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1.
Anna Mani C. R. Sreedharan B. B. Huddar Y. Ramanathan 《Pure and Applied Geophysics》1972,100(1):101-108
Summary Results of measurements of the atmospheric electrical conductivity and potential gradient made during the sixth Scientific Cruise of the Indian Oceanographic Ship INS Kistna in the Bay of Bengal during February–March 1963 are presented. Observations were made when the skies were generally clear and the sea calm, in the geographical area 8°N to 17°N and 80°E to 95°E, on the outward journey of INS Kistna from Madras (80°E, 13°N) to Port Blair (93°E, 12°N) and on the return journey to Madras.Over the ocean where there are no local sources of pollution, the measured values of conductivity and potential gradient are in agreement with theoretical values, assuming that an ion equilibrium exists, that ions are destroyed primarily by collision with small ions of opposite sign and that small ions are produced only by cosmic radiation. The values of electrical conductivity obtained are generally of the same order as those to be expected from theoretical considerations and in general agreement with those obtained during the Carnegie cruises in the Indian Ocean in 1920. There are, however, significant variations near the coast where the electric structure above the ocean is affected by continental sources of pollution. Conductivity values near the land are about half that in the unpolluted air over the ocean but prevailing winds prevent the extension of pollution beyond 100–200 km from the coast in this season.
Zusammenfassung Es wird über Messungen der luftelektrischen Leitfähigkeit und des Potentialgefälles berichtet, welche während der Sechsten Wissenschaftlichen Kreuzfahrt des indischen Ozeanographischen Forschungsschiffes Ins Kistna in der Bengalischen Bucht im Februar und März 1963 ausgeführt wurden. Die Beobachtungen sind im allgemeinen bei klarem Himmel und ruhiger See gemacht worden, und zwar in dem geographischen Bereich zwischen 8 und 17°N und 80 und 95°E während der Ausfahrt der INS Kistna von Madras (80°E, 13°N) nach Port Blair (93°E, 12°N) und auf der Rückreise nach Madras. In den Bereichen des Ozeans, in denen keine örtlichen Pollutionsquellen bestehen, stimmen die gemessenen Werte der Leitfähigkeit und des Potentialgefälles mit den theoretischen Werten überein, die man erhält, wenn man annimmt, dass ein Ionengleichgewicht besteht, dass die schnellen Ionen vorwiegend durch Zusammenstoss mit schnellen Ionen des entgegengesetzten Vorzeichens vernichtet werden, und dass die schnellen Ionen nur durch die kosmische Höhenstrahlung erzeugt werden. Die Werte der Leitfähigkeit stimmen mit denen überein, die man aus theoretischen Überlegungen gewinnt, und auch mit denen, die während der Kreuzfahrten des Forschungsschiffes Carnegie im Indischen Ozean im Jahre 1920 gemessen Küste sind jedoch bedeutsame Abweichungen festzustellen, wo die elektrischen Verhältenisse über dem Ozean durch Pollutionsquellen auf dem Lande beeinflusst werden. Die Leitfähigkeitswerte nahe dem Land sind nur ungefähr halb so gross wie die in der pollutionsfreien Luft des offenen Ozeans-jedoch haben die während der Mess-Jahreszeit vorherrschenden Winde eine Ausbreitung der Pollutionszone auf einen Bereich von 100 bis 200 km von der Küste beschränkt.相似文献
2.
The vertical profiles of ozone and temperature from a series of balloon soundings at Delhi (28°N), Poona (18°N) and Trivandrum (8°N) were studied with synoptic meteorological data. While both ozone and temperature profiles show similar variations over all three stations, ozone maxima being always associated with thermally stable layers, the variations are most pronounced over Delhi, particularly in winter and in early spring when a series of western disturbances pass over north India. Both ozone and temperature profiles over Delhi show a layer structure characterized by a series of maxima and minima in both the vertical distribution of ozone and temperature and these are most pronounced in the lower stratosphere. These variations are associated with the influx of ozone-rich middle latitude stratospheric air over Delhi replacing subtropical air. 相似文献
3.
Problems experienced in continuous recording of surface ozone by the electrochemical method at Poona
The surface ozone recorder developed at Poona uses a Brewer electrochemical bubbler ozone sensor and provides a rapid and convenient method for the continous measurement of ozone concentration near the ground. Continuous recording with the sensor is possible if a constant level of solution can be maintained in the bubbler. This was achieved by incorporating a reservoir of KI solution which automatically syphons the solution into the bubbler. The errors inherent in the system and the successful attempts to remove them and obtain continuous records of surface ozone of the accuracy required are described. 相似文献
4.
B. H. Subbaraya K. S. Appu K. P. Chatterjee A. F. Chizhov V. D. Grinchinkov A. Jayaraman G. A. Khokin V. A. Kononkov I. S. Moshnikov V. Narayanan S. P. Perov O. V. Shtrikov Y. V. Somayajulu C. R. Sreedharan K. S. Zalpuri 《Journal of Earth System Science》1987,96(1):25-40
A total of seventeen vertical profiles of ozone were obtained during an Indo-USSR collaborative experiment on ozonesonde intercomparison conducted at Thumba during March 1983. The vertical distribution of ozone was measured using rocket-borne, balloon-borne as well as ground-based instruments. Four different rocket ozonesondes from India and USSR and the balloon ozonesonde were used to makein situ observations of ozone concentrations in addition to the Dobson spectrophotometric observations of total ozone and Umkehr. The rocket and the balloon launchings were effected in three salvos and measurements were made at different times of the day as well as during night. The results of all these measurements are used to obtain a mean ozone vertical distribution over Thumba foT the spring equinoxial period. The mean profile shows the maximum ozone concentration at 27 km with a value of (3.86±0-52)×1012 molecules per cc. Comparison of this mean profile with available satellite data for the equatorial regions shows that, in general, the Thumba values are lower by 10–15% at altitudes below 40 km and larger at altitudes above 50 km compared to the satellite results. The data also show evidence for a day-to-day variability and a possible day-to-night variability in the ozone vertical distribution with the night-time values higher than the daytime values at all altitudes above 35 km and the difference is found to increase with the increasing altitude. 相似文献
5.
