- 著者
- Daisuke Takasuka Tomoki Miyakawa Masaki Satoh Hiroaki Miura
- 出版者
- (公社)日本気象学会
- 雑誌
- SOLA (ISSN:13496476)
- 巻号頁・発行日
- vol.11, pp.170-176, 2015 (Released:2015-12-21)
- 参考文献数
- 42
- 被引用文献数
- 3 16
The roles of topography on the propagation of the Madden-Julian Oscillation (MJO) are discussed using an aqua-planet of the Nonhydrostatic Icosahedral Atmospheric Model (NICAM) with a 220-km horizontal mesh. Four topographical configurations with different land-sea masks and elevations are tested using a zonally non-uniform fixed-SST distribution. Explicit cloud microphysics is used to obtain MJO-like signals. Broad land cover generally weakens convection because of reduced surface latent heat flux (LHF). Forced lifting because of topography enhances local convection on the upwind side of high topography. It is suggested that the zonal contrasts of LHF are one reason for the delayed eastward propagation of the MJO-like disturbances. When only the eastern portion of the convective envelope is over land where the LHF is small, the LHF becomes rear-heavy, resulting in delayed eastward propagation. As the entire convective envelope proceeds over land, its contrast decreases or even reverses, resulting in faster eastward propagation.