Multi-mission, Decade-long Tropopause Data Record from GPS Radio Occultation

High vertical-resolution GPS radio occultation (RO) temperature profiles from CHAMP, SAC-C, GRACE, COSMIC, and TerraSAR-X are used to produce monthly gridded global tropopause data from 2001-2012. The tropopause data include temperatures and heights corresponding to the lapse-rate tropopause, cold-point tropopause, and 100-mb pressure level. In this talk, we will describe the methodologies used to compute and interpolate the measurements. We will assess the uncertainty associated with the gridded tropopause data, both from the uncertainty in the temperature retrieval of individual profiles and from sampling inhomogeneity. The latter is especially important to consider since the density of observations varies significantly over the past ten years. The dataset will be used to examine the trend and variability of the tropopause, and the results will be compared with published studies based on radiosonde, reanalyses, and CHAMP RO.