The present paper has made a dynamic and diagnostic study of the process of explosive deepening of an extratropical cyclone over North China on April 25-26, 1983, in order to gain an insight into the physical mechanis...The present paper has made a dynamic and diagnostic study of the process of explosive deepening of an extratropical cyclone over North China on April 25-26, 1983, in order to gain an insight into the physical mechanism of explosive development of cyclone over land. It turns out that this cyclone occurred in the strong baroclinic zone, and the vorticity and thermal advection triggered the initial development of the cyclone. Subsequently, as the rainfall increased, the effect of condensational heating became more and more important. During the time period of rapid intensification (from 1200GMT 25 to 0000GMT 26 April, 1983, the central surface pressure fell down from 998. 2 to 988. 3 hPa), the peak of diabatic heating profile continuously descended, leading to a rapid increase in heating amount in the lower troposphere. This condition is favorable to the explosive development of rotational circulation or vortex. The numerical simulations have further demonstrated the importance of the lowering of heating peak for the rapid development of the cyclone.展开更多
In this paper,the processes of the occurrence and development of a mid-tropospheric cyclone (MTC hereinafter) over the South China Sea are successfully simulated,adopting the convective heating profile calculated from...In this paper,the processes of the occurrence and development of a mid-tropospheric cyclone (MTC hereinafter) over the South China Sea are successfully simulated,adopting the convective heating profile calculated from the ana- lysed data.And a series of numerical experiments show that the convective heating rate, especially its vertical profile, plays a key role in the occurrence,development and maintenance of the MTC.When there is highly concentrated convective heating in middle layer(400—450hPa),the MTC could occur and maintain for longer time.And the key to successfully predict the MTC by numerical model is to correctly specify the convective heating profile in the model.展开更多
文摘The present paper has made a dynamic and diagnostic study of the process of explosive deepening of an extratropical cyclone over North China on April 25-26, 1983, in order to gain an insight into the physical mechanism of explosive development of cyclone over land. It turns out that this cyclone occurred in the strong baroclinic zone, and the vorticity and thermal advection triggered the initial development of the cyclone. Subsequently, as the rainfall increased, the effect of condensational heating became more and more important. During the time period of rapid intensification (from 1200GMT 25 to 0000GMT 26 April, 1983, the central surface pressure fell down from 998. 2 to 988. 3 hPa), the peak of diabatic heating profile continuously descended, leading to a rapid increase in heating amount in the lower troposphere. This condition is favorable to the explosive development of rotational circulation or vortex. The numerical simulations have further demonstrated the importance of the lowering of heating peak for the rapid development of the cyclone.
文摘In this paper,the processes of the occurrence and development of a mid-tropospheric cyclone (MTC hereinafter) over the South China Sea are successfully simulated,adopting the convective heating profile calculated from the ana- lysed data.And a series of numerical experiments show that the convective heating rate, especially its vertical profile, plays a key role in the occurrence,development and maintenance of the MTC.When there is highly concentrated convective heating in middle layer(400—450hPa),the MTC could occur and maintain for longer time.And the key to successfully predict the MTC by numerical model is to correctly specify the convective heating profile in the model.
