Introduction

The -new_grid_winds option selects the wind rotation/orientation for the -new_grid option. This orientation should apply to all vector quantities. However, the grib format doesn't have a flag specifying which fields are vector fields. Sometimes you like to treat vector quanties as scalars because it makes interpolation easier (for example a time series of tropical U fields). Another complication is that one often wants to duplicate the default action of copygb which is to only treat U and V as vectors.

The -new_grid_vectors option allows you to select which fields will be interpolated as vectors. The options are,

1. none              -all fields are interpolated as scalars
2. UGRD:VGRD  -only UGRD and VGRD are interpolated as vectors (like default copygbfault behavior)
3. default (2.0.1 and prior)     UGRD,VGRD,UVCSH,VVCSH,UFLX,VFLX,UGUST, VGUST,USTM,VSTM,VDFUA,VDFVA,UOGRD,VOGRD are interpolated as vectors
4. default (2.0.2)         UGRD,VGRD,UVCSH,VVCSH,UFLX,VFLX,UGUST, VGUST,USTM,VSTM,VDFUA,VDFVA,UOGRD,VOGRD,MAXUW,MAXVW are interpolated as vectors
5. default (2.0.3-2.0.6)         UGRD,VGRD,UVCSH,VVCSH,UFLX,VFLX,UGUST, VGUST,USTM,VSTM,VDFUA,VDFVA,UOGRD,VOGRD,MAXUW,MAXVW,UICE,VICE,U-GWD,V-GWD are interpolated as vectors
6. default (2.0.7+)         UGRD,VGRD,UVCSH,VVCSH,UFLX,VFLX,UGUST, VGUST,USTM,VSTM,VDFUA,VDFVA,UOGRD,VOGRD,MAXUW,MAXVW,UICE,VICE,U-GWD,V-GWD,USSD,VSSD are interpolated as vectors

Usage

-new_grid_vectors X
    X = none, default, UGRD:VGRD, UV list
    example UV list:   "UGRD:VGRD:UICE:VICE"