150μg m-3 due to the emissions reduction and increased by 10-175 μg m-3 due to the meteorological condition in Beijing,Shijiazhuang,Cangzhou,Handan,Hengshui,Chengde,Zhangjiakou,and Tangshan from 7 to 14 February.For the horizontal distribution,PM2.5 and different aerosol species concentrations from 7 to 14 February 2020 increased compared with those during the same period in 2019,indicating that the accumulation of pollutants caused by the unfavorable meteorological condition offset the decreases caused by the emissions reduction,leading to the high aerosol concentration during the COVID-19 lockdown.展开更多
Stringent quarantine measures during the Coronavirus Disease 2019(COVID-19)lockdown period(January 23,2020 to March 15,2020)have resulted in a distinct decrease in anthropogenic source emissions in North China Plain c...Stringent quarantine measures during the Coronavirus Disease 2019(COVID-19)lockdown period(January 23,2020 to March 15,2020)have resulted in a distinct decrease in anthropogenic source emissions in North China Plain compared to the paralleled period of 2019.Particularly,22.7%decrease in NO_(2)and 3.0%increase of O_(3)was observed in Tianjin,nonlinear relationship between O_(3)generation and NO_(2)implied that synergetic control of NOx and VOCs is needed.Deteriorating meteorological condition during the COVID-19 lockdown obscured the actual PM2.5 reduction.Fireworks transport in 2020 Spring Festival(SF)triggered regional haze pollution.PM2.5 during the COVID-19 lockdown only reduced by 5.6%in Tianjin.Here we used the dispersion coefficient to normalize the measured PM2.5(DN-PM2.5),aiming to eliminate the adverse meteorological impact and roughly estimate the actual PM2.5 reduction,which reduced by 17.7%during the COVID-19 lockdown.In terms of PM2.5 chemical composition,significant NO_(3)−increase was observed during the COVID-19 lockdown.However,as a tracer of atmospheric oxidation capacity,odd oxygen(Ox=NO_(2)+O_(3))was observed to reduce during the COVID-19 lockdown,whereas relative humidity(RH),specific humidity and aerosol liquid water content(ALWC)were observed with noticeable enhancement.Nitrogen oxidation rate(NOR)was observed to increase at higher specific humidity and ALWC,especially in the haze episode occurred during 2020SF,high air humidity and obvious nitrate generation was observed.Anomalously enhanced air humidity may response for the nitrate increase during the COVID-19 lockdown period.展开更多
This work analyzes and discusses the influence of human activities on the meteorological conditions related to winter haze events in Beijing,Tianjin,and Hebei(i.e.,the Jing-Jin-Ji region)during 1961-2016,using the res...This work analyzes and discusses the influence of human activities on the meteorological conditions related to winter haze events in Beijing,Tianjin,and Hebei(i.e.,the Jing-Jin-Ji region)during 1961-2016,using the results of two numerical simulation experiments based on the Community Atmosphere Model version 5.1.1(http://www.cesm.ucar.edu/models/cesm1.0/cam/docs/ug5_1_1/book1.html)used in the international Climate Variability and Predictability Programme(CLIVAR)Climate of the 20th Century Detection and Attribution Project(C20C+D&A).The results show that,under the influence of human activities,the changes in dynamical and thermal meteorological conditions related to winter haze events in the Jing–Jin–Ji region are conducive to the formation and accumulation of haze,and prevent the diffusion of pollutants.The dynamical conditions mainly include the obvious weakening of the East Asian winter monsoon(EAWM)and the enhancement of the near-surface anomalous southerly wind.The thermal conditions include the obvious increase in surface temperature,and the enhancement of water vapor transport and near-surface inversion.The relative contribution of dynamical and thermal conditions to the variation of haze days in the Jing-Jin-Ji region is analyzed using statistical methods.The results show that the contribution of human activities to the increase of haze days in the Jing-Jin-Ji region is greater than that of natural forcing for the study period.To be specific,the dynamical meteorological factors contribute more to the haze days than the thermal meteorological factors.The contribution of thermal meteorological factors is basically the same in both scenarios.展开更多
[Objective] The paper was to understand the suitable meteorological indexes and key meteorological factors for infection and prevalence of tobacco brown spot. [ Method] Tobacco brown spot disease in five topical mount...[Objective] The paper was to understand the suitable meteorological indexes and key meteorological factors for infection and prevalence of tobacco brown spot. [ Method] Tobacco brown spot disease in five topical mountainous climatic areas of Guizhou Province was investigated, and the difference of biological characteristics of different strains was analyzed indoor. Different meteorological conditions （light, temperature and humidity） were simulated in artificial climate box by using the uniform design method, and the difference of infection ability of Alternaria alternate in different climate zones was analyzed in leaves in vitro by hanging drop method. [ Result] The infection rate of A. alternate in different climate zones of Guizhou Province showed certain difference. In low temperature and mid- die humidity （the humidity is 50% -60%, the temperature is 10 -20 ℃） conditions, the pathogen could infect tobacco leaves, various strains had certain difference, but the difference was small. [ Conclusion] The paper provided theoretical basis for prevalence prediction and control of tobacco brown spot.展开更多
