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GEOPHYSICAL RESEARCH LETTERS, VOL. 28, NO. 15, PAGES 2883–2886, 2001

Northern Hemisphere Atmospheric Effects Due to the July 2000 Solar Proton Event

Charles H. Jackman

NASA Goddard Space Flight Center, Greenbelt, Maryland


Richard D. McPeters

NASA Goddard Space Flight Center, Greenbelt, Maryland


Gordon J. Labow

NASA Goddard Space Flight Center, Greenbelt, Maryland


Eric L. Fleming

NASA Goddard Space Flight Center, Greenbelt, Maryland


Cid J. Praderas

Emergent Information Technologies, Inc., Arlington, Virginia


James M. Russell

Hampton University, Hampton, Virginia


Abstract

The third largest solar proton event in the past thirty years took place during July 14-16, 2000, and had a significant impact on the earth’s atmosphere. These energetic protons produced both HOx (H, OH, HO2) and NOx (N, NO, NO2) constituents in the mesosphere and upper stratosphere at polar latitudes (> 60° geomagnetic) of both hemispheres. The temporal evolution of increases in NO and NO2 during the event at northern polar latitudes were measured by the UARS HALOE instrument. Increases in mesospheric NOx of over 50 ppbv were found in the HALOE measurements. Measurements from the UARS HALOE and NOAA 14 SBUV/2 instruments indicate short-term (∼day) middle mesospheric ozone decreases of over 70% caused by short-lived HOx during the event with a longer-term (several days) upper stratospheric ozone depletion of up to 9% caused by longer-lived NOx. We believe this is the first time that the three constituents NO, NO2, and ozone were all measured simultaneously during a proton event. The observations constitute a dramatic confirmation of the impact of a large particle event in the control of ozone in the polar middle atmosphere and offer the opportunity to test theories of constituent changes driven by particle precipitation.

Received 23 March 2001; accepted 23 May 2001.

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Citation: Jackman, C. H., R. D. McPeters, G. J. Labow, E. L. Fleming, C. J. Praderas, and J. M. Russell (2001), Northern Hemisphere Atmospheric Effects Due to the July 2000 Solar Proton Event, Geophys. Res. Lett., 28(15), 2883–2886.