The kinetic energy generation in either the dry or moist atmosphere may be estimated by the same relationships if we introduce the new concept of generalized available potential energy. The largest magnitude of genera...The kinetic energy generation in either the dry or moist atmosphere may be estimated by the same relationships if we introduce the new concept of generalized available potential energy. The largest magnitude of generalized available potential energy and corresponding reference state of either dry or moist atmosphere are calculated in terms of the mitial conditions and entropy variation of the atmosphere. The obtained relationships are applicable for the statically unstable atmosphere as well. The generalized available potential energy associated with reversible processes reaches the maximum with respect to same initial state. While the generation of kinetic energy in irreversible processes is characterized by sudden changes. When the reference state is assumed to be saturated, we may predict the final temperature and moisture fields corresponding to provided initial state and entropy variation.展开更多
The process of stratospheric sudden warmings from development of planetary waves to.the sudden cooling after reversal of mean zonal circulation will be studied with the primitive equations of heat and momentum balance...The process of stratospheric sudden warmings from development of planetary waves to.the sudden cooling after reversal of mean zonal circulation will be studied with the primitive equations of heat and momentum balances. It will be explained that the sudden warmings may occur only in the polar regions of winter stratosphere where zonal mean temperature decreases poleward. The heating rate in the order of major warmings is produced by developed planetary waves in the stratospheric breaking layers. The particular perturbation structure characterized by large amplitude of wave 1 together with minimum of wave 2 discovered by Labitzke (1977) is crucial for initiation of major warmings. The cooling by the same mechanism can be produced in the regions with reversed mean temperature gradient.展开更多
The stratospheric worm pools, called the 4-day wave also, are mainly the temperature anomalies in the polar regions of winter hemisphere. It will be shown that their occurrence, propagation speed and specific structur...The stratospheric worm pools, called the 4-day wave also, are mainly the temperature anomalies in the polar regions of winter hemisphere. It will be shown that their occurrence, propagation speed and specific structure can be explained by the lower frequency coherent heating resulting from the wave interaction in the breaking layers of the stratosphere. Although their vertical phase slope is negligibly small, the warm pools cannot be considered as a barotropic anomaly.展开更多
The instability of geostrophic wave circulations related to the nonlinear processes involved in the zonal mean heat balance equations is studied.It is found that the planetary waves may be destabilized by thermal forc...The instability of geostrophic wave circulations related to the nonlinear processes involved in the zonal mean heat balance equations is studied.It is found that the planetary waves may be destabilized by thermal forcing in specific baroclinic layers,called the breaking layers.The critical conditions of the instability will be given.In the troposphere,these conditions may be provided in blocking regions and the development of planetary perturbations is characterized distinctly by the unset,maintenance and decay of observed blocks.The whole blocking episode cannot be described as either the barotropic or baroclinic process only.The limitations on the study of wave-wave interaction using spectral models or spectrum analyses will be discussed also.展开更多
The zonal momentum generation in forced stationary waves may exceed the requirement for momentum balance after long,if the waves do not change their patterns.This suggests that the changes in stationary wave patterns ...The zonal momentum generation in forced stationary waves may exceed the requirement for momentum balance after long,if the waves do not change their patterns.This suggests that the changes in stationary wave patterns would be required by maintenance of momentum balance over the external forcings.It will be found that the low frequency anomalies like blocking regimes may produce reversed zonal momentum variations,if they happen in the observed centre areas.The zonal momentum balance in the stationary waves may be maintained effectively by alternation between the normal and blocking circulation regimes.Thus,from the point of long-term zonal momentum balance,we may explain the geographical distributions of the blocking centres and the seasonal variations in blocking areas and frequencies.展开更多
There are some basic problems in previous theoretical studies of baroclinic instability.The derived critical baroclinity was considerably lower than the time averaged mean meridional temperature gradient,especially in...There are some basic problems in previous theoretical studies of baroclinic instability.The derived critical baroclinity was considerably lower than the time averaged mean meridional temperature gradient,especially in the lower troposphere.Also,the linear mechanism of baroclinic disturbance development which is noted restricted by the critical baroclinity was not studied sufficiently.The realistic critical baroclinity and disturbance development are discussed in this study.It will be shown that the critical condition of instability and typical time and space scales of disturbances de- pend on three-dimensional structures of atmosphere and sphericity of the earth,other than the horizontal temperature gradient alone.The variant behaviour of atmospheric disturbances depends highly on their specific scales that may be described by the same theoretical model.Thus,there would be no substantial differences in the basic instability mecha- nism of many disturbances including the polar lows and explosive cyclones.展开更多
He graduated from Sofia University,majoring in physics(meteorology)(1956)andreceived his first scientific degree(“candidate of sciences”)in 1959.Six years later(1965)he received Dr.Sc.degree in the USSR with a thesi...He graduated from Sofia University,majoring in physics(meteorology)(1956)andreceived his first scientific degree(“candidate of sciences”)in 1959.Six years later(1965)he received Dr.Sc.degree in the USSR with a thesis on large scale atmospheric turbulenceand statistical macrostructure of meteorological fields.Since 1959 he has been a member of the Dept.of Meteorology and Geophysics,Univ.of Sofia and professor——head of this department since 1974.Prof.Panchev teaches regu-larly courses in general and dynamic meteorology and he has written textbooks on thesesubjects,the second one of them being published also in English by D.Reidel in 1985.展开更多
文摘The kinetic energy generation in either the dry or moist atmosphere may be estimated by the same relationships if we introduce the new concept of generalized available potential energy. The largest magnitude of generalized available potential energy and corresponding reference state of either dry or moist atmosphere are calculated in terms of the mitial conditions and entropy variation of the atmosphere. The obtained relationships are applicable for the statically unstable atmosphere as well. The generalized available potential energy associated with reversible processes reaches the maximum with respect to same initial state. While the generation of kinetic energy in irreversible processes is characterized by sudden changes. When the reference state is assumed to be saturated, we may predict the final temperature and moisture fields corresponding to provided initial state and entropy variation.
