Noriaki Ohara, Ph.D., P.E.

Education

• B.A. Civil Engineering, Chuo University, Japan, 1997
• M.A. Civil Engineering, Chuo University, Japan, 1999
• Ph.D. Civil Engineering, University of California, Davis, 2003

 

Research Interests

• Hydrologic Modeling
• Snow Hydrology
• Hydrologic Field Observation
• Hydrometeorology
• Theoretical Treatment of Scale Gap

 

Professional Affiliations

• American Society of Civil Engineers (ASCE)
• American Geophysical Union (AGU)
• Japan Society of Civil Engineers

 

Publications

• Jones, B., C. D. Arp, G. Grosse, I. Nitze, M. J. Lara, M. S. Whitman, L. M. Farquharson, M. Kanevskiy, A. D. Parsekian, A. L. Breen, N. Ohara, R. C. Rangel, and K. M. Hinkel, “Identifying historic and future potential lake drainage events on the western Arctic Coastal Plain of Alaska”, Permafrost and Periglacial Processes, accepted, 2020
• Ohara N.*, and K. Yamatani, "Theoretical Stable Hydraulic Section based on the Principle of Least Action”, Scientific Reports, 9, Article number: 7957, 2019. https://www.nature.com/articles/s41598-019-44347-4
• Ishida, K., N. Ohara, A. Ercan, S. Jang, T. Trinh, M.L. Kavvas, K. Carr, M. L. Anderson, “Impacts of Climate Change on Snow Accumulation and Melting Processes over Mountainous Regions in Northern California during the 21st Century”, Science of The Total Environment, accepted, 2019.
• He, S., N. Ohara*, “Modeling Sub-Grid Variability of Snow Depth using the Fokker-Planck Equation Approach”, Water Resources Research, 2019.
• He, S, N. Ohara*, and S.N. Miller “Understanding sub-grid variability of snow depth at 1 km scale using Lidar measurements”, Hydrologic Processes, 2019.
• Ishida, K., A. Ercan, T. Trinh, S. Jang, M. L. Kavvas, N. Ohara, Z. Q. Chen, S. Kure, and Dib. "Trend analysis of watershed-scale annual and seasonal precipitation in Northern California based on dynamically downscaled future climate projections", Journal of Water and Climate Change, 2018.
• Ishida, K., Ercan, A., Trinh, T., Kavvas, M. L., Ohara, N., Carr, K., & Anderson, M. L. “Analysis of future climate change impacts on snow distribution over mountainous watersheds in Northern California by means of a physically-based snow distribution model”, Science of The Total Environment, 645, 1065-1082, 2018.
• Thayer, D., A. D. Parsekian, K. Hyde, H. Speckman, D. Beverly, B. Ewers, M. Covalt, N. Fantello, T. Kelleners, N. Ohara, and T. Rogers “Geophysical Measurements to Determine the Hydrologic Partitioning of Snowmelt on a Snow‐Dominated Subalpine Hillslope”, Water Resources Research, 54 (6), 3788-3808, 2018.
• Ohara, N.*, W.S. Holbrook, K. Yamatani, B.A. Flinchum, and J.T. St. Clair, “Spatial Estimation of Riparian Groundwater Domain within Alluvium Deposit of Mountainous Areas”, Hydrological Processes, 32 (1), 30-38, 2018.
• Ishida, K., N. Ohara, M. L. Kavvas, Z. Q. Chen, and M. L. Anderson. "Impact of air temperature on physically-based maximum precipitation estimation through change in moisture holding capacity of air." Journal of Hydrology, 556, 1050–1063, 2018.
