Accession Number : ADA288464

Title :   CALGYP: A Simulation Model for Calcite and Gypsum Precipitation-Dissolution in Soils.

Descriptive Note : Special rept.,

Corporate Author : COLD REGIONS RESEARCH AND ENGINEERING LAB HANOVER NH

Personal Author(s) : Marion, Giles M.

PDF Url : ADA288464

Report Date : JUL 1994

Pagination or Media Count : 46

Abstract : This report documents the CALGYP model which is designed to simulate calcite and gypsum precipitaflon-dissolution in solution in soils. CALGYP is a process model that is easy to parameterize, and is designed for long-term simulations (> 1000 years). The CALGYP model has five components: soil parameterization, chemical thermodynamic relations, deterministic and stochastic rainfall models, an evapotranspiration model, and subroutines that calculate water, calcium, and sulfate fluxes through the soil. The stochastic rainfall model is based on probability distributions for interarrival times (days between rainfall events) and rainfall amounts and is designed to simulate the long-term mean annual rainfall and variability in annual rainfall for specific sites. The model is currently parameterized for seven climatic sites in the desert Southwest. However, climate (temperature and rainfall) can be altered and other minerals included, which makes the CALGYP model potentially applicable across a wider range of environmental conditions including freezing-thawing systems. A separate program, Rainmodule, is included to facilitate inclusion of new sites and to alter rainfall patterns for current sites. Instructions for utilization and a FORTRAN-77 source code listing are included with the report.

Descriptors :   *COMPUTERIZED SIMULATION, *CALCITE, *GYPSUM, COMPUTER PROGRAMS, MATHEMATICAL MODELS, CALCIUM, STOCHASTIC PROCESSES, WATER, PROBABILITY DISTRIBUTION FUNCTIONS, MOISTURE CONTENT, LONG RANGE(TIME), FORTRAN, FREEZING, CLIMATE, CONCENTRATION(COMPOSITION), THAWING, SULFATES, EVAPOTRANSPIRATION, RAINFALL, SOIL DYNAMICS, SUBROUTINES, CHEMICAL PRECIPITATION, SOIL CHEMISTRY, SOLUBILITY.

Subject Categories : Geology, Geochemistry and Mineralogy
      Soil Mechanics
      Physical Chemistry
      Computer Programming and Software

Distribution Statement : APPROVED FOR PUBLIC RELEASE