[Objective] The study aimed to discuss the relationship of cardiovascular and cerebrovascular diseases to meteorological conditions and forecast method in Nanjing City. [Method] Based on daily cases of cardiovascular ...[Objective] The study aimed to discuss the relationship of cardiovascular and cerebrovascular diseases to meteorological conditions and forecast method in Nanjing City. [Method] Based on daily cases of cardiovascular and cerebrovascular diseases from a hospital in Nanjing City as well as daily meteorological data from Nanjing Meteorological Station from January 2003 to July 2008, the monthly and seasonal variations in quantity of patients suffedng from cardiovascular and cerebrovascular diseases in Nanjing City were analyzed firstly, and then the relationship between mete- orological elements and incidence of the diseases was discussed, finally the forecast model for the incidence of the diseases was established using the stepwise regression method. [Result] Cardiovascular and cerebrovascular diseases in Nanjing City happened all the year round, and the inci- dance was high in the seasonal transition phase from autumn to winter. Daily incidence of the diseases in Nanjing City correlated negatively with dai- ly maximum, minimum and average vapor pressure, daily minimum relative humidity and so forth, but their incidence had positive correlations with diumal range of daily temperature, daily maximum, minimum and average pressure. Daily average number of patients suffering from the diseases obviously correlated with daily average temperature, daily maximum vapor pressure and daily average relative humidity. [ Conclusion] The research could provide scientific references for the prevention and forecast of cardiovascular and cerebrovascular diseases in future.展开更多
Based on the real-time wind direction and speed data from an automatic meteorological monitoring network in Shenzhen, the wind characteristics of Jue Diao Sha maritime area are analyzed. As indicated in the results, t...Based on the real-time wind direction and speed data from an automatic meteorological monitoring network in Shenzhen, the wind characteristics of Jue Diao Sha maritime area are analyzed. As indicated in the results, the wind speed of this area is higher than that over the land, the average wind speed is above 3 m/s and the probability for the maximum wind speed to drop below 20 m/s is above 90%. Moreover, the probability for the hourly swing angle of wind direction to become less than 50o is above 80%, suggesting that the wind conditions in the Jue Diao Sha area could meet the requirements of the sporting events. According to the numerical simulation, this area is the best selected site among three candidates. Furthermore, the characteristics of daily land and sea breezes are such that it is suggested the game will be best carried out from 1000 to 1700 Beijing Standard Time.展开更多
1 INTRODUCTION Meteorological factors, especially precipitation, have close links with geological calamities. According to the statistics, more than 70% of the geological calamities in China occur in rainy seasons. Ma...1 INTRODUCTION Meteorological factors, especially precipitation, have close links with geological calamities. According to the statistics, more than 70% of the geological calamities in China occur in rainy seasons. Many researchers are thus motivated to study extensively to determine their relationship in the prediction of geological calamltles . They either rely on single measurements of rainfall to seek basis for widespread occurrence of geological calamities or treat antecedent diurnal rainfall with equal importance, though with account of the accumulated effect of preceding rainfall. Furthermore, it is common for quite a number of models to use the rainfall recorded at hydrological or meteorological rain gauges as the one for the interested day, reducing the time validity of the prediction. In our analysis, it is found that the landslides and debris flows in Zhejiang province are related with the antecedent precipitation （but not by a simple accumulation）. Critical amounts of accumulated and effective rainfall are used in this work to tell whether there will be geological calamities. Moreover, MM5 is used to forecast rainfall, taking account in equations of the predictand for landslides and debris flows, in attempts to predict the appearance of meteorological condition for geological calamities and improve the rationality of forecasting procedures and time validity of forecasts.展开更多
Objective To investigate the impact of meteorological conditions and PM2.5 on the onset of acute aortic dissection in monsoonal climate. Methods A linear regression analysis was performed in monsoonal climate epidemio...Objective To investigate the impact of meteorological conditions and PM2.5 on the onset of acute aortic dissection in monsoonal climate. Methods A linear regression analysis was performed in monsoonal climate epidemiological survey for a period of four years on the impact of meteorological factors （minimal temperature, mean temperature, maximal temperature, average daily surface temperature, day temperature range, relative humidity, mean wind speed, and atmospheric pressure） and PM2.5 concentration on the daily incidences of acute aortic dissections. Meteorological variables and PM2.5 concentration were retrieved on a daily basis from Beijing Regional Climate Center and the Ministry of Environmental Protection of the People’s Republic of China’s website, and the daily incidences of acute aortic dissections were retrieved from the Clinical Data Analysis and Reporting System in the Emergency and Critical Care Center of Beijing Anzhen Hospital. Results During the study period （from January 2011 to December 2014）, 1164 patients were identified as having acute aortic dissections. The corresponding incidences in spring and autumn were 0.96 and 1.00, respectively, which significantly higher than that in summer and winter. The incidences of acute aortic dissection in a day could be predicted by diurnal temperature range （DTR） using the following linear multiple regression models： incidences of acute aortic dissection = 0.543 ＋ 0.025 × DTR. Conclusion This is the first study to show an attributable effect of DTR on acute aortic events in monsoonal climate. Our study confirms that meteorological variables were important factors influencing the incidence of acute aortic dissection.展开更多
Through observing the phenology of two kinds of fruit trees,apple and peach trees,during their flowering periods in the past seven years,the meteorological conditions in the flowering stages were analyzed and summariz...Through observing the phenology of two kinds of fruit trees,apple and peach trees,during their flowering periods in the past seven years,the meteorological conditions in the flowering stages were analyzed and summarized in this paper.The late frost weather situation occurred in late April in Haiyang City also was elaborated in the paper.According to the data analysis,the terrain effect had induced a large temperature differences between north and south in April in Haiyang.Early flowering of fruit trees is as early as 5 to 8 days in the northern region than that in the southern region;accumulated temperature which was greater than or equal to 0 ℃ and the date of the temperature stably through a boundary,were the important meteorological indicators of the fruit trees' early flowering.The late frost in mid-late April is meteorological disasters of the fruit trees flowering period.The weather background of the occurred late frost,the disaster reasons and the measures for the prevention of late frost were proposed.展开更多
