The Meiyu front heavy rain process in 1-3 June 2000 is numerically simulated in this paper, and results are then analyzed to show the effects of geostrophic balance collapse,unbalanced flow occurrence,low level jet (L...The Meiyu front heavy rain process in 1-3 June 2000 is numerically simulated in this paper, and results are then analyzed to show the effects of geostrophic balance collapse,unbalanced flow occurrence,low level jet (LLJ) development,and gravity waves genesis and propagation on the rainstorm.Analyses indicate that the sudden northwest movement of subtropical high may destruct the local geostrophic balance,leading to an increase in the local pressure gradient and the occurrence of ageostrophic flow,and meanwhile the adjustment of circulation starts to build a new balance.During the process,an LLJ and gravity waves appear correspondingly.The dispersion of unbalanced energy through the divergence/convergence of the geostrophic departure winds, promotes the propagation of strong wind cores along the LLJ,and the dispersion direction is influenced by the steering flow and the moisture concentration area.The development of LLJ is one of important conditions,which induces the heavy rain especially in the left front part of the jet where the convergence and shear of winds occur.It is also found that the genesis of disturbance, meso-vortex,and meso-convective system provides a favorable condition for the rainstorm.The above results are clearly illustrated by the high spatial and temporal resolution simulation data from a mesoscale numerical model.展开更多
An experimental work on the transplant of high resolution limited area model(HIRLAM) is firstly introduced into China.For the implementation,first of all is to adjust a new geographical coordination and to remove the ...An experimental work on the transplant of high resolution limited area model(HIRLAM) is firstly introduced into China.For the implementation,first of all is to adjust a new geographical coordination and to remove the instability caused by the Tibetan Plateau,the roof of the world. Then,we have applied this model to simulate a flood-making torrential rain process which occurred in the Changjiang-Huaihe River Valley in July 1991.That revealed the formation,development and movement of a mesoseale heavy rain system which had made a disastrous flood event in the middle and lower reaches of Changjiang River Valley. The result encourages us to use the HIRLAM for the researches on the Meiyu belt,the salient feature of precipitation of East Asia,and the numerical prediction of heavy rains in China.展开更多
基金supported by the National Natural Science Foundation of China under Grant No.40175023
文摘The Meiyu front heavy rain process in 1-3 June 2000 is numerically simulated in this paper, and results are then analyzed to show the effects of geostrophic balance collapse,unbalanced flow occurrence,low level jet (LLJ) development,and gravity waves genesis and propagation on the rainstorm.Analyses indicate that the sudden northwest movement of subtropical high may destruct the local geostrophic balance,leading to an increase in the local pressure gradient and the occurrence of ageostrophic flow,and meanwhile the adjustment of circulation starts to build a new balance.During the process,an LLJ and gravity waves appear correspondingly.The dispersion of unbalanced energy through the divergence/convergence of the geostrophic departure winds, promotes the propagation of strong wind cores along the LLJ,and the dispersion direction is influenced by the steering flow and the moisture concentration area.The development of LLJ is one of important conditions,which induces the heavy rain especially in the left front part of the jet where the convergence and shear of winds occur.It is also found that the genesis of disturbance, meso-vortex,and meso-convective system provides a favorable condition for the rainstorm.The above results are clearly illustrated by the high spatial and temporal resolution simulation data from a mesoscale numerical model.
基金This is a part of a Sino-Danish co-operative project funded by the National Natural Science Foundation of China and Danish International Development Assistance.
文摘An experimental work on the transplant of high resolution limited area model(HIRLAM) is firstly introduced into China.For the implementation,first of all is to adjust a new geographical coordination and to remove the instability caused by the Tibetan Plateau,the roof of the world. Then,we have applied this model to simulate a flood-making torrential rain process which occurred in the Changjiang-Huaihe River Valley in July 1991.That revealed the formation,development and movement of a mesoseale heavy rain system which had made a disastrous flood event in the middle and lower reaches of Changjiang River Valley. The result encourages us to use the HIRLAM for the researches on the Meiyu belt,the salient feature of precipitation of East Asia,and the numerical prediction of heavy rains in China.
