kirbykat
commented
7 years ago Update on precipitation units from Carlos 06/10/2017:
Sorry. It was simply a Freudian typo. I meant ml rather than mm. Our unit is ml/m2/month... mm (which is what one typically reports) indicates the is the amount of rain accumulated in a vessel. Whether you have a wide bucket or a narrow cylinder, you expect the same height to accumulate as long as rain falls evenly across the surface. However, the ecoclimate guys use precipitation flux instead and when you do that, you need to take into account the amount of surface that you are measuring. 2000mm is 200cm (the height of the volume of water being measured) and 1 meter is 100 centimeters (the width and length of the volume being measured) that means that 2000mm of rainfall annually corresponds to: 200cm100cm100cm = 2,000,000cubic centimeters of water falling across the meter2 per year. One cubic cm is one ml of water so our measurement of 156628ml/m2/month * 12 months =~ 1900000ml/m2/year. In other words, our estimate for the Guna is basically exactly what is expected for eastern panama. All the best,
Carlos
stefelisabeth
xrotwang
Bibiko
A) I’m not sure I know who to contact to update the data on D-PLACE (Simon… is that you or is it still Stephanie? Would you guys mind updating the web page with the new data? ALSO… could someone please update my lab’s web page in D-PLACE’s “team” url? It should be “https://pages.wustl.edu/botero", rather than "http://cabotero.weebly.com/“. Thanks!
B) I believe older variables with the same names as the ones provided here should no longer be distributed to avoid confusion (maybe they could be archived under something like “heritage data”?). The newer data is REALLY much better and we should discourage the use of the older one...
C) NEW DATA AND DATA SOURCES
1) Climate data
Annual mean, annual variance, predictability, constancy and contingency for both precipitation and temperature are now based on the “Baseline Historical (1900-1949), CCSM ecoClimate model”. The source citation is:
Lima-Ribeiro,M. et al. 2015. ecoClimate: a database of climate data from multiple models for past, present, and future for Macroecologists and Biogeographers Biodiversity Informatics 10, 1-21. PDF
Please note that the definitions for these variables remain identical as what we currently have in D-PLACE but that the basic units for precipitation data are now grams per square meter per month. Big shout out to the folks at ecoClimate.org who kindly shared with us the raw data from their models (something that is not typically distributed to end users), allowing us to compute predictability, constancy and contingency just the way we wanted.
2) Physical landscape
The current version of D-PLACE includes elevation and slope data from the GTOPO30 dataset (in fact, our current slope data were computed by Rick Step and he never shared with us the exact methods he used, so I am happy to switch to something I can completely vouch for). We have taken advantage of a newer and more accurate data source for elevation: the Global Multi-resolution Terrain Elevation Data 2010 (Link here: GMTED2010), which has replaced the GTOPO30 data over the years. Please note that elevation data from GMTED2010 comes at a whopping 30 ArcSec resolution (!!!) which I use to compute initial —highly local— estimates that are then down sampled to a 0.5 by 0.5 degree resolution in order to maintain consistency with all other D-PLACE variables.
Citation: Global Multi-resolution Terrain Elevation Data courtesy of the U.S. Geological Survey (Downloaded 14 Jul 2014 from http://topotools.cr.usgs.gov/gmted_viewer/)