甘肃河东玉米种植区春夏气象干旱时空变化特征及其与环流因子关系

甘肃河东玉米种植区属于旱作雨养农业区,农作物生长主要依靠自然降水来维持,春夏干旱是影响该区玉米生长发育的关键因素。利用河东地区13个气象站点1957-2012年气象资料,基于标准化降水蒸散指数从干旱趋势、周期、空间特征及其与环流因子关系方面探讨近56 a来河东玉米种植区春夏干旱演变特征。结果表明：近56 a河东玉米种植区春夏两季均呈干旱化趋势,并自20世纪90年代中期以后,干旱呈加重趋势。干旱变化共经历了3个气候阶段,20世纪80年代之前,春夏旱情较轻;80年代-90年代,夏旱较春旱严重;2000年以后,春旱较夏旱严重。干旱周期变化,春夏干旱周期分别为20 a和14 a,干旱周期性变化主要是受太阳黑子活动影响。春夏干旱发生频率在突变前后差异显著,低频区在突变后转为高频区,易旱区呈扩大状态。ENSO事件是影响该区春夏干旱发生的主要环流因子,尤其对夏旱影响最为显著。近20 a来ENSO事件增强是该区干旱事件不断加重的原因,ENSO暖事件爆发时,该区春夏趋于干旱,由湿向干转变;ENSO冷事件爆发,干旱则有所缓解,由干向湿转变。     

Field data: a study on trend and prediction of fatal traffic injuries prevalence in Shanghai

OBJECTIVE: The main objectives of the study are to analyze fatal traffic-injury trends in 1987-2003 in Shanghai and predict its prevalence in near future and provide scientific data for the local governmental decision on developing practical working methods on traffic-injury prevention and control. METHODS: In this study, epidemiological method and Grey dynamic model GM (1,1) were introduced to analyze and forecast traffic-injury mortality rates respectively. RESULTS: There was an apparent increasing trend of traffic-related injuries in Shanghai from 1987 to 2003 with the rate of growth in motorization. The average rates of annual increase are 3.59% in fatalities (from 7.78 per 100,000 population to 14.18 per 100,000 population) during the period. Pedestrians were the most common type of victims (29.6%), followed by bicyclists (25.1%), and motorcyclists (24.1%). Males accounted for the majority of all victims, over 69%. The population of high-school and lower high-school education level represented 66.4% victims of total road-traffic injuries. And if no special factors effect its development, the traffic fatalities would be up to 17.84 per 100,000 population in 2010, when calculating from equations we found and validated Y(t) = 359.90 x e0.027(t-1)-352.13, (t = 1, 2, ..., N) for Shanghai. CONCLUSION: Our data indicate the risk of fatal traffic injuries has increased in recent years and will go on growing in the near future in Shanghai. The findings showed that Grey dynamic model GM (1,1) is eligible on the prediction and can be a tool for injuries forecasting, implementing effective policies, programs, and interventions for reducing traffic injuries in the big cities.     

The effect of high UV radiation exposure environment on the novel PVC polymers

Environmental Science and Pollution Research - Although plastic induces environmental damages, almost the consumption of poly(vinyl chloride) never stops increasing. Therefore, this work abstracted...