Documentation of the U.S. Geological Survey Oceanographic Time-Series Measurement Database

The filenames in this database have a lot of information encoded in them. The Woods Hole Coastal and Marine Science Center (WHCMSC) uses a different naming system than the Pacific Coastal and Marine Science Center (PCMSC) does; both systems are described in this appendix.

WHCMSC Network Common Data Form (NetCDF) filenames have the following form, in which square brackets [ ] indicate optional elements:

999[9]i[i][A][bbbb]-c[cc][_dd].ee

Sample filenames are 7464sc.nc, 9531Aysi-a.nc, and 9885advs-cal.nc and 10021wh-a.nc.

Descriptions of the NetDCF filename elements follow:

• 999i or 9999i[i] represents the WHCMSC mooring number. The first three or four digits are a number assigned to a platform (mooring or tripod), roughly chronologically, as they are deployed. The next one or two digits identify the height of a sensor or instrument on the mooring or tripod, with number 1 at the top and numbers increasing with depth. The relevant depth is that of the measurement volume. In the case of multiple loggers at the same depth, an order is chosen by importance or to suit the investigator.
• [A] represents an optional capital letter that identifies a temporal portion of the deployment. These letters are used when a mooring was redeployed but a new mooring number was not assigned, or when the dataset was broken into multiple time sections for processing.
• bbbb represents one or more mostly lowercase letters that identify the measurements are contained in the dataset or identify the instrument type. The list of identifiers (table 1–1) has grown to identify more files as more instrument types have been used to collect data.
  - (a hyphen) separates the bbbb and ccc fields.
• ccc represents the lowercase letters that identify processing stage. The “a” indicates a file that has passed the best basic version (BBV) review. “-cal” indicates some uncertainty or provisional status. The list of sensor codes and processing stages used in the names is shown in table 1–2.
• [_dd] is an optional tag for other uses. For example, _d0, _d1, and _d2 are used to indicate relative positions of sensors attached to a single logger. During processing, this position may be used to differentiate data created with precruise or postcruise calibrations, or by omitting suspicious data from one of a benthic acoustic stress sensor’s (BASS's) four axes. This section is sometimes also used to indicate that the data were processed in more than one section.
• ee represents the file type extension. The suffix ".nc" is typically used for files that have passed BBV review. Older netCDF files translated from data that were originally stored in Buoy Format often have ".cdf" extensions, but have been reviewed. In some cases, ".cdf" may be used to indicate provisional status.

Thus, a file named “7464sc-a.nc” contains data collected from the fourth instrument from the top of platform 746. The “sc” indicates that the instrument acquiring the data was a SeaCAT and that the file contains temperature and conductivity data. The “-a” and “.nc” suffix both indicate the file is best basic version (BBV). The naming convention used for files in this database is diagrammed in figure 1–1 for the sample file 7464sc-a.nc. Colors are used to help associate the fields with the codes and their descriptions. This nomenclature system has been used consistently since about 2000. The earliest files in the database may not have all the sections because fewer instrument types and processing options were available when they were created. For instance, the oldest files may have no instrument-type identifier in the name. The instrument identifiers in this example are a subset of those most commonly found; more complete lists of the instruments, processing levels and codes are shown in tables 1–1 and 1–2.

Figure 1-1: WHCMSC Nomenclature summary using 7464sc-a.nc as an example. ID, identifier; BBV, best basic version; NetCDF, Network Common Data Form.

There can be no confusion between a filename for data from of the tenth sensor on platform 991 (starts with 99110) and a file containing data from the first sensor on platform 1002 (starts with 10021) because there are no files in the mooring ID range of 100–199 that have more than nine sensors. There are some filenames with six leading digits to allow for four-digit platform IDs with 10 or more sensors.

Table 1-1: List of instrument codes employed in the NetCDF filenames.
[TRDI, Teledyne RD Instruments; ADCP, acoustic Doppler current profiler; ADV, acoustic Doppler velocimeter; ECO, Environmental Characterization Optics; PCADP, pulse-coherent acoustic Doppler profiler; BASS, benthic acoustic stress sensor; VACM, vector-averaging current meter; VMCM, vector-measuring current meter; MAVS, modular acoustic velocity sensor]

Table 1-2: Codes used to indicate processing level in NetCDF files.
[BBV, best basic version]

PCMSC NetCDF filenames have the following form:

EEEYYSSSiibbb-ccc.ee, as in the sample filename CHC14TDH01vecs-cal.nc.

The filename includes the following elements:

• EEE is the three character experiment identifier (ID), such as “ELW” for Elwha River;
• YY is the second two digits of the year in which the experiment was conducted;
• SSS is a site ID (We can use this to identify different platforms at a site, such as “B1T” for tripod at site B1 and “B1M” for mooring at Site B1. We can also use this for multiple deployments at the same site within a given year, such as “IT1” and “IT2.”);
• Ii is the two digit relative height on platform (Usage is like that of the WHCMSC, but 01 is highest.); and
• bbbb, ccc and ee follow the conventions used in WHCMSC files.

The naming convention used for PCMSC NetCDF files in this database is diagrammed in figure 1–2 for the sample file CHC14TDH01vecs-cal.nc. Colors are used to help associate the fields with the codes and their descriptions. There is no master list of PCMSC experiment and site identifiers; they are documented in the reports that describes the research programs.

Figure 1-2: PCMSC nomenclature summary using CHC14TDH01vecs-cal.nc as an example. ID, identifier; BBV, best basic version; NetCDF, Network Common Data Form.