Declination Of Earth Research Articles

Analysis of the planetary thermal distribution with a simple three-zone maximum-flux model

The large uncertainties in the forecasting of future global climatic conditions endorse the need of developing simple yet credible predicting tools. Here we propose a three-zone steady-state radiative model that maximizes latitudinal heat fluxes and considers the potential effect of the Earth's declination. The model is formulated as a set of five equations and six unknowns (zonal temperatures and widths, and the latitudinal heat transport) that requires specifying the reflected (albedo) and back-to-Earth (greenhouse) radiation fractions and obliges turning the low-latitude temperature into an additional parameter. The results do depend on the Earth declination, with changes of 0.5/1.5 K in the intermediate/high zones, which is interpreted as potentially affecting the greenhouse and high-latitude albedo coefficients. Therefore, we focus on identifying the effects of changes in these parameters – properly selected to represent last-glacial-maximum, modern and end-of the-century conditions. The main change is a large rise of the high-latitude temperature, favored both by a decrease in the high-latitude albedo and an increase in the greenhouse factor. For the other variables, the temporal changes in albedo and greenhouse gases compete among them, resulting in one trend from glacial to modern times and a reversal between preindustrial times and the end of the 21st century (currently a warming-narrowing of the intermediate region and the widening of both the low- and high-latitude zones); however, we note that an increase in the low-latitude temperature would tend to alleviate these changes. Despite its simplicity, the model leads to realistic global trends, becoming a useful simple tool for exploring the sensitivity of the Earth's heat distribution to changes in radiative fluxes and endorsing the validity of the maximum latitudinal-heat-transport premise.

Developments in Jovian Radio Emissions Tomography and Observations Techniques

Jupiter radio emission is known to be the most powerful nonthermal planetary radiation. In recent years specifically space-based observations allow us to permanently cover a large frequency band (from 100 kHz up to 40 MHz combined with ground-based telescopes) of the Jovian spectrum. The Plasma and Wave Science experiment onboard Galileo enables the observation of Jovian kilo-metric and hectometric emissions; Wind/WAVES and ground-based telescopes (mainly Decametric Array in Nancay, France, and UTR-2 in Kharkov, Ukraine) cover also hectometric and mainly decametric emissions. Specific geometrical configurations between Cassini approaching Jupiter and Wind spacecraft orbiting Earth, with Galileo orbiting Jupiter and Wind, in combination with ground-based observations provide a new approach to perform Jovian radio tomography. The tomography technique is used to analyze ray paths of Jovian radio emission observed in different directions (e.g. solar and anti-solar direction) and for different declination of Earth. The developments of Jovian radio emission tomography in recent years treated refraction effects and its connection to the local magnetic field in the radio source as well as the radio wave propagation through the Io torus and the terrestrial ionosphere. Most recently ground-based multi-site and simultaneous Jupiter decametric radio observations by means of digital spectropolarimeter and waveform receiver provide the basis of a new data analysis treatment. The above addressed topics are without exemption deeply connected to the plasma structures the radio waves are generated in and propagating through.

Photovoltaic/wind turbine - a comparative study for coastal areas

Wind and solar energy are both to a large extent affected by the changes in the weather ie they are weather dependent, especially wind. Other factors which have an influence are the change in the earth's declination angle combined with the atmosphere. More regional phenomenon having an effect are features such as mountains and the sea. To determine the effects of different factors a dual system was established to monitor the effectiveness of a photovoltaic array and a wind-driven generator system. This aim was achieved by simulating a radio repeater.

Apparent changes in the rotation rate of Jupiter

The apparent change of Jupiter's rotation rate derived from decameter emission probability histograms is shown to differ from the change derived by comparing dynamic spectra of the radiation. The dynamic spectra indicate that the two major “sources” of radiation shifted longitudes in opposite directions over the period from 1960 through 1965. The drift of histogram features and the drift of spectral features is attributed partly to emission beam divergence as the Earth's declination changes, and partly to a slightly incorrect System III period. The observations are explained by a model in which much of Jupiter's emission (especially the Io-related emission) is beamed in a thin conical sheet from Jupiter's northern hemisphere. On Earth, we observe the two regions where the sheet crosses the ecliptic plane.

Radio Rotation Period of Jupiter

The results of observations of Jupiter at 18 megacycles per second indicate that the apparent rotation period drifts cyclically about a constant mean value. The most probable drift period appears to be 11.9 years, Jupiter's orbital period. The mean rotation period during one orbital period is about 0.3 second longer than that of the system III (1957.0) period. This is in close agreement with the rotation period deduced from decimetric observations and probably represents the true rotation period of the magnetic field. The cyclic drift in the rotation period of source A at 18 megacycles per second is explained on the basis of beaming of the escaping radiation at an angle 6 degrees north of the magnetic equator. The apparent rotation period of source A depends on the rate of change of the Jovicentric declination of Earth.