The fall armyworm(FAW,Lepidoptera:Noctuidae),Spodoptera frugiperda(J.E.Smith),invaded China in mid-December 2018;since then,it has become a great threat to Chinese agricultural production.Qinling Mountains-Huaihe Rive...The fall armyworm(FAW,Lepidoptera:Noctuidae),Spodoptera frugiperda(J.E.Smith),invaded China in mid-December 2018;since then,it has become a great threat to Chinese agricultural production.Qinling Mountains-Huaihe River region(QM-HRR)is the transitional zone between northern and southern China,an important region for both corn and wheat production.Based on the actual occurrence of QM-HRR invaded by FAW in 2019,daily mean surface air temperature and nocturnal wind conditions at 925 hPa were examined,and migratory routes of FAW moths originated in QM-HRR were modeled by a forward-trajectory-analysis approach.The results indicated that migratory activities of FAW adults emerged in QM-HRR were initiated from late June.The moths from western QM-HRR,where has complex topographic terrain,mainly flied to Ningxia and Inner Mongolia before mid September.However,FAW moths from the eastern QM-HRR primarily engaged in high-altitude northward transport assisted by the prevailing southerly winds before mid August,and the North China Plain was identified as the main destination of FAW.Meanwhile,the migration trajectories of FAW moths had a possibility to reach the Northeast China Plain.From mid August,FAW moths in eastern QM-HRR largely migrated southward and returned to the Yangtze River Valley.This study provides detailed information on the occurrence and migration routes of FAW moths from QM-HRR and will be helpful for early warning and development of integrated pest management strategies for the control of this exotic insect pest.展开更多
Windborne debris is one of the most important causes of the envelop destruction according to the postdamage investigations.The problem of windborne debris damage could be summarized as three parts,including windborne ...Windborne debris is one of the most important causes of the envelop destruction according to the postdamage investigations.The problem of windborne debris damage could be summarized as three parts,including windborne debris risk analysis,debris flying trajectories,and impact resistance of envelope analysis.The method of debris distribution is developed.The flying trajectories of compact and plate-like debris are solved by using a numerical method according to the different aerodynamic characteristics.The impact resistance of the envelopes is also analyzed.Besides,the process of windborne debris damage analysis is described in detail.An example of industrial building is given to demonstrate the whole method by using the observed data of typhoon Chanchu(2006).The method developed in this paper could be applied to risk assessment of windborne debris for structures in wind hazard.展开更多
基金supported by the National Natural Science Foundation of China(31901873 and 31727901)the China Postdoctoral Science Foundation(2019M660896)+1 种基金the Central Public-interest Scientific Institution Basal Research Fund,China(CAAS-ZDRW202007)the National Key R&D Program of China(2019YFD0300105)。
文摘The fall armyworm(FAW,Lepidoptera:Noctuidae),Spodoptera frugiperda(J.E.Smith),invaded China in mid-December 2018;since then,it has become a great threat to Chinese agricultural production.Qinling Mountains-Huaihe River region(QM-HRR)is the transitional zone between northern and southern China,an important region for both corn and wheat production.Based on the actual occurrence of QM-HRR invaded by FAW in 2019,daily mean surface air temperature and nocturnal wind conditions at 925 hPa were examined,and migratory routes of FAW moths originated in QM-HRR were modeled by a forward-trajectory-analysis approach.The results indicated that migratory activities of FAW adults emerged in QM-HRR were initiated from late June.The moths from western QM-HRR,where has complex topographic terrain,mainly flied to Ningxia and Inner Mongolia before mid September.However,FAW moths from the eastern QM-HRR primarily engaged in high-altitude northward transport assisted by the prevailing southerly winds before mid August,and the North China Plain was identified as the main destination of FAW.Meanwhile,the migration trajectories of FAW moths had a possibility to reach the Northeast China Plain.From mid August,FAW moths in eastern QM-HRR largely migrated southward and returned to the Yangtze River Valley.This study provides detailed information on the occurrence and migration routes of FAW moths from QM-HRR and will be helpful for early warning and development of integrated pest management strategies for the control of this exotic insect pest.
文摘Windborne debris is one of the most important causes of the envelop destruction according to the postdamage investigations.The problem of windborne debris damage could be summarized as three parts,including windborne debris risk analysis,debris flying trajectories,and impact resistance of envelope analysis.The method of debris distribution is developed.The flying trajectories of compact and plate-like debris are solved by using a numerical method according to the different aerodynamic characteristics.The impact resistance of the envelopes is also analyzed.Besides,the process of windborne debris damage analysis is described in detail.An example of industrial building is given to demonstrate the whole method by using the observed data of typhoon Chanchu(2006).The method developed in this paper could be applied to risk assessment of windborne debris for structures in wind hazard.
