Based on the conventional observation data,daily reanalysis data from NCAR/NCEP,and TBB data derived from FY-2G infrared cloud images in April 2018,a heavy snowfall weather process in central Inner Mongolia from April...Based on the conventional observation data,daily reanalysis data from NCAR/NCEP,and TBB data derived from FY-2G infrared cloud images in April 2018,a heavy snowfall weather process in central Inner Mongolia from April 4 to 6 in 2018 was analyzed.The results show that the low trough at 500 hPa,the southerly wind jet stream at 700 hPa,and the inverted trough on the ground were the main influencing systems causing this blizzard.The transportation of warm and humid air by the southerly wind jet stream at 700 hPa and intense water vapor convergence provided sufficient water vapor conditions for the blizzard,and the moist layer in the blizzard area was deep.The low-level MPV in the blizzard area was<0,and the atmosphere was in a conditional symmetric instability state.The coupling of the upper and lower-level jets induced strong ascending motion.With the invasion of cold air,a low-level cold pad was formed,so that the warm and humid air tilted upward.The secondary circulation updraft triggered by the wet Q vector system released the conditional symmetric instability energy,so that the sloping motion was more intense,and the heavy snowfall appeared.Meanwhile,there was a good correspondence relationship between the blizzard area and the large-value area of low-level wet Q vector divergence.The mesoscale cloud clusters continuously generating,merging,and moving eastward in Hetao area were the direct cause of this blizzard,and the TBB of the cloud clusters was≤-56℃.The blizzard happened in the the edge gradient and large-value area of TBB.展开更多
The enhanced mountain-to-plain convective storms in Beijing on 22 May 2021 were simulated using the highresolution Weather Research and Forecasting model,enabling detailed analyses of convective instability characteri...The enhanced mountain-to-plain convective storms in Beijing on 22 May 2021 were simulated using the highresolution Weather Research and Forecasting model,enabling detailed analyses of convective instability characteristics and underlying causes of stability variations.Generalized potential temperature outperformed traditional potential temperature and equivalent potential temperature in capturing instability variations associated with mid-level latent heating and near-surface evaporative cooling.Local instability variance was primarily governed by potential divergence and the advection of potential instability,with these factors exhibiting out-of-phase distributions.Prior to the onset of heavy precipitation,intense downdrafts transported unstable air from higher levels into more stable regions at lower levels,increasing local near-surface instability,which contributed to the formation of heavy precipitation.During the heavy precipitation stage,vertical divergence between slantwise updrafts and downdrafts in the lowmiddle stable layers led to destabilization,supporting sustained convective development within the precipitation area.At the leading edge of the heavy precipitation,instability enhancement was primarily driven by vertical advection,and less stable air in the lower levels was transported upward,enhancing instability at higher levels.展开更多
Based on conventional meteorological observation data,radar data and numerical forecast product data,the causes of the first large-scale,high-intensity and long-duration rainstorm in Dehong Prefecture during May 11-16...Based on conventional meteorological observation data,radar data and numerical forecast product data,the causes of the first large-scale,high-intensity and long-duration rainstorm in Dehong Prefecture during May 11-16,2022 were analyzed by using the weather dynamic diagnosis and analysis method.The results show that the rainstorm process was caused by strong uplift and condensation in the west and north of Yingjiang under the background of dry and cold northwest air circulation at 500 hPa,the absence of obvious influence of the south branch trough at 700 hPa,and strong southwest jet at 850 hPa.The southwest jet in the boundary layer provided sufficient warm water vapor,unstable energy and uplifting conditions for the rainstorm.Low-level convergence,high-level divergence and strong upward movement in the whole layer were conducive to the uplift and condensation of a large number of warm and humid air in the northwest of Yingjiang in Dehong Prefecture,which enhanced the development of mesoscale convective system(MCS)and prolonged the life history ofβmesoscale convective system.The application of satellite,radar and other mesoscale data has an important reference value for the tracking,correction,forecast and early warning of the rainstorm process.展开更多
基金Supported by the Meteorological Science and Technology Innovation Project of North China(HBXM202415)Research Project of the Meteorological Bureau of Inner Mongolia Autonomous Region(nmqxkjcx202311).
