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Thunderstorm Connected with Sporadic E Propagation Flavio Egano, Ik3xtv Documento N

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Thunderstorm Connected with Sporadic E Propagation Flavio Egano, Ik3xtv Documento N Thunderstorm connected with Sporadic E propagation Flavio Egano, ik3xtv documento n. 128 del 5 Settembre 2008 Is it possible that sporadic E propagation is • Ionospheric absorption Weather connected with thunderstorms? Recent •D Region structure / moving ions in the When I began my research on propagation researches seem to support this hypothesis. Ionosphere studies, I mainly focused on solar and geomagnetic activities and inside the Communications are possible through the The influence of g.w. seems more pronounced ionosphere mechanism, I was convinced that plasma irregularities into the Ionosphere in the E in the formation of the night F2 layer, which only in this area should develop research region, these irregularities are called sporadic E. would help provide a small but continuous because propagation supporting was limited in We have therefore single and even double hop source of new ionization, contributing to the this context. In reality I realized that the weather propagation. Occasionally lightning storms maintenance of residual ionization during the has a significant impact on propagation. Some occur near the centre (point of reflection) of the night. But the dynamics associated with significant studies conducted by a New Zealand Paths of radio contacts. The assumptions of sporadic E openings are convinced that the OM, Bob Gide, ZL3NE , show how we can lightning storms are a possible source of ignition gravity waves play a decisive role. forecast openings on the 6 and 2 meters Ham for the E sporadic, especially for the more bands as they are closely associated with the intense irregularities able to support the weather conditions. Similarly weather conditions propagation for frequencies up to 144 Mhz. play an important role in the sporadic E This hypothesis, however, is not fully accepted formation. Es clouds are often associated with by the international amateur radio community frontal system of low pressure, the study since the effect of thunderstorm on Sporadic E focuses primarily on what could be the catalyst has not yet been proved with scientific evidence, in the formation of ionized curtain: Atmospheric although there is a recent publication of an gravity waves are generated by these moving article on the prestigious scientific journal frontal systems associated with atmospheric "Nature" where discusses on the connection tides. In other words training the more intense between Thunderstorms and ionosphere. The sporadic E (144 mhz) may be related mainly to most likely theory to explain the mechanism is thunderstorm effect, while the regular Es (HF the "Wind shear theory" . range and 50 MHz) could be mostly related to Recent measurements have found a high dynamics of atmospheric tides. But the HF content of Ion metal inside the curtain of Es: Fe propagation may be closely related to weather and Mg as well as O2 and NO: the major ions conditions. We are therefore faced with a further and dominant ion into the region E. Within the complication. Atmospheric tides curtain of ions are present quantities of major The atmospheric tides are mainly generated in metal ions, catalytic from meteoric rain. Some of Possible effects associated with sprites the troposphere and in the stratosphere where the open questions are these: Sprites are similar to lightning phenomena but the atmosphere is periodically heated for the that develop in the stratosphere at a height of absorption of solar radiation by water vapour • The role of metal ions (and meteorites cosmic between 10 and 100 km, are therefore of and ozone. The tides generated are then able to dust) electric shocks lasting a few tenths of a second spread from these regions and go up to the • The role of sprites (How is the interaction with that develop because of the potential difference mesosphere and thermosphere. The the ionosphere?) between the clouds and the high atmosphere atmospheric tides can be measured as regular • The role of lightning fluctuations in the wind, temperature, density • The role of atmospheric gravity waves The project and pressure. Despite the atmospheric tides • The role of ionospheric winds and the jet The project consists to investigate the spatial- have much in common with the ocean tides, stream temporal correlation between the openings of They are distingued for two key features: The • The role of the geomagnetic field Es in 144 MHZ and thunderstorms. atmospheric tides are caused primarily by • the action of solar radiation Propagation on 144 MHz: constantly monitored warming from the sun (could be a link with the through reports of many active OM that record daytime occurrence sporadic E as well as the date, time, frequency