Difference between revisions of "Category:Marine Sediment Working Group"

Revision as of 23:29, 7 March 2017

Credit: Hannes Grobe (Own work) CC BY 3.0, via Wikimedia Commons

Overview

In the Linked Earth context, a working group (WG) is a self-organized coalition of knowledgeable experts, whose activities are governed herewith. This page is dedicated to the discussion of data and metadata standards for marine sedimentary archives (see this page for a definition of Marine Sediment Archive), and aims to formulate a set of recommendations for such a standard.

Members

The group currently has one coordinator, Julie Richey (USGS)

Specific tasks

We recommend that discussions focus on the following considerations, and explore potential commonalities.

For each observation type, we recommend:

• structuring discussions around what scientific questions one would want to ask of the data
• listing essential, recommended, and optional information for:
  • the measurements themselves
  • any inference made from the measurements (e.g. calibration to temperature)
  • the underlying uncertainties, and what those numbers correspond to (e.g. 1-sigma or 2-sigma?)
• providing an ideal data table, so the community knows what to report and how to report it.
• providing separate recommendations for new and legacy datasets, and for how to label measured and inferred variable (e.g. Mg/Ca is measured, temperature is inferred)
• thinking about how the rest of the paleoscience community, or other (non)scientists may make use of the data you describe.

Marine sediments are a very ubiquitous archive on which many types of observations are made, and involving thousands of people around the world. It seems wise for this WG to rally around sub-groups start dedicated to data standards about the following sensors/observation types.

Previous standardization efforts

A discussion regarding paleoclimate data standards was started during the PMIP Ocean Workshop: Understanding changes since the Last Glacial Maximum (hereafter, PMIP_LGM) in Corvallis, OR in December 2013. Given the expertise of the working group members, the discussion focus on sedimentary archives. Meeting notes can be found here and summarized in the sections below.

The recommendations made at the workshop concerned new datasets only. It was recognized that different sets of standards would be necessary for legacy datasets.

Types of Data

There are three principle types of data that are relevant for the paleoceanography/paleoclimatology community:

• Original data values – this would include raw values of all variables measured or otherwise determined on the substrate of interest, recorded against an unambiguous sample identifier (for instance, depth in the archive). This includes age control points (ACP) used to derive the age model of the paleo-time series, including radioisotopes (14C, excess 210Pb), and benthic stack comparison. All data that are reported for the first time in a scientific publication should be treated as original. The procedure of obtaining original data should be documented such as to allow full replication of the results. In the LinkedEarth Ontology, the original data values are referred as Category:MeasuredVariable_©.

Depth can be problematic as a unique identifier since there are several to calculate or report depth in a sample (i.e., top-depth, mid-depth, depth interval.) and IODP uses several depth scales.

Deborah Khider (talk) 15:29, 7 March 2017 (PST): I probably forgot ways of expressing depth, please add comments below.

• Derived data values – this category refers to values of variables derived from other variables, derived or raw, original or compiled, reported against an unambiguous sample identifier and accompanied with a documentation of the derivation procedure such as to allow full replication of the result. This category includes algorithms of any kind relating depth to age that have been used to assign ages to values of raw or derived variables. In the LinkedEarth Ontology, derived data values are referred to as Category:InferredVariable_©.

The derivation procedure is contained in the Category: CalibrationModel_©.

• Compilation of data values – this refers to raw values of all variables from published sources, gathered for the purpose of quantitative treatment, recorded against an unambiguous sample identifier and labelled with an unambiguous reference to the publication where such data were originally presented. Reporting of data compilations is required wherever these are used to derive patterns or variables from the data other than those reported in the original publication.

Geochemical Data

Foraminiferal Geochemistry

Stable isotopes

In the following table, enter the metadata that you'd wish every member of the stable isotope community would enter to make their data reproducible. To add more lines, follow this guide. For a definition of Essential (E)/ Recommended (R)/ Desired (D), see this page.

To gather rapid feedback on whether the proposed metadata should be essential, recommended or optional, answer the polls below:

Trace Metals

Mg/Ca

In the following table, enter the metadata that you'd wish every member of the Mg/Ca community would enter to make their data reproducible. To add more lines, follow this guide. For a definition of Essential (E)/ Recommended (R)/ Desired (D), see this page.

To gather rapid feedback on whether the proposed metadata should be essential, recommended or optional, answer the polls below:

Organic Geochemistry

Alkenones

GDGTs

Compound specific isotopes

Physical Data

Grain Size

Micropaleontological Data

• Report raw counts if available. And if not, at least
• Minimum number of specimens counted
• Size fraction

If the data were used to infer temperature or sea ice concentration, then the method (MAT, WA-PLS, etc) and the training set should be mentioned/required metadata.

Polls

Here are three example polls that the group might want to consider:

For NEW DATASETS:

For LEGACY DATASETS:

This is an example poll. To vote on what should be considered Legacy, see this page.