Sunrise Effect on Long Wave Propagation along the Tashkent-Patiala Path

Abstract

Data from the 164 kHz long wave propagation observations at Patiala are analysed to find the factors responsible for the observed sunrise effect. Monthly variation of solar zenith angle at the sunrise time is similar to the monthly variation of the total ozone content which points to the presence of ozone screening layer at pre-sunrise time. The results also indicate that at the midpoint of Tashkent-Patiala path cosmic ray ionization plays an important role during sunrise. The start of sunrise effect is a result of UV light grazing the ozone screening layer and the release of electrons at <img src='/image/spc_char/lembda.gif' border=0>=98 is due to the photodetachment of NO₃.