Masayoshi ISHII, Hirotaka KAMAHORI, Hisayuki KUBOTA, Masumi ZAIKI, Ryo MIZUTA, Hiroaki KAWASE, Masaya NOSAKA, Hiromasa YOSHIMURA, Naga OSHIMA, Eiki SHINDO, Hiroshi KOYAMA, Masato MORI, Shoji HIRAHARA, Yukiko IMADA, Kohei YOSHIDA, Toru NOZAWA, Tetsuya TAKEMI, Takashi MAKI, Akio NISHIMURA, Global Historical Reanalysis with a 60-km AGCM and Surface Pressure Observations: OCADA, Journal of the Meteorological Society of Japan. Ser. II, 2024, Volume 102, Issue 2, Pages 209-240, Released on J-STAGE March 09, 2024, Advance online publication January 17, 2024, Online ISSN 2186-9057, Print ISSN 0026-1165, https://doi.org/10.2151/jmsj.2024-010, https://www.jstage.jst.go.jp/article/jmsj/102/2/102_2024-010/_article/-char/en,
Abstract:
A historical atmospheric reanalysis from 1850 to 2015 was performed using an atmospheric general circulation model assimilating surface pressure observations archived in international databases, with perturbed observational sea surface temperatures as a lower boundary condition. Posterior spread during data assimilation provides quantitative information on the uncertainty in the historical reanalysis. The reanalysis reproduces the evolution of the three-dimensional atmosphere close to those of the operational centers. Newly archived surface pressure observations greatly reduced the uncertainties in the present reanalysis over East Asia in the early 20th century. A scheme for assimilating tropical cyclone tracks and intensities was developed. The scheme was superior to the present several reanalyses in reproducing the intensity close to the observations and the positions. The reanalysis provides possible images of atmospheric circulations before reanalyses with full-scale observations become available, and opportunities for investigating extreme events that occurred before World War II. Incorporating dynamical downscaling with a regional model that includes detailed topography and sophisticated physics is an application of historical reanalysis to reveal the details of past extreme events. Some examples of past heavy rainfall events in Japan are shown using a downscaling experiment, together with dense rainfall observations over the Japanese islands.
A historical atmospheric reanalysis from 1850 to 2015 was performed using an atmospheric general circulation model assimilating surface pressure observations archived in international databases, with perturbed observational sea surface temperatures as a lower boundary condition. Posterior spread during data assimilation provides quantitative information on the uncertainty in the historical reanalysis. The reanalysis reproduces the evolution of the three-dimensional atmosphere close to those of the operational centers. Newly archived surface pressure observations greatly reduced the uncertainties in the present reanalysis over East Asia in the early 20th century. A scheme for assimilating tropical cyclone tracks and intensities was developed. The scheme was superior to the present several reanalyses in reproducing the intensity close to the observations and the positions. The reanalysis provides possible images of atmospheric circulations before reanalyses with full-scale observations become available, and opportunities for investigating extreme events that occurred before World War II. Incorporating dynamical downscaling with a regional model that includes detailed topography and sophisticated physics is an application of historical reanalysis to reveal the details of past extreme events. Some examples of past heavy rainfall events in Japan are shown using a downscaling experiment, together with dense rainfall observations over the Japanese islands.