[Objective] The research aimed to study statistical forecast method for O3 concentration near the ground in Pudong District of Shanghai based on meteorological condition analysis. [Method] Via observation and statisti...[Objective] The research aimed to study statistical forecast method for O3 concentration near the ground in Pudong District of Shanghai based on meteorological condition analysis. [Method] Via observation and statistical analysis of the O3 concentration near the ground in Pudong District of Shanghai from 2006 to 2008, by considering meteorological condition, a kind of simple and practical new method suiting for forecast of the O3 concentration and pre-warning of the high-concentration O3 pollution event in whole year was established. [Result] Meteorological condition had obvious influence on O3 concentration near the ground. O3 concentration was the biggest in sunny day, followed by cloudy day. O3 concentration near the ground had typical seasonal change characteristics, and high value mainly happened in summer. Meteorological condition generating high-concentration O3 included sunny day, strong UV radiation, low relative humidity, high temperature and small wind speed, etc. By surveying historical weather chart, 10 kinds of main weather situations affecting Shanghai were summed. Under each weather situation, occurrence probability of the high-concentration O3 near the ground and average O3 concentration were conducted statistics. We found that occurrence probability of the high-concentration O3 was the biggest under northwest side of the subtropical high type, followed by internal type of the subtropical high. By introducing HPPI and WDI and comprehensively considering various meteorological factors, forecasting equation of the O3 concentration was established based on stepwise regression. The equation had good fitting effect and predictability on the daily maximum O3 concentration. [Conclusion] The method also could provide reference for O3 forecast in other areas.展开更多
[ Objective] The study aimed to analyze the spatial distribution of agricultural meteorological conditions in Sanjiang Plain during nearly 50 years. [ Method] Accumulated temperature of Sanjiang Plain was computed bas...[ Objective] The study aimed to analyze the spatial distribution of agricultural meteorological conditions in Sanjiang Plain during nearly 50 years. [ Method] Accumulated temperature of Sanjiang Plain was computed based on meteorological observation data from different meteorological stations in Sanjiang Plain, including temperature, precipitation, sunshine time, etc. A spatial interpolation map involving varieties of meteorological elements in neady 50 years was generated based on the Kriging interpolation, and the spatial distribution characteristics of those meteorological ele- ments were analyzed. [ Result] Temperature of Sanjiang Plain decreased with the increase of latitude and altitude, and the annual average temper- atura varied from 2.5 to 4.5 ~（3 generally, showing a zonal distribution. Precipitation of Sanjiang Plain changed spatially and the annual average pre- cipitation varied from 500 to 600 mm symmetrically in northwest-southeast direction. Spatial distribution of the annual average wind speed in San- jiang Plain was identical with the spatial pattern of topography here, and the annual average wind speed changed from 3.0 to 3.6 rn/s in most re- gions. Relative air humidity of Sanjiang Plain in summer half year was relatively high and always above 65%. The maximum sunshine hours of San- jiang Plain in one year distributed similarly to the annual changing curve of solar declination, and both of them presented a normal distribution and changed with geographic latitude. The days from the beginning to the end of daily average temperature ~〉 10 ~C in Sanjiang Plain were 135 -146 d, and its distribution presented a latitudinal trend, with certain vertical zonality. [ Conclusion] The research could provide scientific references for the reasonable arrangement of agricultural production and effective prevention of meteorological disasters in Sanjiang Plain.展开更多
To reveal the multivariate relationships between man-made and meteorological factors on dust storm frequency, the LUCC data, NDVI remote sensing data and meteorological data for the period of 1983-2013 were combined w...To reveal the multivariate relationships between man-made and meteorological factors on dust storm frequency, the LUCC data, NDVI remote sensing data and meteorological data for the period of 1983-2013 were combined with dust storm frequency data, and the possible impacts of meteorological and anthropogenic factors on dust storm frequency were analyzed by using regression analysis and PCA (Principal Component Analysis). Results show that the inter-annual dust storm frequency increased gradually. In particular, an increasing trend in recent years, after 2009, is conspicuous. The monthly frequency of dust storms shows higher values between the months of February and May, with the highest mean number of events occurring in April, which accounts for 29% of the annual dust storm frequency. The annual dust storm frequency is positively correlated with wind speed and negatively correlated with precipitation;the monthly dust storm frequency is positively correlated with wind speed, but no significant correlation can be found with precipitation. The relationship between temperature and dust storms is not simply linear, however, a certain correlation with an unremarkable statistical significance can be found between them. Human activities also affect the dynamics of dust storms indirectly via changing vegetation coverage and direct dust emissions. The multivariate analysis further confirmed the association between dust storm frequency and meteorological factors and NDVI. The high loadings of dust storm frequency, wind speed, precipitation and NDVI on a PC indicate that the increased precipitation and NDVI will decrease dust storm frequency, and increased wind speed will increase dust storm frequency.展开更多
基金supported by the National Key R&D Program of China(No.2022YFF0802501)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.2022416)+1 种基金the Natural Science Basic Research Program of Shaanxi(No.2022JQ-267)the State Key Laboratory of Loess and Quaternary Geology(No.SKLLQG2335).
