Based on conventional observation data and the temperature data of meteorological stations in China,the circulation patterns,weather systems and causes were analyzed by using principles of synoptic meteorology,weather...Based on conventional observation data and the temperature data of meteorological stations in China,the circulation patterns,weather systems and causes were analyzed by using principles of synoptic meteorology,weather dynamics and thermodynamics diagnostic analysis method for the strong cooling and continuous low-temperature weather process in early and middle January of 2010 in middle and lower reaches of Yellow River.The results showed that the cold air from polar region was transported towards south by northerly steering airflow behind trough at 500 hPa level.The stable cold vortex center in Northeast Asia played a role in blocking the cold air eastward,promoting and strengthening the accumulation of cold air.The deep low trough in Siberia oppressed high pressure ridge to collapse,thus the strong cold air broke out and moved southward.The main reason for the rapid temperature decrease and continuous cold weather was the intense cold advection of temperature at 850 hPa level.The evolution of the cold advection center was consistent with the moving path of strong cold air.There was negative vorticity advection from the upper to the lower layer in middle and lower reaches of Yellow River.The strong negative vorticity advection was conducive to the movement of the high-pressure system.The smaller the value of negative vorticity advection,the stronger cold air.The negative vorticity advection center corresponded with the strong cooling center.The cold advection center appeared 12-24 h in advance compared with strong cooling center and the 'negative vorticity advection core' appeared earlier than strong cooling weather.All these features provided favorable consultation materials for the forecast of strong cooling weather.展开更多
文摘Based on conventional observation data and the temperature data of meteorological stations in China,the circulation patterns,weather systems and causes were analyzed by using principles of synoptic meteorology,weather dynamics and thermodynamics diagnostic analysis method for the strong cooling and continuous low-temperature weather process in early and middle January of 2010 in middle and lower reaches of Yellow River.The results showed that the cold air from polar region was transported towards south by northerly steering airflow behind trough at 500 hPa level.The stable cold vortex center in Northeast Asia played a role in blocking the cold air eastward,promoting and strengthening the accumulation of cold air.The deep low trough in Siberia oppressed high pressure ridge to collapse,thus the strong cold air broke out and moved southward.The main reason for the rapid temperature decrease and continuous cold weather was the intense cold advection of temperature at 850 hPa level.The evolution of the cold advection center was consistent with the moving path of strong cold air.There was negative vorticity advection from the upper to the lower layer in middle and lower reaches of Yellow River.The strong negative vorticity advection was conducive to the movement of the high-pressure system.The smaller the value of negative vorticity advection,the stronger cold air.The negative vorticity advection center corresponded with the strong cooling center.The cold advection center appeared 12-24 h in advance compared with strong cooling center and the 'negative vorticity advection core' appeared earlier than strong cooling weather.All these features provided favorable consultation materials for the forecast of strong cooling weather.
