Tropospheric Disturbances Research Articles

Large-Scale Disturbances in the Summertime Stratosphere

Abstract High-level balloon data from the region of western Europe through North America to eastern Asia were used to investigate disturbances in the summertime stratosphere from 27–36 km. Systematic diurnal variations were found, with amplitudes up to 2 m sec−1, but the patterns were more complex than would be expected from simple tidal theory. Traveling planetary waves were also found at these altitudes, propagating westward at 30° of longitude per day. The waves were detected as periodic oscillations in the u component, with amplitudes up to 4 m sec−1, extending from 25–45N, and from 25–45 km in the vertical. A solution to the barotropic vorticity equation was found which possesses many of the observed features when applied to 10 mb (31 km) data. While it is suspected that both the diurnal wind patterns and the traveling waves are forced by tropospheric disturbances, the causes of neither could be determined.

Equatorial Spread-F and Tropospheric Tropical Disturbances

Equatorial spread-F and tropical disturbances, supplying data on typhoon, geomagnetic activity and atmospheric pressure waves

Variation of temperature in the troposphere and lower stratosphere

Correlation coefficients are evaluated between temperatures at 500 mb and at three levels in the lower stratosphere (highest 60 mb) and, respectively, the pressure at the tropopause and the height of the 300-mb level for Larkhill and Lerwick for each month of the year. Similar coefficients are also given for Malta and (for different levels) for Arctic Bay for January, April, July and October. The Dines type of relationship is confirmed for those regions and seasons affected by travelling depressions and anticyclones. There is no significant correlation between similar parameters for Aden and tropical islands in the Pacific. The relation between temperature in the lower stratosphere and, respectively, the level of the tropopause and the height of the 300-mb level decreases by a factor of 2 or more between the levels of 150 mb and 60 mb at Larkhill, Lerwick and Malta, indicating a marked decrease with height in the effect of tropospheric disturbances on stratospheric temperatures. The stratospheric correlation coefficients for Larkhill and Lerwick have a significant minimum in the winter.

Variation of temperature in the troposphere and lower stratosphere

AbstractCorrelation coefficients are evaluated between temperatures at 500 mb and at three levels in the lower stratosphere (highest 60 mb) and, respectively, the pressure at the tropopause and the height of the 300‐mb level for Larkhill and Lerwick for each month of the year. Similar coefficients are also given for Malta and (for different levels) for Arctic Bay for January, April, July and October. The Dines type of relationship is confirmed for those regions and seasons affected by travelling depressions and anticyclones. There is no significant correlation between similar parameters for Aden and tropical islands in the Pacific. The relation between temperature in the lower stratosphere and, respectively, the level of the tropopause and the height of the 300‐mb level decreases by a factor of 2 or more between the levels of 150 mb and 60 mb at Larkhill, Lerwick and Malta, indicating a marked decrease with height in the effect of tropospheric disturbances on stratospheric temperatures. The stratospheric correlation coefficients for Larkhill and Lerwick have a significant minimum in the winter.

The dynamical influence of large‐scale heat sources and sinks on the quasi‐stationary mean motions of the atmosphere

AbstractThe classical convective theory for the influence of large‐scale zonally asymmetric heating and cooling on the quasi‐stationary mean motions is re‐examined and shown to be inconsistent with observation. Scale considerations indicate that the classical mechanism cannot be applied to heating on a scale larger than that responsible for sea‐breezes. In analogy with the theory of orographically produced stationary disturbances, heat sources and sinks of planetary dimensions produce quasi‐static and quasi‐geostrophic perturbations. A thermally active model is constructed in which all motions except those of large scale are filtered out a priori. The small perturbations produced by an idealized large‐scale distribution of heat sources and sinks acting on a horizontally uniform baroclinic zonal current confined between rigid horizontal planes are then studied. The influence of surface friction is taken into account. Calculations are also performed on a model with no friction and on the assumption that entropy is advected horizontally. The results generally show good agreement with those for the more general model. When the stratosphere is taken into account, the disturbances in the upper troposphere are reduced in magnitude. The conditions for resonance in the absence of friction are determined. The passage through the resonant state is shown to modify significantly the character of the motions. The observed normals are discussed at some length in light of the theoretical computations. It is found that the magnitude and spatial distribution of the model disturbances display substantial correspondence with observation when allowance is made for orographic effects. Finally a method is suggested for quantitatively deducing the three‐dimensional field of non‐adiabatic heating and cooling from the observed normal maps by dynamical considerations.

Dynamics of Baroclinic Disturbances in the Upper Troposphere

Dynamics of Baroclinic Disturbances in the Upper Troposphere

The Motion of Barotropic Disturbances in the Upper Troposphere

Oscillations of a barotropic model of the upper troposphere are studied, taking into account the existence of a zone of intense westerly circulation found in this region of the atmosphere. The fundamental frequencies of these oscillations are determined and some comments are made with regard to their dispersive properties. DOI: 10.1111/j.2153-3490.1949.tb01266.x

The Motion of Barotropic Disturbances in the Upper Troposphere

The Motion of Barotropic Disturbances in the Upper Troposphere