Category talk:MARPA Working Group
- 1 initiation -- JEG (talk) 14:53, 28 September 2016 (PDT)
- 2 Created a MARPA Template discussion -- Edassie (talk) 09:43, 2 March 2017 (PST)
What are the most important/controversial aspects to discuss?
Hi MARPA people!
Here is the place to write up about the MARPA Template! You like it say it :) You like it BUT have suggestions ... it is the time and place to say it You do not like it :( ... it is also the time and place to say it , but please tell us what you would rather see !
Anyway it is time to raise your voice!
Re: Created a MARPA Template discussion -- Deborah Khider (talk) 09:44, 2 March 2017 (PST)
Please discuss any terms that need to be added or re-defined. Also identify the required, recommended and optional metadata.
- Suggestions for modification/additions to the MARPA template by Thomas Felis:
We need to state at a prominent place of this worksheet, if a core drilled from a coral colony is without gap over its total length, i.e., if the individual core segments fit seamlessly. This has not always been the case for coral cores drilled in the pre-2000s. Related to this, we need to assign an age model error to the final chronology of the coral time series, which can be different for different time intervals of the record.
About: List of chronology methods: Add „counting of annual cycles in (temperature sensitive) seasonally-resolved stable isotopic/geochemical proxies” as a chronology method; add “supported by density banding” as an option for this method. I do not think that mentioning the software is necessary here. Clearly state that counting of annual cycles in seasonally-resolved coral proxies is corroborated by annual density-band pairs, if this is the case. In other words, provide evidence that skeletal density-band pairs are actually annual, which is not always the case. Note that for annually-resolved coral proxy records, where the age model is just based on an presumed annual pattern of observed density band pairs, the uncertainty of the chronology can me much larger compared to seasonally resolved coral records, where the age model is based on a combination of counting of annual cycles in geochemical proxies corroborated by the density-banding pattern.
Publishing Info: Change “PROXY ARCHIVE” “Coral Core” to “PROXY ARCHIVE” “Coral”. Add as “MANDATORY field” “Data citation” that includes the data citation doi (for PANGAEA) or the data citation url (for NOAA Paleo).
Time series Data: Indicate at column header that “Depth” is referring to “Distance from top/youngest part” of core/colony. Better give “Depth” in “cm”, not “mm”. Monthly interpolated data should not have more digits after the decimal point than raw measured data. Better limit the “Years A.D.” column to 3 digits after the decimal point.
Data Metadata: Analytical Error Assessment: Add a line for reporting for coral Sr/Ca and other element/Ca ratio measurements the average value obtained for a reference material such as the JCp-1, following Hathorne et al. (2013, doi: 10.1002/ggge.20230).
Chronology Section: CHRONOLOGY METHOD: I would not give the name of a software here, I would rather give more specific information such as: “counting of annual cycles in (temperature sensitive) stable isotopic/geochemical proxies” (“supported by density banding”), or “density-band counting”, or “counting of presumed annual cycles in coral d13C”.
Age model from AGER/Analyseries: I am not sure if it is helpful or more confusing to add detailed intermediate steps and associated datasets, between the originally measured geochemical record and the final monthly interpolated record (or what is actually shown in these two sub-worksheets?). This could lead to an inflation of datasets, if each dataset is getting its own data citation in the end, leading to confusion among future users of these data.
Best wishes, Thomas
- 1st comment on the MARPA Template from Janice Lough...
Found the template! Some comments/suggestions as follows: 1) Geochemical data – ability to include other geochemical tracers not listed in menu? 2) Other types of record? e.g. coral luminescence? 3) Present focus on geochemical tracers but what about other dated records – am thinking specifically about coral growth variables, i.e. skeletal density, linear extension and calcification. 4) How do reconstructions of climate variables fit into the scheme? e.g. SST, SSS etc 5) What about metadata describing material that has been collected (e.g. coral cores) but a) has not been analysed or b) there is still material is available for other researchers to work with. I am thinking specifically here about coral cores as, for example, AIMS has an extensive collection of cores from east and west coast Australian reefs – only a small fraction of these have been analysed geochemically and there is plenty of scope to share this material more widely but it is, at present, only visible in our internal database. Also, I am aware of other coral core collections where coral core material has been collected but nothing has ever appeared in publications – presumably the physical samples are still sitting somewhere – it is, I think, important to identify these as far as possible. Anyway, just some initial thoughts and look forward to seeing this initiative develop further. Best wishes