NetCDF synoptic data for multiple profiles

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Short Description

Synoptic data for several profiles with different number of locations along each profile.

Further Descriptions

Version Discrete Sampling Geometry trajectoryProfile

Data for multiple locations along one or several profiles (trajectories) are stored in a netCDF file in accordance with the concept of a Discrete Sampling Geometry with featureType=trajectoryProfile. An example (output from NCDUMP) for geometry as well as data is shown in P_synop_ncdump_2D.pdf.

This type of data is essentially identical with netCDF synoptic data at multiple locations. All relevant differences, which are the same for all geophysical variables, are explained for variable water level.

float Mesh0_node_Wasserstand_2d(nMesh0_data_time, nMesh0_trajectory, nMaxMesh0_trajectory_nodes) ;

 :long_name = "Wasserstand [ node ]" ;
 :units = "m" ;
 :name_id = 3 ;
 :_FillValue = 1.e+31f ;
 :ancillary_variables = "Mesh0_node_Gesamtwassertiefe_2d" ;
 :cell_measures = "area: Mesh0_node_Wasserflaeche_2d" ;
 :cell_methods = "nMesh0_data_time: point area: mean" ;
 :comment = "ancillary variables may be used for visualization and data analysis as threshold and plot subgrid mask" ;
 :coordinates = "Mesh0_node_lon Mesh0_node_lat Mesh0_node_x Mesh0_node_y Mesh0_trajectory_long_name Mesh0_trajectory_node_distance" ;
 :grid_mapping = "Mesh0_crs" ;
 :standard_name = "sea_surface_height" ;

The following essential differences with respect to data defined for multiple locations exist:

  1. There are two instead of one (horizontal) dimensions: nMesh0_trajectory corresponds to the number of trajectories and nMaxMesh0_trajectory_nodes reflects the (maximum) number of locations for a trajectory. Using the two independent dimensions allows easy access to data along a single trajectory.
  2. Auxiliary coordinate variable Mesh0_trajectory_node_distance is available. With this coordinate variable it is easy to display data along a trajectory in dependence on coordinate profile-meter.

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