View source for UKCA & UMUI Tutorials: Things to know before you start

[[UKCA & UMUI Tutorials | Back to UKCA & UMUI Tutorials]]

<span style="color: red">'''You should not use the UKCA Tutoral jobs for scientific studies. They are designed to be used as training aids.'''</span>

UKCA jobs at UM8.2 are currently being prepared and scientifically validated prior to release.

==PUMA and HECToR/MONsooN==

Before you begin this tutorial you should first get a PUMA and a HECToR or MONSooN account as the UKCA Tutorial is based around jobs which run on these supercomputers, using PUMA to submit them.

Further information about how to apply for these account can be found on the '''[[Getting Started with UKCA]]''' page.

This tutorial can be run on both HECToR and MONSooN. In the UMUI '''Search &rarr; Filter...''' for: 

* The HECToR experiment is <span style="color: red">'''xirb'''</span>
* The MONSooN experiment is <span style="color: red">'''xirc'''</span>

==UM Training and the FCM Tutorial==

There is some information about the UM here:

http://cms.ncas.ac.uk/wiki/UmTraining

You must also have completed the NCAS-CMS [http://cms.ncas.ac.uk/wiki/Fcm UM FCM Tutorial]. This tutorial assumes that you have had some experience in using the UM, and know how to copy an existing job to your account and run it. 

If you have never used the UM before you should also view the NCAS-CMS [http://cms.ncas.ac.uk/wiki/UmTraining UM Training] pages, which has a basic [http://cms.ncas.ac.uk/wiki/UmTraining/IntroToUMUI introduction to the UMUI].

You will also find the NCAS-CMS pages very useful: [http://cms.ncas.ac.uk/ cms.ncas.ac.uk].

==Archiving==

By default the UKCA Tutorial jobs are set to archive data to

 /work/n02/n02/<span style="color:blue">userid</span>/um/<span style="color:blue">jobid</span>/archive/

on HECToR, and to

 /nerc/<span style="color:red">ukca</span>/<span style="color:blue">userid</span>/<span style="color:blue">jobid</span>/

on MONSooN (if you are not in the '''ukca''' project group you will need to set your project group here). 

This will be known as your <span style="color:magenta">'''archive'''</span> directory throughout the rest of this tutorial.

'''Note:''' On MONSooN, if you have made some changes to a job and resubmit it, the files in your '''archive''' directory will not be over-written. You will need to either delete these files, or move this directory before starting your job again, e.g.

On MONSooN <tt>cd</tt> into your 

 /nerc/<span style="color:red">group</span>/<span style="color:blue">userid</span>/

and do

 mv <span style="color:blue">jobid</span> <span style="color:blue">jobid</span>.old

etc. This now means that when your job runs new output will be copied to the '''archive''' directory, which is created by the UM if it does not exist.

On HECToR the files in your 

 /work/n02/n02/<span style="color:blue">userid</span>/um/<span style="color:blue">jobid</span>/archive

'''are''' over-written every-time the job runs.

Archiving is controlled in the UMUI in the [[UKCA & UMUI Tutorial 1#Main Switch + General Questions|'''Model Selection &rarr; Post Processing &rarr; Main Switch + General Questions''']] panel.

==Knowledge of scripting and programming languages==

UKCA (and the UM) is written in Fortran 90, and so you should have some knowledge of this language, as well as some knowledge of the Unix/Linux command-line. You will not be asked to do anything advanced, but you will need to add to arrays and other code blocks.

==Structure==

UKCA is not one particular chemistry scheme, but is in fact a '''framework''' for adding a chemistry scheme to the UM. Although in this tutorial you will adapt an exisiting scheme, you could extend this to replacing all tracers and reactions and add in a completely different scheme.

===UKCA Chemistry Tutorials===

These Tutorials are actually one large problem which someone who uses UKCA may be required to do: add some tracers, reactions, deposition, and diagnostics. To make this problem more manageable it has broken down into a series of small <span style="color:green">'''tasks'''</span> which you will be asked to complete. Each Tutorial explains how to make the necessary changes (in general terms), and then you will be asked to make the required changes to your UKCA job.

To accompany each Task which requires UMUI or UKCA code changes, there are worked solutions (held in the same UMUI Experiment as the original Tutorial Base Job) along with sample output and a wiki page detailing the changes in full. If at any point you have difficulty completing one of the Tasks you can take a copy of the worked solution job and carry on from there. There is also sample output provided for each of the tasks.

====Solutions====

The solutions to these tasks can be found in the UMUI (as other jobs in the Tutorial experiments '''xirb''' and '''xirc''') under the '''ukca''' user. The code-changes required can be viewed at the [https://puma.nerc.ac.uk/trac/UM/log/UM/branches/dev/luke/vn8.2_UKCA_Tutorial_Solns vn8.2_UKCA_Tutorial_Solns PUMA Trac page] (password required).

==Model Configuration==

The UKCA Tutorial job is at UM version 8.2 job using a Global Atmosphere 4.0 atmosphere-only configuration. It has a resolution of N96L85 (1.875 degrees by 1.25 degrees, with 85 vertical levels up to 85km). The current UKCA & UMUI Tutorial job uses the '''CheST/StratTrop''' chemistry scheme.

While you may be interested in using UKCA at a different UM version, many aspects of this tutorial will be directly transferable. For instance, many of the UMUI panels and much of the UKCA source code are the same at UM7.3 as at UM8.2.

==Data Manipulation and Plotting==

In these Tutorials you will only be asked to use [http://badc.nerc.ac.uk/help/software/xconv/ Xconv] for basic data manipulation and plotting. Xconv can be found on HECToR at

 /work/n02/n02/hum/bin/xconv

and on the MONSooN ibm02 at

 /projects/um1/bin/xconv

and the MONSooN postproc03 at

 /usr/local/bin/xconv

and which can also be used to extract UM fields as netCDF. Xconv should already be in your <tt>$PATH</tt>.

Both IDL (using the [http://cms.ncas.ac.uk/documents/IDL/idl_guide.html Met Office library]) and Python (using either [http://cfpython.bitbucket.org/ cf-python] or [http://scitools.org.uk/iris/ Iris]) are able read the UM PP/FieldsFile format directly, although use of these tools will not be covered by these Tutorials.

==Further Information==

More information on UKCA can be found by browsing this wiki. More detailed information on UKCA can also be found in the {{pdf|Umdp84_vn82.pdf|UKCA documentation paper for vn8.2 of the MetUM}}.

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''Written by [[User:Nla27 | Luke Abraham]] 2013''