Greeshma Nizy Eujine Sreedharan Chandrakaran Natesan Sankar 《Arabian Journal of Geosciences》2017,10(20):454
Atterberg Limit Tests, unconfined compressive strength tests, and California Bearing Ratio Tests were conducted on the two minerals—kaolinite and bentonite—after subjecting them to stabilization with lime, enzyme, and enzymatic lime. The purpose of the study was to evaluate the effectiveness of enzymatic lime as a stabilizer over lime and enzyme. Results establish that enzymatic lime stabilization is the better stabilizer in terms of strength development. The unconfined compressive strength and California Bearing Ratio values of enzymatic lime stabilized samples have increased up to 5 and 30 times in the case of kaolinite mineral, but to only less than 1.5 times in the case of bentonite mineral. The study thus indicates that enzymatic lime stabilization is predominantly effective for clays containing kaolinite minerals. 相似文献
6.
The temporal evolution of pressure in solar coronal loops is studied using the ideal theory of magnetohydrodynamic turbulence in cylindrical geometry. The velocity and the magnetic fields are expanded in terms of the Chandrasekhar-Kendall (C-K) functions. The three-mode representation of the velocity and the magnetic fields submits to the investigation of chaos. When the initial values of the velocity and the magnetic field coefficients are very nearly equal, the system shows periodicities. For randomly chosen initial values of these parameters, the evolution of the velocity and the magnetic fields is nonlinear and chaotic. The consequent plasma pressure is determined in the linear and nonlinear regimes. The evidence for the existence of chaos is established by evaluating the invariant correlation dimension of the attractorD
2, a fractal value of which indicates the existence of deterministic chaos. 相似文献
7.
The latitudinal and temporal variations in the vertical profiles of ozone over the Indian subcontinent are discussed. In the equatorial atmosphere represented by Trivandrum (8°N) and Poona (18°N), while tropospheric ozone shows marked seasonal variations, the basic pattern of the vertical distribution of ozone in the stratosphere remains practically unchanged throughout the year, with a maximum at about 28 to 26 km and a minimum just below the tropopause. The maximum total ozone occurs over Trivandrum in the summer monsoon season and the latitudinal anomaly observed over the Indian monsoon area at this time is explained as arising from the horizontal transport of ozone-rich stratospheric air from over the thermal equator to the southern regions.In the higher latitudes represented by New Delhi (28°N), the maximum occurs at 23 km. Delhi, which lies in the temperate regime in winter, shows marked day-to-day variations in association with western disturbances and the strong westerly jet stream that lies over north and central India at this time.Although the basic pattern of the vertical distribution of ozone in the equatorial atmosphere is generally the same in all seasons, significant though small changes occur in the lower stratosphere and in the troposphere. There are small perturbations in the ozone and temperature structures, distinct ozone maxima being always associated with temperature inversions. There are also large perturbances not related to temperature, ozone-depleted regions normally reflecting a stratification of either destructive processes or materials such as dust layers or clouds at these levels. Particularly interesting are the upper tropospheric levels just below the tropopause where the ozone concentration is consistently the smallest, in all seasons and at all places where soundings have been made in India. 相似文献
8.
The use of geosynthetics as a ground improvement technique offers the advantages such as space saving, environmental sensitivity, material availability, technical superiority, higher cost savings and less construction time. Coir geotextiles can be considered as an efficient replacement to its synthetic counterparts due to its economy and excellent engineering properties. The present study aims at exploring the possibilities of utilising coir geocells as a potential reinforcement material for shallow foundations and thereby increasing the load carrying capacity of soil. Geocells were fabricated from coir geotextiles with the aim of providing an additional confinement to the soil. An enumerated parametric study was conducted by varying the relative density, depth of the first layer, width and height of coir geocell. The surface displacement profiles of the non-reinforced and coir geocell-reinforced soil indicate that the footing rotation and heave are considerably reduced with the provision of geocell. The results of the relative density study indicate that bearing capacity characteristics increase with denseness of the soil sample. It was also observed that geocell arrangement and configuration play a pivotal role in the performance characteristics of reinforced soil. 相似文献
9.
The theory of ideal magnetohydrodynamic turbulence in cylindrical geometry is used to study the steady-state structure of a coronal loop. The pressure profile is derived from MHD equations by representing the velocity and magnetic fields as the superposition of Chandrasekhar-Kendall functions. Such a representation brings out the three-dimensional structure of the pressure in the coronal loop. The radial, azimuthal, and axial variations of the pressure for a constant density loop are discussed in detail. The pressure has an oscillatory behavior for different azimuthal angles at some radial positions. This study predicts more features in pressure than can be compared with the presently available observations. 相似文献
10.
Summary Measurements of spectral ultraviolet irradiance require spectroradiometers with high resolution and stability, and well known behavior of the instrument. A UV-spectrophotometer is described and methods of calibrations are shown. A set of measurements in the Utah Rocky Mountains (Snowbird-Hidden Peak, in 3300 m elevation) compared to those at the Wasatch Front (Logan, 1400 m) is discussed. Several sets of measurements are used to show the effect of solar zenith angle, elevation and cloudcover on direct solar and diffuse irradiance.At the time of the instrument design and measurements all were at Utah State University, Department of Soil Science and Biometeorology, Logan, Utah.With 11 Figures 相似文献