Showing papers in "Journal of the Atmospheric Sciences in 1965"
TL;DR: In this paper, the effect of latent heat release by deep cumulus convection in a conditionally unstable atmosphere is investigated and a method devised to include this effect directly in the equations for large scale flow is then applied to the hurricane formation problem by incorporating it into timedependent, circular symmetric dynamic hurricane models, either in gradient-wind balance or unbalanced.
Abstract: The effect on large scale motions of latent heat release by deep cumulus convection in a conditionally unstable atmosphere is investigated and a method devised to include this effect directly in the equations for large scale flow This method is then applied to the hurricane formation problem by incorporating it into time-dependent, circular symmetric dynamic hurricane models, either in gradient-wind balance or unbalanced Numerical integrations of a two-level approximation of the balanced model have been carried out for two different formulations of the problem (including or not including a frictional radial flow), both starting from a hypothetical initial state characterized by a weak barotropic circular vortex with a maximum tangential velocity of 10 m sec−1 at a distance of 1412 km from the center The results obtained without frictional radial flow showed slow intensification of the tangential flow, to about 25 m sec−1, and establishment of a strong radial temperature gradient in the upper
826 citations
TL;DR: In this article, the basic premise that the Earth was without a primordial atmosphere and that its secondary atmosphere has arisen primarily from local heating and volcanic action associated with continent building was adopted.
Abstract: This study adopts the basic premise that the Earth was without a primordial atmosphere and that its secondary atmosphere has arisen primarily from local heating and volcanic action associated with continent building. Since no oxygen can be derived in this way, the initial formation of oxygen from photochemical dissociation of water vapor is found to provide the primitive oxygen in the atmosphere. Because of the Urey self-regulation of this process by shielding H2O vapor with O2, O3, and CO2, primitive oxygen levels cannot exceed O2∼0.001 present atmospheric level (P.A.L.). The analysis of photochemistry of the atmospheric constituents is made possible by measurements of solar radiation with space vehicles and the now excellent data on uv absorption. The rates of oxidation of lithospheric materials are examined in this primitive atmosphere and, because of active species of oxygen present, found adequate to make unnecessary the usual assumption of high oxygenic levels in the pre-Cambrian eras to ac...
311 citations
TL;DR: Modification of mathematical method of Jacchia for satellite drag density of upper atmosphere is discussed in this paper, where the satellite is assumed to be a fixed point in the upper atmosphere of the Earth.
Abstract: Modification of mathematical method of Jacchia for satellite drag density of upper atmosphere
191 citations
TL;DR: In this article, a vertical rotating annulus of liquid is subject to a horizontal temperature gradient, provided that the coefficient of kinematical viscosity, ν¯, is not too great and the angular velocity of rotation,Ω is sufficiently high, four distinct regimes of hydrodynamical flow are possible, as shown in previous work by Hide.
Abstract: When a vertical rotating annulus of liquid is subject to a horizontal temperature gradient, provided that the coefficient of kinematical viscosity, ν¯, is not too great and the angular velocity of rotation,Ω is sufficiently high, four distinct regimes of hydrodynamical flow are possible, as shown in previous work by Hide. Only one of these regimes is characterized by symmetry about the axis of rotation. The principal properties of the flow depend largely on the dimensionless parameters Π2≡d/(b−a), Π4gdΔρ/ρ¯Ω2(b−a)2, Π5≡4Ω2(b−a)5/ν¯2d and Π6≡ν¯/κ¯, where d is the depth of the fluid,b and a are the radi of curvature of the surfaces of the annulus, g is the acceleration of gravity, ρ¯ is the mean density of the fluid, Δρ is the density contrast associated with the impressed horizontal temperature gradient and κ¯ is the thermal diffusivity of the fluid. In a diagram with log10Π5 as abscissa and log10Π4 as ordinate, axisymmetric flow is found outside an anvil-shaped region whose upper boundary lies be...
174 citations
TL;DR: In this paper, a numerical method of solving the equation of radiative transfer for a plane parallel, horizontally homogeneous medium is presented, which is applicable for problems with nonconservative scattering as well as for conservative scattering problems.
Abstract: A numerical method of solving the equation of radiative transfer for a plane parallel, horizontally homogeneous medium is presented. The method is applicable for problems with nonconservative scattering as well as for conservative scattering problems. Comparison of results for the reflected and transmitted radiation from this method with existing solutions for conservative Rayleigh scattering shows that, for optical depths up to 1-0, the present scheme is accurate to within ±0.007 unit total intensity and ±1.0 per cent polarization for an incident flux of π units per unit normal area. Results are presented for the reflected and transmitted intensity and per cent polarization for optical depths 2.0 and 4.0, for a particular problem of conservative Rayleigh scattering.
