Data file Description
The DMS data are grouped by "contribution". A contribution
number
identifies each data set. These contribution numbers correspond
to those in the Kettle et al., 1999 publication. Contribution numbers
greater than 134 have been assigned for those contributions made
after the Kettle et al., 1999 work.
The DMS database also contains the following information for
each
contribution.
Contributor:
Each data set is assigned a contributor. Most sets have one
contributor, a few have more than one. In the original Kettle et. al.
publication, a number of sets had "digitized" listed for contributor,
where Kettle had digitized the DMS concentration values directly from
published tables and figures. For these data sets the
"contributor" is listed as "Kettle_D".
Platform:
If known, a platform is listed for each contribution set. This platform
is generally a ship name, but some entries are listed as "unknown ship"
or "from shore" or "helicopter".
Region:
Each data set is given a "region" that is descriptive of where the
measurements were made. There is no rigid classification. "North
Atlantic", "North Sea" , or "Great Barrier Reef" are all valid
examples.
Reference:
If the DMS values have been published, one or more literature
references are given, otherwise the value "unpublished" is listed.
After selection of the data, the data file can be downloaded by
clicking on "Download This Data Set". Each file consists of 4 sections.
A header gives the date and time the data file was created on
the
DMS data server and the selection limits that was used for the
data file selection.
The data then follow in tab delimited columns with one
header row.
The columns are as follows
ContributionNumber:
The contribution number for the data set. Information
about each contribution set is given in third section.
DateTime:
The date and time of each DMS measurement is given in
ISO-8601
format: "YYYY-MM-DD hh:mm:ss". All dates and times are UTC. A few
of the early DMS measurements only
have dates and no times. For these measurements a time of 12:00:00 is
given and the "flag" value is set to 1.
Lat:
The latitude of the DMS measurement in decimal degrees, positive north,
negative south.
Lon:
The longitude of the DMS measurement in decimal degrees, positive east,
negative west.
swDMS:
The concentration of DMS (dimethylsulfide) in the seawater sample in
units of nano moles per liter (nM/L).
DMSPaq:
The concentration in nM/L of aqueous DMSP (dimethylsulfoniopropionate),
if
given, if not given, a 'missing value' of -999 is listed
DMSPp:
The concentration in nM/L of particulate DMSP
(dimethylsulfoniopropionate), if
given, if not given, a 'missing value' of -999 is listed
DMSPt:
The concentration in nM/L of total DMSP, (DMSPt = DMSPaq + DMSPp) if
given, if not given, a 'missing value' of -999 is listed
wdepth:
The depth of the ocean at position of swDMS sample in meters, if given,
if not given, a 'missing value' of -999 is listed
sdepth:
The depth in meters of the sample that was analyzed for seawater DMS,
if given, if not given, a 'missing value' of -999 is given. All samples
in this database are assumed to be 'surface' samples that were
collected the top 20 meters of the water column.
chl:
Seawater chlorophyll in units of micrograms per liter. if not given, a 'missing value' of -999 is listed.
SST:
The reported sea surface temperature at the time and position of the
seawater DMS sample in degrees C, if given, if not given, a 'missing
value' of -999 is listed.
SAL:
The reported salinity, in units of psu, at the time and position of the
seawater DMS sample, if given, if not given, a 'missing value' of -999
is listed.
wspd:
The reported wind speed, in meters per second, at the time and position
of the seawater DMS sample, if given, if not given, a 'missing value'
of -999 is listed.
flag:
A flag value of 1 indicates that only the date for the sample has been
given. A time of 12:00:00 has been assigned to the sample. A value of 0
indicates that there is no data flag. In the future, other flag values
may be assigned.
The third section of the data file lists information about
each
data set included in the data file. This includes the
contribution number, the contributor, the platform,
the region, the literature references and the start
and end dates.
The final section includes the full citations for all the
literature references.
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