Bias Correction for CMIP5 Wind Forcing: Implications for Projections of 21st Century Sea Level around Japan
Abstract
Precise assessment of regional coastal sea level rise is needed for planning climate change adaptation. However, the CMIP5 data, widely used for future projection, include some bias originating from their coupled models. For example, the position of westerlies over the North Pacific shifts southward by a few degrees compared to observations (JRA-55), leading to the southward shift of the Kuroshio Extension as well. This bias gives serious uncertainty in projections around Japan, where sea surface temperatures and coastal sea levels are strongly affected by the Kuroshio variations. In this study, we try to correct the CMIP5-based surface winds to reduce those errors. EOF analysis of the surface winds based on the CMIP5 data (MIROC5 and MRI-CGCM3) during 1960-2100 indicate that the first two modes correspond to the meridional shift of the westerlies and a change in the magnitude of the westerlies, respectively, which is consistent with observations. These modes also include the enhancing and poleward shifting trends of the westerlies. We reconstruct the surface wind forcing by combining the spatial pattern based on the observed modes with the temporal change based on the CMIP5 mode. Impact of the reconstructed wind forcing on the projections of the 21th century sea level around Japan is discussed.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMOS51E1293Y
- Keywords:
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- 1225 Global change from geodesy;
- GEODESY AND GRAVITYDE: 1641 Sea level change;
- GLOBAL CHANGEDE: 4217 Coastal processes;
- OCEANOGRAPHY: GENERALDE: 4556 Sea level: variations and mean;
- OCEANOGRAPHY: PHYSICAL