171 citations
TL;DR: In this article, the relationship between the parameters A and b of the radar reflectivity equation Z=ARB, and the type of drop-size distribution has been investigated, and cases have been plotted against logA and b as rectangular co-ordinates.
Abstract: Raindrop data from 34 storms, taken at the University of Miami, Florida, using a raindrop camera, have been analyzed. The relationship between the parameters A and b of the radar reflectivity equation Z=ARB, and the type of drop-size distribution has been investigated. Parameters A and b control not only the pattern of the family of size-distribution curves but also the type of the individual curves. Cases have been plotted against logA and b as rectangular co-ordinates. Reviewed in relation to rainfall types, these showed thunderstorms occupying a region of larger A (300 to 1000) and moderate b (from 1.25 to 1.65). Both A and b are smaller for rainshowers; for continuous rains the value of b ranges widely, from 1.0 to 2.0, while A never exceeds 600. The same sort of data-display has been reviewed in relation to radar echo characteristics to provide a more comprehensive and continuously varying relation between the parameters and the storm-pattern characteristics.
109 citations
104 citations
TL;DR: In this paper, principal component analysis has been used to determine the number of linearly independent pieces of information that may be inferred from Umkehr observations, and it has been shown that there are at most four such pieces this paper.
Abstract: Principal component analysis has been used to determine the number of linearly independent pieces of information that may be inferred from Umkehr observations. The analysis indicates that there are at most four such pieces of information in each Umkehr curve. A simple physical explanation is given for this result. The linearized evaluation method of Dutsch (1959) has been examined by eigenvalue analysis to determine the number of pieces of information that may be computed from the system. The result of the statistical analysis is confirmed, viz., that there are at most four pieces of information about the vertical distribution of ozone to be determined. In particular, there is no possibility of determining, from Umkehr observations, whether or not there exists a secondary maximum of ozone concentration in the lower stratosphere. Methods of obtaining smoothed vertical distributions are discussed and it is pointed out that the distributions obtained are not invariant under different scalings of the...
100 citations
TL;DR: In this paper, a set of energy equations is derived which are applicable to the stratosphere as an open system, interpreted as energy conversions and fluxes, are evaluated using data from January 1958.
Abstract: The dynamics of the large-scale circulation pattern of the stratosphere in mid-winter is examined. A set of energy equations is derived which is applicable to the stratosphere as an open system. The terms of these equations, interpreted as energy conversions and fluxes, are evaluated using data from January 1958. The computed energy conversions were similar in sign to those found in the troposphere, and varied only in magnitude during the month, reaching maximum values prior to and during the stratosphere warming. The energy flux terms indicate a considerable amount of energy was transferred into the stratosphere through a correlation of the vertical velocity and geopotential, at the expense of energy of the troposphere. The possibility of a stratosphere-troposphere coupling is investigated further through harmonic analyses of the height field at levels from 1000 mb to 10 mb at 50N. A vertical consistency of the long waves is revealed, throughout the depth studied, and evidence is found for the e...
93 citations
TL;DR: In this paper, the response of an unbounded ocean to circularly symmetric time varying wind stresses is analyzed and a simple analytic approximation to the depth dependence of static stability in the oceans is introduced and shown to give more realistic results than a constant static stability model.
Abstract: The response of an unbounded ocean to circularly symmetric time varying wind stresses is analyzed. A continuously stratified ocean is first considered. The model includes bottom friction, but the Coriolis parameter is a constant. It is shown that in a stratified ocean both barotropic and baroclinic currents are generated by wind stresses. The barotropic current, however, has its amplitude limited by bottom friction, so that the baroclinic mode dominates for long period forcing. A simple analytic approximation to the depth dependence of static stability in the oceans is introduced and shown to give more realistic results than a constant static stability model. A two-layer model including both a variable Coriolis parameter and bottom friction is analysed. This simple model indicates that both bottom friction and the variation of the Coriolis force enhance the baroclinic mode.
93 citations
TL;DR: In this paper, the spectral energy equations for zonal and eddy kinetic and available potential energies were used to investigate the energetics of the lowest 30 km of the atmosphere during the months of January and February 1963.
