To determine the grid resolutions of the WRF model in the typhoon simulation,some sensitivity analysis of horizontal and vertical resolutions in different conditions has been carried out.Different horizontal resolutio...To determine the grid resolutions of the WRF model in the typhoon simulation,some sensitivity analysis of horizontal and vertical resolutions in different conditions has been carried out.Different horizontal resolutions(5,10,20,30 km),nesting grids(15 and 5 km),different vertical resolutions(35-layers,28-layers,20-layers)and different top maximum pressures(1 000,2 000,3 500,5 000 Pa)had been used in the mesoscale numerical model WRF to simulate the Typhoon Kai-tak.The simulation results of typhoon track,wind speed and sea level pressure at different horizontal and vertical resolutions have been compared and analyzed.The horizontal and vertical resolutions of the model have limited effect on the simulation effect of the typhoon track.Different horizontal and vertical resolutions have obvious effects on typhoon strength(defined by wind speed)and intensity(defined by sea level pressure,SLP),especially for sea level pressure.The typhoon intensity simulated by the high-resolution model is closer to the real situation and the nesting grids can improve computational accuracy and efficiency.The simulation results affected by vertical resolution using 35-layers is better than the simulation results using 20-layers and 28-layers simulations.Through comparison and analysis,the horizontal and vertical resolutions of WRF model are finally determined as follows:the two-way nesting grid of 15 and 5 km is comprehensively determined,and the vertical layers is 35-layers,the top maximum pressure is 2 000 Pa.展开更多
We set four sets of simulation experiments to explore the impacts of horizontal resolution(HR)and vertical resolution(VR)on the microphysical structure and boundary layer fluxes of tropical cyclone(TC)Hato(2017).The s...We set four sets of simulation experiments to explore the impacts of horizontal resolution(HR)and vertical resolution(VR)on the microphysical structure and boundary layer fluxes of tropical cyclone(TC)Hato(2017).The study shows that higher HR tends to strengthen TC.Increasing VR in the upper layers tends to weaken TC,while increasing VR in the lower layers tends to strengthen TC.Simulated amounts of all hydrometeors were larger with higher HR.Increasing VR at the upper level enhanced the mixing ratios of cloud ice and cloud snow,while increasing VR at the lower level elevated the mixing ratios of graupel and rainwater.HR has greater impact on the distributions of hydrometeors.Higher HR has a more complete ring structure of the eyewall and more concentrated hydrometeors along the cloud wall.Increasing VR at the lower level has little impact on the distribution of TC hydrometeors,while increasing VR at the upper level enhances the cloud thickness of the eyewall area.Surface latent heat flux(SLHF)is influenced greatly by resolution.Higher HR leads to larger water vapor fluxes and larger latent heat,which would result in a stronger TC.A large amount of false latent heat was generated when HR was too high,leading to an extremely strong TC,VR has a smaller impact on SLHF than HR.But increasing VR at the upper-level reduces the SLHF and weakens TC,and elevating VR at the lower-level increases the SLHF and strengthens TC.The changes in surface water vapor flux and SLHF were practically identical and the simulation results were improved when HR and VR were more coordinated.The friction velocity was greater with higher VR.Enhancing VR at the lower level increased the friction velocity,while increasing VR at the upper level reduced it.展开更多
High resolution satellite images are rich source of geospatial information. Nowadays, these images contain finest spectral and spatial information of ground realities in different electromagnetic spectrum. Many image ...High resolution satellite images are rich source of geospatial information. Nowadays, these images contain finest spectral and spatial information of ground realities in different electromagnetic spectrum. Many image processing softwares, algorithms and techniques are available to extract such information from these images. Multi spectral as well as panchromatic (PAN) high resolution satellite images are missing, one important information, regarding ground features and realities that information is attribute information which is not directly available in high resolution satellite images. From very first day, this information used to be collected through indirect ways using GPS, digitizing, geo-coding, geo tagging, field survey and many other techniques. Our real world has vertical labels for ground observer to identify and use this information. These vertical labels are present in form of names, logos, icons, symbols and numbers. These vertical labels ease us to work in real world. Satellites are unable to read these labels due to their vertical orientation. Making satellite/aerial imagery rich of attribute information, we have the possibility to design our world accordingly. Just like vertical labels we can also place real physical horizontal label for space sensors, to make this information directly available in high resolution satellite/aerial imagery. This work is about possibilities of such techniques and methods.展开更多
