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Reference:   If the DMS values have been published, one or more literature references are given, otherwise the value "unpublished" is listed.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.

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.