Abstract: The spectral energy equations for zonal and eddy kinetic and available potential energies are used to investigate the energetics of the lowest 30 km of the atmosphere during the months of January and February 1963. A major stratospheric warming, manifested in the reversal of the stratospheric meridional temperature gradient and destruction of the polar-night stratospheric vortex, began in mid-January. Data for eight standard pressure levels, from 850 to 10 mb, for every fifth day were utilized. The horizontal wind field was estimated by using both the geostrophic approximation and a modified stream function. The vertical motion field (dp/dt) was estimated both by the adiabatic technique and by the solution of the omega equation. The variation of the energy exchanges with height (pressure) indicates that the lower and middle troposphere and the middle stratosphere were baroclinically active regions before and during the warming. The principal path of energy flow in these regions was from zonal to ...
TL;DR: In this paper, the authors investigated the initiation of cumulus clouds over mountainous terrain by means of a numerical model, which is similar to Ogura's (1963) but include an extra buoyancy term due to water vapor.
Abstract: The initiation of cumulus clouds over mountainous terrain is investigated by means of a numerical model. Two-dimensional motion is simulated over a mountain and valley. Changes at the mountain surface of both temperature and water vapor initiate the motion. The equations are similar to Ogura's (1963) but include an extra buoyancy term due to water vapor. Five cases have been numerically integrated. Cases 1 and 4 are included to demonstrate the dynamic effect of water vapor by comparison with a previously integrated “dry model.” Case 1, which allows evaporation at the mountain surface, causes the upslope motion to develop at a 20 per cent faster rate than the dry case. Case 4, which allows no evaporation at the surface, augments the motion over that of the dry case by approximately 10 per cent. A comparison of the results with Braham and Draginis' (1960) observation of potential temperature and water vapor over the Santa Catalinas shows some similarities but indicates that the numerical model has ...
TL;DR: In this article, the properties of mesoscale eddies in the wake of islands are investigated in the light of their apparent resemblance to the Karman vortex-street pattern, and estimates for the rate of shedding of eddy pairs, the lateral and longitudinal spacing between the vortices, and the life-time of the eddies and drag of the island are made.
Abstract: The properties of mesoscale eddies in the wake of islands are investigated in the light of their apparent resemblance to the Karman vortex-street pattern. By use of the theoretical results from drag theory and the observed quantities such as cross-stream diameter of the obstacle, wind speed and the dimensions of the pattern, estimates are made for the rate of shedding of eddy pairs, the lateral and longitudinal spacing between the vortices, and the life-time of the eddies and drag of the island. These estimates for the various characteristic parameters of the eddy pattern are in good agreement with their corresponding values in the laboratory experiments where stable vortex streets become discernible. Effects of the tip, ground, and neighboring obstacles are neglected and the problem is treated essentially as two-dimensional flow. Use of this theory makes possible a computation of the lateral coefficient of eddy viscosity. The results provide support for the usual assumption made in meteorologica...
TL;DR: In this article, the response of a simple bounded-ocean model to a fluctuating wind stress is studied and the linear response and the resulting steady non-linear circulations are computed.
Abstract: The response of a simple bounded-ocean model to a fluctuating wind stress is studied. Both the linear response and the resulting steady non-linear circulations are computed. The results of this analysis show that the structures of the steady and fluctuating ocean circulations are strongly dependent on the frequency of the forcing.
TL;DR: In this paper, it is inferred that the quantity of rainfall is mostly governed by those properties of the atmosphere which determine the size, strength, and duration of the updrafts.
Abstract: Two groups of days, one with “heavy rain” and one with “light rain,” have been studied. Radar observations, cloud photographs and visual counts of cloud-to-ground lightning were examined. It is concluded that, at least in convective clouds in southeastern Arizona and probably in convective clouds in other geographical regions as well, the microphysical properties of the clouds are not of dominant importance in determining how much precipitation reaches the ground. It is inferred that the quantity of rainfall is mostly governed by those properties of the atmosphere which determine the size, strength and duration of the updrafts. The observations also show that as the quantity of rainfall increases so does the frequency of cloud-to-ground lightning.
TL;DR: In this article, the photochemistry of ozone and radiative heating in the mesosphere are reduced from differential-integral equations to much simpler differential-algebraic equations which are more readily incorporated into hydrodynamic models.
Abstract: The equations for the photochemistry of ozone and radiative heating in the mesosphere are, for certain regions, reduced from differential-integral equations to much simpler differential-algebraic equations which are more readily incorporated into hydrodynamic models. The simplified equations are first solved for joint radiative-photochemical equilibrium; the distributions obtained are in fair agreement with the more detailed calculations of Leovy (1964). The equations for temperature and ozone, with advection included, are linearized in terms of perturbations on the equilibrium fields, and a brief discussion of the effect of photo-chemistry, radiative transfer and their interaction on the thermal response to a field of motion is presented. Finally, the problem of the joint photochemical-radiative relaxation of perturbations in the absence of motion is investigated. It is found that the coupling sharply accelerates thermal relaxation above 35 km, and appreciably accelerates photochemical relaxatio...