• Pleasants, M.S.*, T. Kelleners, and N. Ohara, "Analysis of snowpack dynamics during the spring melt season using point measurements and numerical modeling", Hydrological Processes, 31(25), 4568-4585, 2017.
• He, S.*, and N. Ohara, “A new formula for estimating the threshold wind speed for snow movement”, Journal of Advances in Modeling Earth Systems (JAMES), 9(7), 2514-2525, 2017.
• Johnson, R. and N. Ohara*, “Dynamic Equilibrium Modeling of Snow and Inland Glaciers under the Evolving Climate in Wyoming”, Journal of Hydrologic Engineering, ASCE, 23(1), 04017056, 2017..
• Jang, S.*, M.L. Kavvas, K. Ishida, T. Trinh, N. Ohara, S. Kure, Z.Q. Chen, M.L. Anderson, G. Matanga, and K. J. Carr, “A Performance Evaluation of Dynamical Downscaling of Precipitation over Northern California”, Sustainability, 2017. doi:10.3390/su9081457.
• Jang, S.*, S. Kure, N. Ohara, M.L. Kavvas, Z.Q. Chen, K. J. Carr and, M.L. Anderson, “Application of WEHY-HCM for Modeling Interactive Atmospheric-Hydrologic Processes at Watershed Scale to a Sparsely Gauged Watershed”, Sustainability, 2017. doi:10.3390/su9091554.
• Trinh, T.Q.*, M.L. Kavvas, K. Ishida, K. J. Carr, and N. Ohara, "Projected 21st Century Climate Change on Snow Conditions over Shasta Dam Watershed by means of Dynamical Downscaling", Hydrological Processes, 2017. 31:2887–2901. https://doi.org/10.1002/hyp.11231.
• Ohara, N.*, M.L. Kavvas, M.L. Anderson, Z.Q. Chen, and K. Ishida, "Characterization of Extreme Storm Events using A Numerical Model Based Precipitation Maximization Procedure in Feather, Yuba, and American River Watersheds in California", Journal of Hydrometeology, 18 (5), 1413-1423, 2017.
• Ohara, N.*, “An Eulerian Equation for Snow Accumulation Downstream of an Object”, Water Resource Research, Volume 53, Issue 2, 1525–1538, 2017.
• Peel, T., M. Ahmed, and N. Ohara, “Investigating Safety-Effectiveness of Wyoming Snow Fence Implementations along a Rural Mountainous Freeway”, Transportation Research Record (TRR), 2017.
• Trinh, T.Q.*, S. Jang, K. Ishida, N. Ohara, Z.Q. Chen, M.L. Anderson, Y. Darama, M.L. Kavvas, “Reconstruction of Historical Inflows into and Water Supply from Shasta Dam by Coupling Physically Based Hydroclimate Model with Reservoir Operation Model." Journal of Hydrologic Engineering, ASCE, 10.1061/(ASCE)HE.1943-5584.0001391, 04016029. 2016.
• Chen, J.F.*, M.L. Kavvas, K. Ishida, T.Q. Trinh, N. Ohara, M.L. Anderson, and Z.Q. Chen, Role of Snowmelt in Determining whether the Maximum Precipitation Always Results in the Maximum Flood." Journal of Hydrologic Engineering, ASCE, 10.1061/(ASCE)HE.1943-5584.0001366, 04016032, 2016.
• Amin M.Z.M., A. J. bin Shaaban, N. Ohara*, M.L.Kavvas, Z.Q.Chen, S. Kure, and S. Jang, “Climate Change Assessment of Water Resources in Sabah and Sarawak, Malaysia, Based on the Dynamically Downscaled GCM Projections Using a Regional Hydroclimate Model”, Journal of Hydrologic Engineering, 10.1061/(ASCE)HE.1943-5584.0001242, 05015015., 2015.
• Ishida*, K., M.L. Kavvas, S. Jang, Z.Q. Chen, N. Ohara, M.L. Anderson, “Physically Based Estimation of Maximum Precipitation over Three Watersheds in Northern California: Relative Humidity Maximization Method”, Journal of Hydrologic Engineering, ASCE, 20(10), 04015014, 2015.
