'JULD_ADJUSTED' contains the best estimate of float timing available for this float. If necessary, it contains adjusted
timing variables due to clock drift. The times can be adjusted either in real time or in delayed mode due to clock drift
or estimation of times based on float behaviour by a float expert. The 'JULD_ADJUSTED_STATUS' variable indicates how the
'JULD_ADJUSTED' value was filled and indicates whether the time is estimated or measured. This may lead to times where
'JULD_ADJUSTED' is filled, but 'JULD' contains 'FillValue' because the time is estimated rather than measured.
N_CYCLE variable group
The N_CYCLE variable group contains duplicated cycle timing information from the N_MEASUREMENT variable group, plus a few
variables that pertain to the entire cycle. There are new cycle timing variables which aim to completely describe the
float's trajectory for velocity calculations and which are described in the User's Manual. Some of the other new variables
will be described below:
The 'CLOCK_OFFSET' variable has been added to address clock drift which can occur over time in some Argo float versions
that provide times for dated events or dated measurements. To correct for drift, a clock offset must be applied where
clock offset is defined as a float time minus UTC time.
'REPRESENTATIVE_PARK_PRESSURE' is the best pressure value assigned to the drift phase. The STATUS variable indicates
how this pressure was determined.
'CYCLE_NUMBER_INDEX' clearly links the N_CYCLE and N_MEASUREMENT variable groups. This variable indicates the cycle number
for the information contained in that index of the N_CYCLE array. It also is the profile cycle number associated with the
trajectory cycle in that index of the N_CYCLE array.
'CYCLE_NUMBER_INDEX_ADJUSTED' contains a cycle numbering which has been assessed and adjusted to be correct, especially for
the purposes of trajectory calculations. If a cycle is recovered during delayed mode and no profile file is created, the
cycle must be added into the 'CYCLE_NUMBER_ADJUSTED(N_MEASUREMENT)' and 'CYCLE_NUMBER_ADJUSTED_INDEX(N_CYCLE)' variables.
Real time and Delayed mode trajectory files
With trajectory file format 3.1, Argo is moving to a two-file system for trajectory files. There will be a Real Time (R)
and a Delayed Mode (D) trajectory file.
R files will contain only real time data and will be created by DACs. Real time data means raw data plus any cycle
timing estimates that can be done in real time. Estimated data will be in the 'JULD_ADJUSTED' variable. If this is
not possible, there will be only raw data in 'JULD' variable in the R files.
D files will contain all data, ie both real time and delayed mode data, and will be created by the PI/scientist responsible
for the float. The delayed mode data will go in the ADJUSTED variables in the N_MEASUREMENT array and any cycle timing
variables in the N_CYCLE array that cannot be filled in real time.
D files will exist either when a float dies and all cycles have been d-moded or when some cycles have been d-moded.
If the float is still alive, no cycles will be added to the D file by the DAC in real time. Cycles will be added
only when they have been d-moded by the PI or scientist responsible for the float.
This means that a float could have only an R file or both an R and a D file depending on the stage of
delayed mode data.
For example, a float has completed 100 cycles; the first 25 are d-moded, but the next 75 are not. WMO_Rtraj.nc contains
real time data for all 100 cycles. WMO_Dtraj.nc contains real time and delayed mode data for the first 25 cycles.