This section presents some hints in MARS terms on how to name the different products. This is meant as a guideline and shows the keywords that select a specific data set, but not all keywords necessary to retrieve the data. Usually, operational archive data can be identified with the following MARS directives:

 ```class = od domain = g expver = 1 ```

# Atmospheric high-resolution forecast

 ```stream = oper ```

## Analysis

 ```type = an ```
• Surface

 ```levtype = sfc ```
• Model levels

 ```levtype = ml levelist = 1/to/137 ```
• Pressure levels

 ```levtype = pl levelist = 1000/850/500... ```
• Isentropic levels

 ```levtype = pv/pt ```

## Forecast

 ```type = fc step = 12/to/240/by/12 ```

## First Guess

 ```type = fg step = 6 ```

## Errors in Analysis

 ```type = ea ```

## Errors in First Guess

 ```type = ef ```

# Wave deterministic models

 ```stream = wave ```

# Ensemble Forecast System

 ```stream = enfo/waef ```

## Control Forecast

 ```type = cf step = 12/to/360/by/12 ```

## Calibration/Validation Forecast

 ```type = cv number = 1/2 step = 12/to/360/by/12 ```

## Perturbed Forecast

 ```type = pf number = 1/to/50 step = 12/to/240/by/12 ```

## Forecast Probabilities

 ```type = fp step = 24/to/240/by/24 ```

## Forecast mean probabilities

 ```type = fp step = 144-168/144-240/192-240 ```

## Ensemble means

 ```type = em/es ```

## Clusters

 ```type = cm/es ```

## Tubes

 ```type = tu step = 96 reference = 48/72/96 ```

## Extreme Forecast Index (EFI)

 ```type = efi step=12/to/108/by/24 step=102-126/240/30-150/30-54/54-78/6-126/6-30/78-102 ```

## Trajectory forecast

 ```type = tf obstype = 32 ```

# Boundary conditions

 ```stream = scda ```

# Multi-Analyses Ensemble

 ```stream = maed/amap ```

## Seasonal Forecast

 ```system = 4 method = 0/1 ```

Atmospheric

 ```stream = seas levtype = ml/pl/sfc ```

Wave

 ```stream = wasf ```

Ocean

 ```stream = seas levtype = dp product = inst/tims/tacc/tavg section = h/m/z/v ```

## Monthly Forecast

 ```stream = mofc/wamf ```

## Monthly means

Deterministic

 ```stream = mnth/wamo ```

Climatology

 ```stream = mnth/wamo type = cl ```

Monthly forecast

 ```stream = mofm/wmfm (old system) stream = mnfm/mfwm ```

Seasonal forecast

 ```stream = sfmm/swmm ```

Multi-model seasonal forecast

 ```stream = msmm type = em origin = egrr/lfpw ```

# Special datasets

## Reanalyses ERA-15/ERA-40/ERA-Interim

 ```class = er/e4/ei ```

## Demeter

 ```class = dm ```

## Provost

 ```class = pv ```

## ECSN-Hyretics

 ```class = cs ```

# Research or Member State's experiments

 ```class = rd class = at/be/hr/dk/fi/fr/de/gr/hu/is/ie/it/nl/no/pt/si/es/se/ch/tr/uk expver = aaaa ```

# Other Centres' data

```stream = ammc/cwao/edzw/egrr/lfpw/rjtd/kwbc
```