a. Summary

This sub theme aims at developing improvement or the model taken in newly for many processes in the chill area (the ocean, ice sheet, etc.) by a climate model. Therefore, while improving the modeling technique of many process (interaction of the formation and the ocean of sea ice) in a chill area climate system based on the existing model, the model which treats growth, attenuation, and a flow of an ice sheet separately is made. Furthermore, ice sheet change is connected to a climate model, and the model which can predict change accompanying the warming is built. This fiscal year performed the final adjustment of the climate - ice sheet joint model turned to the climate change modeling in a scale in 1000. Moreover, the analysis of the role of the climate-ice sheet combination in a global warming experiment (scenario experiment) and a glacial epoch cycle experiment was started.

b. Research purpose

An ice sheet is ashore, there is sea ice in earth top north-south two poles at sea, and those generation change is directly linked with the climate change of an earth scale. For this reason, in connection with warming, an ice sheet and sea ice react sensitively, and we dissolve, or are anxious about affecting still wide range climate and sea surface change. So, into this group, the atmosphere / ocean / sea ice / ice sheet joint model which finally works on an Earth Simulator are built, and the prediction experiment of global warming or sea surface change is conducted. First, it strives for grasp of an indefinite element through various sensitivity experiments, improving a partial model. Furthermore, it aims at raising the accuracy of a prediction experiment, conducting the reappearance experiment of the present or the past using the combined model. Moreover, since the past climate and the restoration of ice sheet change / sea level by the data of a seabed sediment or geographical feature have come to be considerably performed with high precision about the last glacial epoch or subsequent ones 20,000 years ago, the model is verified through trying the numerical simulation reproducing this.

c. research program, method, schedule

About the ice sheet, manufacture of a partial model was briefly performed by FY 2002, and the response characteristic has been investigated. In FY 2003, improved each portion or the parallelization optimization of the ice sheet model program was carried out for Earth Simulators, and the coupling agent was developed and the characteristic of combination of a climate model and an ice sheet dynamics model was investigated. The ice sheet in FY 2004 performs combination with an air model.

d. The research program in FY 2004

The final adjustment of the climate - ice sheet joint model turned to the climate change modeling in a scale in 1000 is performed. The analysis of the role of the climate-ice sheet combination in a global warming experiment (scenario experiment) and a glacial epoch cycle experiment is started.

e. Reports in FY 2004

Highly precise-ization of the ice sheet model developed in the University of Tokyo climate center and the sea ice model introduced into MIROC has so far been performed (e. g., Ogura et al., 2004; Saito and Abe-Ouchi, 2005). The program was prepared so that a numerical simulation which combined these air sea sea ice joint general circulation models and ice sheet models could be done in the current fiscal year (Fig. 53). Furthermore, examination was begun for what kind of influence the chill areas, such as an ice sheet of the South Pole or Greenland and sea ice, receive in global warming. CO2 When a greenhouse gas level was stable even by twice, 4 times, and about 8 times, the integral experiment of how climate and an ice sheet answer over a long period of time was conducted by a unit of 300 year in 800 in about 1200, respectively, and the response experiment of the ice sheet model which considers the result of an air sea joint model as an input was started.

Fig. 53: Chart figure showing joint procedure of ice sheet model and general circulation model

f. Consideration

It is thought that the original research program has been attained from the above thing. Succeedingly, it is a future subject to investigate the response characteristic of the climate of a high latitude region by numerical simulation or a sensitivity experiment, and it needs to repeat examination further through creation of the integrated model of the ice sheet-air-ocean from now on. I want to put emphasis on a bidirectional combination of an ice sheet and the atmosphere in FY 2005 in addition to the joint model construction of one way.

g. Research presentation

Ogura, T., A. Abe-Ouchi and H. Hasumi, Effects of sea ice dynamics on the Antarctic sea ice distribution in a coupled ocean atmosphere model. Journal of Geophysical Res., Vol. 109, No. C4, C04025, 2004.

Saito, F. and A. Abe-Ouchi, Dependence of simulation and sensitivity of Greenland ice sheet to numerical procedures for ice sheet dynamics. Submitted to Annalds of Glaciology, 42, 2005.

Paper announcement

Ogura, T., A. Abe-Ouchi and H. Hasumi, Effects of sea ice dynamics on the Antarctic sea ice distribution in a coupled ocean atmosphere model. Journal of Geophysical Res., Vol. 109, No. C4, C04025, 2004.

Kageyama, M., S.P. Harrison and A. Abe-Ouchi, The depression of tropical snowlines at the Last Glacial Maximum: what can we learn from climate model experiments? Quaternary International, in press, 2005.

Saito, F. and A. Abe-Ouchi, Thermal Structure of Dome Fuji and East Queen Maud Land, Antarctica, simulated by a three-dimensional ice sheet model. Annals of Glaciology, 38, in press, 2005.

Saito, F. and A. Abe-Ouchi, Dependence of simulation and sensitivity of Greenland ice sheet to numerical procedures for ice sheet dynamics. Submitted to Annalds of Glaciology, 42, 2005.

Yamagishi, T., A. Abe-Ouchi, F. Saito, T. Segawa and T. Nishimura (2005) Reevaluation of paleo-accumulation parameterization overnorthern hemisphere ice sheet during the ice age with a high resolution atmospheric GCM and a 3-D ice sheet model. Submitted to Annals of Glaciology, 42.