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Influence of topography on temperature variations in the tropical tropopause layer

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Please use this identifier to cite or link to this item:http://hdl.handle.net/2115/63930

Title: Influence of topography on temperature variations in the tropical tropopause layer
Authors: Kubokawa, Hiroyasu Browse this author
Satoh, Masaki Browse this author →KAKEN DB
Suzuki, Junko Browse this author
Fujiwara, Masatomo Browse this author →KAKEN DB
Keywords: extreme events
topography
gravity waves
tropical tropopause layer
Issue Date: Oct-2016
Publisher: American Geophysical Union
Journal Title: Journal of geophysical research atmospheres
Volume: 121
Issue: 19
Start Page: 11556
End Page: 11574
Publisher DOI: 10.1002/2016JD025569
Abstract: 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.
Rights: http://creativecommons.org/licenses/by-nc-nd/4.0/
Type: article
URI: http://hdl.handle.net/2115/63930
Appears in Collections:環境科学院・地球環境科学研究院 (Graduate School of Environmental Science / Faculty of Environmental Earth Science) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)

Submitter: 藤原 正智

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