Dependence of Atmospheric Transparency Variations on Solar Activity

The atmospheric spectral transparency variations at 344 nm and 369 nm, averaged at eight Soviet stations between 69°N and 55°N, have been compared with sunspot numbers, or Wolf numbers (WN). The data were taken for the seasonal interval May-August during the period 1972 – 1989. Good negative correlations –0.76 and –0.82 have been found. The correlation coefficient between aerosol extinction at 344 nm and WN is equal to +0.75. Insignificant correlation is found for the transparency variations at 344 nm for stations situated to the south of latitude 50°. The best correlation with WN for both transparency and aerosol extinction at northern stations occurs for the shift of WN ahead of the optical parameters by 6 months. The connection of transparency with cosmic rays in Apatity is also examined. It displays a sign opposite to that for WN, smaller values of the correlation coefficient, and an improbable shift of transparency ahead of cosmic ray intensity. The relative changes of the transparency during a solar cycle can be evaluated at 10% in the ozone-free UVA region     

Electrification of volcanic plumes

Volcanic lightning, perhaps the most spectacular consequence of the electrification of volcanic plumes, has been implicated in the origin of life on Earth, and may also exist in other planetary atmospheres. Recent years have seen volcanic lightning detection used as part of a portfolio of developing techniques to monitor volcanic eruptions. Remote sensing measurement techniques have been used to monitor volcanic lightning, but surface observations of the atmospheric electric Potential Gradient (PG) and the charge carried on volcanic ash also show that many volcanic plumes, whilst not sufficiently electrified to produce lightning, have detectable electrification exceeding that of their surrounding environment. Electrification has only been observed associated with ash-rich explosive plumes, but there is little evidence that the composition of the ash is critical to its occurrence. Different conceptual theories for charge generation and separation in volcanic plumes have been developed to explain the disparate observations obtained, but the ash fragmentation mechanism appears to be a key parameter. It is unclear which mechanisms or combinations of electrification mechanisms dominate in different circumstances. Electrostatic forces play an important role in modulating the dry fall-out of ash from a volcanic plume. Beyond the local electrification of plumes, the higher stratospheric particle concentrations following a large explosive eruption may affect the global atmospheric electrical circuit. It is possible that this might present another, if minor, way by which large volcanic eruptions affect global climate. The direct hazard of volcanic lightning to communities is generally low compared to other aspects of volcanic activity.     

The Global Atmospheric Electrical Circuit and Climate

Evidence is emerging for physical links among clouds, global temperatures, the global atmospheric electrical circuit and cosmic ray ionisation. The global circuit extends throughout the atmosphere from the planetary surface to the lower layers of the ionosphere. Cosmic rays are the principal source of atmospheric ions away from the continental boundary layer: the ions formed permit a vertical conduction current to flow in the fair weather part of the global circuit. Through the (inverse) solar modulation of cosmic rays, the resulting columnar ionisation changes may allow the global circuit to convey a solar influence to meteorological phenomena of the lower atmosphere. Electrical effects on non-thunderstorm clouds have been proposed to occur via the ion-assisted formation of ultra-fine aerosol, which can grow to sizes able to act as cloud condensation nuclei, or through the increased ice nucleation capability of charged aerosols. Even small atmospheric electrical modulations on the aerosol size distribution can affect cloud properties and modify the radiative balance of the atmosphere, through changes communicated globally by the atmospheric electrical circuit. Despite a long history of work in related areas of geophysics, the direct and inverse relationships between the global circuit and global climate remain largely quantitatively unexplored. From reviewing atmospheric electrical measurements made over two centuries and possible paleoclimate proxies, global atmospheric electrical circuit variability should be expected on many timescales.     

Atmospheric Electrification in Dusty,Reactive Gases in the Solar System and Beyond

Detailed observations of the solar system planets reveal a wide variety of local atmospheric conditions. Astronomical observations have revealed a variety of extrasolar planets none of which resembles any of the solar system planets in full. Instead, the most massive amongst the extrasolar planets, the gas giants, appear very similar to the class of (young) brown dwarfs which are amongst the oldest objects in the Universe. Despite this diversity, solar system planets, extrasolar planets and brown dwarfs have broadly similar global temperatures between 300 and 2500 K. In consequence, clouds of different chemical species form in their atmospheres. While the details of these clouds differ, the fundamental physical processes are the same. Further to this, all these objects were observed to produce radio and X-ray emissions. While both kinds of radiation are well studied on Earth and to a lesser extent on the solar system planets, the occurrence of emissions that potentially originate from accelerated electrons on brown dwarfs, extrasolar planets and protoplanetary disks is not well understood yet. This paper offers an interdisciplinary view on electrification processes and their feedback on their hosting environment in meteorology, volcanology, planetology and research on extrasolar planets and planet formation.     

Charge analysis on lightning discharges to the ground in Chinese inland plateau (close to Tibet)

Since the summer of 1996, scientists from China and Japan have conducted a joint observation of natural cloud-to-ground lightning discharges in the Zhongchuan area that is located close to Qinghai-Xizang (Tibet) Plateau, China. It has been found that the long-duration of intracloud discharge processes, just before the first return stroke, lasted more than 120 ms for 85% of cloud-to-ground flashes in this area, with a mean duration of 189.7 ms and a maximum of 300 ms. We present the results of charge sources neutralized by four ground flashes and two intracloud discharge processes, just before the first return stroke, by using the data from a 5-site slow antenna network synchronized by GPS with 1 s time resolution. The result shows that the altitudes of the neutralized negative charge for three negative ground flashes were between 2.7 to 5.4 km above the ground, while that of neutralized positive charges for one positive ground flash and one continuing current process were at about 2.0 km above the ground. The comparison with radar echo showed that the negative discharges initiated in the region greater than 20 dBZ or near the edge of the region with intense echoes greater than 40 dBZ, while positive discharge initiated in the weak echo region.     

Association Between Extraterrestrial Phenomena And Weather Changes In The Northern Hemisphere In Winter

This paper includes a discussion of the validity of theobjections which are usuallyraised against the physical plausibility of the correlationsbetween extraterrestrialphenomena and changes in circulation in the lower atmosphere.The behaviour of the winterlower troposphere in the Northern Hemisphere was analysed bothon a month-to-month timescale and on a day-to-day time scale. The mechanisms which cansatisfactorily explainthe behaviour of the winter lower troposphere on these timescales have been described.The basic features of the results presented were explained bymeans of a mechanism basedon the propagation of planetary waves. Attention was focussedon studying the connectionsamong the changes in the pressure and temperature fields, thechanges in solar/geomagnetic activity and QBO phases by the method of composites. It hasbeen found that the compositeswithout considering QBO phases are similar to the QBO-eastpatterns under the highestactivities. Pressure deviations during QBO-west high solaractivity or low geomagneticactivity and temperature deviations during QBO-east/west lowgeomagnetic activity provedto be of negligible statistical significance.