- 著者
- Seiji YUKIMOTO Yukimasa ADACHI Masahiro HOSAKA Tomonori SAKAMI Hiromasa YOSHIMURA Mikitoshi HIRABARA Taichu Y. TANAKA Eiki SHINDO Hiroyuki TSUJINO Makoto DEUSHI Ryo MIZUTA Shoukichi YABU Atsushi OBATA Hideyuki NAKANO Tsuyoshi KOSHIRO Tomoaki OSE Akio KITOH
- 出版者
- Meteorological Society of Japan
- 雑誌
- 気象集誌. 第2輯 (ISSN:00261165)
- 巻号頁・発行日
- vol.90A, pp.23-64, 2012 (Released:2012-06-07)
- 参考文献数
- 157
- 被引用文献数
- 354 622
A new global climate model, MRI-CGCM3, has been developed at the Meteorological Research Institute (MRI). This model is an overall upgrade of MRI’s former climate model MRI-CGCM2 series. MRI-CGCM3 is composed of atmosphere-land, aerosol, and ocean-ice models, and is a subset of the MRI’s earth system model MRI-ESM1. Atmospheric component MRI-AGCM3 is interactively coupled with aerosol model to represent direct and indirect effects of aerosols with a new cloud microphysics scheme. Basic experiments for pre-industrial control, historical and climate sensitivity are performed with MRI-CGCM3. In the pre-industrial control experiment, the model exhibits very stable behavior without climatic drifts, at least in the radiation budget, the temperature near the surface and the major indices of ocean circulations. The sea surface temperature (SST) drift is sufficiently small, while there is a 1 W m-2 heating imbalance at the surface. The model’s climate sensitivity is estimated to be 2.11 K with Gregory’s method. The transient climate response (TCR) to 1 % yr-1 increase of carbon dioxide (CO2) concentration is 1.6 K with doubling of CO2 concentration and 4.1 K with quadrupling of CO2 concentration. The simulated present-day mean climate in the historical experiment is evaluated by comparison with observations, including reanalysis. The model reproduces the overall mean climate, including seasonal variation in various aspects in the atmosphere and the oceans. Variability in the simulated climate is also evaluated and is found to be realistic, including El Niño and Southern Oscillation and the Arctic and Antarctic oscillations. However, some important issues are identified. The simulated SST indicates generally cold bias in the Northern Hemisphere (NH) and warm bias in the Southern Hemisphere (SH), and the simulated sea ice expands excessively in the North Atlantic in winter. A double ITCZ also appears in the tropical Pacific, particularly in the austral summer.
- 著者
- Shun-ichi I. Watanabe Hiroyuki Tsujino Akihiko Murata Masayoshi Ishii
- 出版者
- Meteorological Society of Japan
- 雑誌
- SOLA (ISSN:13496476)
- 巻号頁・発行日
- vol.15, pp.183-188, 2019 (Released:2019-09-05)
- 参考文献数
- 31
- 被引用文献数
- 1
We evaluated the impact of sea surface temperature (SST) improvement realized by increasing horizontal resolution of an ocean model on dynamical downscaling (DDS) over Japan, focusing on the effects of the Kuroshio on summer precipitation in Japan. Two sets of SSTs were simulated using a high-resolution North Pacific (NP) model and a low-resolution global (GLB) ocean model. Using these SSTs as the lower boundary conditions for the atmosphere, two DDS experiments were conducted (NP-run and GLB-run). In NP-run, summer precipitation increases over the Kuroshio and reduces over Pacific coastal areas of Japan compared with GLB-run. Due to weaker southerly winds north of the Kuroshio in NP-run, the water vapor flux transported to Japan is smaller than in GLB-run. Both the pressure adjustment and the vertical mixing mechanisms weaken the southerly winds, with the latter being slightly more effective. Increasing the horizontal resolution of the ocean model, so that the Kuroshio is more realistically reproduced, improves the accuracy of simulated precipitation over Japan.
- 著者
- Seiji YUKIMOTO Hideaki KAWAI Tsuyoshi KOSHIRO Naga OSHIMA Kohei YOSHIDA Shogo URAKAWA Hiroyuki TSUJINO Makoto DEUSHI Taichu TANAKA Masahiro HOSAKA Shokichi YABU Hiromasa YOSHIMURA Eiki SHINDO Ryo MIZUTA Atsushi OBATA Yukimasa ADACHI Masayoshi ISHII
- 出版者
- Meteorological Society of Japan
- 雑誌
- 気象集誌. 第2輯 (ISSN:00261165)
- 巻号頁・発行日
- vol.97, no.5, pp.931-965, 2019 (Released:2019-09-19)
- 参考文献数
- 135
- 被引用文献数
- 212 428
The new Meteorological Research Institute Earth System Model version 2.0 (MRI-ESM2.0) has been developed based on previous models, MRI-CGCM3 and MRI-ESM1, which participated in the fifth phase of the Coupled Model Intercomparison Project (CMIP5). These models underwent numerous improvements meant for highly accurate climate reproducibility. This paper describes model formulation updates and evaluates basic performance of its physical components. The new model has nominal horizontal resolutions of 100 km for atmosphere and ocean components, similar to the previous models. The atmospheric vertical resolution is 80 layers, which is enhanced from the 48 layers of its predecessor. Accumulation of various improvements concerning clouds, such as a new stratocumulus cloud scheme, led to remarkable reduction in errors in shortwave, longwave, and net radiation at the top of the atmosphere. The resulting errors are sufficiently small compared with those in the CMIP5 models. The improved radiation distribution brings the accurate meridional heat transport required for the ocean and contributes to a reduced surface air temperature (SAT) bias. MRI-ESM2.0 displays realistic reproduction of both mean climate and interannual variability. For instance, the stratospheric quasi-biennial oscillation can now be realistically expressed through the enhanced vertical resolution and introduction of non-orographic gravity wave drag parameterization. For the historical experiment, MRI-ESM2.0 reasonably reproduces global SAT change for recent decades; however, cooling in the 1950s through the 1960s and warming afterward are overestimated compared with observations. MRI-ESM2.0 has been improved in many aspects over the previous models, MRI-CGCM3 and MRI-ESM1, and is expected to demonstrate superior performance in many experiments planned for CMIP6.