Influence of topography on temperature variations in the tropical tropopause layer

• Kubokawa, Hiroyasu

• Satoh, Masaki

• Suzuki, Junko

• Fujiwara, Masatomo

抄録

Temperature variations in the tropical tropopause layer (TTL) play an important role in dehydration in the upper troposphere and lower stratosphere. Equatorial Kelvin waves associated with the Madden-Julian Oscillation (MJO) are known to induce remarkable temperature variations in the TTL. In this study, the influence of topography on temperature variations in the TTL is investigated by using radiosonde data, satellite data, reanalysis data, and numerically simulated data. When MJO convection passes over the radiosonde sites, temperature variations near mountainous regions are larger than those measured in regions of lower elevation. The difference in temperature amplitude reaches similar to 1-2K. Large temperature variations over mountainous regions were also found in other data sets. Numerically simulated data from the Nonhydrostatic Icosahedral Atmospheric Model (NICAM) are also used to investigate the temperature variations in the TTL. The results show that the temperature variations associated with Kelvin waves become large over mountainous regions. A sensitivity test using the stretched version of NICAM gave two important results: (i) the height of mountains affects the magnitude of the temperature variations in the TTL, and (ii) the terrain-following coordinate system used in the model produces the artificially high-temperature variation in the TTL. When Kelvin waves pass over mountainous regions, topographic gravity waves are excited and superimposed on the Kelvin waves, thereby producing large temperature variations over these regions. The mountainous region of the Indonesian Maritime Continent is a favorable location for large temperature variations in the TTL.

収録刊行物

• Journal of geophysical research atmospheres

  Journal of geophysical research atmospheres 121 (19), 11556-11574, 2016-10

  American Geophysical Union

キーワード

• extreme events
• topography
• gravity waves
• tropical tropopause layer

詳細情報

• CRID: 1050001339021745792
• NII論文ID: 120005898549
• HANDLE: 2115/63930
• ISSN: 2169897X
• 本文言語コード: en
• 資料種別: journal article
• データソース種別:
  • IRDB
  • CiNii Articles