Using the WRF(Weather Research Forecast)model,this work performed analysis and simulation on the rainband change during the landfall of Typhoon Haitang(2005)and found that breaking may occur over land and oceans leads...Using the WRF(Weather Research Forecast)model,this work performed analysis and simulation on the rainband change during the landfall of Typhoon Haitang(2005)and found that breaking may occur over land and oceans leads to distinct asymmetric precipitation.The breaking is related to the topographic effect as well as interactions between the typhoon and midlatitude systems at upper levels.During the landfall,divergent flows at the 200-hPa level of the South-Asian high combined with divergent flows at the periphery of the typhoon to form a weak,inverted trough in the northwest part of the storm,with the mid- and low-level divergence fields on the west and northwest side of the typhoon center maintaining steadily.It intensifies the upper-level cyclonic flows,in association with positive vorticity rotating counterclockwise together with air currents that travel stepwise into a vorticity zone in the vicinity of the typhoon core, thereby forming a vorticity transfer belt in 22–25°N that extends to the eastern part of the storm.It is right here that the high-level vorticity band is subsiding so that rainfall is prevented from developing,resulting in the rainbelt breaking,which is the principal cause of asymmetric precipitation occurrence.Migrating into its outer region,the banded vorticity of Haitang at high levels causes further amplification of the cyclonic circulation in the western part and transfer of positive vorticity into the typhoon such that the rainband breaking is more distinct.展开更多
Isospin effects on particle emission of fissioning isobaric sources and isotopic sources , and its dependence on the excitation energy are studied via Smoluchowski equations. It is shown that with increasing the isos...Isospin effects on particle emission of fissioning isobaric sources and isotopic sources , and its dependence on the excitation energy are studied via Smoluchowski equations. It is shown that with increasing the isospin of fissioning systems, charged-particle emission is not sensitive to the strength of nuclear dissipation. In addition, we have found that increasing the excitation energy not only increases the influence of nuclear dissipation on particle emission but also greatly enhances the sensitivity of the emission of pre-scission neutrons or charged particles to the isospin of the system. Therefore, in order to extract dissipation strength more accurately by taking light particle multiplicities it is important to choose both a highly excited compound nucleus and a proper kind of particles for systems with different isospins.展开更多
基金Natural Foundamental Research and Development Project"973"Program(2009CB421503)Natural Science Foundation of China(4097503740775033)
文摘Using the WRF(Weather Research Forecast)model,this work performed analysis and simulation on the rainband change during the landfall of Typhoon Haitang(2005)and found that breaking may occur over land and oceans leads to distinct asymmetric precipitation.The breaking is related to the topographic effect as well as interactions between the typhoon and midlatitude systems at upper levels.During the landfall,divergent flows at the 200-hPa level of the South-Asian high combined with divergent flows at the periphery of the typhoon to form a weak,inverted trough in the northwest part of the storm,with the mid- and low-level divergence fields on the west and northwest side of the typhoon center maintaining steadily.It intensifies the upper-level cyclonic flows,in association with positive vorticity rotating counterclockwise together with air currents that travel stepwise into a vorticity zone in the vicinity of the typhoon core, thereby forming a vorticity transfer belt in 22–25°N that extends to the eastern part of the storm.It is right here that the high-level vorticity band is subsiding so that rainfall is prevented from developing,resulting in the rainbelt breaking,which is the principal cause of asymmetric precipitation occurrence.Migrating into its outer region,the banded vorticity of Haitang at high levels causes further amplification of the cyclonic circulation in the western part and transfer of positive vorticity into the typhoon such that the rainband breaking is more distinct.
基金the Teaching ＆ Researching Foundation for Outstanding Teachers of Southeast University
文摘Isospin effects on particle emission of fissioning isobaric sources and isotopic sources , and its dependence on the excitation energy are studied via Smoluchowski equations. It is shown that with increasing the isospin of fissioning systems, charged-particle emission is not sensitive to the strength of nuclear dissipation. In addition, we have found that increasing the excitation energy not only increases the influence of nuclear dissipation on particle emission but also greatly enhances the sensitivity of the emission of pre-scission neutrons or charged particles to the isospin of the system. Therefore, in order to extract dissipation strength more accurately by taking light particle multiplicities it is important to choose both a highly excited compound nucleus and a proper kind of particles for systems with different isospins.