• Ishida, K.*, M.L. Kavvas, S. Jang, Z.Q. Chen, N. Ohara, M.L. Anderson, ”Physically Based Estimation of Maximum Precipitation over Three Watersheds in Northern California: Atmospheric Boundary Condition Shifting”, Journal of Hydrologic Engineering, ASCE, 20(4), 04014052, 2015.
• Ohara, N.*, “A Practical Formulation of Snow Surface Diffusion by Wind for Watershed Scale Applications”, Water Resources Research, Vol. 50, Issue 6, 5074-5089, 2014.
• Ohara, N.*, S. Kure, S. Jang, Z.Q. Chen and M.L. Kavvas, “Modeling of Interannual Snow and Ice Storage in High Altitude Region by Dynamic Equilibrium Concept”, Journal of Hydrologic Engineering, ASCE, 19(12), 04014034, 2014.
•  Ohara, N.*, M.L. Kavvas, Z.Q.Chen, L. Liang, M. Anderson, J. Wilcox and L.Mink, “Modelling atmospheric and hydrologic processes for assessment of meadow restoration impact on　flow and sediment in a sparsely gauged California watershed”, Hydrological Processes, 28, 3053–3066, 2014.
• Oh, N.H.*, B. Pellerin, P. Bachand, P. Hernes, S. Bachand, N. Ohara, M. L. Kavvas, B. Bergamaschi, and W. Horwath. “The Role of Irrigation Runoff and Winter Rainfall on Dissolved Organic Carbon Loads in an Agricultural Watershed”, Agriculture, Ecosystems and Environment, Volume 179, 1 October, 1–10, 2013.
• Kavvas, M.L.*, S. Kure, Z.Q. Chen, N. Ohara, and S. Jang, “WEHY-HCM for Modeling Interactive Atmospheric-Hydrologic Processes at Watershed Scale. I: Model Description”, Journal of Hydrologic Engineering, ASCE, Vol. 18, No. 10, pp. 1262-1271, 2013.
• Kure, S., S. Jang*, N. Ohara, M. L. Kavvas, and Z. Q. Chen, “WEHY-HCM for Modeling Interactive Atmospheric-Hydrologic Processes at Watershed Scale. II: Model Application to Ungauged and Sparsely Gauged Watersheds”, Journal of Hydrologic Engineering, ASCE, Vol. 18, No. 10, pp. 1272-1281, 2013.
• Kure, S., S. Jang*, N. Ohara, M.L. Kavvas, and Z.Q. Chen, “Hydrological Impact of Regional Climate Change for the Snowfed and Glacierfed River Basins in the Republic of Tajikistan: Statistical Downscaling of Global Climate Model Projections”, Hydrological Processes, 2012.
• Kure, S., S. Jang*, N. Ohara, M.L. Kavvas, and Z.Q. Chen, “Hydrologic Impact of Regional Climate Change for the Snowfed and Glacierfed River Basins in the Republic of Tajikistan: Hydrological Response of flow to Climate Change”, Hydrological Processes, 2012.
• Chen, Z.Q., Kavvas, M.L, Ohara, N.*, Anderson, M. L., and Yoon, J. “A Coupled Regional Hydro-Climate Model and its Application to the Tigris-Euphrates basin”, Journal of Hydrologic Engineering, ASCE, Vol. 16, No. 12, 1059–1070, 2011.
• Ohara, N.*, Kavvas, M.L., Anderson, M.L., Chen, Z.Q., and Yoon J. “A Water Balance Study for the Tigris-Euphrates River Basin”, Journal of Hydrologic Engineering, ASCE, Vol. 16, No. 12, 1071–1082, 2011.
• Chen, Z.Q., Kavvas, M.L, Ohara N.*, and Anderson, M.L. “Impact of Water Resources Utilization on the Hydrology of Mesopotamian Marshlands”, Journal of Hydrologic Engineering, ASCE, Vol. 16, No. 12, 1083–1092, 2011.