文摘The process of stratospheric sudden warmings from development of planetary waves to.the sudden cooling after reversal of mean zonal circulation will be studied with the primitive equations of heat and momentum balances. It will be explained that the sudden warmings may occur only in the polar regions of winter stratosphere where zonal mean temperature decreases poleward. The heating rate in the order of major warmings is produced by developed planetary waves in the stratospheric breaking layers. The particular perturbation structure characterized by large amplitude of wave 1 together with minimum of wave 2 discovered by Labitzke (1977) is crucial for initiation of major warmings. The cooling by the same mechanism can be produced in the regions with reversed mean temperature gradient.
文摘The stratospheric worm pools, called the 4-day wave also, are mainly the temperature anomalies in the polar regions of winter hemisphere. It will be shown that their occurrence, propagation speed and specific structure can be explained by the lower frequency coherent heating resulting from the wave interaction in the breaking layers of the stratosphere. Although their vertical phase slope is negligibly small, the warm pools cannot be considered as a barotropic anomaly.
文摘The instability of geostrophic wave circulations related to the nonlinear processes involved in the zonal mean heat balance equations is studied.It is found that the planetary waves may be destabilized by thermal forcing in specific baroclinic layers,called the breaking layers.The critical conditions of the instability will be given.In the troposphere,these conditions may be provided in blocking regions and the development of planetary perturbations is characterized distinctly by the unset,maintenance and decay of observed blocks.The whole blocking episode cannot be described as either the barotropic or baroclinic process only.The limitations on the study of wave-wave interaction using spectral models or spectrum analyses will be discussed also.
文摘The zonal momentum generation in forced stationary waves may exceed the requirement for momentum balance after long,if the waves do not change their patterns.This suggests that the changes in stationary wave patterns would be required by maintenance of momentum balance over the external forcings.It will be found that the low frequency anomalies like blocking regimes may produce reversed zonal momentum variations,if they happen in the observed centre areas.The zonal momentum balance in the stationary waves may be maintained effectively by alternation between the normal and blocking circulation regimes.Thus,from the point of long-term zonal momentum balance,we may explain the geographical distributions of the blocking centres and the seasonal variations in blocking areas and frequencies.
文摘There are some basic problems in previous theoretical studies of baroclinic instability.The derived critical baroclinity was considerably lower than the time averaged mean meridional temperature gradient,especially in the lower troposphere.Also,the linear mechanism of baroclinic disturbance development which is noted restricted by the critical baroclinity was not studied sufficiently.The realistic critical baroclinity and disturbance development are discussed in this study.It will be shown that the critical condition of instability and typical time and space scales of disturbances de- pend on three-dimensional structures of atmosphere and sphericity of the earth,other than the horizontal temperature gradient alone.The variant behaviour of atmospheric disturbances depends highly on their specific scales that may be described by the same theoretical model.Thus,there would be no substantial differences in the basic instability mecha- nism of many disturbances including the polar lows and explosive cyclones.
文摘He graduated from Sofia University,majoring in physics(meteorology)(1956)andreceived his first scientific degree(“candidate of sciences”)in 1959.Six years later(1965)he received Dr.Sc.degree in the USSR with a thesis on large scale atmospheric turbulenceand statistical macrostructure of meteorological fields.Since 1959 he has been a member of the Dept.of Meteorology and Geophysics,Univ.of Sofia and professor——head of this department since 1974.Prof.Panchev teaches regu-larly courses in general and dynamic meteorology and he has written textbooks on thesesubjects,the second one of them being published also in English by D.Reidel in 1985.
