Climate Change Projection and Weather Forecasting

Downscaling(regional climate projection)

 You might have heard about the impact of climate change at global scales, such as reduction of sea ice in Arctic and sea level rise. Recently it has been suggested that climate change may be related to extreme weather events, including frequent wild fire and heat waves. In Japan,the record breaking hot summer of 2010 caused high number of casualties due to heat stroke, and frequent extreme rainfall events are frequently broadcasted in the media; such extreme weather events may be linked to climate change.
 However, is it really the case?
 Extreme weather events are hardly resolved in current climate models due totheir coarse resolution. In the Kusaka group, we utilize downscale approach to assess the regional scale climate impacts from global climate change.
 The downscale approach can largely be divided into two categories; dynamical and statistical. The Kusaka group is conducting dynamical downscaling, whereby large-scale change from climate models are used as forcing for a regional climate model. The history of dynamical downscaling is short and there remains inherent uncertainties arising from this approach. However, if used properly, the dynamical downscale approach may greatly contribute to risk assessment and reduction from climate change.
 We are diligently working on the further improvement of downscale approach through various phenomena across the scales.

(Asuka Suzuki-PARKER)

Schematic diagram of dynamical downscaling

Horizontal resolution of global circulation models is generally too low to resolve the complex topography of Japanese archipelago. Downscaling with high-resolution regional model allows us to obtain spatially detailed climate data.

Reference: A. Suzuki-Parker
  • Doan, Q.V., and H. Kusaka, 2016: Numerical study on regional climate change due to the rapid urbanization of greater Ho Chi Minh City's metropolitan area over the past 20 years, International Journal of Climatology, 36(10), 3633–3650, DOI: 10.1002/joc.4582,2016/08/01 (Acknowledgments: CCS) .
  • Doan, Q., H. Kusaka and Q.B. Ho, 2016: Impact of future urbanization on temperature and thermal comfort index in a developing tropical city: Ho Chi Minh City, Urban Climate, 17, 20-31, DOI: :10.1016/j.uclim.2016.04.003, 2016/06/08 (Acknowledgments: CCS) .
  • Kusaka, H., A. Suzuki-Parker, T. Aoyagi, S. A. Adachi, Y. Yamagata, 2016: Assessment of RCM and urban scenarios uncertainties in the climate projections for August in the 2050s in Tokyo., Climatic Change., 137 (3), DOI 10.1007/s10584-016-1693-2, 427-438, 2016/05/23(Acknowledgement: S-5-3,RECCA, SOUSEI,CCS) .
  • Suzuki-Parker, A., H. Kusaka, 2015: Assessment of the impact of metropolitan-scale urban planning scenarios on the moist thermal environment in a warmed climate: A study of the Tokyo metropolitan area using regional climate modeling. Advances in Meteorology, doi:/10.1155/2015/693754, 2015/05/06(Acknowledgement :SOUSEI、ICSP in CCS) .
  • Takane, Y., Kusaka, H., Hara, M., 2012: Urban climate projection in the 2070’s Augusts for the three major metropolitan areas under the IPCC SRES A2 emission scenario: Dynamical downscaling by the WRF-UCM. Journal of Heat Island Institute International., 7, 18-26. 2012/11/29 (Acknowledgement: RECCA,S-8) .
  • Kusaka, H., Takata, T., Takane, Y., 2010: Reproducibility of regional climate in central Japan using the 4-km resolution WRF model. SOLA, 6, 113-116. 2010/09/04 (Acknowledgement: S5) .
  • Kusaka, H., Chen, F., Tewari, M., Dudhia, J., Gill, D.O., Duda, M. G., Wang, W., Miya, Y., 2012: Numerical Simulation of Urban Heat Island Effect by the WRF Model with 4-km Grid Increment: An Inter-Comparison Study between the Urban Canopy Model and Slab Model. J. Meteor. Soc. Japan., 90B, 33-45. (Acknowledgement: S5, T2K) .
  • Kusaka, H., Hara, M., Takane, Y., 2012: Urban climate projection by the WRF model at 3-km horizontal grid incremet: Dynamical downscaling and predicting heat stress in the 2070’s August for Tokyo, Osaka, and Nagoya metropolies. J. Meteor. Soc. Japan., 90B, 47-64. (Acknowledgement: S5) .

Weather Forecast Research・
 Passage of Low Pressure Systems and Fronts

With the increasingly improve the accuracy of numerical weather forecasting, we can predict the weather with a pretty high correct rate in a synoptic scale. On the other hand, we still cannot explain many weather phenomena in an area with complex terrain, like Japan Islands. So our lab is focusing on the topics like these:

  • Impact evaluation of double-cyclone around the East Pacific Area
  • Reappear and predict the cyclone activities around the Japan Islands with modeling
  • Elucidation for the formation mechanism of precipitation area when cold front passes through
  • Elucidation for the formation mechanism of precipitation area when cyclone passes through

(Manami ISHIKAWA and Wataru HIRATA)

The type of impact evaluation of double-cyclone around the East Pacific Area

 a) The precipitation area is expands widely
 b) The precipitation area is expands only to the Hokuriku region
 c) Occur the precipitation jump
  • Hirata W., H. Kusaka, 2013: Climatology of Precipitation during the Passage of the Double Cyclone. Geophysical Review of Japan., 86(4), 338-353. 2013/07/01 (Acknowledgement: S-8) .