Publication List

 

Kamiguchi, K., A. Kitoh, T. Uchiyama, R. Mizuta, and A. Noda, 2006: Changes in precipitation-based extremes indices due to global warming projected by a global 20-km-mesh atmospheric model. SOLA, 2, 64-67, doi:10.2151/sola.2006-017. http://www.jstage.jst.go.jp/article/sola/2/0/2_64/_article [ bib | DOI | http | pdf ]

Future changes in extremes indices on precipitation were projected with a 20-km horizontal grid atmospheric general circulation model. At the end of the 21st Century, heavy precipitation was shown to increase enormously in South Asia, the Amazon, and West Africa, while a dry spell was shown to increase in South Africa, south Australia, and the Amazon, suggesting that the risk of water-related disasters will be higher in these regions. In the Asian monsoon region, heavy precipitation increases notably in Bangladesh and in the Yangtze River basin due to the intensified convergence of water vapor flux in summer. In the Amazon, a dry spell greatly increases due to a reduction in the Walker circulation caused by an El Niño-like change in SST prescribed as boundary condition.

 

Uchiyama, T., R. Mizuta, K. Kamiguchi, A. Kitoh, and A. Noda, 2006: Changes in temperature-based extremes indices due to global warming projected by a global 20-km-mesh atmospheric model. SOLA, 2, 68-71, doi:10.2151/sola.2006-018. http://www.jstage.jst.go.jp/article/sola/2/0/2_68/_article [ bib | DOI | http | pdf ]

Changes in temperature-based extremes over land due to global warming estimated by a global 20-km-mesh atmospheric model are analyzed using Frich's five extremes indices. At the end of the 21st Century, under the Intergovernmental Panel on Climate Change (IPCC) SRES A1B scenario, the model projects that the total number of frost days (Fd) decreases by more than 20 days per year and the length of the growing season (GSL) increases by about 14-34 days in northern mid and high latitudes. The heat wave duration index (HWDI) and the percentage of time with a daily minimum temperature above the present-day 90th percentile (Tn90) increase worldwide. The intra-annual extreme temperature range (ETR) decreases in northern high latitudes, east Asia, and eastern North America by 1.3-3.9^o C, but it increases by 1.0 ^o C in the Amazon. The high-resolution simulation reveals that changes in these indices are influenced by regional properties, such as the altitude and distance from the coast.

 

Kitoh, A., M. Hosaka, Y. Adachi, and K. Kamiguchi, 2005: Future projections of precipitation characteristics in east asia simulated by the mri cgcm2. Advances in Atmospheric Sciences, 22, 467-478. http://www.iap.ac.cn/html/qikan/aas/aas2005/200504/0504mle.htm [ bib | http | pdf ]

Projected changes in precipitation characteristics around the mid-21st century and end-of-the-century are analyzed using the daily precipitation output of the 3-member ensemble Meteorological Research Institute global ocean-atmosphere coupled general circulation model (MRI-CGCM2) simulations under the Special Report on Emissions Scenarios (SRES) A2 and B2 scenarios. It is found that both the frequency and intensity increase in about 40 intensity decrease in about 20 only a few percent from decade to decade of the 21st century and between the A2 and B2 scenarios. Over the rest of the globe (about one third), the precipitation frequency decreases but its intensity increases, suggesting a shift of precipitation distribution toward more intense events by global warming. South China is such a region where the summertime wet-day frequency decreases but the precipitation intensity increases. This is related to increased atmospheric moisture content due to global warming and an intensified and more westwardly extended North Pacific subtropical anticyclone, which may be related with an El Niño-like mean sea surface temperature change. On the other hand, a decrease in summer precipitation is noted in North China, thus augmenting a south-to-north precipitation contrast more in the future.

Keywords: global warming, precipitation, GCM, East Asia

 

Mizuta, R., T. Uchiyama, K. Kamiguchi, A. Kitoh, and A. Noda, 2005: Changes in extremes indices over japan due to global warming projected by a global 20-km-mesh atmospheric model. SOLA, 1, 153-156, doi:10.2151/sola.2005-040. http://www.jstage.jst.go.jp/article/sola/1/0/1_153/_article [ bib | DOI | http | pdf ]

Changes in indices of extremes between the present-day climate and a future warmer climate are projected over Japan using a global 20-km-mesh atmospheric model. Comparisons with observed data show that the indices on temperature extremes are represented well in the model, while less intense precipitation biases are found. In the future climate simulation around 2090, the number of frost days decreases by 20-45 days with larger decrease along the Sea of Japan than the other area. Growing season length increases about a month. Changes in the temperature extremes are not uniform over Japan, showing usefulness of projections using a high-resolution model. Although changes in precipitation extremes are small and not significant over a large part of Japan, statistically significant increase in indices of heavy precipitation is found in western part of Japan and Hokkaido.