Graphical Abstract

• Tweet

Geng, B., M. Katsumata, and K. Taniguchi, 2020: Modulation of the diurnal cycle of precipitation near the southwestern coast of Sumatra by mixed Rossby-gravity waves. J. Meteor. Soc. Japan, 98, 463-480.
Special Edition on Years of the Maritime Continent (YMC)
https://doi.org/10.2151/jmsj.2020-026
Graphical Abstract

Plain Language Summary: The impact of mixed Rossby-gravity waves (MRGWs) on the diurnal cycle of precipitation over the southwestern coastal area of Sumatra was investigated using data captured during a pilot field campaign of the Years of the Maritime Continent (YMC) project. The results suggest that local convergence induced by the land–sea contrast is mainly responsible for driving the diurnal cycle. Notwithstanding, MRGWs exert a significant impact on the amplitude of diurnal convection and precipitation by modulating the dynamic structure of the atmosphere.

Highlights:

• Diurnal convection and precipitation over the land and ocean were enhanced (suppressed) when MRGW-induced offshore (onshore) wind perturbations dominated over the radar domain.
• Stronger large-scale low-level convergence and more intense sea- and land-breeze circulations were observed with the intensification of MRGW-induced offshore wind perturbations.
• However, diurnal precipitation displayed a similar well-defined phase, coherent with the regular evolution of sea- and land-breeze circulations, regardless of wind perturbations induced by MRGWs.