---
title: MPAS
---
(MPAS-DYAMOND-SUMMER)=
# MPAS

## 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 variables as the basis for the horizontal discretization in the fluid-flow solver. For a more detailed description, see [Skamarock et al. 2012](http://www2.mmm.ucar.edu/people/skamarock/Papers/mpas_mwr_2012_final.pdf).

**Contact:**  
[Falko Judt](mailto:fjudt@ucar.edu), National Center for Atmospheric Research (NCAR), USA

## Data structure

```{note}
Use:
    cdo -setgrid,mpas:GRIDFILE INFILE OUTFILE

to set the grid.
Use `get_dyamond_winter MPAS.*grid` to get the 3.75km grid file, and `get_dyamond_summer MPAS.*grid` to get the 7.5km grid file.
```

### Horizontal
For DYAMOND, MPAS employs the following meshes:

| Global mean mesh spacing | Number of grid columns |
|-------------------------|------------------------|
| 15 km                   | 2,621,442              |
| 7.5 km                  | 10,485,762             |
| 3.75 km                 | 41,943,042             |

### Vertical
The number of vertical levels is 75 ([csv file](MPAS_Vertical_Grid.csv)).

## Data access

### History Files, Output Interval: PT03H
Output will be written for all levels.

| Variable              | Description                                 |
|-----------------------|---------------------------------------------|
| uReconstructZonal     | zonal component of horizontal velocity      |
| vReconstructMeridional| meridional component of horizontal velocity |
| w                     | vertical velocity                           |
| temperature           | actual temperature                          |
| pressure              | pressure                                    |
| qv                    | water vapor mixing ratio                    |
| qc                    | cloud water mixing ratio                    |
| qi                    | ice mixing ratio                            |
| qr                    | rain water mixing ratio                     |
| qs                    | snow mixing ratio                           |
| qg                    | graupel mixing ratio                        |
| ni                    | cloud ice number concentration              |
| nr                    | rain number concentration                   |
| skintemp              | ground or water surface temperature         |
| sst                   | sea-surface temperature                     |
| snow                  | snow water equivalent                       |
| snowh                 | physical snow depth                         |
| vegfra                | vegetation fraction                         |
| sh2o                  | soil equivalent liquid water                |
| smois                 | soil moisture                               |
| tslb                  | soil layer temperature                      |