文摘Based on the conventional observation data,daily reanalysis data from NCAR/NCEP,and TBB data derived from FY-2G infrared cloud images in April 2018,a heavy snowfall weather process in central Inner Mongolia from April 4 to 6 in 2018 was analyzed.The results show that the low trough at 500 hPa,the southerly wind jet stream at 700 hPa,and the inverted trough on the ground were the main influencing systems causing this blizzard.The transportation of warm and humid air by the southerly wind jet stream at 700 hPa and intense water vapor convergence provided sufficient water vapor conditions for the blizzard,and the moist layer in the blizzard area was deep.The low-level MPV in the blizzard area was<0,and the atmosphere was in a conditional symmetric instability state.The coupling of the upper and lower-level jets induced strong ascending motion.With the invasion of cold air,a low-level cold pad was formed,so that the warm and humid air tilted upward.The secondary circulation updraft triggered by the wet Q vector system released the conditional symmetric instability energy,so that the sloping motion was more intense,and the heavy snowfall appeared.Meanwhile,there was a good correspondence relationship between the blizzard area and the large-value area of low-level wet Q vector divergence.The mesoscale cloud clusters continuously generating,merging,and moving eastward in Hetao area were the direct cause of this blizzard,and the TBB of the cloud clusters was≤-56℃.The blizzard happened in the the edge gradient and large-value area of TBB.
基金funded by the Beijing Municipal Science and Technology Commission [grant number Z221100005222012]the Department of Science and Technology of Hebei Province [grant number 22375404D]+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences [grant number XDB0760303]the National Natural Science Foundation of China [grant numbers U2233218 and 42275010]the Open Foundation of the Key Open Laboratory of Urban Meteorology,China Meteorological Administration [grant number LUM-2023-06]。
文摘The enhanced mountain-to-plain convective storms in Beijing on 22 May 2021 were simulated using the highresolution Weather Research and Forecasting model,enabling detailed analyses of convective instability characteristics and underlying causes of stability variations.Generalized potential temperature outperformed traditional potential temperature and equivalent potential temperature in capturing instability variations associated with mid-level latent heating and near-surface evaporative cooling.Local instability variance was primarily governed by potential divergence and the advection of potential instability,with these factors exhibiting out-of-phase distributions.Prior to the onset of heavy precipitation,intense downdrafts transported unstable air from higher levels into more stable regions at lower levels,increasing local near-surface instability,which contributed to the formation of heavy precipitation.During the heavy precipitation stage,vertical divergence between slantwise updrafts and downdrafts in the lowmiddle stable layers led to destabilization,supporting sustained convective development within the precipitation area.At the leading edge of the heavy precipitation,instability enhancement was primarily driven by vertical advection,and less stable air in the lower levels was transported upward,enhancing instability at higher levels.
基金Supported by the Self-funded Research Project of Yunnan Meteorological Bureau in 2025(YZ202554)Key Open Laboratory of Heavy Precipitation in River Basins of the China Meteorological Administration(2023BHR-Y09).
文摘Based on conventional meteorological observation data,radar data and numerical forecast product data,the causes of the first large-scale,high-intensity and long-duration rainstorm in Dehong Prefecture during May 11-16,2022 were analyzed by using the weather dynamic diagnosis and analysis method.The results show that the rainstorm process was caused by strong uplift and condensation in the west and north of Yingjiang under the background of dry and cold northwest air circulation at 500 hPa,the absence of obvious influence of the south branch trough at 700 hPa,and strong southwest jet at 850 hPa.The southwest jet in the boundary layer provided sufficient warm water vapor,unstable energy and uplifting conditions for the rainstorm.Low-level convergence,high-level divergence and strong upward movement in the whole layer were conducive to the uplift and condensation of a large number of warm and humid air in the northwest of Yingjiang in Dehong Prefecture,which enhanced the development of mesoscale convective system(MCS)and prolonged the life history ofβmesoscale convective system.The application of satellite,radar and other mesoscale data has an important reference value for the tracking,correction,forecast and early warning of the rainstorm process.
