.. _recipes_steric_patterns:

Calculate sterodynamic sea-level patterns from CMIP6 models
===========================================================

Overview
--------

The recipe recipe_steric_patterns calculates sterodynamic sea-level change
patterns from CMIP6 model datasets. Patterns are calculated for the SSP2-4.5,
SSP3-7.0 and SSP5-8.5 scenarios.

These patterns are useful because we can emulate spatially-resolved
sterodynamic sea-level rise from global thermal expansion at a fraction of the
computational cost of running a fully-coupled Earth system model or ocean model.

The methods for this recipe are derived from those in Palmer et al. (2020) which
themselves are rooted in the IPCC AR5 report.

.. note::
  The regrid setting in the recipe is set to a (180, 360) grid to put
  all models on the same grid.


Available recipes and diagnostics
---------------------------------

Recipes are stored in esmvaltool/recipes/

* recipe_steric_patterns.yml

Diagnostics are stored in esmvaltool/diag_scripts/steric_patterns/

* steric_patterns.py: generates sterodynamic patterns from input datasets
* sub_funcs.py: set of sub functions to assist with the main script


User settings in recipe
-----------------------

#. Script steric_patterns.py

   *Required settings for script*

   None

   *Optional settings for script*

   None

   *Required settings for variables*

   * short_name
   * additional_datasets
   * exp

   *Optional settings for variables*

   None

   *Required settings for preprocessor*

   * regular_grid: regrids data to a (180, 360) grid

   *Optional settings for preprocessor*

   None


Variables
---------

#. Script steric_patterns.py

* zostoga (ocean, monthly, time)
* zos (ocean, monthly, longitude, latitude, time)


Observations and reformat scripts
---------------------------------

None


References
----------

* Palmer, M. D., Gregory, J. M., Bagge, M., Calvert, D., Hagedoorn, J. M.,
  & Howard, T., et al. (2020). Exploring the drivers of global and local
  sea-level change over the 21st century and beyond. Earth's Future, 8,
  e2019EF001413. https://doi.org/10.1029/2019EF001413

* Perks, R., & Weeks, J. (2023). MetOffice/ProFSea-tool: v1.0.0 (v1.0.0).
  Zenodo. https://doi.org/10.5281/zenodo.10255468


Example plots
-------------

.. _fig_steric_patterns_1:
.. figure::  /recipes/figures/steric_patterns/detrended.png
   :align:   center
   :width: 80%

   Detrended zostoga, correcting for model drift using the pre-industrial
   (PiControl) experiment following Palmer et al., (2020). This is done for
   each model and scenario.

.. _fig_steric_patterns_2:
.. figure::  /recipes/figures/steric_patterns/regressions.png
   :align:   center
   :width: 80%

   Example of the regressions between the global thermal expansion (zostoga) and
   local dynamic sea-level height (zos) for three random grid-cells. The coordinate
   for each of the grid-cells is shown in the top-right corner of each panel.

.. _fig_steric_patterns_3:
.. figure::  /recipes/figures/steric_patterns/predictions.png
   :align:   center
   :width: 80%

   Example end-of-century predictions from the UKESM1-0-LL model patterns
   for each SSP, as well as a timeseries of globally-averaged mean-squared
   error. Two polar artifacts can be seen in each map panel, seemingly
   occuring due to ESMValTool's regridding functionality. This seems to occur
   more often on low-resolution models as opposed to high-res.