M. Fujiwara, J. Suzuki, A. Gettelman, M. I. Hegglin, H. Akiyoshi, and K. Shibata

Wave activity in the tropical tropopause layer in 9 reanalysis data sets

Sub-seasonal variability including equatorial waves significantly influences the dehydration and transport processes in the tropical tropopause layer (TTL). This study investigates the activity of equatorial Kelvin waves, mixed-Rossby gravity waves, and MJO in the TTL in 9 reanalysis (RA) data sets and 4 chemistry climatemodels (CCMs) using the zonal wavenumber-frequency spectral analysis method. It is found that the TTL wave activities show significant difference among the RAs, ranging from 0.7 to 1.4 with respect to the averages from the RAs. The TTL activities in the CCMs lie generally within the range of those in the RAs, with some exceptions. The broad range of wave activity found in the different RAs decreases our confidence in their validity.
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