Output Grids for Transects

Several tasks for producing transects use a common methodology for producing the comparison grid for each transect:

# The approximate horizontal resolution (in km) of each transect.  Latitude/
# longitude between observation points will be subsampled at this interval.
# Use 'obs' to indicate no subsampling. Use 'mpas' to indicate plotting of
# model data on the native grid, in which case comparison with observations
# will take place on the observation grid.
#horizontalResolution = mpas
#horizontalResolution = obs
horizontalResolution = 5

# The name of the vertical comparison grid.  Valid values are 'mpas' for the
# MPAS vertical grid, 'obs' to use the locations of observations or
# any other name if the vertical grid is defined by 'verticalComparisonGrid'.
# If horizontalResolution is 'mpas', model data (both main and control) will be
# plotted on the MPAS vertical grid, regardless of the comparison grid.
#verticalComparisonGridName = mpas
#verticalComparisonGridName = obs
verticalComparisonGridName = uniform_0_to_4000m_at_10m

# The vertical comparison grid if 'verticalComparisonGridName' is not 'mpas' or
# 'obs'.  This should be numpy array of (typically negative) elevations (in m).
verticalComparisonGrid = numpy.linspace(0, -4000, 401)

# A range for the y axis (if any)
verticalBounds = []

The horizontalResolution of all transects can be obs, mpas or a number of kilometers. If obs, model data are sampled at latitude and longitude points corresponding to the observations. If the horizontal grid is mpas, then the native MPAS-Ocean mesh is used for both the horizontal and vertical grids. If a number of kilometers is given, linear interpolation between observation points is performed with approximately the requested resolution. The distance between observation points is always divided into an integer number of segments of equal length so the resolution may be slightly above or below horizontalResolution.

The vertical grid is determined by two parameters, verticalComparisonGridName and verticalComparisonGrid. If verticalComparisonGridName = mpas, but horizontalResoltuion is not mpas, the MPAS-Ocean vertical coordinate will be interpolated horizontally from grid cell centers to the latitude and longitude of each point along the transect, and the observations will be interpolated vertically to the resulting grid. If verticalComparisonGridName = obs, the vertical grid of the observations is used instead. If verticalComparisonGridName is anything else, it is taken to be the name of a user-defined vertical grid (best to make it descriptive and unique, e.g. uniform_0_to_4000m_at_10m) and verticalComparisonGrid should be assigned a valid array of positive-up depth values (in the form of a python list or numpy array), e.g.:

verticalComparisonGrid = numpy.linspace(0, -4000, 401)

produces points between 0 and -4000 m sampled every 10 m.

verticalBounds is a list of minimum and maximum limits for the vertical axis of the transect. The default is an empty list, which means matplotlib selects the axis limits to encompass the full range of the vertical grid.

Note

Some types of transects (e.g. those produce with geojson files) do not have a vertical grid associated with them (just horizontal latitude/longitude points), meaning that verticalComparisonGridName = obs is not a valid option for tasks with these transects.