Home   Help   Model I   Model II   Model III   Model IV   p° Calculator 

Model IV:  H+ - NH4+ - Na+ - SO42− - NO3− - Cl− - H2O

Parametrics:  lapse rate

Here, an air parcel (of initial volume 1 m3) containing an aerosol is moved adiabatically over a range of pressures in the atmosphere. The equilibrium state of the aerosol is calculated for the corresponding changes in temperature and relative humidity. A maximum of 100 points can be generated. Further information on the input and output, and the assumptions made in these calculations, can be found here.

First, choose the form of output required:

Normal       Column       Graph

Next, specify the problem in the input fields below.

Atmospheric Pressure

The air parcel is allowed to move between a minimum of 500 mb and maximum of 1000 mb pressure. Enter the range of pressures, within these limits, followed by the number of points to be calculated:

Start value:      End value:      No. of points:

Ambient Conditions

Enter the initial temperature and relative humidity of the air parcel:

Temperature (180 - 330 K):      Relative Humidity (0.1 - 1.0):

(See inputs for details of restrictions on the temperature range, related to the chemical composition of the system.)

Inorganic Composition in Moles per m3

H+:      NH4+:     Na+:   NH3 (ammonia):
SO42−:      NO3−:     Cl−:
Show Options:     Hide Options (and set to default values):

Other Chemical Components

The amounts of organic compounds present can be entered here. First, click the button to select compounds from the library or create new ones for this session.

Trace Gases

Check the boxes below to disable the partitioning of selected trace gases into the vapour phase. (The default for each gas is that partitioning is calculated.)

Prevent partitioning of the following gases:

HNO3 HCl NH3 H2SO4

Solid Phases

Check the boxes below to prevent the formation of selected solids, according to the restrictions that apply for this model. This enables the properties of metastable, supersaturated, aqueous aerosols to be investigated. The default for each calculation is that all solids can form.

No boxes should be checked for any systems containing both NH4+ and Cl− ions.

Omit the following solids:

Ice H2SO4 · H2O H2SO4 · 2H2O
H2SO4 · 3H2O H2SO4 · 4H2O H2SO4 · 6.5H2O
HNO3 · H2O HNO3 · 2H2O HNO3 · 3H2O
HCl · 3H2O (NH4)2SO4 (NH4)3H(SO4)2
NH4HSO4 NH4NO3 2NH4NO3 · (NH4)2SO4
3NH4NO3 · (NH4)2SO4


To submit your calculation, click here: