This study uses multiple sea surface temperature （SST） datasets to perform a parallel comparison of three super El Nifios and their effects on the stratosphere. The results show that, different from ordinary El Nifi...This study uses multiple sea surface temperature （SST） datasets to perform a parallel comparison of three super El Nifios and their effects on the stratosphere. The results show that, different from ordinary El Nifios, warm SST anomalies appear earliest in the western tropical Pacific and precede the super El Nifio peak by more than 18 months. In the previous winter, relative to the mature phase of El Nifio, as a precursor, North Pacific Oscillation-like circulation anomalies are observed. A Pacific-North America （PNA） teleconnection appears in the extratropical troposphere during the mature phase, in spite of the subtle differences between the intensities, as well as the zonal position, of the PNA lobes. Related to the negative rainfall response over the tropical Indian Ocean, the PNA teleconnection in the winter of 1997/98 is the strongest among the three super El Nifios. The northern winter stratosphere shows large anomalies in the polar cap temperature and the circumpolar westerly, if the interferences from other factors are linearly filtered from the circulation data. Associated with the positive PNA response in a super El Nino winter, positive polar cap temperature anomalies and circumpolar easterly anomalies, though different in timing, are also observed in the mature winters of the three super El Nifios. The stratospheric polar vortex in the next winter relative to the 1982/83 and 1997/98 events is also anomalously weaker and warmer, and the stratospheric circulation conditions remain to be seen in the coming winter following the mature phase of the 2015/16 event.展开更多
This paper applies the meshfree Smoothed Particle Hydrodynamics （SPH） method with Graphical Processing Unit （GPU） parallel computing technique to investigate the highly complex 3-D dam-break flow in urban areas in...This paper applies the meshfree Smoothed Particle Hydrodynamics （SPH） method with Graphical Processing Unit （GPU） parallel computing technique to investigate the highly complex 3-D dam-break flow in urban areas including underground spaces. Taking the advantage of GPUs parallel computing techniques, simulations involving more than 107 particles can be achieved. We use a virtual geometric plane boundary to handle the outermost solid wall in order to save considerable video card memory for the GPU computing. To evaluate the accuracy of the new GPU-based SPH model, qualitative and quantitative comparison to a real flooding experiment is performed and the results of a numerical model based on Shallow Water Equations （SWEs） is given with good accuracy. With the new GPU-based SPH model, the effects of the building layouts and underground spaces on the propagation of dambreak flood through an intricate city layout are examined.展开更多
基金supported by the Startup Foundation for Introducing Talent of Nanjing University of Information Science and Technology (Grant No. 2016r060)the National Key Research and Development Program (Grant No. 2016YFA0602104)+2 种基金the National Natural Science Foundation of China (Grant Nos. 41575041, 41430533 and 91437105)the Chinese Academy of Sciences (Grant No. XDA11010402)the China Meteorological Administration Special Public Welfare Research Fund (Grant No. GYHY201406001)
文摘This study uses multiple sea surface temperature （SST） datasets to perform a parallel comparison of three super El Nifios and their effects on the stratosphere. The results show that, different from ordinary El Nifios, warm SST anomalies appear earliest in the western tropical Pacific and precede the super El Nifio peak by more than 18 months. In the previous winter, relative to the mature phase of El Nifio, as a precursor, North Pacific Oscillation-like circulation anomalies are observed. A Pacific-North America （PNA） teleconnection appears in the extratropical troposphere during the mature phase, in spite of the subtle differences between the intensities, as well as the zonal position, of the PNA lobes. Related to the negative rainfall response over the tropical Indian Ocean, the PNA teleconnection in the winter of 1997/98 is the strongest among the three super El Nifios. The northern winter stratosphere shows large anomalies in the polar cap temperature and the circumpolar westerly, if the interferences from other factors are linearly filtered from the circulation data. Associated with the positive PNA response in a super El Nino winter, positive polar cap temperature anomalies and circumpolar easterly anomalies, though different in timing, are also observed in the mature winters of the three super El Nifios. The stratospheric polar vortex in the next winter relative to the 1982/83 and 1997/98 events is also anomalously weaker and warmer, and the stratospheric circulation conditions remain to be seen in the coming winter following the mature phase of the 2015/16 event.
基金Project supported by the National Basic Research Development Program of China(973 Program,No.2012CB719705)the National Natural Science Foundation of China(Grant Nos.91024032,70833003)
文摘This paper applies the meshfree Smoothed Particle Hydrodynamics （SPH） method with Graphical Processing Unit （GPU） parallel computing technique to investigate the highly complex 3-D dam-break flow in urban areas including underground spaces. Taking the advantage of GPUs parallel computing techniques, simulations involving more than 107 particles can be achieved. We use a virtual geometric plane boundary to handle the outermost solid wall in order to save considerable video card memory for the GPU computing. To evaluate the accuracy of the new GPU-based SPH model, qualitative and quantitative comparison to a real flooding experiment is performed and the results of a numerical model based on Shallow Water Equations （SWEs） is given with good accuracy. With the new GPU-based SPH model, the effects of the building layouts and underground spaces on the propagation of dambreak flood through an intricate city layout are examined.
