Data specifications in CPD3 are broken down into several components. In most contexts these components have default values that will be filled in if they are not explicitly specified.
- Station
-
The station is generally the three letter GAW station code for the physical site in question. Stations are not case sensitive.
An additional station called the "default station" is also present. The default station is assigned the code
_
(a single underscore) and is generally always present in all data. It is most commonly used to provide configuration defaults and can generally be ignored in data querying. - Archive
-
The archive is the "type" of data being accessed. For example the
raw
archive generally specifies data as it comes out of the acquisition system with no mentor QC applied. Once those data have been passed by the mentor and had corrections applied it enters into theclean
archive. Passed data averaged to one hour intervals are placed in theavgh
archive. There are additional special archives that includeconfiguration
andevents
for the system configuration and event logs, respectively. Archives are not case sensitive.Archives can also have an
_meta
suffix that contains metadata about the data or configuration in the "main" archive. For example theraw_meta
archive contains the metadata about theraw
archive. That metadata specifies things like physical units and output formats. - Variable
-
The variable is what is normally considered as an individual parameter in a time series or a column in a table. For example a single wavelength of scattering would be a single variable. In this context the green scattering from the "S11" nephelometer would be
BsG_S11
.In archives that are not directly tied to measurements (e.g. the
configuration
archive) the variable specifies the next level of the heirarchy being addressed. For exampleprocessing
specifies the configuration for parts of the automatic processing system.Variables are case sensitive.
- Flavors
-
The flavors of a parameter are the usually hidden qualifies of it. Parameters may have zero or more flavors applied to them. For example the
pm1
flavor species that the value is size selected to less than 1μm diameter. Flavors are not case sensitive.Some common flavors include:
- PM1
-
Data have been size selected to less than 1μm diameter.
- PM25
-
Data have been size selected to less than 2.5μm diameter.
- PM10
-
Data have been size selected to less than 10μm diameter.
- stats
-
This value represents statistics about the average rather than the averaged value itself. For example, this would contain quantiles within the averaging period.
- cover
-
This value contains the coverage fraction (zero to one) of data within the averaging period. For example an hourly average with 45 minutes of valid data would have a coverage of 0.75. When absent, this is assumed to be one (whole time period present). This is normally used to calculate correctly weighted averages to prevent single points from throwing the average off.