文摘The Northeast Plain in China ranks among the top five regions that have been significantly impacted by haze pollution.To effectively control pollution,it is crucial to accurately assess the effects of emission reduction measures.In this study,we analyzed surveillance data and found substantial decreases(ranging from 19.0%to 50.1%)in average annual mass concentrations of key pollutants(such as CO,SO_(2),NO_(2),and PM_(2.5))in the Northeast Plain from 2016 to 2020.To precisely determine the contributions of meteorological conditions and emission reductions to the improvement of air quality in the Northeast Plain,we conducted three scenario simulations.By comparing source emissions in December 2016 and 2020 using the WRF-Chem model(except for SO_(2)),we observed significant reductions of 21.3%,8.8%,and 9.8%in mass concentrations of PM_(2.5),NO_(2),and CO,respectively,from 2016 to 2020.This highlights the essential role that meteorological conditions play in determining air quality in the Northeast Plain.Moreover,further reducing source emissions by 30%in December 2016 resulted in subsequent reductions of 25.3%,29.0%,4.5%,and 30.3%in mass concentrations of PM_(2.5),SO_(2),NO_(2),and CO,respectively,under the same meteorological conditions.Notably,source emission reduction was effective for PM_(2.5),SO_(2),and CO,but not for NO_(2).The improvement in air quality in the Northeast Plain from 2016 to 2020 can be attributed to the combined effects of improved meteorological conditions and reduced pollution sources.
基金supported by the National Natural Science Foundation of China(Grant No.91744311).
文摘We used observed concentrations of air pollutants,reanalyzed meteorological parameters,and results from the Goddard Earth Observing System Chemical Transport Model to examine the relationships between concentrations of maximum daily 8-h average ozone(MDA8 O_(3)),PM_(2.5)(particulate matter with diameter of 2.5μm or less),and PM_(2.5)components and 2-m temperature(T2)or relative humidity(RH),as well as the effectiveness of precursor emission reductions on the control of O_(3) and PM_(2.5) in Beijing–Tianjin–Hebei(BTH)under different summertime temperature and humidity conditions.Both observed(simulated)MDA8 O_(3) and PM_(2.5) concentrations increased as T2 went up,with linear trends of 4.8(3.2)ppb℃^(−1) and 1.9(1.5)μg m^(−3)℃^(−1),respectively.Model results showed that the decreases in MDA8 O_(3) from precursor emission reductions were more sensitive to T2 than to RH.Reducing a larger proportion of volatile organic compound(VOC)emissions at higher T2 was more effective for the control of summertime O_(3) in BTH.For the control of summertime PM_(2.5) in BTH,reducing nitrogen oxides(NOx)combined with a small proportion of VOCs was the best measure.The magnitude of reduction in PM_(2.5) from reducing precursor emissions was more sensitive to RH than to T2,with the best efficiency at high RH.Results from this study are helpful for formulating effective policies to tackle O_(3) and PM_(2.5) pollution in BTH.
基金Supported by Shaanxi"13115"Public Service Platform Construction Program for Science&Technology Innovation Projects(2010FWPT-17)~~
文摘In order to take advantage of the climate resources more effectively ac- cording to the local circumstances and to plan and develop the citrus industry in Southern Shaanxi more reasonably. On the basis of the investigation of freeze dam- age to citrus occurring in Southern Shaanxi in the winter of 2010, the climatic back- ground for the formation of this freeze damage was analyzed. In combination with the freeze damage indicators during the overwintering period and the harmful accu- mulated cold during the cold wave, indexes for grading the freeze damage in southern Shaanxi were analyzed and verified, and the perspective of grading the freeze damage using the harmful accumulated cold during the cold wave was also presented. Through analyzing the extremely lowest temperature and the harmful ac- cumulated cold in the winter of 2010 and in history at 12 citrus growing counties （districts） in Ankang area and Hanzhong area, the reasons why the freeze damage to citrus during the overwintering period was severer in the west than in the east of Southern Shaanxi were discussed, and the results obtained were basically consistent with the actual situation observed from investigation. Finally, defensive countermea- sures against the freeze damage to citrus during the overwintering period were put forward from several aspects.
基金Supported by The Project of Guilin Science and Technology in Guangxi (2009011405)
文摘By comparative analysis on the meteorological conditions and occurrences of rice planthoppers in Guilin of Guangxi during recent 5 years,the temperature,precipitation,wind direction,wind velocity,humidity were chosen as the factors that affected the migration of rice planthopper in Guilin.Thinking of meteorological conditions and injurious number in early period,regression analysis method was used to establish the work system for grade forecast of meteorological conditions that affected the migration of rice planthopper.The forecast factors and targets were divided as 5 grades in the work system.Using one-week's weather forecast conclusion that local observatory had published,whether the meteorological conditions and injurious number were favorable or not was analyzed synthetically.The meteorological conditions grades that affected the migration of rice planthopper for each day in future 1-7 days were predicted.This is a practical forecast work system and the forecast accuracy for each day is larger than 70%.The work system has positive function in the manufacture practice.
