The Impact of the Assimilation of Dropsonde Observations during PALAU2005 in ALERA

Qoosaku Moteki; Ryuichi Shirooka; Kunio Yoneyama; Biao Geng; Masaki Katsumata; Tomoki Ushiyama; Hiroyuki Yamada; Kazuaki Yasunaga; Naoki Sato; Hisayuki Kubota; Krishnaredikari Krishna Reddy; Hiroki Tokinaga; Ayako Seiki; Mikiko Fujita; Yukari N. Takayabu; Masanori Yoshizaki; Hiroshi Uyeda; Takashi Chuda

doi:10.2151/sola.2007-025

Qoosaku Moteki, Ryuichi Shirooka, Kunio Yoneyama, Biao Geng, Masaki Katsumata, Tomoki Ushiyama, Hiroyuki Yamada, Kazuaki Yasunaga, Naoki Sato, Hisayuki Kubota, Krishnaredikari Krishna Reddy, Hiroki Tokinaga, Ayako Seiki, Mikiko Fujita, Yukari N. Takayabu, Masanori Yoshizaki, Hiroshi Uyeda, Takashi Chuda

Author information

Qoosaku Moteki
Institute of Observational Research for Global Change, JAMSTEC
Ryuichi Shirooka
Institute of Observational Research for Global Change, JAMSTEC
Kunio Yoneyama
Institute of Observational Research for Global Change, JAMSTEC
Biao Geng
Institute of Observational Research for Global Change, JAMSTEC
Masaki Katsumata
Institute of Observational Research for Global Change, JAMSTEC
Tomoki Ushiyama
Institute of Observational Research for Global Change, JAMSTEC
Hiroyuki Yamada
Institute of Observational Research for Global Change, JAMSTEC
Kazuaki Yasunaga
Institute of Observational Research for Global Change, JAMSTEC
Naoki Sato
Institute of Observational Research for Global Change, JAMSTEC
Hisayuki Kubota
Institute of Observational Research for Global Change, JAMSTEC
Krishnaredikari Krishna Reddy
Institute of Observational Research for Global Change, JAMSTEC
Hiroki Tokinaga
Institute of Observational Research for Global Change, JAMSTEC
Ayako Seiki
Institute of Observational Research for Global Change, JAMSTEC
Mikiko Fujita
Institute of Observational Research for Global Change, JAMSTEC
Yukari N. Takayabu
Institute of Observational Research for Global Change, JAMSTEC
Center of Climate System Research, the University of Tokyo
Masanori Yoshizaki
Institute of Observational Research for Global Change, JAMSTEC
Hiroshi Uyeda
Hydrospheric Atmospheric Research Center, Nagoya University
Takashi Chuda
Ocean Research Institute, the University of Tokyo

JOURNAL FREE ACCESS
Supplementary material

2007 Volume 3 Pages 97-100

DOI https://doi.org/10.2151/sola.2007-025

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Abstract

The effect of the assimilation of dropsonde data over the tropical western Pacific was investigated in an objective analysis. In June 2005, 30 dropsondes were released on four separate flight days. The data impact was assessed using the objective analysis dataset of “ALERA.” The analysis of the zonal wind field over the tropical western Pacific in ALERA revealed large errors corresponding to active convection. These errors were reduced by 1-3 m s^-1 due to the assimilation of the dropsondes. The impact signal due to the assimilation of the dropsondes propagated northward and appeared significantly around Japan. The phase and group speeds of the impact signal at 700 hPa were approximately 3 m s^-1 and 12 m s^-1, respectively. The former speed was consistent with the mean meridional wind speed, and the latter speed roughly corresponded to the meridional group speed of Rossby waves with wavelengths of a few thousand kilometers.

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