茨城大学
理学部
理学科(地球環境科学コース)

准教授

若月 泰孝

ワカヅキ ヤスタカ
YASUTAKA WAKAZUKI

学位

  1. 博士(理学) 名古屋大学

論文

  1. 研究論文(学術雑誌) 共著 Current and future carbon budget at Takayama site, Japan, evaluated by a regional climate model and a process-based terrestrial ecosystem model Kuribayashi, M., N. Noh, T. M. Saitoh, A. Ito, Y. Wakazuki, H. Muraoka International Journal of Biometeorology 2016/12/06 10.1007/s00484-016-1278-9. Accurate projection of carbon budget in forest ecosystems under future climate and atmospheric carbon dioxide (CO2) concentration is important to evaluate the function of terrestrial ecosystems, which serve as a major sink of atmospheric CO2. In this study, we examined the effects of spatial resolution of meteorological data on the accuracies of ecosystem model simulation for canopy phenology and carbon budget such as gross primary production (GPP), ecosystem respiration (ER), and net ecosystem production (NEP) of a deciduous forest in Japan. Then, we simulated the future changes in canopy phenology and carbon budget of the forest by incorporating high-resolution meteorological data downscaled by a regional climate model. The ecosystem model overestimated GPP and ER when we inputted low-resolution data, which have warming biases over mountainous landscape. But, it reproduced canopy phenology and carbon budget well, when we inputted high-resolution data. Under the future climate, earlier leaf expansion and delayed leaf fall by about 10 days compared with the present state was simulated, and also, GPP, ER and NEP were estimated to increase by 25.2%, 23.7% and 35.4%, respectively.
  2. 研究論文(学術雑誌) 共著 気候差分ダウンスケーリング法による関東・中部山岳域の確率論的気候変化予測 若月泰孝, 原政之, 藤田実季子, 馬燮銚, 井上忠雄, 木村富士男, 小池俊雄 土木学会論文集B1(水工学) 土木学会 72/ 4, I_55-I_60 2016/02 The incremental dynamical downscaling and analysis system (InDDAS) which has been developed from the pseudo-global-warming method by appending partial functions was applied for a probabilistic regional scale climate change projection with the target regions of Kanto and Japan Alps. In InDDAS, the most reliable future state was projected by a regional climate model (RCM) simulation with an ensemble mean among the climatological increments of multiple general circulation model (GCM) simulations. In addition, the uncertainty of the future projections is estimated by RCM simulations with the multi-modal statistical increments calculated by the singular vector decomposition of the multiple GCMs. An increase of rainfall with the change ratio of 7-16 % was projected in Kanto region, where the most reliable value was 10 %. The change ratios of the vicinity quantiles of extreme rainfall was projected to be larger than that of rainfall and was almost the same as the value explained by the Clausius–Clapeyron effect.
  3. 研究論文(学術雑誌) 共著 Incremental dynamical downscaling for probabilistic analysis based on multiple GCM projections. Wakazuki, Y., R. Rasmussen Geophysical Research Letters American Geophysical Union 42, 10,847-10,855 2015/12/23 10.1002/2015GL066242 A dynamical downscaling method for probabilistic regional-scale climate change projections was developed to cover the inherent uncertainty associated with multiple general circulation model (GCM) climate simulations. The climatological increments estimated by GCM results were statistically analyzed using the singular vector decomposition. Both positive and negative perturbations from the ensemble mean with the magnitudes of their standard deviations were extracted and added to the ensemble mean of the climatological increments. The analyzed multiple modal increments were utilized to create multiple modal lateral boundary conditions for the future climate regional climate model (RCM) simulations by adding them to reanalysis data. The incremental handling of GCM simulations realized approximated probabilistic climate change projections with the smaller number of RCM simulations. For the probabilistic analysis, three values of a climatological variable simulated by RCMs for a mode were analyzed under an assumption of linear response to the multiple modal perturbations.
  4. 研究論文(学術雑誌) 共著 Numerical Experiments of Meso-α-Scale Precipitation Systems under Baiu-Front-Like Idealized Environments Wakazuki Yasutaka, Watanabe Tomoya SOLA Meteorological Society of Japan 11/ 0, 150-155 2015/12/02 1349-6476 URL To investigate the variability of the structure and evolution of meso-α-scale precipitation systems generated in the Baiu frontal zone, numerical experiments using a cloud-resolving non-hydrostatic model were performed with idealized Baiu-front-like environments. The environment was constructed based on hydrostatic and geostrophic balances, and temperature and relative humidity were designed by using Gaussian functions to realize the frontal structure and moist conveyor belt in the lower atmosphere. In order to generate meso-α-scale precipitation systems, temperature perturbation associated with a shallow depression was introduced. Long-lived band-shaped meso-α-scale precipitation systems with the internal multiscale structures as are often observed in the Baiu frontal zone were simulated under the given simplified environments. The variability of features of the meso-α-scale precipitation systems with respect to relative humidity in the middle troposphere in the Baiu frontal zone was examined as an example. The moister environment produced the more rainfall. Additionally, rainfall was intensified under a specific humidity condition.
  5. 研究論文(学術雑誌) 共著 放射性plume 軌跡のためのシミュレータ開発 青山 智夫, 若月 泰孝 Journal of Computer Chemistry, Japan Society of Computer Chemistry, Japan 14/ 3, 74-76 2015/09/25 1347-1767 URL Under nuclear power plant accident, by the ventilation of containment vessel, suspended particulate matter (SPM) is emitted; it attracts radioactive compounds, and the plume diffuses in air. It soaks into the human body. We are required to run away from the invisible plumes. The routes do not exist at any time. We recognize status soon, and should select priority persons to escape from there. We code a real-time plume tracer, which reads 4D-winds of Meso Scale Model (MSM), calculates time-development of plumes. The precision for reach time of plumes is 3–5 min, inner 8 km points from emission.

研究発表

  1. ポスター発表 A statistical downscaling using high resolution regional climate model simulation results American Geophysical Union fall meeting 2016/12/12
  2. 口頭発表(一般) Incremental dynamical downscaling for probabilistic climate change projection and a dynamical approach for precipitation nowcast ICHARM Research & Development Seminar 2016/12/01
  3. ポスター発表 中部山岳域の積雪の気候変化と昇温 気象学会2016年度秋季大会 2016/10/28
  4. 口頭発表(一般) 広島豪雨における気象防災情報の伝達と避難行動に関する現地調査 気象学会2016年度秋季大会 2016/10/28
  5. 口頭発表(一般) 確率論的地域気候変化予測 に関する研究 AICSセミナー 2016/09/08

担当授業科目

  1. 地球環境科学演習I
  2. 気象学特論I
  3. 環境と人間
  4. 地球環境科学入門I
  5. 大気環境の科学I

教育実績

  1. 筑波大学地球学類・地球科学専攻 講義・研究指導 2011/06/01-現在

所属学協会

  1. 土木学会
  2. American Geophysical Union
  3. 水文・水資源学会
  4. 日本気象学会