Abstract3D general circulation and chemical global transport-photochemical middle atmosphere models have been used for simulation of ozone, wind and temperature response to one of the strongest solar proton events (SPEs) of the 23rd solar cycle – 14 July 2000. It was assumed in the photochemical scheme that approximately one molecule of NO and two molecules of OH are produced for each pair of ions that are created due to the ionization of the air by solar protons. These NO and OH molecules disturb the photochemical system in the stratosphere and mesosphere. SPE-induced ionization rates have been calculated using high time-resolution satellite measurements of solar proton fluxes provided by GOES. According to the calculations a maxima of ionization rates occurred on 15 July 2000, and it was localized in the mesosphere at high latitudes. 3D photochemical calculations showed that ozone was strongly reduced in the mesosphere and stratosphere over the Northern polar region during and after SPE. A similar effect in ozone was found in HALOE/UARS data by different groups of authors including present study. At the same time a weak negative response of ozone over the South Pole (night conditions) was found in the simulations. The calculated ozone response has been introduced into the radiative module of the GCM. The results of model runs showed that ozone depletion caused by SPE leads to the disturbances in temperature and dynamics mostly over high latitudes of the Northern hemisphere. The simulations revealed a cooling (several Kelvin) and reduced zonal wind in the region of ozone depletion in the middle atmosphere. No response was found over the south polar region (nigh in July). The response in temperature, wind, and amplitude of the tides was found above the levels of ozone depletion. A preliminary analysis showed that this unusual effect is mostly connected by non-linear interaction between gravity waves and the zonal mean state, but a clear and detailed explanation needs further investigation.


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    Title :

    Dynamical response of the middle atmosphere to solar proton event of July 2000: Three-dimensional model simulations


    Contributors:

    Published in:

    Advances in Space Research ; 37 , 8 ; 1602-1613


    Publication date :

    2005-05-19


    Size :

    12 pages




    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English