Difference between revisions of "UKCA & UMUI Tutorial 8"
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==Henry's Law Specification Definition== |
==Henry's Law Specification Definition== |
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+ | |||
+ | ===Chemistry Scheme Specification=== |
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+ | |||
+ | Within the UKCA code, whether a species is wet deposited or not is controlled in the '''ukca_chem_<span style="color:blue">scheme</span>.F90''' file. In the '''chch_defs_<span style="color:blue">scheme</span>''' array there are lines like |
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+ | |||
+ | chch_t( 10,'HONO2 ', 1,'TR ',' ', 1, <span style="color:red">'''1'''</span>, 0), & ! 10 DD: 7,WD: 4, |
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+ | chch_t( 11,'H2O2 ', 1,'TR ',' ', 1, <span style="color:red">'''1'''</span>, 0), & ! 11 DD: 8,WD: 5, |
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+ | |||
+ | Where the <span style="color:red">'''1'''</span> in the 7th column turns on wet deposition of that species (being 0 otherwise). You will need to change the 0 to a '''1''' for the species that you wish to now wet deposit. |
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+ | |||
+ | ===Setting Henry's Law values=== |
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In the '''ukca_chem_<span style="color:blue">scheme</span>.F90''' the parameters required to calculate <math>H_{eff}</math> are held in the '''henry_defs_<span style="color:blue">scheme</span>''' array, and has format |
In the '''ukca_chem_<span style="color:blue">scheme</span>.F90''' the parameters required to calculate <math>H_{eff}</math> are held in the '''henry_defs_<span style="color:blue">scheme</span>''' array, and has format |
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<math> |
<math> |
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− | 1 |
+ | 1+\frac{k(aq)}{H^{+}} |
</math> |
</math> |
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+ | |||
+ | where |
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+ | |||
+ | <math> |
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+ | k(aq) = k\left(298\right) \exp \left(-\frac{\Delta H}{R}\left[\left(\frac{1}{T}\right) - \left(\frac{1}{298}\right)\right]\right) |
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+ | </math> |
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+ | |||
+ | In this case, columns 3 and 4 contain the values of <math>k(298)</math> and <math>-{\Delta H}/R</math> used in the above formula. Similarly, if the dissasociates a second time then a further factor of <math>1+k(aq)/H^{+}</math>, where <math>k(aq)</math> is calculated from the values of <math>k(298)</math> and <math>-{\Delta H}/R</math> in columns 5 and 6. |
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+ | |||
+ | '''Note:''' As with the 2D dry deposition values in '''depvel_defs_<span style="color:blue">scheme</span>''', the order of ''henry_defs_<span style="color:blue">scheme</span>''' also assumes that the values are in the same order as the species (that wet deposit) in the '''chch_defs_<span style="color:blue">scheme</span>''' array. |
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! The following formula is used to calculate the effective Henry's Law coef, |
! The following formula is used to calculate the effective Henry's Law coef, |
Revision as of 16:48, 24 June 2013
Adding Wet Deposition
The formulationn used in UKCA is described in Giannakopoulos (1999)[1]. This scheme uses the following formula to calculate the effective Henry's Law coefficient
where is the rate constant at 298K.
References
- Giannakopoulos, C., M. P. Chipperfield, K. S. Law, and J. A. Pyle (1999), Validation and intercomparison of wet and dry deposition schemes using 210Pb in a global three-dimensional off-line chemical transport model, J. Geophys. Res., 104(D19), 23761–23784, doi:10.1029/1999JD900392.
Henry's Law Specification Definition
Chemistry Scheme Specification
Within the UKCA code, whether a species is wet deposited or not is controlled in the ukca_chem_scheme.F90 file. In the chch_defs_scheme array there are lines like
chch_t( 10,'HONO2 ', 1,'TR ',' ', 1, 1, 0), & ! 10 DD: 7,WD: 4, chch_t( 11,'H2O2 ', 1,'TR ',' ', 1, 1, 0), & ! 11 DD: 8,WD: 5,
Where the 1 in the 7th column turns on wet deposition of that species (being 0 otherwise). You will need to change the 0 to a 1 for the species that you wish to now wet deposit.
Setting Henry's Law values
In the ukca_chem_scheme.F90 the parameters required to calculate are held in the henry_defs_scheme array, and has format
for the 1st dissociatation | for the 1st dissociatation | for the 2nd dissociatation | for the 2nd dissociatation |
Columns 3 and 4 are used if the species dissociates in the aqueous phase. In this case, is futher multiplied by a factor of
where
In this case, columns 3 and 4 contain the values of and used in the above formula. Similarly, if the dissasociates a second time then a further factor of , where is calculated from the values of and in columns 5 and 6.
'Note: As with the 2D dry deposition values in depvel_defs_scheme, the order of henry_defs_scheme also assumes that the values are in the same order as the species (that wet deposit) in the chch_defs_scheme array.
! The following formula is used to calculate the effective Henry's Law coef, ! which takes the affects of dissociation and complex formation on a species' ! solubility (see Giannakopoulos, 1998) ! ! H(eff) = K(298)exp{[-deltaH/R]x[(1/T)-(1/298)]} ! ! The data in columns 1 and 2 above give the data for this gas-aqueous transfer, ! Column 1 = K(298) [M/atm] ! Column 2 = -deltaH/R [K-1] ! ! If the species dissociates in the aqueous phase the above term is multiplied by ! another factor of 1+{K(aq)/[H+]}, where ! K(aq) = K(298)exp{[-deltaH/R]x[(1/T)-(1/298)]} ! The data in columns 3 and 4 give the data for this aqueous-phase dissociation, ! Column 3 = K(298) [M] ! Column 4 = -deltaH/R [K-1] ! The data in columns 5 and 6 give the data for a second dissociation, ! e.g for SO2, HSO3^{-}, and SO3^{2-} ! Column 5 = K(298) [M] ! Column 6 = -deltaH/R [K-1]
Written by Luke Abraham 2013