TL;DR: In this article, it is inferred that large eddies in the planetary boundary layer of the atmosphere should take the form of horizontal roll vortices with an orientation between that of the surface wind and that of geostrophic flow.
Abstract: Turbulent shear flow generally contains large eddies which appear to be due to a shear instability of the profile of the mean flow. By analogy with laboratory experimental results, it is inferred that large eddies in the planetary boundary layer of the atmosphere should take the form of horizontal roll vortices with an orientation between that of the surface wind and that of the geostrophic flow. The vertical extent and intensity of the vertical motions associated with these roll vortices often may be sufficient to give rise to bands of clouds in the lower atmosphere. For an adiabatic boundary layer the spacing of cloud bands formed by this mechanism is tentatively predicted to be given by the relation L=200U/sinϕ, where L is measured in meters, U is the geostrophic speed near the ground in meters per second and ϕ is latitude.
TL;DR: In this article, the authors used conventional radar data to study airflow and also confirmed a number of important features of an airflow model previously proposed by the author (1964), such as that an updraft was present within, and was largely responsible for, the radar vault.
Abstract: Various features of the radar echo from a severe local storm are interpreted with the purpose of defining the nature of its updraft. The analysis illustrates the methodology of using conventional radar data to study airflow and also confirms a number of important features of an airflow model previously proposed by the author (1964). For example, it is confirmed that an updraft was present within, and was largely responsible for, the radar vault. The updraft within the vault was inclined upward with a component toward the storm's left flank below the level of the tropopause and in the reverse sense at higher levels. A novel feature of this analysis is that shafts of precipitation descending from neighboring storms are shown to have been drawn toward, and upward within, the vault. A study of the shape of these shafts of precipitation has permitted inferences to be made concerning the nature of the inflow toward the updraft.
TL;DR: In this paper, the structure of ice grown in water supercooled to temperatures between −2C and −7.5C has been studied and recorded by flash photography and a stepped growth mechanism has been suggested to explain the observed observations.
Abstract: The structure of ice grown in water supercooled to temperatures between −2C and −7.5C has been studied and recorded by flash photography. The ice structures formed below −3C are not co-planar with the basal plants of the seed crystals but are split into two, and occasionally more, segments. At temperatures below −5.5C secondary splitting occurs on the major growth segments, the complexity of the structure increasing with increased supercooling. A stepped growth mechanism has been suggested to explain thew observations. The three-dimensional structures so formed are sufficiently, complex to retain unfrozen liquid and so give rise to spongy ice.
TL;DR: In this paper, a life cycle classification for severe local storms is proposed, which adds a quasi-steady SR mature stage, to the well-known Byers-Braham classification.
Abstract: A life cycle classification for severe local storms is proposed, which adds a fourth stage, the quasi-steady SR Mature Stage, to the well-known Byers-Braham classification. A combined analysis of the surface weather and radar echoes from three neighboring severe local storms reveals that each storm went through a similar, well-defined metamorphosis at the onset of its SR Mature Stage. The distinctive character of this stage is attributed to the rotational properties of the updraft, which in the storms studied developed when the updrafts had become vigorous enough to produce giant hail.
TL;DR: Diurnal variation of upper atmosphere density and temperature as affected by solar heating and atmospheric heat transfer as mentioned in this paper, as well as atmospheric convexity and humidity, are analyzed in detail.
Abstract: Diurnal variation of upper atmosphere density and temperature as affected by solar heating and atmospheric heat transfer
TL;DR: In this paper, the influence of circulation changes in redistributing photochemical constituents through the mesosphere is attributed to atmospheric vertical motion, while stratospheric temperatures rose and fell by 10C during the period 21−29 June 1963.
Abstract: Mesurements of electron densities in the mesosphere at 43S (Christchurch, N. Z.) have shown that relatively constant values exist in summer, but large variations occur in winter. During the period 21–29 June 1963, isopleths of electron density descended and ascended by approximately 10 km, while stratospheric temperatures rose and fell by 10C. Both effects are ascribed to atmospheric vertical motion. This instance of “anomalous” ionospheric absorption shows the influence of circulation changes in redistributing photochemical constituents through the mesosphere.
