.. _MPAS-DYAMOND-WINTER:

MPAS
========================================

**Provided by** National Center for Atmospheric Research (NCAR), USA


Model description
-----------------

MPAS is an atmospheric model that consists of an atmospheric fluid-flow solver (the dynamical core) and a subset of the Advanced Research WRF (ARW) model atmospheric physics. 
The dynamical core solves the fully compressible non-hydrostatic equations of motion.
MPAS uses an unstructured centroidal Voronoi mesh (grid, or tessellation) and C-grid staggering of the state variable as the basis for the horizontal discretisation in the fluid-flow solver. 
For a more detailed description, see `Skamarock et al. (2012) <https://doi.org/10.1175/MWR-D-11-00215.1>`__. 

MPAS is a community model and can be downloaded from https://mpas-dev.github.io.


Experiment runs
-----------------

NCAR ran 4 experiments, the nominal 3.75-km simulations and lower-resolution counterparts with resolutions of 7.5 km, 15 km, and 30 km. 


MPAS 3.75km atmosphere-only
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Location: 
        :file:`/fastdata/ka1081/DYAMOND/data/winter_data/DYAMOND_WINTER/NCAR/MPAS-3km/DW-ATM/` *(standardized data by DKRZ)*

        :file:`/fastdata/ka1081/DYAMOND/.input_winter_data/MPAS_3.75km/` *(non-standardized data)*
        with grid data in :file:`x1.41943042.static.nc`.

Setup: 
        MPAS-Atmosphere coupled to a 1-D slab ocean model and NOAH land model.

Resolution:
        * 3.75 km (41943042 horizontal grid cells), 55 vertical levels with the model top at 30 km. 
        * The sponge layer begins at 22 km. 
        * The ocean and land models have the same horizontal resolution.

Comments: 
        * Initial SST are from the data provided by DYAMOND. SSTs and mixed layer currents are predicted by the 1-D ocean model. 
        * The 1-D slab ocean model is a conventional bulk ocean mixed layer model based on the formulation of `Pollard et al. (1973) <https://www.tandfonline.com/doi/abs/10.1080/03091927208236105>`__.
        * The NOAH land surface model is described in `Niu et al. (2011) <https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2010JD015139>`__. 
        * The NOAH land model was initialized with soil temperature and soil moisture from the provided DYAMOND initial condition file.

Data description: 
        NCAR provide the same variables as for their DYAMOND summer contribution (see :ref:`MPAS-DYAMOND-SUMMER`) plus the following ocean mixed layer variables in the :file:`ocean/` folder:

 .. code:: bash

	float t_oml(Time, nCells) ;
		t_oml:units = "K" ;
		t_oml:long_name = "ocean mixed layer temperature" ;
	float h_oml(Time, nCells) ;
		h_oml:units = "m" ;
		h_oml:long_name = "ocean mixed layer depth" ;
	float hu_oml(Time, nCells) ;
		hu_oml:units = "m^2 s^{-1}" ;
		hu_oml:long_name = "ocean mixed layer integrated u (zonal velocity)" ;
	float hv_oml(Time, nCells) ;
		hv_oml:units = "m^2 s^{-1}" ;
		hv_oml:long_name = "ocean mixed layer integrated v (meridional velocity)" ;


 Data description of the standardized data by DKRZ will come soon. 

Contact person: 
        `Falko Judt (UCAR) <fjudt@ucar.edu>`__ and `Rosimar Rios-Berrios (UCAR) <rberrios@ucar.edu>`__




See also
--------