Structure of the Solar Dust Corona and its Interaction with the other Coronal Components

We developed a new technique for registration of the far solar corona from ground-based observations at distances comparable to those obtained from space coronagraphs. It makes possible visualization of fine details of studied objects invisible by naked eye. Here we demonstrate that streamers of the electron corona sometimes punch the dust corona and that the shape of the dust corona may vary with time. We obtained several experimental evidences that the far coronal streamers (observed directly only from the space or stratosphere) emit only in discrete regions of the visible spectrum like resonance fluorescence of molecules and ions in comets. We found that interaction of the coronal streamers with the dust corona can produce molecules and radicals, which are known to cause the resonance fluorescence in comets.

Past Annual Variations of the Karst Denudation Rates

We used the quantitative theory of solubility of karst rocks of Shopov et. al, (1989, 1991a) in dependence of the temperature and other thermodynamic parameters to make reconstructions of past carbonate denudation rates. This theory produced equations assessing the carbonate denudation rates in dependence on the temperature or on the precipitation. We estimated the averaged denudation rate in the region to 14 mm/kyr or 38 t/km2 per year. We used this estimate as starting point and substituted our proxy records of the annual temperature and the annual precipitation in the equations of dependence of karst denudation rate on precipitation and temperature. This way we reconstructed variations of the annual karst denudation rate for the last 280 years in dependence on the annual precipitation and for the last 1250 years in dependence on the temperature. Both reconstructions produce quite reasonable estimate of the variations of carbonate denudation, which is within observed variation of 8- 20 mm/kyr (86% variation). Precipitation dependence of carbonate denudation produces 79 % variation in the denudation rate in result of the reconstructed variation of 300 mm/yr from the driest to the wettest year during the last 280 years. Temperature dependence of carbonate denudation due to temperature dependence of solubility of the carbonate dioxide produce only 9.3% variation in the denudation rate in result of the reconstructed variation of 4.7 deg. C during the last 1250 years, so it is negligible in respect of the precipitation dependence.