TL;DR: In this paper, numerical computations related to the problem of diffuse reflection and transmission of the solar ultraviolet radiation by the earth's atmosphere in the presence of ozone have been carried out to include all orders of scattering.
Abstract: Numerical computations related to the problem of diffuse reflection and transmission of the solar ultraviolet radiation by the earth's atmosphere in the presence of ozone have been carried out to include all orders of scattering. A part of the computations is presented to show the strong and variable effect of multiple scattering on umkehr observations.
TL;DR: In this article, the first particles of ice in small cumulonimbus clouds way form as a result of a mechanism involving the violent breakup of drops is presented, supported by observations that ice nucleation occurs at relatively warm temperatures if a supercooled drop is subjected to a shock wave.
Abstract: Evidence supporting the hypothesis that the first particles of ice in small cumulonimbus clouds way form as a result of a mechanism involving the violent breakup of drops is presented. The hypothesis is supported by observations that: (1) ice nucleation occurs at relatively warm temperatures if a supercooled drop is subjected to a shock wave; (2) the bag mode of drop breakup occurs when drops are subjected to a shock wave; (3) and, the bag mode of drop breakup may occur in natural clouds even though the air is motionless except for turbulence introduced by the cloud drops themselves (i.e., shock waves or unnatural forms of turbulence are not required to promote the bag mode of drop breakup). The mechanism can only he effective in cases when clouds contain large supercooled drops. It is believed that the hypothesized mechanism may supply a critical link in the understanding of cloud glaciation by providing a means of triggering the avalanche mechanism involving ice splinter formation during drop f...
TL;DR: In this article, heat transfer and temperature in the symmetric flow in a rotating cylindrical annulus of fluid with a radial temperature contrast were measured using two different apparatuses under identical experimental conditions.
Abstract: Measurements of heat transfer and of temperature in the symmetric flow in a rotating cylindrical annulus of fluid with a radial temperature contrast are presented. The measurements were made using two different apparatuses under identical experimental conditions. These results are compared with a semi-quantitative visual study of the flow in such a system under similar conditions. These experiments were performed with and without a rigid lid in contact with the upper surface of the fluid and included the special case of zero rotation.
TL;DR: In this paper, a series of eleven meteorological rocket soundings from 0400 MST 7 February 1964 through 0205 MST 8 February 1964 over White Sands Missile Range, New Mexico were used to determine diurnal temperature variations between 30 and 60 km.
Abstract: Diurnal temperature variations between 30 and 60 km have been determined in a series of eleven meteorological rocket soundings from 0400 MST 7 February 1964 through 0205 MST 8 February 1964 over White Sands Missile Range, New Mexico. The soundings were spaced at 2-hour intervals and temperatures were measured with thermistor type instrumentation suspended on a parachute. Minimum temperatures were recorded near 0400 to 0600 MST and maximum temperatures occurred about 1400 MST. The temperature range decreased from near 20C at 55 km to 15C at 45 km and to near 5C at 35 km. Significant non-diurnal heating was also present. Additional sets of temperature soundings made at 1400 and 1600 MST on 21 November 1964 and 0400 and 0600 MST on the 22nd over White Sands Missile Range were available for comparison. These soundings indicated a day to night variation of 15C from 63 km down to 55 km with marked dampening of variation thereafter. The November soundings may not represent the entire diurnal range since...
TL;DR: In this article, a previously derived theoretical expression for the rate of sintering between two ice spheres is applied to the case of adhesion between ice particles down to temperatures of −40C.
Abstract: A previously derived theoretical expression, supported by experimental observations, for the rate of sintering between two ice spheres is applied to the case of adhesion between ice particles down to temperatures of −40C. Appreciable bonding is shown to take place between the particles within 10 seconds of contact even at −40C. The results predicted by the theory are found to be in quantitative agreement with the degree of sintering observed in aggregates of ice particles from natural ice fogs.
TL;DR: In this paper, pressure, density, temperature and wind measurements in mesosphere were obtained from rocket soundings to determine the structure of the Earth's magnetic field, and they were used to estimate the density and temperature of the mesosphere.
Abstract: Pressure, density, temperature and wind measurements in mesosphere resulted from rocket soundings to determine structure
TL;DR: Martian atmospheric heating from solar radiation absorption in UV and visible by oxygen and ozone and in near IR by carbon dioxide, noting vertical distribution of gases and absorption as discussed by the authors, is shown in Figure 1.
Abstract: Martian atmospheric heating from solar radiation absorption in UV and visible by oxygen and ozone and in near IR by carbon dioxide, noting vertical distribution of gases and absorption