MARS/Dissemination
Specifies the target grid which can be either a Gaussian or a Latitude/Longitude grid.
grid=<value> 

MARS requests specifying grid=av
will return the archived model grid. For Latitude/Longitude output, the format is in degrees, i.e. grid = 2.5/2.5, where the first number denotes the eastwest resolution (longitude) and the second denotes the northsouth resolution (latitude). The grid spacing needs to be an integer fraction of 90 degrees (latitude range from the Equator to the Pole), e.g. 0.225, 0.25, 0.28125, 0.3, 0.4, ...
Output on a Gaussian grid is specified by a letter denoting the type of Gaussian grid followed by an integer (the grid number) representing the number of lines between the Pole and Equator, e.g.
grid = F160
 full (or regular) Gaussian grid with 160 latitude lines between the pole and equatorgrid = N320
 ECMWF original reduced Gaussian grid with 320 latitude lines between the pole and equator, see Reduced Gaussian Grids for grid numbers used at ECMWFgrid = O640
 ECMWF octahedral (reduced) Gaussian grid with 640 latitude lines between the pole and equator
Not all grid names and grid number combinations are supported. Currently, the Gaussian grid names and numbers supported for MARS retrievals are:
Octahedral reduced Gaussian (O grids)  O1280  O1024  O640  O512  O400  O320  O256  O200  O160  O128  O96  O80  O64  O48  O32 
Original reduced Gaussian (N grids)  N1280  N1024  N640  N512  N400  N320  N256  N200  N160  N128  N96  N80  N64  N48  N32 
Regular (Full) Gaussian (F grids)  F1280  F1024  F640  F512  F400  F320  F256  F200  F160  F128  F96  F80  F64  F48  F32 
MARS requests specifying an unsupported grid will fail. For example, a retrieval request with grid=O123
will return an error. If the letter denoting the type of Gaussian grid is omitted, e.g. grid=320
, a full (or regular) Gaussian grid with 320 grid lines is returned.
For other keywords controlling the interpolation see the diagram below.
Examples

Dissemination lat/lon grids allowed are describe for each data set in the Catalogue pages