! 
! gpi data read from gpi data file:
      integer,parameter :: 
     |  mxgpidays = 10000     ! maximum number of days of gpi data
      integer :: 
     |  ngpidays,             ! number of days of gpi data
     |  gpi_iyd(mxgpidays),   ! yearday (7-digit) of gpi data
     |  iyd_beg,iyd_end       ! beginning and ending year-dates on gpi 
                              ! data file
      real ::
     |  gpi_f107d(mxgpidays), ! daily 10.7 cm flux
     |  gpi_f107a(mxgpidays), ! 81-day average 10.7 cm flux
     |  gpi_kp(8,mxgpidays)   ! 3-hourly kp
      common/comgpi_real/ gpi_f107d,gpi_f107a,gpi_kp
      common/comgpi_int/ ngpidays,gpi_iyd,iyd_beg,iyd_end