采用国产水动力学模型(integrated flood model system,IFMS),对“23·7”海河流域永定河系特大洪水中永定河泛区洪水演进及淹没范围变化进行精细化模拟复盘。将模拟结果与卫星遥感监测获取的泛区淹没范围进行对比,最大淹没面积误...采用国产水动力学模型(integrated flood model system,IFMS),对“23·7”海河流域永定河系特大洪水中永定河泛区洪水演进及淹没范围变化进行精细化模拟复盘。将模拟结果与卫星遥感监测获取的泛区淹没范围进行对比,最大淹没面积误差仅为8.8%,验证了该模型在永定河泛区洪水模拟中的可靠度。构建的永定河泛区模型可以准确反映分洪口门启闭、蓄滞洪量变化及泛区进退洪淹没过程。基于该模型,进一步研究雨带北移对该地区未来防洪情势的影响。结果表明:同等重现期的设计洪水受雨带北移影响后,将导致泛区防洪情势愈加严峻,雨带北移影响下的20 a一遇设计洪水最大淹没范围与现状情景下50 a一遇设计洪水最大淹没范围持平。因此,为更好地应对未来防洪情势的发展,需要针对永定河泛区提出更加合理的防洪规划并科学制定工程与非工程相结合的防洪措施。展开更多
Treated by freezing,1-year-old dormant branches of four Parthenocissus species were used as test materials to determine the electro-conductivities.According to Logistic equation fitting,the semi-lethal low temperature...Treated by freezing,1-year-old dormant branches of four Parthenocissus species were used as test materials to determine the electro-conductivities.According to Logistic equation fitting,the semi-lethal low temperatures were calculated.The result showed that the semi-lethal low temperatures and freezing tolerance of the examined species were ranked as: Parthenocissus quinquefolia(-16.63 ℃),P.tricuspidata(-10.78 ℃),P.laetecirens(-10.29 ℃),and P.henryana(-7.72 ℃).By comparing several physiological indexes including water saturation deficit,soluble sugar,soluble protein,MDA,and proline contents,it was found that after cold stressing for a whole winter the soluble sugar and proline contents were well correlated to semi-lethal low temperatures.So both of them could be used as the physiological indexes for cold tolerance identification and selection of cold-resistant variety.展开更多
文摘Treated by freezing,1-year-old dormant branches of four Parthenocissus species were used as test materials to determine the electro-conductivities.According to Logistic equation fitting,the semi-lethal low temperatures were calculated.The result showed that the semi-lethal low temperatures and freezing tolerance of the examined species were ranked as: Parthenocissus quinquefolia(-16.63 ℃),P.tricuspidata(-10.78 ℃),P.laetecirens(-10.29 ℃),and P.henryana(-7.72 ℃).By comparing several physiological indexes including water saturation deficit,soluble sugar,soluble protein,MDA,and proline contents,it was found that after cold stressing for a whole winter the soluble sugar and proline contents were well correlated to semi-lethal low temperatures.So both of them could be used as the physiological indexes for cold tolerance identification and selection of cold-resistant variety.