The model inputs are essentially the same as those for the comprehensive type calculation, but with temperature varied over a range specified by the user. There is flexibility in the output of results, with a choice between the normal mode used for the single-problem calculations, column mode (useful for pasting results into other programs), and graphs. The input fields and output quantities are described below.
normal: the results for each problem will be output sequentially in verbose form (the same way as for single calculations) to a single html page.
column: the results for the complete set of calculations will be output as columns, one per variable. Because of the large number of variables, the columns are separated into several groups and are output to a single html page one after the other. The variable names (i.e., the column headers) are the same as those used in batch type calculations.
graph: all the results are made available for graph plotting. The user selects the x and y variables from an html page that appears when the calculations are complete, and the graph will be displayed in the browser window.
Temperature. Enter a value within the specified range.
initial RH, or moles of water: this is the first value in the range for which model calculations will be carried out. Remember that RH is entered as a fraction, not a percentage.
final RH, or moles of water: this is the last value in the range for which model calculations will be carried out.
number of points: the number of different RHs, or total water contents, for which calculations will be carried out. The minimum number is 2, i.e. the initial and final values only, and the maximum is 100. Relative humidities, or total water contents, will be equispaced across the range.
For example, if RH is varied from 0.8 to 0.9, with 5 points calculated, then the model determines the equilibrium properties of the system at RH = 0.800, 0.825, 0.850, 0.875 and 0.900.
total water option: if the total amount of water in the 1 m3 volume is being varied, it is normally allowed to partition between vapour and condensed phases. Checking the box confines all the water to the condensed (i.e., liquid and solid) phases. This option is useful for calculating the properties of aqueous solutions.
Ionic Composition: enter the numbers of moles of each ion per m3 of atmosphere, ensuring that charge balance is correct to at least one part in 104. Note that model results are not affected by scaling the numbers of moles only where the both the relative humidity is fixed and the trace gases are not being partitioned into the vapour phase.
Other Chemical Components: if organic compounds have been added to the system (by pressing the Manage Compounds button and then selecting or creating the compounds) enter the numbers of moles of species per m3 of atmosphere in the box provided. There may also be options associated with each compound, such as the ability to switch dissociation on or off, or to restrict the compound to one of the two possible liquid phases (aqueous and hydrophobic).
Trace Gases: the model can either report the equilibrium partial pressures of the inorganic trace gases (HNO3, HCl, HBr, and H2SO4), and any organic trace gases, that would exist above the condensed phase, or calculate the actual partitioning of the species between the aerosol and vapour phases.
For example, consider a system containing 1.0E-6 moles of H2SO4, and the same amount of HNO3, in 1 m3 at 298.15 K and a fixed RH of 50%. If no HNO3 is allowed to partition into the vapour phase, then at equilibrium the amount of HNO3 in the liquid phase is remains at 1.0E-6 mol, and the equilibrium pHNO3 is 0.1125E-3 atm. If partitioning is enabled, then 0.99988E-6 mol of HNO3 resides in the gas phase, at a partial pressure of 0.2408E-7 atm. The default is that partitioning is enabled. Check the boxes to prevent partitioning for each trace gas, as required.
Solid Phases: at low relative humidities aerosols may exist in a metastable liquid state (i.e., solids have not precipitated even though the droplets are saturated or supersaturated with respect to them). The properties of such aerosols can be investigated within the model by checking the boxes to prevent the formation of individual solid phases.
Normal: this is the form of verbose output used for single problems. A description of the calculated quantities is given here.
Column: the output is the same as that for the "column" option in batch calculations. Details of the quantities output, and definitions of the column headers, are given here.
Graph: the user will be presented with an html page from which to select the x and y variables to be plotted. Only non-zero quantities will be included in the lists of variables. Graphical output is also available for "batch" calculations. Further assistance is given on the graph selection pages, to which users are automatically directed at completion of calculations for which graphical output has been selected.