Based on the success of several 2-D (latitude, longitude) linear barotropic instability models at matching some of the observed characteristics of the cloud level, polar region of the Venus atmosphere, a more realistic, linear, 3-D (height, latitude and longitude) model has been developed to further test the hypothesis that the observed features can be described by linear instability theory. The approach taken is to vary the model input parameters to see whether it is possible to produce modes that resemble the observations of wave activity and to compare those input parameters with other observations of the mean state. Sensitivity studies show that in addition to a well-documented dependence on the mean zonal wind, the growth and propagation of unstable modes depends on the latitude variation of the mean temperature (and hence static stability). These studies have lead to the specification of a model basic state wind and temperature field that produces modes which are matched to observations of spatial structure, preferred wavenumber and phase speed of the polar disturbances. Wavenumber 2 is found to have the shortest growth time and unlike the 2-D results wavenunibers 1–3 share a nearly common period of about 3 days. The derived basic state has a temperature field that is quite similar to Pioneer Venus observations; however, in some regions the model basic state wind field departs from cyclostrophic values based on temperature observations.
Thermal structure measurements obtained by the two VEGA balloons show the Venus middle cloud layer to be generally adiabatic. Temperatures measured by the two balloons at locations roughly symmetric about the equator differed by about 6.5 kelvins at a given pressure. The VEGA-2 temperatures were about 2.5 kelvins cooler and those of VEGA-1 about 4 kelvins warmer than temperatures measured by the Pioneer Venus Large Probe at these levels. Data taken by the VEGA-2 lander as it passed through the middle cloud agreed with those of the VEGA-2 balloon. Study of individual frames of the balloon data suggests the presence of multiple discrete air masses that are internally adiabatic but lie on slightly different adiabats. These adiabats, for a given balloon, can differ in temperature by as much as 1 kelvin at a given pressure.
Abstract The method used to determine the condition of marine biological resources is still conventional, not systematic and not comprehensive. So far, the methods used include divers where the depth of observation is very limited. Another method using sonar for which the acquisition of data is still qualitative. For this reason, it is necessary to strive for new methods that can guarantee careful and accurate observation. This study proposes the detection, classification and quantification of underwater target algorithms using Intelligent Biomass Active Sonar Transducer (IBAST) using a microcontroller unit. IBAST uses acoustic pulses and features that are narrow spectral so as to provide the ability to detect underwater targets (underwater targets) accurately and be able to classify such targets as fish, zooplankton, marine mammals, coral reefs, and other targets. IBAST uses a tracking algorithm and output detector which reduces errors in target detection. The application of the algorithm will be carried out to test the classification method and quantification of underwater targets. This research is very useful in the aspects of quantification of marine life, protection of fishery resources and seabed habitat.
The evolution of ozone (O 3 ) observed by the Microwave Limb Sounder on board the Upper Atmosphere Research Satellite is described for 14 Aug through 20 Sep 1992, in relation to the polar vortex. The development of an ozone hole is observed in column O 3 , and a corresponding decrease is seen in O 3 mixing ratio in the polar lower stratosphere, consistent with chemical destruction. The observations also suggest that poleward transport associated with episodes of strong planetary wave activity is important in increasing O 3 in the mid‐stratosphere.
The typical 1-2 m/sec vertical winds encountered by the Vega balloons probably result from thermal
convection. The consistent 6.5-kelvin differential between the Vega 1 and Vega 2 temperatures is attributable
to disturbances of synoptic or planetary scale. According to the Doppler tracking the winds were stronger
than on earlier missions, perhaps because of solar thermal tides. The motions of Vega 2 may have been
affected by waves from mountainous terrain.
The evidence and interpretations pertaining to the surface phase composition of Io and the mechanisms by which Io's surface influences its atmosphere are discussed. The mechanism by which Io's surface and/or atmosphere supplies neutral and ionic species to the region around the satellite and ultimately to the Jovian magnetosphere is also discussed. A model is suggested in which the global SO2 gas abundance is primarily controlled by buffering in the brightest, coldest regions. The net SO2 flux across the disk is limited by regional cold trapping on high albedo regions and possibly by the resistance of a tenuous non-SO2 residual atmosphere. The continuing migration of SO2 toward cooler regions and those lacking SO2 sources is opposed by SO2 destruction and planetary ejection processes, including sputtering, thus preventing buildup of thick, ubiquitous SO2 coverage.
Abstract This work describes the development of a diagnostic model designed to deduce characteristics of the mean circulation of a portion of the upper atmosphere of Venus. The model will use remotely sensed, global scale temperatures and solves momentum and mass flux equations. The solutions are dependent on externally specified, and inexactly known parameters.
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