Rui Ito, Hirokazu Endo, Tomoaki Ose, Tosiyuki Nakaegawa
Received 24 May, 2024
Accepted 16 September, 2024
Published online 30 January, 2025

Rui Ito¹⁾, Hirokazu Endo²⁾, Tomoaki Ose²⁾, Tosiyuki Nakaegawa²⁾

1) Japan Agency for Marine-Earth Science and Technology, Japan
2) Meteorological Research Institute, Japan Meteorological Agency, Japan

Future changes in sea-level pressure (SLP) around Japan are investigated using the Coupled Model Intercomparison Project phase 6 (CMIP6) projections, and their impacts on future regional change of surface air temperature and precipitation, including their extremes, are estimated based on observed statistics. The SLP patterns around Japan are quantified by defining a surface wind index, and are compared with the CMIP5 projections, revealing a similar mean change but a reduction in inter-model uncertainty. The future seasonal cycle represented by the index indicates that the spring SLP pattern will appear earlier, but the autumn pattern will be delayed. The CMIP6 models projecting stronger winds from warm (wet) areas tend to simulate a warmer (wetter) future climate over Japan, which is consistent with the statistical relationships in observations. The impact of future SLP changes on regional climate is assessed using the index based on observed relationships. The results indicate that future westerly anomalies (relative to the present day) in summer will increase mean precipitation on the Sea of Japan side of eastern and western Japan, but decrease extreme precipitation on the Pacific side of eastern Japan. The southerly anomalies in winter and autumn will increase mean and extreme precipitation over western Japan.

[Full Text]

Copyright (c) 2025 The Author(s) CC-BY 4.0