The files taperecorder* contain the following paper: Mote, P.\ W., Rosenlof, K.\ H., McIntyre, M.\ E., Carr, E.\ S., Gille, J.\ C., Holton, J.\ R., Kinnersley, J.\ S., Pumphrey, H.\ C., Russell, J.\ M., Waters, J.\ W., 1996: An atmospheric tape recorder:\ the imprint of tropical tropopause temperatures on stratospheric water vapor. J.\ Geophys.\ Res., 101, 3989--4006. The files tape2* contain the following paper: Mote, P.\ W., Dunkerton, T.\ J., McIntyre, M.\ E., Ray, E.\ A., Haynes, P.\ H., Russell, J.\ M.\ III, 1998: Vertical velocity, vertical diffusion, and dilution by midlatitude air in the tropical lower stratosphere. J. Geophys. Res., 103, 8651--8666. This last arrives at vertical profiles of vertical diffusivity and sideways (isentropic) dilution that have remarkably low minima near 21 km.