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Monthly archive of atmospheric fields:

Raw data

The IFS writes its data into the MOFC (1090) stream in MARS. All of the data are archived using their original model representation (Reduced Gaussian Grid or Spherical Harmonics). Upper-air fields are archived every 12 hours, whereas surface fields are archived every 3, 6, 12 or 24 hours.

Wave model monthly forecasts are archived as stream WAMF (1095).

 In order to retrieve these fields from MARS, two MARS command lines have to be added: method=1, and system=2, but may change, if the monthly forecasting system is modified. Look at the System Change Notice to see which system value is valid. For the control forecast TYPE=CF, for perturbed forecasts TYPE=FC.

Here is an example of MARS retrieval:

retrieve, class="od",expver=0001,stream=mofc,type=fc,method=1,system=2,levtype=pl, level=500,param=Z,number=1/to/50,date=20020327,time=00,step=12/to/768/by/12, target="out"

Weekly Means

Monthly forecast weekly means are calculated for all atmospheric variables and stored in the stream MOFM (1094) and type FCMEAN.

Wave model forecast means (weekly means) are calculated and stored in the stream WMFM (1096).

Monthly forecast weekly maximum (type FCMAX), minimum (type FCMIN) and standard deviation (type FCSTDEV) have also been calculated and archived for all surface fields.

The weeks are as follow:

 Week 1: day   5 to day 11 (FCPERIOD=05-11)
 Week 2: day 12 to day 18 (FCPERIOD=12-18)
Week 3: day 19 to day 25 (FCPERIOD=19-25)
Week 4: day 26 to day 32 (FCPERIOD=26-32)

Here is an example of MARS retrieval for weekly means:

retrieve, class="od",expver=0001,stream=mofm,type=fc,method=1,system=2,levtype=pl, level=500,param=Z,number=1/to/50,date=20020327, time=00, fcperiod=05-11, target="out"

Ensemble means and standard deviation

Ensemble means and standard deviations are archived in MARS only for a limited number of fields: temperature at 850 and 500 hPa and geopotential at 1000 and 500 hPa.

To retrieve these fields, stream=MOFC, TYPE=EM (ensemble mean) or TYPE=ES (ensemble standard deviation).

example:

class=od,expver=0001,stream=mofc,type=em,method=1,system=2,levtype=pl,level=500, param=Z,date=20020327,time=00,step=24, target="out"

EPSgrams

In order to avoid retrieving 51 members to create EPSgrams, several fields have been reordered, and the minimum, 25%, median, 75% and maximum of the ensemble distribution have been archived. These fields are: T850, total cloud cover, 2-metre temperature, total precipitation and 10 metre scalar wind speed. 

To retrieve these fields: STREAM=MOFC, TYPE=ED, NUMBER=0 (minimum), NUMBER=12 (25%), NUMBER=25 (MEDIAN), NUMBER=37 (75%) or NUMBER=50 (MAXIMUM)

example:

class=od,expver=0001,stream=mofc,type=ed,method=1,system=2,number=25,levtype=pl, level=500,param=Z,date=20020327,time=00,step=24, target="out"

Monthly archive of ocean fields:

Ocean fields in the coupled forecasts:

The ocean data are archived together with the atmospheric data, and are distinguished by the 'LEVTYPE' attribute, which is set to 'DEPTH' or 'DP'. Ocean variables are archived as instantaneous fields (product=inst), accumulated fields (product=tacc) or time series (product=tims). The fields are archived along horizontal (section=h), meridional (section=m) or zonal sections (section=z).

Ocean fields in the accelerated forecast:

Fluxes and ocean data created during the 12 days of ocean real-time forecast ( to create the ocean initial conditions) are stored on MARS under TYPE=OF (ocean fields) and FF (forcing fields).