Effects of energetic solar proton events on the cyclone development in the North Atlantic

Short-term effects of the energetic solar proton events (SPE) on the different characteristics of the lower atmosphere were studied in the North Atlantic region, which is an area of intensive cyclone genesis and development. The data of aerological soundings over the set of Danish stations (Greenland, Faeroe Islands and Denmark), the vorticity data at the different pressure levels and weather charts at the Earth's surface were used. It was shown that the SPE under study are accompanied by noticeable pressure and temperature decreases at the high-latitudinal stations in the cold (October-March) half of year as well as by relative vorticity increases in the troposphere. The most pronounced effects were found in the region of the arctic front near the south-eastern Greenland coasts and Iceland. The weather chart analysis showed that the effects discovered seem to be related to the intensification of the deepening of well developed cold cyclones in this region. The results obtained suggest that the SPE with particle energies sufficient to penetrate the stratospheric heights may influence the cyclone evolution over the northern part of the Atlantic Ocean, a possible physical mechanism involving the radiative forcing of the cloudiness changes which may be associated with cosmic ray variations. (C) 2004 Elsevier Ltd. All rights reserved.