and geographic seasonal frequency concentrated more in location. summer), while those of the oceans are mainly Thunderstorms: represented by the recording of caused by the lunar gravitational field. This spherical (low pulse radio frequency emitted by means that most atmospheric tides have lightning) published by various meteorological periods of oscillation with the length of 24 hours institutes on the internet. of the day sun, while the ocean have longer periods related to the lunar day (time between Discussion two successive transits moon) accounts for During the month of June, sporadic E and about 24 hours and 51 minutes . The spherical are very common, and is not a atmospheric tides propagate into the surprise that both can occur in the same atmosphere where the density varies location. In this particular case, however, significantly with the altitude. One consequence sporadic E and the position of the thunderstorm, of this is that their amplitudes grow shows a spatial-temporal distribution very exponentially when the salt tide in regions similar. These results indicate that the effects of progressively more rarefied air. A ground-level a convective storm generating gravity waves ozone, the atmospheric tides can be localized that propagate from the lower atmosphere into but slight fluctuations as regular pressure the upper atmosphere support and stimulate surface with periods of 24 and 12 hours. the generation of sporadic E? Is possible that However, at a greater altitudes, the amplitude of this result indicates a dynamic process to the tides is very large. In the mesosphere (~ medium-latitudes similar to what occurs in height of 50 - 100 km) atmospheric tides can tropical atmosphere where some phenomena as reach speeds of 50 m /s and are often the Atmospheric gravity waves TID (Travelling ionosphere disturbance) and major cause of air movement. Atmospheric gravity waves (not to be confused equatorial spread F are really caused by with the more well note gravitational waves convective motion ? It is not possible answering Atmosphere dynamics on Earth from the theory of relativity by A. Einstein) are this question because the data are not yet Since the fluid is a continuous medium, a variations of elastic type that spread into the sufficient and we can not even exclude that this travelling disturbance will result. In the earth's atmosphere because its thermal stratification. is something random. But I believe that these atmosphere, gravity waves are important for Their wavelengths ranging from a few hundred results are cause for further studies and transferring momentum from the troposphere to meters to hundreds of kilometres, with periods collaboration between scientists and OM the mesosphere. Gravity waves are generated ranging from a few minutes to several hours. operating on VHF. The research that I have in the troposphere by frontal systems or by The fluctuations of the resulting causing small done can only detect the presence of the Es airflow over mountains. At first waves propagate fluctuations in atmospheric variables (pressure, and the simultaneous presence of storms. More through the atmosphere without affecting its temperature, humidity'...) but have a significant scientific data are necessary to analyze the mean velocity. But as the waves reach more impact on the structure of the ionosphere. The phenomenon in detail, for example using rarefied air at higher altitudes, their amplitude gravity waves have a key role inside the ionospheric radar and ionosonde located increases, and non linear effects cause the Ionosphere and then in the propagation of radio around Europe. Further studies should be breaking of the waves transferring their waves. The atmospheric gravity waves interact conducted on the high dynamic atmosphere to momentum to the mean flow. This process plays with: better understand the role of gravity waves. a key role in controlling the dynamics of the Analysis practice middle atmosphere. The clouds in gravity waves • sporadic E formation With the help of internet I did an analysis of the can look like Altostratus clouds, and are • tropospheric propagation various sporadic E opening on 144 Mhz sometimes confused with them, but the • influence in the F region occurred in recent years, comparing the formation mechanism is different. • Ionospheric disturbance distribution of Thunderstorms in Europe. I used Thunderstorm connected with Sporadic E propagation Flavio Egano, ik3xtv documento n. 128 del 5 Settembre 2008 as database the German site www.wetterzentrale.de , charts showing the number of daily lightning in Europe and their intensity and the site www.vhf-contest.com where there is a database that maps showing the location of many vhf contacts. While not finding mathematician evidence , crossing the data I have noted a considerable statistical correlation of openings associated Es with
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