The CLM also allows you to set up and run cases with a single-point or a local region as well
as global resolutions. This is often useful for running quick cases for testing, evaluating
specific vegetation types, or land-units, or running with observed data for a specific site.
There are three different ways to do this: normal-supported site,
CLM_USRDAT_NAME, and with PTCLM.
|normal supported site -- to run for a supported single point or regional dataset.|
|PTCLM -\- to easily setup simulations to run for tower sites..|
PTS_MODEand PTCLM only works for a single point, while the other two options can also work for regional datasets as well.
Running for a normal supported site is a great solution, if one of the supported single-point/regional datasets, is your region of interest (see the Section called Running Supported Single-point/Regional Datasets). All the datasets are created for you, and you can easily select one and run, out of the box with it using a supported resolution from the top level of the CESM scripts. The problem is that there is a very limited set of supported datasets. You can also use this method for your own datasets, but you have to create the datasets, and add them to the XML database in scripts, CLM and to the DATM. This is worthwhile if you want to repeat many multiple cases for a given point or region.
In general the Section called Running
PTS_MODE configurations is the quick and dirty method
that gets you started without having to create datasets -- but has limitations. It's
good for an initial attempt at seeing results for a point of interest, but since you
can NOT restart with it, it's usage is limited. It is the quickest method as you can
create a case for it directly from create_newcase. Although you
can't restart, running a single point is very fast, and you can run for long
simulation times even without restarts.
CLM_USRDAT_NAME is the best way to setup cases quickly
where you have to create your own datasets (see
the Section called Creating your own single-point/regional surface datasets). With this method you don't have to
change DATM or add files to the XML database -- but you have to follow a strict
naming convention for files. However, once the files are named and in the proper
location, you can easily setup new cases that use these datasets. This is good
for treating all the required datasets as a "group" and for a particular
model version. For advanced CLM developers who need to track dataset changes with
different model versions you would be best off adding these datasets as supported
datasets with the "normal supported datasets" method.
Lastly PTCLM is a great way to easily create datasets,
setup simulations and run simulations for tower sites. It takes advantage of both
normal supported site functionality and
CLM_USRDAT_NAME internally. A big advantage to it, is that it's one-stop
shopping, it runs tools to create datasets, and runs create_newcase
and sets the appropriate env variables for you. So you only have to learn how to run
one tool, rather than work with many different ones. PTCLM is described in the next
chapter Chapter 6.
Finally, if you also have meteorology data that you want to force your CLM simulations
with you'll need to setup cases as described in the Section called Running with your own atmosphere forcing.
You'll need to create CLM datasets either according to
CLM_USRDAT_NAME. You may also need to modify DATM to use
your forcing data. And you'll need to change your forcing data to be in a format that
DATM can use.
In the PTCLM chapter the the Section called Converting AmeriFlux Data for use by PTCLM in Chapter 6
section tells you how to use AmeriFlux data for atmospheric forcing.