文摘Based on the data of 18 cases during the past 30 years from 1978 to 2007,the major meteorological conditions for outbreak of blue-green alga in Hongze Lake were analyzed.The results showed that the main meteorological conditions that affected the production and outbreak of blue-green alga were unusual high monthly average temperature,less precipitation and more sunshine hours in ten days.Through the selection of 1 or 0 factors on the values of above meteorological conditions over the years,if the conditions were accorded with the outbreak of blue-green alga,the factor was signed as 1,or it would be signed as 0;if there was outbreak of blue-green alga within ten days,it was signed as 1,or it would be signed as 0;crossing interrelated and integrated prediction method was adopted to establish the prediction equation for outbreak of blue-green alga,the historical fitting rate was 87.5%,and the predicting accuracy rate in 2008-2009 was 87.5%.In addition to meteorological conditions,outbreak of blue-green alga was also influenced by industrial pollutions,etc.,which should be considered in the forecasting procedures.
文摘Guilin sugar orange has advantages of good taste, harvest during the Spring Festival, marketable market, and it has got swift and violent development in recent years. Sugar orange yield and quality is closely related to meteorological conditions, so in order to study the effect of meteorological conditions on the Guilin sugar orange, the local conditions of each orange-planting county in Guilin is analyzed, and study is also carried out on the severe weather and its defense measures. The suitable growth temperature for sugar orange is 23-29 ℃, and sugar orange is not tolerant to waterlogging and drought, like light, and has no resistance to ice cold. The main meteorological disasters include high temperature, low temperature, flood, drought, wind, hail, etc. Reasonable selection of orchard, scientific management, especially the management of plant diseases and insect pests, is the key to ensure high-quality high sand sugar orange.
文摘The recent year's monitor results of Beijing indicated that the pollution level of fine particles PM 2.5 showed an increasing trend. To understand pollution characteristics of PM 2.5 and its relationship with the meteorological conditions in Beijing, a one-year monitoring of PM 2.5 mass concentration and correspondent meteorological parameters was performed in Beijing in 2001. The PM 2.5 levels in Beijing were very high, the annual average PM 2.5 concentration in 2001 was 7 times of the National Ambient Air Quality Standards proposed by US EPA. The major chemical compositions were organics, sulfate, crustals and nitrate. It was found that the mass concentrations of PM 2.5 were influenced by meteorological conditions. The correlation between the mass concentrations of PM 2.5 and the relative humidity was found. And the correlation became closer at higher relative humidity. And the mass concentrations of PM 2.5 were negtive-correlated to wind speeds, but the correlation between the mass concentration of PM 2.5 and wind speed was not good at stronger wind.
基金supported by the National Natural Science Foundation of China (Nos.42175084,21577126,and 41561144004)the Department of Science and Technology of China (Nos.2018YFC0213506,2018YFC0213503,and 2016YFC0202702)+4 种基金the National Research Program for Key Issues in Air Pollution Control in China (No.DQGG0107)supported by the“Zhejiang 1000 Talent Plan”and Research Center for Air Pollution and Health in Zhejiang UniversityPengfei Li is supported by the National Natural Science Foundation of China (No.22006030)the Initiation Fund for Introducing Talents of Hebei Agricultural University (No.412201904)the Hebei Youth Top Q15 Fund (No.BJ2020032)。
文摘To guarantee the blue skies for the 2022 Winter Olympics held in Beijing and Zhangjiakou from February 4 to 20,Beijing and its surrounding areas adopted a series of emission control measures.This provides an opportunity to determine the impacts of large-scale temporary control measures on the air quality in Beijing during this special period.Here,we applied the WRF-CMAQ model to quantify the contributions of emission reduction measures and meteorological conditions.Results show that meteorological conditions in 2022 decreased PM_(2.5)in Beijing by 6.9 and 11.8μg/m^(3)relative to 2021 under the scenarios with and without emission reductions,respectively.Strict emission reduction measures implemented in Beijing and seven neighboring provinces resulted in an average decrease of 13.0μg/m^(3)(-41.2%)in PM_(2.5)in Beijing.Over the entire period,local emission reductions contributed more to good air quality in Beijing than nonlocal emission reductions.Under the emission reduction scenario,local,controlled regions,other regions,and boundary conditions contributed 47.7%,42.0%,5.3%,and 5.0%to the PM_(2.5)concentrations in Beijing,respectively.The results indicate that during the cleaning period with the air masses from the northwest,the abatements of PM_(2.5)were mainly caused by local emission reductions.However,during the potential pollution period with the air masses from the east-northeast and west-southwest,the abatements of PM_(2.5)were caused by both local and nonlocal emission reductions almost equally.This implies that regional coordinated prevention and control strategies need to be arranged scientifically and rationally when heavy pollution events are forecasted.
基金This study was supported by the National Key R&D Program of China[grant number 2017YFB0503901)the National Natural Science Foundation of China[grant numbers 41830109 and 41830966]the Major Scientific and Technological Innovation Projects of Shandong Province[grant number 2018YFJH0901].
