Convective Activity and Moisture Variation During Field Experiment MISMO in the Equatorial Indian Ocean

Abstract

The field experiment Mirai Indian Ocean cruise for the Study of the MJO-convection Onset (MISMO) took place in the central equatorial Indian Ocean from October to December 2006 on the research vessel Mirai. During MISMO, intensive Doppler radar, radiosonde, and other observations were conducted to collect atmospheric and oceanic features when convection associated with the intraseasonal variability was initiated. The Mirai was stationed at 2∘S-2∘N and 79∘E-82∘E from October 24 to November 25. Satellite-based cloud data analysis was used to detect convectively active intraseasonal variations in the latter half of observation, although it was weak and its eastward-propagating signal dissipated before arriving on the maritime continent. We examine the features of convective activity and related moisture variation during this stationary observation period, focusing on difference in features between convectively inactive and active periods. We confirmed that stratiform clouds played a key role in regulating moisture distribution features in the convectively active intraseasonal period.