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Dynamical Downscaling with Dr. Shoji Kusunoki, Meteorological Research Institute
This session introduces students to concepts relating to
- time-slice experiment using global atmospheric model.
- the validation of presentday simulation by observational data,
- the analysis of future change in climate over countries of students.
We have been carrying out global warming projections with 20-km mesh Atmospheric Global Circulation Model (AGCM, Mizuta et al. 2012). Main target of our study is extreme events which are often caused by tropical cyclones and heavy rainfall in the East Asian summer monsoon season. The Earth simulator is used for calculation. High horizontal resolution AGCM experiments are conducted using the time-slice method (Bengtsson et al. 1996; IPCC 2001; Kusunoki et al. 2011), which is two-tier global warming projection using an Atmosphere-Ocean General Circulation Model (AOGCM) and an AGCM with horizontal resolution higher than that of the atmospheric part of the AOGCM. For present-day climate simulation, observed historical Sea Surface Temperature (SST) by HadISST1 (Rayner et al. 2003) are prescribed to the model from 1979 to 2003 (25 years). For the end of 21st century climate simulation from 2075 to 2099 (25 years), changes in the Multi-Model Ensemble (MME) of SSTs projected by Coupled General Circulation Models (CGCMs) of Coupled Model Intercomparison Project 5 (CMIP5) are superposed to the detrended observed historical SST. Changes in MME of SSTs are evaluated by the difference between the historical simulations (20th century) and future simulation of Representative Concentration Pathways 8.5 (RCP8.5) emission scenario (IPCC 2013).
Horizontal resolution of the 20-km mesh AGCM is so high that statistical or dynamical downscaling is not necessary for some cases. Since this model covers the whole world, we can directly investigate future climate change over any regions in the earth by this AGCM. We have developed a very simple graphical tool for verifying present-day simulation by observational data and for analyzing future change in climate over countries of students. We will introduce how to use this tool. Finally, we will intend to make figures for future changes in surface air temperature and precipitation of specified local regions.
- Understand the concept of time-slice experiment using global atmospheric model and experimental design of 20-km mesh AGCM.
- Learn how to use a very simple graphical tool for analyzing model output data.
- Make figures for future changes in surface air temperature and precipitation of specified local regions.
Obtain experiences of analyzing model output data for global warming projection.
Summary for Policymakers
Chapter 2: Observations: Atmospheric and Surface
Chapter 9: Evaluation of Climate Models
Chapter 12 Long-term Climate Change: Projections, Commitments and Irreversibility
Chapter 11: Regional Climate Projections
Chapter 14 Climate Phenomena and their Relevance for Future Regional Climate Change
Annex I Atlas of Global and Regional Climate Projections
Bengtsson, L., M. Botzet and M. Esch, 1996: Will greenhouse gasinduced warming over the next 50 years lead to higher frequency and greater intensity of hurricanes? Tellus, 48A, 57-73.
IPCC, 2013: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T. F., D. Qin, G.-K. Plattner, M. Tignor, S. K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P. M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1535 pp. http://www.climatechange2013.org/
Kusunoki, S., R. Mizuta, and M. Matsueda, 2011: Future changes in the East Asian rain band projected by global atmospheric models with 20-km and 60-km grid size. Climate Dynamics, 37, 2481–2493, doi:10.1007/s00382-011-1000-x.
Mizuta, R., H. Yoshimura, H. Murakami, M. Matsueda, H. Endo, T. Ose, K. Kamiguchi, M. Hosaka, M. Sugi, S. Yukimoto, S. Kusunoki, and A. Kitoh, 2012: Climate simulations using MRI-AGCM3.2 with 20-km grid. J. Meteorol. Soc. Japan, 90A, 233–258, doi:10.2151/jmsj.2012-A12.
Rayner, N. A., D. E. Parker, E. B. Horton, C. K. Folland, L. V. Alexander, D. P. Rowell, E. C. Kent and A. Kaplan, 2003: Global analyses of sea surface temperature, sea ice, and night marine air temperature since the late nineteenth century. J. Geophys. Res., 108(D14), 4407, doi:10.1029/2002JD002670.