文摘The impacts of the meteorological condition and emissions reduction on the aerosol concentration over the Beijing-Tianjin-Hebei(BTH) region during the COVID-19 lockdown were analyzed by conducting three numerical experiments,including one with the meteorological field in 2019 and MEIC-2019(2019 monthly Multi-resolution Emissions Inventory for China),one with the meteorological field in 2020 and MEIC-2019,and one with the meteorological field in 2020 and MEIC-2020,via a WRF-Chem model.The numerical experiments were performed from 3 to 16 February in 2019 and in 2020,during which a severe fog-haze event(3-16 February 2020) occurred in the BTH region,with a simulated maximum daily PM2.5 of 245μg m-3 in Tangshan and 175μg m-3 in Beijing.The results indicate that the daily PM2.5 decreased by 5-150μg m-3 due to the emissions reduction and increased by 10-175 μg m-3 due to the meteorological condition in Beijing,Shijiazhuang,Cangzhou,Handan,Hengshui,Chengde,Zhangjiakou,and Tangshan from 7 to 14 February.For the horizontal distribution,PM2.5 and different aerosol species concentrations from 7 to 14 February 2020 increased compared with those during the same period in 2019,indicating that the accumulation of pollutants caused by the unfavorable meteorological condition offset the decreases caused by the emissions reduction,leading to the high aerosol concentration during the COVID-19 lockdown.
基金supported by the Tianjin Natural Science Foundation(No.18JCYBJC23100)the Tianjin Science and Technology Foundation(No.18ZXSZSF00160)+1 种基金the National Natural Science Foundation of China(No.41771242)the China Postdoctoral Science Foundation(No.2019M660984).
文摘Stringent quarantine measures during the Coronavirus Disease 2019(COVID-19)lockdown period(January 23,2020 to March 15,2020)have resulted in a distinct decrease in anthropogenic source emissions in North China Plain compared to the paralleled period of 2019.Particularly,22.7%decrease in NO_(2)and 3.0%increase of O_(3)was observed in Tianjin,nonlinear relationship between O_(3)generation and NO_(2)implied that synergetic control of NOx and VOCs is needed.Deteriorating meteorological condition during the COVID-19 lockdown obscured the actual PM2.5 reduction.Fireworks transport in 2020 Spring Festival(SF)triggered regional haze pollution.PM2.5 during the COVID-19 lockdown only reduced by 5.6%in Tianjin.Here we used the dispersion coefficient to normalize the measured PM2.5(DN-PM2.5),aiming to eliminate the adverse meteorological impact and roughly estimate the actual PM2.5 reduction,which reduced by 17.7%during the COVID-19 lockdown.In terms of PM2.5 chemical composition,significant NO_(3)−increase was observed during the COVID-19 lockdown.However,as a tracer of atmospheric oxidation capacity,odd oxygen(Ox=NO_(2)+O_(3))was observed to reduce during the COVID-19 lockdown,whereas relative humidity(RH),specific humidity and aerosol liquid water content(ALWC)were observed with noticeable enhancement.Nitrogen oxidation rate(NOR)was observed to increase at higher specific humidity and ALWC,especially in the haze episode occurred during 2020SF,high air humidity and obvious nitrate generation was observed.Anomalously enhanced air humidity may response for the nitrate increase during the COVID-19 lockdown period.
基金This study was jointly supported by the National Key Research and Development Program of China(2017YF0603703 and 2017YF0605004)the Atmospheric Pollution Control of the Prime Minister Fund of China(DQGG0104).
文摘This work analyzes and discusses the influence of human activities on the meteorological conditions related to winter haze events in Beijing,Tianjin,and Hebei(i.e.,the Jing-Jin-Ji region)during 1961-2016,using the results of two numerical simulation experiments based on the Community Atmosphere Model version 5.1.1(http://www.cesm.ucar.edu/models/cesm1.0/cam/docs/ug5_1_1/book1.html)used in the international Climate Variability and Predictability Programme(CLIVAR)Climate of the 20th Century Detection and Attribution Project(C20C+D&A).The results show that,under the influence of human activities,the changes in dynamical and thermal meteorological conditions related to winter haze events in the Jing–Jin–Ji region are conducive to the formation and accumulation of haze,and prevent the diffusion of pollutants.The dynamical conditions mainly include the obvious weakening of the East Asian winter monsoon(EAWM)and the enhancement of the near-surface anomalous southerly wind.The thermal conditions include the obvious increase in surface temperature,and the enhancement of water vapor transport and near-surface inversion.The relative contribution of dynamical and thermal conditions to the variation of haze days in the Jing-Jin-Ji region is analyzed using statistical methods.The results show that the contribution of human activities to the increase of haze days in the Jing-Jin-Ji region is greater than that of natural forcing for the study period.To be specific,the dynamical meteorological factors contribute more to the haze days than the thermal meteorological factors.The contribution of thermal meteorological factors is basically the same in both scenarios.
基金Supported by Major Special Project of Guizhou Branch([2011] No.6003)National Natural Science Foundation of China (41040039)
文摘[Objective] The paper was to understand the suitable meteorological indexes and key meteorological factors for infection and prevalence of tobacco brown spot. [ Method] Tobacco brown spot disease in five topical mountainous climatic areas of Guizhou Province was investigated, and the difference of biological characteristics of different strains was analyzed indoor. Different meteorological conditions （light, temperature and humidity） were simulated in artificial climate box by using the uniform design method, and the difference of infection ability of Alternaria alternate in different climate zones was analyzed in leaves in vitro by hanging drop method. [ Result] The infection rate of A. alternate in different climate zones of Guizhou Province showed certain difference. In low temperature and mid- die humidity （the humidity is 50% -60%, the temperature is 10 -20 ℃） conditions, the pathogen could infect tobacco leaves, various strains had certain difference, but the difference was small. [ Conclusion] The paper provided theoretical basis for prevalence prediction and control of tobacco brown spot.
