UKCA Chemistry and Aerosol Tutorial 10: Difference between revisions
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[[UKCA Chemistry and Aerosol Tutorials | Back to UKCA Chemistry and Aerosol Tutorials]] |
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==What you will learn in this Tutorial== |
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In this tutorial you will learn how the wet deposition of chemical species is handelled in UKCA. You will then add-in the wet deposition of one of your new tracers. |
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==Task 10.1: Add wet deposition of a species== |
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<span style="color:green">'''Task 10.1:''' Add in wet deposition for '''BOB''', using the following values:</span> |
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{| border="1" |
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! <math>\ k(298)\ </math> || <math>\ -\left({\Delta H}/R\right)\ </math> || <math>\ k(298)</math> for the 1st dissociation || <math>\ -\left({\Delta H}/R\right)</math> for the 1st dissociation || <math>\ k(298)</math> for the 2nd dissociation || <math>\ -\left({\Delta H}/R\right)</math> for the 2nd dissociation |
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|- |
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| <math>\ 0.21 \times 10^{+06}\ </math> || <math>\ 0.87 \times 10^{+04}\ </math> || <math>\ 0.2 \times 10^{+02}\ </math> || <math>\ 0.0\ </math> || <math>\ 0.0\ </math> || <math>\ 0.0\ </math> |
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|} |
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'''Note:''' If you were unable to successfully complete [[UKCA Chemistry and Aerosol Tutorial 9#Task 9.1: adding new dry deposition values|Task 9.1]], then please take a copy of the '''i''' job from the Tutorial experiment (''Tutorial: solution to Task 9.1 - add new dry deposition'') and work from there, as this will allow you to only make the changes required for this task. Please also make a new branch and merge-in branch '''branch''' at revision number '''rev''' to allow you to proceed. |
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==Adding Wet Deposition== |
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The formulation used in UKCA is described in Giannakopoulos (1999)[1]. This scheme uses the following formula to calculate the effective Henry's Law coefficient |
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<math> |
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H_{eff} = 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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where <math>k\left(298\right)</math> is the rate constant at 298K. |
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During this tutorial you will be tasked with adding the wet deposition of one of your new tracers. |
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'''References''' |
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# 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. |
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==Turning on Wet Deposition for a Species== |
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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 |
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{| border="1" |
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| <math>\ k(298)\ </math> || <math>\ -\left({\Delta H}/R\right)\ </math> || <math>\ k(298)</math> for the 1st dissociation || <math>\ -\left({\Delta H}/R\right)</math> for the 1st dissociation || <math>\ k(298)</math> for the 2nd dissociation || <math>\ -\left({\Delta H}/R\right)</math> for the 2nd dissociation |
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|} |
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Columns 3 and 4 are used if the species dissociates in the aqueous phase. In this case, <math>H_{eff}</math> is further multiplied by a factor of |
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<math> |
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1+\frac{k(aq)}{H^{+}} |
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</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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and column 3 contains the values of <math>k(298)</math> and column 4 contains the value of <math>-{\Delta H}/R</math>. Similarly, if the species dissociates a second time then a further factor of <math>1+k(aq)/H^{+}</math> is applied, where this value of <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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Examples for this array are |
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0.2100E+06, 0.8700E+04, 0.2000E+02, 0.0000E+00, 0.0000E+00, 0.0000E+00,& ! 4 HONO2 |
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0.8300E+05, 0.7400E+04, 0.2400E-11,-0.3730E+04, 0.0000E+00, 0.0000E+00,& ! 5 H2O2 |
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===Increase the value of JPDW=== |
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Similar to when adding dry deposition of a species you will need to increase the size of the '''JPDW''' counter. This is done with a hand-edit, the value of '''JPDW''' being set in the '''CNTLATM''' file in your <tt>$HOME/umui_jobs/<span style="color:blue">jobid</span></tt> directory. |
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==Solution to Task 10.1: Add wet deposition of a species== |
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Please see [[Solution to UKCA Chemistry and Aerosol Tutorial 10 Task 10.1 |this page]] for a solution of [[#Task 10.1: Add wet deposition of a species|Task 10.1]]. |
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---- |
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''Written by [[User:Nla27 | Luke Abraham]] 2014'' |
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