Moisture Variations observed over the Tropical Indian Ocean during CINDY2011

A field observational campaign called CINDY/DYNAMO was conducted over the central equatorial Indian Ocean in October 2011 - January 2012. During the campaign, large-scale-organized convection associated with a Madden-Julian oscillation (MJO) broke out, and some other notable variations were observed.

Water vapor data show prominent semi-diurnal and 5-day-period variations over R/V Mirai. Peaks of the semi-diurnal variations coincide with pressure minimum, and it is suggested that the semi-diurnal cycle is associated with the atmospheric tide. The peak of 5-day-period cycle is associated with meridional wind (v) variations. Filtered v anomalies at mid-levels in objective analysis data show westward phase velocities, and the structure is consistent with mixed Rossby-Gravity (MRG) waves.