STUDIES ON RELATIONSHIP BETWEEN PHYSICAL ENVIRONMENT AND BIOTOPE AROUND A RIVER FOR ENVIRONMENTAL CONSERVATION

Investigator: Shuichi Ikebuchi

Abstract: Ecological aspects related to physical systems of rivers and lakes is investigated through observation of biotopes in rivers and lake. The relationship between hydrological and hydraulic conditions and an ecological system is investigated by the observation and numerical hydraulic model. This study is expanded to discuss the methodology for evaluating urbanization effects on river discharge; and basin simulation for water quantity, water quality and ecology with GIS and remote sensing.

Publications:

S. Ikebuchi : Proc. of International Conference on Large Scale Water Resources Development in Developing Countries, 1997.

S. Ikebuchi, A. Kosida & M. Tomomura : Annuals. Disas. Prev. Res. Inst., Kyoto Univ., No.39 B-2, 1996.

S. Ikebuchi, K. Tomita & M. Tomomura : Journal of Japan Society of Hydrology and Water Resources, Vol.9, No.6, 1996.

SYSTEMS APPROACH ON PLANNING AND MANAGEMENT AGAINST DROUGHT

Investigator: Shuichi Ikebuchi

Abstract: A model for long range and real time reservoir operations is developed, considering the medium and long range weather forecast provided by the meteorological agency. The reasoning employed by the reservoir operator to make the appropriate decision on the reservoir operations, in the presence of uncertainty and inevitable errors in the forecast, is modeled through a rule-based scheme. A fuzzy inference procedure is used to evaluate the rules and produce the control output. The forecast inputs are of medium and long range inflow rates and trends. The operations are conducted according to "control levels" that are related to control actions designed to keep the reservoir state as near as possible to the target one. The focus is on drought management, and the results show that the model behavior is coherent with the model formulation.

Publications:

S. Ikebuchi : Proc. of the Symposium Disaster Prevention Technology, 1995.

S. Ikebuchi : Annuals. Disas. Prev. Res. Inst., Kyoto Univ., No. 28 A, 1995.

ANALYSIS OF VERTICAL PROFILE OF RAIN DROP SIZE DISTRIBUTION RELATED TO RAINFALL TYPE

Investigators: Eiichi Nakakita & Shuichi Ikebuchi

Abstract: The rainfall intensity on the ground is usually not equivalent to the rainfall intensity estimated from the conventional radar. To improve the accuracy of the radar-estimated rainfall, we observe and analyze the vertical profile of the rain drop size distribution (DSD), then create a new formulation of the vertical rainfall type, rainfall intensity and observed DSD from the Disdrometer is developed. Then, the analysis of the vertical profile of DSD in the selected rainfall type is carried out to investigate the possibility of determine relationships among parameters for the DSD.

Publications:

E. Nakakita, S. Ikebuchi, K. Nakagawa, T. Sato. B. E. Vieux and T. Takasao : Weather Radar Technology for Water Resources Management. UNESCO Press, Montevideo, 1997.

E. Nakakita, S. Ikebuchi, K. Nakagawa, T. Sato. B. E. Vieux and T. Takasao : Annual Journal of Hydraulic Engineering, JSCE, Vol.40, pp.297-302, 1996.

K.Nakagawa, E. Nakakita, S. Ikebuchi, T. Sato, T. Takasao : Proceedings of The International Conference on Water Resources & Environment Research: Towards The 21st Century, Vol.1, 1996.

STOCHASTIC AND PHYSICALLY BASED ANALYSIS OF PRECIPITATION AND DEVELOPMENT OF RAINFALL PREDICTION METHOD

Investigators: Eiichi Nakakita & Shuichi Ikebuchi

Abstract: A short-term rainfall prediction method using volume scanning radar information is physically based on a conceptual rainfall model (instability field model) using the principles of water balance and thermodynamics. The method is improved for practical use. Firstly, Kalman Filtering theory is introduced into this model to take uncertainties and stochastic concept into account, because this conceptual has been considered as a deterministic one. Secondly, a factor which influence on accuracy of prediction i.e. a translation vector of typhoon, is discussed. Moreover, temporal and spatial variability of rainfall distribution over mountainous area is discussed. It is made clear that the temporal and spatial variability of rainfall distribution over mountainous area has a kind of hierarchical structure in terms of time scale. Also, a design rainfall distribution is proposed based on the scale structure.

Publications:

E. Nakakita, T. Ueda, N. Okada and S. Ikebuchi : Proceedings on Fifth Symposium on Water Resources, 1997.

E. Nakakita, S. Sugimoto, S. Ikebuchi, T. Nakamura, M. Okuda, A. Yamaji, T. Takasao : Annual Journal of Hydraulic Engineering, JSCE, Vol.40, 1996.

E. Nakakita, S. Ikebuchi, T. Nakamura, M. Kanmuri, M. Okuda, A. Yamaji and T. Takasao : Journal of Geophysical Research, Vol.101, No.D21, 1996.

NUMERICAL APPROACH ON EFFECT OF TOPOGRAPHY TO SEVERE RAINFALL USING CLOUD MICROPHYSICS MODEL

Investigators: Satoru Oishi, Eiichi Nakakita & Shuichi Ikebuchi

Abstract: The effect of topography to severe rainfall from cumulus, cumulonimbus is investigated numerically. To represent bottom topography in AE-type primitive model, we use sigma-coordinate and tensor analysis. The Poisson equation translated into sigma-coordinate has been solved numerically by using FFT and a iteration method. We obtain reasonable result from this method. Knowledge about effect of topography on severe rainfall is obtained from investigation of the numerical result. A couple of knowledge are: 1) the sigma coordinate is introduced in inelastic model and the convergence method for solving pressure equation is shown to be reasonable; 2) the effect of topography which is lower than the height of cloud base of cumulus is shown to be just as a trigger of cumulus generation; 3) the effect of topography which is higher than the height of cloud base of cumulus is decided by the vertical wind at the area where second generated cumulus grows.

Publications:

S. Oishi, Y. Kitani, E. Nakakita and S. Ikebuchi : Annual Journal of Hydraulic Engineering, JSCE, Vol.41, 1997.

S. Oishi, Y. Kitani, E. Nakakita and S. Ikebuchi : Journal of Hydroscience and Hydraulic Engineering, Vol.14, No.2, 1996.

DEVELOPMENT OF FLOOD CONTROL SUPPORTING SYSTEMS USING INFORMATION SCIENCE.

Investigators: Satoru Oishi, Eiichi Nakakita & Shuichi Ikebuchi

Abstract: Severe rainfall prediction method using artificial intelligence (SRAI), which can forecast the time series variation and spatial distribution of severe rainfall is developed for supporting the flood control management. This method is the unprecedented method in the sense that severe rainfall is predicted mainly based on the physical processes of cloud development, the qualitative reasoning (QR), and the model based reasoning (MBR).

Publications:

S. Oishi and S. Ikebuchi : Qualitative Reasoning -The Tenth International Workshop-, AAAI Technical Report WS-96-01, 1996.

S. Oishi and S. Ikebuchi : Proceedings of the Symposium on Advanced Utilization of Water Resources System, 1995.

S.Oishi. N. Watanabe and S. Ikebuchi : Annuals. Disas. Prev. Res. Inst., Kyoto Univ., No.38 B-2, 1995.