Geophysical Variables Sample Clauses

Geophysical Variables. The geophysical variables, like the co-ordinate variables, are stored as 2D arrays with the INSTANCE dimension set to 1. Each geophysical variable has at least one ancillary variable named using the conventions described in section 3.4.3 containing the SeaDataNet qualifier flags for that variable.

Geophysical Variables. The geophysical variables are of two types. First, there are the variables measured at each level in the profile, such as current velocities for an ADCP., Like the profile z co-ordinates, these are stored as 3-D arrays with the INSTANCE dimension set to 1. The second type are only measured at a single level for each time step, such as bottom currents measured in shallow water by ADCP bottom tracking. These are stored in 2-D arrays of dimension (INSTANCE, MAXT) Each geophysical variable has at least one ancillary variable named using the conventions described in section 3.4.3 containing the SeaDataNet qualifier flags for that variable.

Geophysical Variables. The ‘geophysical variables’ are the measured variables in the data file, such as temperature and salinity for a CTD profile. Their name indicates the origins of the CF conventions, but has absolutely no relevance. ‘Geophysical variables’ may contain chemical, biological or geological parameters in addition to physical ones. The geophysical variables have the following mandatory attributes: • long_name – free text label • units – plain text label taken from the UDUNITS-2 database (xxxx://xxx.xxxxxxx.xxxx.xxx/software/udunits/udunits-2/udunits2.html) • coordinates – lists the co-ordinate variables for the measurement value as a space-delimited list. For example this could be “TIME DEPTH LATITUDE LONGITUDE” for a CTD or “TIME HEIGHT LATITUDE LONGITUDE” for a radiosonde. • SeaDataNet mandatory semantic attributes (sdn_parameter_urn, sdn_parameter_name, sdn_uom_urn, sdn_uom_name as described in section2.3) and optional instrument attributes (sdn_instrument_urn, sdn_instrument_name, sdn_fall_rate_urn, sdn_fall_rate_nameas described insection 2.4.2).. A _FillValue attribute may be included if the data object includes absent data. Note that the CF standard_name attribute is not mandatory. This is to simplify the inclusion of parameters for which there are no standard names into SeaDataNet NetCDF. However, the CF Standard Names have become widely used and so significantly enhance interoperability. Consequently, their inclusion is STRONGLY recommended to the extent that SeaDataNet partners should engage with the CF community to extend the Standard Name list where required.

Geophysical Variables. The geophysical variables, like the z co-ordinates, are stored as 2D arrays with the INSTANCE dimension set to 1. Each geophysical variable has at least one ancillary variable named using the conventions described in section 3.4.3 containing the SeaDataNet qualifier flags for that variable.