Results are reported from the World Meteorological Organization's Fifth International Cloud Modeling Workshop, Case 5, Part 1. The purpose of this simulation was to check numerical solvers of the gas-aqueous chemical system and discuss the effect of cloud chemistry on the gas-phase species. Six m... Show moreResults are reported from the World Meteorological Organization's Fifth International Cloud Modeling Workshop, Case 5, Part 1. The purpose of this simulation was to check numerical solvers of the gas-aqueous chemical system and discuss the effect of cloud chemistry on the gas-phase species. Six models of assorted spatial and temporal scales employing various numerical solver techniques were limited to box models using updated Lelieveld and Cruizen (1991) initial conditions. The base simulation, a two-hour midday run, 30 minutes clear air, one-hour cloudy air, and 30 minutes clear air, found that models agree on major constituent concentrations such as ozone (O₃) varying by 1% between models. Minor constituent concentrations, such as formic acid (HCOOH), were highly variable, with a 50% discrepancy between models possibly due to aqueous phase diffusion. This case found cloud effects of -1 to -2% in O₃ concentrations and -20 to -43% in formaldehyde (CH₂pO), both agreeing with recent results of similar studies. Optional simulations included intermittent cloud, different chemistry mechanisms, and varying pH. Show less
