Teruyuki Nishimura

Responses of the Kuroshio and the Kuroshio Extension to global warming in a high‐resolution climate model

[1] Using a high-resolution atmosphere-ocean coupled climate model, responses of the Kuroshio and the Kuroshio Extension (KE) to global warming are investigated. In a climate change experiment with atmospheric CO 2 concentration ideally increased by 1% year -1 , the current velocity of the Kuroshio and KE increases, while the latitude of the Kuroshio separation to the east of Japan does not change significantly. The increase of the current velocity is up to 0.3 m s -1 at 150°E. This acceleration of the Kuroshio and KE is due to changes in wind stress over the North Pacific and consequent spin-up of the Kuroshio recirculation gyre. The acceleration of the currents may affect sea level along the southern coast of Japan and northward heat transport under global warming.

Re-evaluation of paleo-accumulation parameterization over Northern Hemisphere ice sheets during the ice age examined with a high-resolution AGCM and a 3-D ice-sheet model

Abstract Simulations of the Northern Hemisphere ice sheet at the Last Glacial Maximum (LGM; 21 kyr BP) are performed using a high-resolution atmospheric general circulation model (AGCM) in order to re-evaluate the conventional surface temperature- or elevation-based parameterization. The influence of precipitation change on the steady-state topography of the Laurentide ice sheet at the LGM is estimated using an AGCM with a horizontal resolution of ∼1° and a three-dimensional thermomechanically coupled ice-sheet model. The ice volume estimated by the AGCM simulation is much larger than that indicated by the conventional parameterization. Through sensitivity analysis of the AGCM and ice-sheet model, it is found that the rate of precipitation change depends on the location of the ice sheet, and that the rate of precipitation change due to surface elevation change is higher than the rate unrelated to surface elevation change on the Laurentide ice sheet. The rate of precipitation is also shown to exhibit seasonality and regionality due to effects such as interior desertification and the concentration of storm tracks.