CMIP-GHG-Concentration-Generation

Generation of historical concentrations for CMIP (and other) experiments. We use observations from multiple data sets to create a composite data set which can be used for running models that participate in the Coupled Model Intercomparison Project (CMIP) and similar experiments. The key characteristics of the outputs are:

• a consistent data format which follows CMIP (specifically input4MIPs) conventions
• a consistent time span and spatial coverage for all 43 greenhouse gases of interest (plus composite products for baskets of gases like HFCs, as these are required by some models)
• an approach for combining information from multiple observational networks into one composite data product
• an approach for deriving the seasonality (variation in concentrations over a year) and latitudinal gradients (variation in concentrations from North Pole to South Pole) of the concentrations which can be used to extend these effects (seasonality and latitudinal gradients) both back in time and forward in time. The approach needs to be relatively simple because no high-detail data is available to extend these effects back in time and the approach must be consistent with the outputs of running a simple climate model to extend these effects forward in time (it is typically too expensive to do this forward extension using a more complex model)
  • this is the trickiest and most scientifically interesting part of the work

Status

Status: Prototype, we can now produce files in the right format and are moving onto actually crunching the data

Installation

For all of our dependency management we use poetry. Assuming you have poetry, you can then install the project using

poetry install --only main

Creating the outputs

To create all the outputs, after having installed the project, simply run

poetry run doit run --verbosity=2

Development

Installation

As for installation above, except now you will want to install the development dependencies too, set up pre-commit etc. so the Makefile is your friend. Simply run

make virtual-environment

You can then create the outputs as above, although the development outputs are probably more helpful. For these, the Makefile is once again your friend so just run the following, which sets the required environment variables too

make all-dev