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

A method is developed for estimating the cloud top pressure and the cloud amount when clouds occur between the 100 mb and 200 mb level in the tropics. The method depends on the fact that the radiance in the High Resolution Infrared Radiation Sounder channel 3 (691 cm-1) is affected by clouds at those levels but is not affected much by clouds below the 200 mb level. Channel 3 radiances are used together with radiances from channel 4 (704 cm-1) to construct a diagram from which the cloud top pressure and cloud amount can be estimated. Satellite observations of radiances (equivalent brightness temperatures) in those two channels are entered into the diagram to yield the cloud parameters. The result from TIROS N data for June 11, 1979 near 1ºS, 106 E, are compared to published computations for that date. The results here show that overcast clouds reached the 100 mb level. The published data show clouds with about 50 cloud cover which do not reach the 200 mb level.  

A dynamic-stochastic model based on random forcing of Adem thermodynamic climate model is considered. The way of including simplified atmospheric water budget is proposed. Computed fields of standard deviations of ocean mixed layer monthly temperature anomalies and turbulent heat flux monthly anomalies are quite realistic. Inputs of the anomalies of the wind drift currents advection and anomalies of latent heat flux are found to be the most important sources of the upper ocean layer variability. Autoregressive models of the ocean mixed layer monthly anomalies are discussed.

This paper discusses the correlation between northers, which lash the coasts of the Gulf of Mexico, and frosts which occur in Las Vigas, Veracruz, based on the climatological records of this place from 1959-1987. The frosts are classified according to their origin and type. The first being radiative and the second ones white frosts, which are more frequent in this region. From the correlation analysis between the northers and the white frost, it was found a correlation coefficient r = 0.480, which is significative at 1%.

Some of the fundamental problems related to the current approach to global climate change from modelling and observational stand points are discussed. The author offers his personal opinion and suggests caution in terms of an all out effort to understand the problem through numerical modelling based on GCMs models. At the same time he advises other approaches i.e. statistical and other studies of atmospheric phenomena different from temperature in seeking evidences of climate change. He emphazises in particular the need to find, for political reasons and as soon as possible, a clear signal that the greenhouse gas affect is being enhanced and that this has an impact on the general circulation of the atmosphere.

Numerical simulations with the Naval Research Laboratory limited area model were performed using initial conditions derived from gridded analyses of the Colorado State University composite Atlantic prehurricane cloud cluster and depression. For each type of disturbance, simulations were made with initial conditions consisting of the zonal mean wind superimposed on the axially symmetric component of the flow about the vortex center. These simulations were compared with ones in which the initial conditions were specified from the gridded analyses in their full 3-dimensional complexity. When the full asymmetries were retained in the initial conditions, both the prehurricane cloud cluster and the prehurricane depression developed into a mature hurricane in the numerical integrations. When the asymmetries, with the exception of those associated with the zonal mean wind, were not present in the initial conditions, the prehurricane depression showed no significant development during the first 60 hours of integration, after which it intensified slightly, and the prehurricane cloud cluster developed into a weak depression. Associated with the wave-like asymmetries in the initial wind and temperature fields are large-scale eddy fluxes of angular momentum and heat. The data reveal that these are organized in such a way as to induce a secondary radial circulation which picks up moisture as it spirals inward over a large stretch of ocean and pumps dry air outward in the upper troposphere and lower stratosphere. We argue that it is this circulation which initially organizes the convection over warm ocean water and triggers a chain of events that ultimately leads to the intensification of the disturbance into a hurricane. The absence of such fluxes when the initial conditions consist of the zonal mean wind superimposed on the axially symmetric component of the flow is sufficient to keep the disturbance from intensifying into a hurricane.  

