The nonlinear coupled-mode equations are rewritten by even and odd modes.We study modulation instability(MI) of dispersion-shifted fiber couplers when either even or odd mode is launched alone by using zero-dispersion...The nonlinear coupled-mode equations are rewritten by even and odd modes.We study modulation instability(MI) of dispersion-shifted fiber couplers when either even or odd mode is launched alone by using zero-dispersion wavelength relatively long(quasi-cw) pulses.The result shows that there are new types of MI in both the normal-dispersion and the anomalous-dispersion regimes.MI is concerned with forth-order dispersion and has no relation with third-order dispersion.Quasi-cw can be changed into pulses array under certain conditions.We can extract super short pulse from this.Furthermore,the bandwidth of gain spectra widens and its strength accretes as the input power increases.展开更多
Based on the conventional observation data,satellite,radar,automatic observation and other refined monitoring data,the severe hail weather in Hohhot City on July 29,2015 was analyzed at multiple scales.The results sho...Based on the conventional observation data,satellite,radar,automatic observation and other refined monitoring data,the severe hail weather in Hohhot City on July 29,2015 was analyzed at multiple scales.The results showed that from the perspective of synoptic-scale system,high-altitude cold air invaded Mongol shortwave trough,and the North China small high pressure and the subtropical high formed a warm shear line;the surface convergence line triggered severe convection weather.Unstable vertical structure,continuous increase of low-level humidity,more drier of high altitudes and the wind direction shear at 180° triggered hailstorm and lightning weather in Hohhot.α-scale convective cloud clusters were maintained in Hohhot,and the ground "herringbone" shear line oscillated violently between the north and the south.Strong lightning and big hails appeared on the ground.The "herringbone" shear line lifted slowly to the north,and there was short-time heavy precipitation on the ground.Radar products showed "bow echo",and the echo had a hanging structure;a mesoscale cyclone was formed 3 km away from the ground.On the radar wind profile,it can be seen that low-layer warm advection and strong wind shear triggered strong hailstorm in Hohhot.The disappearance of low- level warm advection and the maintenance of strong vertical shear of wind produced short-time heavy precipitation.There was a small difference between short-time heavy precipitation and hail in echo top height,but the coverage was significantly reduced.In Hohhot City,vertically integrated liquid water content quickly increased during the hail,and decreased during the short-time heavy precipitation.展开更多
Mongolian Terms Commonly Used in Meteorological Services that was issued by the China Meteorological Administration is China s first traditional Mongolian standard in meteorological industry. In the process of formula...Mongolian Terms Commonly Used in Meteorological Services that was issued by the China Meteorological Administration is China s first traditional Mongolian standard in meteorological industry. In the process of formulation, the compilation unit fully complied with the principles of scientificity, practicability, universality and versatility, and used literal translation, free translation, and the combination of literal translation and free translation to translate and compile 71 mongolian terms commonly used in meteorological services. The standard fills the blank of standardization construction of basic traditional Mongolian language in the meteorological industry of China.展开更多
基金National Natural Science Foun-dation of China (No.60468001)
文摘The nonlinear coupled-mode equations are rewritten by even and odd modes.We study modulation instability(MI) of dispersion-shifted fiber couplers when either even or odd mode is launched alone by using zero-dispersion wavelength relatively long(quasi-cw) pulses.The result shows that there are new types of MI in both the normal-dispersion and the anomalous-dispersion regimes.MI is concerned with forth-order dispersion and has no relation with third-order dispersion.Quasi-cw can be changed into pulses array under certain conditions.We can extract super short pulse from this.Furthermore,the bandwidth of gain spectra widens and its strength accretes as the input power increases.
文摘Based on the conventional observation data,satellite,radar,automatic observation and other refined monitoring data,the severe hail weather in Hohhot City on July 29,2015 was analyzed at multiple scales.The results showed that from the perspective of synoptic-scale system,high-altitude cold air invaded Mongol shortwave trough,and the North China small high pressure and the subtropical high formed a warm shear line;the surface convergence line triggered severe convection weather.Unstable vertical structure,continuous increase of low-level humidity,more drier of high altitudes and the wind direction shear at 180° triggered hailstorm and lightning weather in Hohhot.α-scale convective cloud clusters were maintained in Hohhot,and the ground "herringbone" shear line oscillated violently between the north and the south.Strong lightning and big hails appeared on the ground.The "herringbone" shear line lifted slowly to the north,and there was short-time heavy precipitation on the ground.Radar products showed "bow echo",and the echo had a hanging structure;a mesoscale cyclone was formed 3 km away from the ground.On the radar wind profile,it can be seen that low-layer warm advection and strong wind shear triggered strong hailstorm in Hohhot.The disappearance of low- level warm advection and the maintenance of strong vertical shear of wind produced short-time heavy precipitation.There was a small difference between short-time heavy precipitation and hail in echo top height,but the coverage was significantly reduced.In Hohhot City,vertically integrated liquid water content quickly increased during the hail,and decreased during the short-time heavy precipitation.
文摘Mongolian Terms Commonly Used in Meteorological Services that was issued by the China Meteorological Administration is China s first traditional Mongolian standard in meteorological industry. In the process of formulation, the compilation unit fully complied with the principles of scientificity, practicability, universality and versatility, and used literal translation, free translation, and the combination of literal translation and free translation to translate and compile 71 mongolian terms commonly used in meteorological services. The standard fills the blank of standardization construction of basic traditional Mongolian language in the meteorological industry of China.
