A Mathematical Model for River Ice Processes

• Main Authors: Lal, A. M., Shen, Hung T.
• Other Authors: CLARKSON UNIV POTSDAM NY
• Format: Text
• Language: English
• Published: 1993
• Subjects: Snow; Ice and Permafrost; *ICE MECHANICS; *ICE FORMATION; THERMAL PROPERTIES; VELOCITY; MATHEMATICAL MODELS; INPUT; SIMULATION; TEMPERATURE; STABILITY; PRODUCTION; DISTRIBUTION; INTERACTIONS; DYNAMICS; LAYERS; THERMODYNAMICS; WATER; ONE DIMENSIONAL; FORMULATIONS; OBSERVATION; OHIO RIVER; CHANNELS(WATERWAYS); DECAY; ACCUMULATION; HYDRAULICS; EQUATIONS; RIVERS; UNSTEADY FLOW; METEOROLOGICAL PHENOMENA; FLOW; GEOMETRY; TRANSPORT; ICE; SURFACES; DEPTH; ENERGY; NUMERICAL ANALYSIS; Lawrence River; Ice; permafrost
• Online Access: http://www.dtic.mil/docs/citations/ADA266847; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA266847

River ice processes are complex phenomena that are affected by many factors, including meteorological conditions, thermal inputs, hydraulic conditions and channel geometry. In this study a one-dimensional model called RICE is developed for simulating ice processes in rivers. In the river hydraulics component, the flow condition is determined by an implicit finite- difference solution of one-dimensional unsteady flow equations. In the thermal component, distributions of water temperature and ice concentration are determined by a Lagrangian-Eulerian solution scheme for equations of transport of thermal energy and ice. A two-layer formulation is introduced to model the ice transport. In this formulation the total ice discharge is considered to consist of the surface ice discharge and the discharge of suspended ice distributed over the depth of the flow. The effect of surface ice on ice production, as well as the formation of skim ice and border ice, is included. The dynamic formation and stability of the ice cover is formulated according to existing equilibrium ice jam theories with due consideration to the interaction between the ice cover and the flow. The undercover ice accumulation is formulated according to the critical velocity criterion. The growth and decay of the ice cover is simulated using a finite-difference formulation applicable to composite ice covers consisting of snow, ice and frazil layers. The model has been applied to the St. Lawrence River and the Ohio River system, with simulated results comparing favorably with field observations. Future improvements on the mathematical model as well as theoretical formulations on various ice processes are discussed.