• Ohara, N.*, Chen, Z.Q., Kavvas, M.L., Fukami, K., and Inomata, H. “Reconstruction of Historical Atmospheric data by A Hydroclimate Model for Mekong River Basin”, Journal of Hydrologic Engineering, ASCE, Vol. 16, No. 12, 1030–1039, 2011.
• Shaaban, A.J., Amin M.Z.M., Chen, Z.Q., and Ohara, N.* “Regional Modeling Of Climate Change Impact On Peninsular Malaysia Water Resources”, Journal of Hydrologic Engineering, ASCE, Vol. 16, No. 12, 1040–1049, 2011.
• Kure, S.*, Kavvas, M.L., Ohara, N., and Jang, S., “Upscaling of Coupled Land Surface Process Modeling for Heterogeneous Landscapes: Stochastic Approach”, Journal of Hydrologic Engineering, ASCE, Vol. 16, No. 12, 1017–1029, 2011.
• Florsheim, J.L.*, B.A. Pellerin, N.H. Oh, N. Ohara, P.A.M. Bachand, S.M. Bachand, B.A. Bergamaschi, P.J. Hernes, M.L. Kavvas, “From deposition to erosion: Spatial and temporal variability of sediment sources, storage, and transport in a small agricultural watershed”, Geomorphology, Volume 132, Issues 3–4, 272–286, 2011.
• Ohara, N., Kavvas, M. L.*, Kure, S., Chen, Z. Q., Jang, S., and Tan, E. “A Physically-Based Estimation of Maximum Precipitation over American River Watershed, California”, Journal of Hydrologic Engineering, ASCE, Vol. 16, issue 4, 351-361, 2011.
• Kavvas, M.L.*, Z.Q. Chen, M.L. Anderson, N. Ohara, J.Y. Yoon, and Fu Xiang. “A Study of Water Balances over the Tigris-Euphrates Watershed”, Physics and Chemistry of the Earth, Elsevier, Vol. 36, 197-203, 2011.
• Ohara, N.*, Kavvas, M.L., Easton, D., Dogrul, C. E., Yoon, J., and Chen, Z.Q. “The Role of Snow in Runoff Processes in a Sub-alpine Hillslope : Field Study in the Ward Creek Watershed, Lake Tahoe, California during 2000 and 2001 Water Years”, Journal of Hydrologic Engineering, ASCE, Vol. 16, No. 6, pp. 521-533, 2010.
• Fu Xiang, Kavvas, M.L.*, Chen, Z.Q., Bandeh, H., Ohara, N., Kim, S., Jand S.H., Churchwell, R. “Experimental Study of Debris Capture Efficiency of Trash Racks”, Journal of Hydro-environmental Research, No.3, 138-147, 2009.
• Ohara, N.*, Kavvas, M. L., and Chen, Z. Q., “Stochastic Upscaling for Snow Accumulation and Melt Processes with PDF Approach”, Journal of Hydrologic Engineering, ASCE, Vol 13, issue 12, 1103-1118, 2008.
• Kavvas, M. L., Yoon, J*, Chen, Z. Q., Liang, L., Dogrul, E. C., Ohara, N., Aksoy, H., Anderson, M. L., Reuter, J., and Hackley, S. “Watershed Environmental Hydrology Model: Environmental Module and Its Application to a California Watershed”, Journal of Hydrologic Engineering, ASCE, Vol. 11, issue 3, 261-272, 2006.
• Ohara, N.*, and Kavvas, M. L. “Field Observations and Numerical Model Experiments for The Snowmelt Process At A Field Site”, Advances in Water Resources, Elsevier, 29, 194-211, 2006.
• Kavvas, M. L.*, Chen, Z. Q., Dogrul, J., Yoon, J., Ohara, N., Liang, L., Aksoy, H., Anderson, M. L, Yoshitani, J., Fukami, K. and Matsuura, T. “Watershed Environmental Hydrology (WEHY) Model Based On Upscaled Conservation Equations: Hydrologic Module”, Journal of Hydrologic Engineering, ASCE, Vol. 9, issue 6, 2004.
• Shimura, K., Ohara, N.*, Matsuki, H., and Yamada, T. “Study on Flood Wave Using Unsteady Flow Analysis”, Journal of Japan Society of Hydrology and Water Resources, Vol. 14, No. 3, May, 2001. (in Japanese)