MDI and GONG Inferences of the Changing Solar Interior C. Barban, R. Howe, F. Hill, R. W. Komm, J. Leibacher, C. Toner and friends
The combined Global Oscillation Network Group (GONG) and the Solar Oscillations Investigation (SOI) using the Michelson Doppler Imager (MDI) instrument aboard the SOHO spacecraft provide data sets that now cover more than six years and allow us to probe the changing dynamics of the convection zone in unprecedented detail. Here we present the latest combined results from both projects, showing the evolution of the migrating zonal flows close to the surface and also changes close to and below the base of the convection zone, as well as changes in the mode parameters related to surface magnetic activity variation in time and latitude.	The GONG project uses a network of six terrestrial observing stations, each with a 256x256 pixel camera. Data are collected up to degree l=250, but routine analysis produces only spectra up to l=200 and frequencies up to l=150. The typical duty cycle is around 87 per cent. The network has been in operation since May 1995. The new GONG+ cameras, with 10242 pixels were deployed in 2001.
	The MDI instrument aboard the SOHO spacecraft has been collecting medium-l data since May 1996, using a 1024x1024 pixel camera with the results binned to 256x256. The data are produced and analyzed up to l=300.

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