SNAP documentation
MRI
The MRI files can be found in /group_workspaces/jasmin/snap/mri/phase1. The files can be found in directories of the form YYYYMMDD, where the date is the start date. Inside these directories, the files are the form <VAR>_MRI_phase1_YYYYMMDD_<NN>.nc, where <VAR> is OGWD (Orographic gravity wave tendencies), PV, Precip, T2m, T, U10, U, V10, V and Z (geopotential height), and <NN> runs from 01 to 51 (I DON'T KNOW WHAT THIS IS).
Each of the <VAR>_MRI_phase1_YYYYMMDD_<NN>.nc files contain
- OGWD: double lat (lat), double lon (lon), double plev(plev), double time(time) and float OGWD(time, plev, lat, lon), but plev is only upper levels
- PV: float x(x), float y(y), double theta(theta), float t(t) and float PV(t, theta, y, x)
- Precip: double lat (lat), double lon (lon), double time(time) and float Precip(time, lat, lon).
- T2m: double lat (lat), double lon (lon), double time(time) and float T2m(time, lat, lon).
- T: double lat (lat), double lon (lon), double plev(plev), double time(time) and float T(time, plev, lat, lon).
- U10: double lat (lat), double lon (lon), double time(time) and float U10(time, lat, lon).
- U: double lat (lat), double lon (lon), double plev(plev), double time(time) and float U(time, plev, lat, lon).
- V10: double lat (lat), double lon (lon), double time(time) and float V10(time, lat, lon).
- V: double lat (lat), double lon (lon), double plev(plev), double time(time) and float V(time, plev, lat, lon).
- Z: double lat (lat), double lon (lon), double plev(plev), double time(time) and float Z(time, plev, lat, lon).
where
- PV is the only variable to use x, y and t - instead of lon, lat and time. And this dimensions are floats rather than doubles
- lon/x = 240
- lat/y = 121
- time/t = 64 (6 hour intervals, so 16 days)
- plev = 37 (is 15 for OGWD)
- theta = 5 (in PV file only)
Putting all the variables into one file
All these variables are put into file with the script /home/users/stringer/snap/bin/conformMri.scr, which requires two arguments: the directory containing the data and the value of <NN>. The script then carries out the following
- Loop across all the input files
- Copies files to work directory, /home/users/stringer/snap/data, so will only modify copies.
- Converts the double variable to floats.
- Flip the latitude
- Ensure that dimensions all have the same name
- Rename plev in OGWD to pres_upp, so it does get confused with the plev in the other files - which has a number of extra pressure levels
- Put the data all into one file
- Rename dimensions and variables according to the table below and add and delete attributes
Variable | Long name | New variable name | New long name |
---|---|---|---|
time | time | t | time |
lon/x | longitude | longitude | longitude |
lat/y | latitude | latitude | latitude |
theta | none | theta | potential temperature |
plev | pressure level | p/p_2 | pressure |
OGWD | Orographic gravity wave tendencies | GWOD* | Orographic gravity wave tendencies |
Precip | Precipitation | TP | Rainfall rate |
PV | none | PV | Potential vorticity |
T2m | Near-Surface Air Temperature | T2 | 2 metre temperature |
T | Air Temperature | T | Temperature |
U10 | Eastward Near-Surface Wind | U10 | 10 metre U wind component |
U | Eastward Wind | U | U velocity |
V10 | Northward Near-Surface Wind | V10 | 10 metre V wind component |
V | Northward Wind | V | V velocity |
Z | Geopotential Height | ZH* | Geopotential height (geopotential is in ERA-Interim files but not geopotential height) |