Please cite one of the following papers in reference to these data sets:

1)Hudson, R. D. and A. M. Thompson, Tropical tropospheric ozone from total ozone mapping spectrometer by a modified residual method, J. Geophys. Res., 103, 22129-22145, 1998.

2)Thompson, A. M., and R. D. Hudson, Tropical tropospheric ozone (TTO) maps from Nimbus 7 and Earth-Probe TOMS by the Modified-Residual method: Evaluation with sondes, ENSO signals and trends from Atlantic regional time series, J. Geophys. Res., 104, 1999.