基金Supported by the"Meteorology and Health"Subject of Shanghai Science and Technology Committee(QXJK201214)
文摘[Objective] The study aimed to discuss the relationship of cardiovascular and cerebrovascular diseases to meteorological conditions and forecast method in Nanjing City. [Method] Based on daily cases of cardiovascular and cerebrovascular diseases from a hospital in Nanjing City as well as daily meteorological data from Nanjing Meteorological Station from January 2003 to July 2008, the monthly and seasonal variations in quantity of patients suffedng from cardiovascular and cerebrovascular diseases in Nanjing City were analyzed firstly, and then the relationship between mete- orological elements and incidence of the diseases was discussed, finally the forecast model for the incidence of the diseases was established using the stepwise regression method. [Result] Cardiovascular and cerebrovascular diseases in Nanjing City happened all the year round, and the inci- dance was high in the seasonal transition phase from autumn to winter. Daily incidence of the diseases in Nanjing City correlated negatively with dai- ly maximum, minimum and average vapor pressure, daily minimum relative humidity and so forth, but their incidence had positive correlations with diumal range of daily temperature, daily maximum, minimum and average pressure. Daily average number of patients suffering from the diseases obviously correlated with daily average temperature, daily maximum vapor pressure and daily average relative humidity. [ Conclusion] The research could provide scientific references for the prevention and forecast of cardiovascular and cerebrovascular diseases in future.
基金Project on Meteorological Conditions for Selection of Site of Maritime Sporting Base for 26th Summer Universiade 2011
文摘Based on the real-time wind direction and speed data from an automatic meteorological monitoring network in Shenzhen, the wind characteristics of Jue Diao Sha maritime area are analyzed. As indicated in the results, the wind speed of this area is higher than that over the land, the average wind speed is above 3 m/s and the probability for the maximum wind speed to drop below 20 m/s is above 90%. Moreover, the probability for the hourly swing angle of wind direction to become less than 50o is above 80%, suggesting that the wind conditions in the Jue Diao Sha area could meet the requirements of the sporting events. According to the numerical simulation, this area is the best selected site among three candidates. Furthermore, the characteristics of daily land and sea breezes are such that it is suggested the game will be best carried out from 1000 to 1700 Beijing Standard Time.
基金"The pre-warning and prediction system for unexpected geological calamities in Zhejiangprovince and demonstration of its application - A "provincial key project from the science and technologybureau of Zhejianga key project "the study on forecasting system for heavy rains in Zhejiang province"
文摘1 INTRODUCTION Meteorological factors, especially precipitation, have close links with geological calamities. According to the statistics, more than 70% of the geological calamities in China occur in rainy seasons. Many researchers are thus motivated to study extensively to determine their relationship in the prediction of geological calamltles . They either rely on single measurements of rainfall to seek basis for widespread occurrence of geological calamities or treat antecedent diurnal rainfall with equal importance, though with account of the accumulated effect of preceding rainfall. Furthermore, it is common for quite a number of models to use the rainfall recorded at hydrological or meteorological rain gauges as the one for the interested day, reducing the time validity of the prediction. In our analysis, it is found that the landslides and debris flows in Zhejiang province are related with the antecedent precipitation （but not by a simple accumulation）. Critical amounts of accumulated and effective rainfall are used in this work to tell whether there will be geological calamities. Moreover, MM5 is used to forecast rainfall, taking account in equations of the predictand for landslides and debris flows, in attempts to predict the appearance of meteorological condition for geological calamities and improve the rationality of forecasting procedures and time validity of forecasts.
基金This study was supported by National Science Foundation Council of China （No.81700383）, Jilin Provincial Industrial Innovation Special Fund Project （No.2016C041）, Beijing Natural Science Foundation of China （8152019）, Beijing Municipal Science and Technology of Chinese Medicine Development Funds Youth Research Project （No. QN2016-20）, and Basic-Clinical Scientific Research Cooperation of Capital Medical University fund （No.17JL72）. The authors declare no conflict of interest.
文摘Objective To investigate the impact of meteorological conditions and PM2.5 on the onset of acute aortic dissection in monsoonal climate. Methods A linear regression analysis was performed in monsoonal climate epidemiological survey for a period of four years on the impact of meteorological factors （minimal temperature, mean temperature, maximal temperature, average daily surface temperature, day temperature range, relative humidity, mean wind speed, and atmospheric pressure） and PM2.5 concentration on the daily incidences of acute aortic dissections. Meteorological variables and PM2.5 concentration were retrieved on a daily basis from Beijing Regional Climate Center and the Ministry of Environmental Protection of the People’s Republic of China’s website, and the daily incidences of acute aortic dissections were retrieved from the Clinical Data Analysis and Reporting System in the Emergency and Critical Care Center of Beijing Anzhen Hospital. Results During the study period （from January 2011 to December 2014）, 1164 patients were identified as having acute aortic dissections. The corresponding incidences in spring and autumn were 0.96 and 1.00, respectively, which significantly higher than that in summer and winter. The incidences of acute aortic dissection in a day could be predicted by diurnal temperature range （DTR） using the following linear multiple regression models： incidences of acute aortic dissection = 0.543 ＋ 0.025 × DTR. Conclusion This is the first study to show an attributable effect of DTR on acute aortic events in monsoonal climate. Our study confirms that meteorological variables were important factors influencing the incidence of acute aortic dissection.