Using satellite-derived insolation (Tarpley, 1979), a method is developed to assess total short-wave radiation depletion due to El Chichon stratospheric aerosols under cloudless conditions. Seven daily digital images are mapped on a 1x1 longitude-latitude grid of Mexico from May 1982 to December 1983. Cloudless conditions are determined using hourly sunshine data at several of the points of the array. The spatial and temporal resolution of satellite-derived irradiance permits the study of the evolution of the aerosol layers through the extinction of solar radiation. The results are expressed as extinction anomalies with respect to the mean values of the corresponding digital images of 1984. During May 1982 high extinction values covered most of Mexico. From June to August 1982 solar irradiance returned almost to normal values as easterlies were well organized shifting the aerosol cloud westwards. After September 1982 solar radiation extinction increased reaching the highest values in December 1982 (27.5%). During January to May 1983 extinction remained high but variable, between 10 to 22%. From June to August 1983 solar radiation returned again to normal conditions in most of the country although some areas persisted with important extinction anomalies (13%). During September to December 1983 solar radiation extinction remained between 16 and 14% showing that the stratosphere still contained a large amount of residual aerosol. The decay of the perturbation behave as a dampened harmonic oscillator with seasonal oscillation, maximum and minimum occurring in local winter and local summer, respectively.  

The diurnal variations of the concentrations of atmospheric pollutants in the Metropolitan Manila area is studied. The pollutants included in the study are SO2, CO, NO2, NO, HC, Ox and particulate matter. The data consist of hourly observations from five (5) monitoring stations at selected urban centers for the period covering 1975-1978. The results show two types of concentration variations exhibited by the pollutants depending upon whether they are photochemically reactive (N0x, SO2, HC and Ox) or non-photochemically reactive (CO and particulate matter). The variation corresponding to non-photochemically reactive pollutants show two maxima, one in the morning at 8:00 am and a secondary in the evening from 8:00-9:00 pm. However, the photochemically reactive pollutants exhibit only a single maximum at about noontime or early afternoon. The dependence of the diurnal variation with respect to the season has also been studied. In general, the trend of the variations for all pollutants are similar but the concentration of the pollutants is lower during the southwest monsoon season.

The contribution in rain acidification caused by the oxides of nitrogen which are further oxidised to nitrates and subsequently release of hydrogen ions in the atmosphere while reacting with rain droplets has been studied from the period 1976 to 1987 using the data of ten BAPMON stations of India. It was observed that there exists a significantly strong inverse correlation (r = -0.845 ± 0.083) between the rainfall pH and the corresponding concentration of nitrates at about 1% L. S. which indicates that rapid decrease in rain pH in India is mainly caused by the sudden increase in nitrate radicals which are formed by the oxidation of nitrogen oxides which are the ultimate outcome of automobile pollution caused by the rise in vehicular population in India.

In the very origins of formalism as a theory of arts, and in the context of the debate concerning a certain determinist formulation of “materialism” (that of G. Semper), an antinomy emerges between the perceptual or phenomenic dimension of art and its physical- material dimension. Both dimensions seem equally necessary in order to specify the peculiar condition of art, which for formalism entails the difference between the diverse artistic practices. This antinomy is linked to the formalist ambition of establishing the foundations for the autonomy of the arts by specifying them through a double principle: first, an “aesthetic” principle, which emphasizes the specificity of the arts? different “sensuous spheres”, and secondly, a “poietic” principle, which emphasizes the plurality of the technical processes of the different arts. Eduard Hanslick (a foundational author of formalism, from the middle of the 19th century) formulated this problematic for the art of music in terms of the “elementary materials of music”. After exploring his formulation, we will quickly point to some parallelisms with formalist authors of roughly the same period such as Konrad Fiedler and Alois Riegl. We will finish by indicating how, in the future evolution of formalism as “modernism”, i.e., as the main discourse about modern art, the viewpoint of the act of artistic creation would be finally displaced by that of reception and the spectator as vantage point for treating this issue of the “materiality” of art.

The purpose of this discussion is to recover the notion of transdisciplinarity as a possible structural link between philosophy and literature, establishing certain epistemological coordinates that rest on the idea of poetic reason by the Spanish philosopher Maria Zambrano, as well as in the invitation to intellection through beauty by the Argentinean writer Leopoldo Marechal. Therefore, first, we would like to briefly introduce the notion of transdisciplinarity, following the definitions of Basarab Nicolescu, and then approach the poetic word as a condition of possibility of the knowledge of reality. From there, we will explain the most characteristic features of the concept of poetic reason and intellection through beauty, to open up a dialogic space between them and, thus, propose a transdisciplinary nature of the poetic word in our path to knowledge.