基金The National Natural Science Foundation of China under contract Nos 51809023,51839002 and 51879015the Open Research Foundation of the Key Laboratory of the Pearl River Estuarine Dynamics and Associated Process Regulation,the Ministry of Water Resources under contract No.2018KJ03
文摘To determine the grid resolutions of the WRF model in the typhoon simulation,some sensitivity analysis of horizontal and vertical resolutions in different conditions has been carried out.Different horizontal resolutions(5,10,20,30 km),nesting grids(15 and 5 km),different vertical resolutions(35-layers,28-layers,20-layers)and different top maximum pressures(1 000,2 000,3 500,5 000 Pa)had been used in the mesoscale numerical model WRF to simulate the Typhoon Kai-tak.The simulation results of typhoon track,wind speed and sea level pressure at different horizontal and vertical resolutions have been compared and analyzed.The horizontal and vertical resolutions of the model have limited effect on the simulation effect of the typhoon track.Different horizontal and vertical resolutions have obvious effects on typhoon strength(defined by wind speed)and intensity(defined by sea level pressure,SLP),especially for sea level pressure.The typhoon intensity simulated by the high-resolution model is closer to the real situation and the nesting grids can improve computational accuracy and efficiency.The simulation results affected by vertical resolution using 35-layers is better than the simulation results using 20-layers and 28-layers simulations.Through comparison and analysis,the horizontal and vertical resolutions of WRF model are finally determined as follows:the two-way nesting grid of 15 and 5 km is comprehensively determined,and the vertical layers is 35-layers,the top maximum pressure is 2 000 Pa.
基金National Key R&D Program of China(2016YFA0602701)National Natural Science Foundation of China(42075064)
文摘We set four sets of simulation experiments to explore the impacts of horizontal resolution(HR)and vertical resolution(VR)on the microphysical structure and boundary layer fluxes of tropical cyclone(TC)Hato(2017).The study shows that higher HR tends to strengthen TC.Increasing VR in the upper layers tends to weaken TC,while increasing VR in the lower layers tends to strengthen TC.Simulated amounts of all hydrometeors were larger with higher HR.Increasing VR at the upper level enhanced the mixing ratios of cloud ice and cloud snow,while increasing VR at the lower level elevated the mixing ratios of graupel and rainwater.HR has greater impact on the distributions of hydrometeors.Higher HR has a more complete ring structure of the eyewall and more concentrated hydrometeors along the cloud wall.Increasing VR at the lower level has little impact on the distribution of TC hydrometeors,while increasing VR at the upper level enhances the cloud thickness of the eyewall area.Surface latent heat flux(SLHF)is influenced greatly by resolution.Higher HR leads to larger water vapor fluxes and larger latent heat,which would result in a stronger TC.A large amount of false latent heat was generated when HR was too high,leading to an extremely strong TC,VR has a smaller impact on SLHF than HR.But increasing VR at the upper-level reduces the SLHF and weakens TC,and elevating VR at the lower-level increases the SLHF and strengthens TC.The changes in surface water vapor flux and SLHF were practically identical and the simulation results were improved when HR and VR were more coordinated.The friction velocity was greater with higher VR.Enhancing VR at the lower level increased the friction velocity,while increasing VR at the upper level reduced it.
文摘High resolution satellite images are rich source of geospatial information. Nowadays, these images contain finest spectral and spatial information of ground realities in different electromagnetic spectrum. Many image processing softwares, algorithms and techniques are available to extract such information from these images. Multi spectral as well as panchromatic (PAN) high resolution satellite images are missing, one important information, regarding ground features and realities that information is attribute information which is not directly available in high resolution satellite images. From very first day, this information used to be collected through indirect ways using GPS, digitizing, geo-coding, geo tagging, field survey and many other techniques. Our real world has vertical labels for ground observer to identify and use this information. These vertical labels are present in form of names, logos, icons, symbols and numbers. These vertical labels ease us to work in real world. Satellites are unable to read these labels due to their vertical orientation. Making satellite/aerial imagery rich of attribute information, we have the possibility to design our world accordingly. Just like vertical labels we can also place real physical horizontal label for space sensors, to make this information directly available in high resolution satellite/aerial imagery. This work is about possibilities of such techniques and methods.