文摘Through observing the phenology of two kinds of fruit trees,apple and peach trees,during their flowering periods in the past seven years,the meteorological conditions in the flowering stages were analyzed and summarized in this paper.The late frost weather situation occurred in late April in Haiyang City also was elaborated in the paper.According to the data analysis,the terrain effect had induced a large temperature differences between north and south in April in Haiyang.Early flowering of fruit trees is as early as 5 to 8 days in the northern region than that in the southern region;accumulated temperature which was greater than or equal to 0 ℃ and the date of the temperature stably through a boundary,were the important meteorological indicators of the fruit trees' early flowering.The late frost in mid-late April is meteorological disasters of the fruit trees flowering period.The weather background of the occurred late frost,the disaster reasons and the measures for the prevention of late frost were proposed.
基金Supported by Special Item of the Science Research for Public Service Industry (Meteorology) ,China (GYHY201206027,GYHY200906026)
文摘[Objective] The research aimed to study statistical forecast method for O3 concentration near the ground in Pudong District of Shanghai based on meteorological condition analysis. [Method] Via observation and statistical analysis of the O3 concentration near the ground in Pudong District of Shanghai from 2006 to 2008, by considering meteorological condition, a kind of simple and practical new method suiting for forecast of the O3 concentration and pre-warning of the high-concentration O3 pollution event in whole year was established. [Result] Meteorological condition had obvious influence on O3 concentration near the ground. O3 concentration was the biggest in sunny day, followed by cloudy day. O3 concentration near the ground had typical seasonal change characteristics, and high value mainly happened in summer. Meteorological condition generating high-concentration O3 included sunny day, strong UV radiation, low relative humidity, high temperature and small wind speed, etc. By surveying historical weather chart, 10 kinds of main weather situations affecting Shanghai were summed. Under each weather situation, occurrence probability of the high-concentration O3 near the ground and average O3 concentration were conducted statistics. We found that occurrence probability of the high-concentration O3 was the biggest under northwest side of the subtropical high type, followed by internal type of the subtropical high. By introducing HPPI and WDI and comprehensively considering various meteorological factors, forecasting equation of the O3 concentration was established based on stepwise regression. The equation had good fitting effect and predictability on the daily maximum O3 concentration. [Conclusion] The method also could provide reference for O3 forecast in other areas.
文摘[ Objective] The study aimed to analyze the spatial distribution of agricultural meteorological conditions in Sanjiang Plain during nearly 50 years. [ Method] Accumulated temperature of Sanjiang Plain was computed based on meteorological observation data from different meteorological stations in Sanjiang Plain, including temperature, precipitation, sunshine time, etc. A spatial interpolation map involving varieties of meteorological elements in neady 50 years was generated based on the Kriging interpolation, and the spatial distribution characteristics of those meteorological ele- ments were analyzed. [ Result] Temperature of Sanjiang Plain decreased with the increase of latitude and altitude, and the annual average temper- atura varied from 2.5 to 4.5 ~（3 generally, showing a zonal distribution. Precipitation of Sanjiang Plain changed spatially and the annual average pre- cipitation varied from 500 to 600 mm symmetrically in northwest-southeast direction. Spatial distribution of the annual average wind speed in San- jiang Plain was identical with the spatial pattern of topography here, and the annual average wind speed changed from 3.0 to 3.6 rn/s in most re- gions. Relative air humidity of Sanjiang Plain in summer half year was relatively high and always above 65%. The maximum sunshine hours of San- jiang Plain in one year distributed similarly to the annual changing curve of solar declination, and both of them presented a normal distribution and changed with geographic latitude. The days from the beginning to the end of daily average temperature ~〉 10 ~C in Sanjiang Plain were 135 -146 d, and its distribution presented a latitudinal trend, with certain vertical zonality. [ Conclusion] The research could provide scientific references for the reasonable arrangement of agricultural production and effective prevention of meteorological disasters in Sanjiang Plain.
文摘To reveal the multivariate relationships between man-made and meteorological factors on dust storm frequency, the LUCC data, NDVI remote sensing data and meteorological data for the period of 1983-2013 were combined with dust storm frequency data, and the possible impacts of meteorological and anthropogenic factors on dust storm frequency were analyzed by using regression analysis and PCA (Principal Component Analysis). Results show that the inter-annual dust storm frequency increased gradually. In particular, an increasing trend in recent years, after 2009, is conspicuous. The monthly frequency of dust storms shows higher values between the months of February and May, with the highest mean number of events occurring in April, which accounts for 29% of the annual dust storm frequency. The annual dust storm frequency is positively correlated with wind speed and negatively correlated with precipitation;the monthly dust storm frequency is positively correlated with wind speed, but no significant correlation can be found with precipitation. The relationship between temperature and dust storms is not simply linear, however, a certain correlation with an unremarkable statistical significance can be found between them. Human activities also affect the dynamics of dust storms indirectly via changing vegetation coverage and direct dust emissions. The multivariate analysis further confirmed the association between dust storm frequency and meteorological factors and NDVI. The high loadings of dust storm frequency, wind speed, precipitation and NDVI on a PC indicate that the increased precipitation and NDVI will decrease dust storm frequency, and increased wind speed will increase dust storm frequency.