### Diagnostics Files, Output Interval: PT15M

| Variable           | Description                                    |
|--------------------|------------------------------------------------|
| taux               | surface zonal momentum flux, in N m^{-2}       |
| tauy               | surface meridional momentum flux, in N m^{-2}  |
| olrtoa             | top-of-atmosphere outgoing longwave radiation flux, in W m^{-2} |
| cldcvr             | cloud cover (max of 3D field cloudfraction along vertical) |
| vert_int_qv        | vertically integrated water vapor mixing ratio, in kg m^{-2} |
| vert_int_qc        | vertically integrated cloud water mixing ratio, in kg m^{-2} |
| vert_int_qr        | vertically integrated rain mixing ratio, in kg m^{-2} |
| vert_int_qi        | vertically integrated ice mixing ratio, in kg m^{-2} |
| vert_int_qs        | vertically integrated snow mixing ratio, in kg m^{-2} |
| vert_int_qg        | vertically integrated graupel mixing ratio, in kg m^{-2} |
| refl10cm_1km       | diagnosed 10 cm radar reflectivity at 1 km AGL, in dBZ |
| precipw            | precipitable water, in kg m^{-2}               |
| u10                | 10-meter zonal wind, in m s^{-1}               |
| v10                | 10-meter meridional wind, in m s^{-1}          |
| q2                 | 2-meter specific humidity, in kg kg^{-1}       |
| t2m                | 2-meter temperature, in K                      |
| th2m               | 2-meter potential temperature, in K            |
| mslp               | mean sea-level pressure, in Pa                 |
| relhum_200hPa      | relative humidity at 200 hPa, in %             |
| relhum_250hPa      | relative humidity at 250 hPa, in %             |
| relhum_500hPa      | relative humidity at 500 hPa, in %             |
| relhum_700hPa      | relative humidity at 700 hPa, in %             |
| relhum_850hPa      | relative humidity at 850 hPa, in %             |
| relhum_925hPa      | relative humidity at 925 hPa, in %             |
| dewpoint_200hPa    | dewpoint temperature at 200 hPa, in K          |
| dewpoint_250hPa    | dewpoint temperature at 250 hPa, in K          |
| dewpoint_500hPa    | dewpoint temperature at 500 hPa, in K          |
| dewpoint_700hPa    | dewpoint temperature at 700 hPa, in K          |
| dewpoint_850hPa    | dewpoint temperature at 850 hPa, in K          |
| dewpoint_925hPa    | dewpoint temperature at 925 hPa, in K          |
| temperature_200hPa | temperature at 200 hPa, in K                   |
| temperature_250hPa | temperature at 250 hPa, in K                   |
| temperature_500hPa | temperature at 500 hPa, in K                   |
| temperature_700hPa | temperature at 700 hPa, in K                   |
| temperature_850hPa | temperature at 850 hPa, in K                   |
| temperature_925hPa | temperature at 925 hPa, in K                   |
| height_200hPa      | geometric height at 200 hPa, in m              |
| height_250hPa      | geometric height at 250 hPa, in m              |
| height_500hPa      | geometric height at 500 hPa, in m              |
| height_700hPa      | geometric height at 700 hPa, in m              |
| height_850hPa      | geometric height at 850 hPa, in m              |
| height_925hPa      | geometric height at 925 hPa, in m              |
| uzonal_200hPa      | zonal wind at 200 hPa, in m/s                  |
| uzonal_250hPa      | zonal wind at 250 hPa, in m/s                  |
| uzonal_500hPa      | zonal wind at 500 hPa, in m/s                  |
| uzonal_700hPa      | zonal wind at 700 hPa, in m/s                  |
| uzonal_850hPa      | zonal wind at 850 hPa, in m/s                  |
| uzonal_925hPa      | zonal wind at 925 hPa, in m/s                  |
| umeridional_200hPa | meridional wind at 200 hPa, in m/s             |
| umeridional_250hPa | meridional wind at 250 hPa, in m/s             |
| umeridional_500hPa | meridional wind at 500 hPa, in m/s             |
| umeridional_700hPa | meridional wind at 700 hPa, in m/s             |
| umeridional_850hPa | meridional wind at 850 hPa, in m/s             |
| umeridional_925hPa | meridional wind at 925 hPa, in m/s             |
| w_200hPa           | vertical velocity at 200 hPa, in m/s           |
| w_250hPa           | vertical velocity at 250 hPa, in m/s           |
| w_500hPa           | vertical velocity at 500 hPa, in m/s           |
| w_700hPa           | vertical velocity at 700 hPa, in m/s           |
| w_850hPa           | vertical velocity at 850 hPa, in m/s           |
| w_925hPa           | vertical velocity at 925 hPa, in m/s           |
| omega_200hPa       | pressure velocity at 200 hPa, in Pa s^{-1}     |
| omega_250hPa       | pressure velocity at 250 hPa, in Pa s^{-1}     |
| omega_500hPa       | pressure velocity at 500 hPa, in Pa s^{-1}     |
| omega_700hPa       | pressure velocity at 700 hPa, in Pa s^{-1}     |
| omega_850hPa       | pressure velocity at 850 hPa, in Pa s^{-1}     |
| omega_925hPa       | pressure velocity at 925 hPa, in Pa s^{-1}     |
| vorticity_200hPa   | relative vorticity at 200 hPa, in s^{-1}      |
| vorticity_250hPa   | relative vorticity at 250 hPa, in s^{-1}      |
| vorticity_500hPa   | relative vorticity at 500 hPa, in s^{-1}      |
| vorticity_700hPa   | relative vorticity at 700 hPa, in s^{-1}      |
| vorticity_850hPa   | relative vorticity at 850 hPa, in s^{-1}      |
| vorticity_925hPa   | relative vorticity at 925 hPa, in s^{-1}      |
| cape               | convective available potential energy (surface parcel), in J kg^{-1} |
| cin                | convective inhibition (surface parcel), in J kg^{-1} |
| acswupb            | accumulated all-sky upward surface shortwave radiation flux, in J m^{-2} |
| acswdnb            | accumulated all-sky downward surface shortwave radiation flux, in J m^{-2} |
| acswnetb           | accumulated all-sky net surface shortwave radiation flux, in J m^{-2} |
| acswdnt            | accumulated all-sky downward TOA shortwave radiation flux, in J m^{-2} |
| acswnett           | accumulated all-sky net TOA shortwave radiation, in J m^{-2} |
| aclwupb            | accumulated all-sky upward surface longwave radiation flux, in J m^{-2} |
| aclwdnb            | accumulated all-sky downward surface longwave radiation flux, in J m^{-2} |
| aclwnetb           | accumulated all-sky net surface longwave radiation, in J m^{-2} |
| aclwupt            | accumulated all-sky upward surface longwave radiation flux, in J m^{-2} |
| aclwdnt            | accumulated clear-sky downward surface longwave radiation flux, in J m^{-2} |
| aclwnett           | accumulated all-sky net TOA longwave radiation flux, in J m^{-2} |
| rainc              | accumulated convective precipitation, in mm    |
| rainnc             | accumulated total grid-scale precipitation, in mm |

## Initialisation and Boundary conditions

### Soil Initialisation
Soil initialisation is done via ERA-5.

### Input Data
Input data are generated from ERA-5.

### Treatment of SST and Sea Ice
MPAS uses the provided [IFS data (7 day means)](https://swift.dkrz.de/v1/dkrz_ab6243f85fe24767bb1508712d1eb504/SAPPHIRE/DYAMOND/ecmwf-sst-sic-dyamond.tar.gz?temp_url_sig=88d89c89f45fa6ca0ecc0d5e5c3a85c75058ed33&temp_url_expires=4757-02-11T11:35:51Z).