Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

A multiple linear regression analysis of particulate, gas, and meteorological data is presented for different sites in California. The results of the regression analysis provide some insight into visibility -impairing processes. One remarkable factor is little or no association between visibility and the abundant sulfur component with diameter less than 0.65 µm. One must conclude that it was the growth of particles above 0.65 µm that caused the poor visibility; growth that was favored by the higher humidities but that may also reflect the ultimate sources of the sulfur. This study has shown the key role played by particulate size in atmospheric extinction. Those conditions that encourage the formation or growth of particles in the optically effective part of the accumulation mode are linked to reduced visibility. These results are in good agreement with Mie theory, and allow a much better match between theory and experiments than those gained by summing all mass below 2.5 µm or even key chemical constituents in the less than 2.5 µm regime.

A study of the regions of Mexico that have been affected by the premature and tardy frosts are presented in this paper The most severe ones have occurred mainly in September of the years 1909, 1917, 1974, 1975, 1979 and 1988 and in June of 1979 The presence of tropical cyclones and the manifestation of the frost are related. It is found that the phenomenon of either the premature or tardy frosts has connection with the presence of tropical cyclones; being this a necessary, but no sufficient condition, since there are other cases with tropical cyclones in which the frost is not present over the high lands of the Central Plateau.

In this second part of a continuing study of the relative structure of transient baroclinic waves an analysis of the behavior of waves in a three-level, quasi-nondivergent model is presented. The procedures applied in the analysis are a straightforward expansion of those used in Part I in which the two-level model was used. The increased algebraic work required by the three level case is eased somewhat by working in the complex domain with respect to the relative amplitudes and phases, but otherwise the methodology is maintained. However, the use of the complex domain makes it possible to obtain the steady states as the roots to cubic equations where complex roots indicate sloping waves. In addition, the stability analysis of the derived steady states goes easier in the new procedure. In view of the discovery of these advantages it was considered worthwhile to reconsider the two-level case where it is possible to solve the time-dependent problem in a closed form (section 2). Section 3 contains the analysis of the three-level case permitting not only vertical changes of the static stability but also deviations from a linear windprofile. While the results in the case of a straight windprofile are a natural extension of the two-level case, it is found that increasing negative windshears in the upper layer will destabilize the steady state solutions.

In the third and final paper in the series on the relative structure of transient atmospheric waves we consider a model atmosphere with a continuous specification of the zonal wind and the static stability in the basic state. The vertical variations of the parameters in the basic state (except the stability) and in the perturbations will be represented as series expansions in functions appropriate to the vertical variation of the static stability parameter. For the stability we shall consider two cases. The first is a constant static stability in the whole model, and the second is a case where the stability varies as inversely proportional to the square of the pressure. In the first case we may use trigonometric functions to describe the vertical variation. In the second case we derive the appropriate structure functions in the paper, but it turns out that to satisfy the upper boundary condition it is necessary to assume that the top of the atmosphere is located at a pressure larger than zero. The relative structure is in each case obtained as a solution to the stationary equations for the relative amplitude and the relative phase angle. Such solutions are in simple cases obtained directly, but in more complicated cases by numerical integrations carried out to a point where an asymptotic steady state is obtained.

In order to determine the climate type of the region of mont-lozere, france, the apatial and temporal patterns of rainfall and temperature were analysed using monthly records published in metereological and climatological bulletins. the climate type was dedifined essentyally from the origins and seasonal distribution of rainfall and the importance of the summer drought. the drought season and its intensity was determined using three criteria: the summer drought index, ombrothermic diagrams and rainfall and temperature continentality, the results indicated that, on the onde hand, at mont-lozere there exist three altitude related thermic classes, and on the other, that the region under study is situated in a transitional region between temperate and mediterranean climates. The region, during a particular year, may be onder the influence of either climate. The vegetation in not order the influence of an intermediate climate, but rather frequent changes between opposing climatic regimes.

New calculations are presented on the eddy diffusion coefficient profile in the height range 30-200 km in Mars' atmosphere based on the integration of the coupled continuity and motion equations for atomic oxygen and carbon monoxide. Values in the range 2 x 107 - 4 x 108 cm2 s-1 are determined and are able to explain the observed altitude profiles of these compounds. The eddy diffusion coefficient altitude profile deduced is compatible with others reported in the literature and we discuss its effect upon the concentration of the different atmospheric constituents. The turbopause level is located between 130 and 140 km, the molecular diffusion being the fastest transport process at altitudes above 160 km.  

We have designed an objective scheme to diagnose the statistics of extratropical cyclones, cyclogenesis and cyclolysis. It uses as much as possible the same criteria which are used for subjective analyses and allows an evaluation of model performance not captured by standard model diagnostics. Examples of possible applications to forecast and simulation experiments are presented in this paper.

From the visible satellite pictures of summer we have analized the variability of the southeast border of the Californian stratus cover. From the combination of the positions of the borders three cases are obtained: The borders towards the southwest, from south Baja California point, from Eugenia point and Conception point respectively. In summer the return point of the extreme northeast of this border is the Eugenia point. Shifting of stratus cover towards the north or west is associated with the presence of tropical storms or hurricanes which are near the southwest coast of Baja California, or also by the passage of an upper level trough. Also studies about this topic are reviewed.

An update is given of a previous paper by the same title, an explanation is given of the way greenhouse gases operate to raise the surface temperature of a planet. The paper in general is designed to be understandable to a wide range of disciplines. The argument is advanced that the role of radiative transfer has been overemphasized relative to other climatological processes and, in particular, that the roles of deep convection in the tropics and of evaporation from tropical oceans have been underemphasized and inadequately modeled in our calculations of climatic effects of increased CO2 to date.

The variations of the thermal characteristics of the near-surface ocean layers exert a significant impact on the heat influx to the atmosphere, and through this on the atmosphere circulation. To examine the ocean heat sources, the estimates of the current state of the oceanic thermal field drawn from operational temperature measurements are needed. The distribution of these measurements over the depth is highly irregular. Relatively detailed information is available only on the sea surface temperature (SST) measured both in situ from opportunity ships and drifting buoyes and by means of remote sensing from satellites. To obtain immediately the upper ocean mixed layer depth h, which in conjunction with the SST represents one of the main parameters characterizing oceanic near-surface heat storage, the measurements of vertical temperature profiles are needed. The number of XBT measurements commonly contained in operational data bases is highly restricted (~ 150 daily XBT measurements in the Northern Hemisphere) and is not enough for immediate obtaining of the mixed layer depths over the spacious ocean domains. In this connection indirect methods of estimating h are needed. One of the methods based on variational approach has been proposed by Resnyansky (1985). The estimates of h were obtained from the temporal sequences of SST at an ocean location. The values of h corresponding to minimal differences between modelled and observed SSTs within a given time interval are taken as a resultant estimate. The method has been tested using simulated data. The present paper is devoted to the further testing of the method using the actual observations at ocean weather station Papa in the North Eastern Pacific over the period from 1972 to 1974. The dependence of the estimation uncertainties on the model parameters as well as on the type of the basic state set to stabilize the estimates is considered.