Hi everybody !
I'm a PhD student aiming to work on Species Distributions Models. A have a large data base for french beetles and I like to see wich environmental variables will be correlated to my distribution.
So I started with the Worldclim dataset and I downloaded the temperature data (1950-2000) from the worldclim website. As is said on their website, I'm getting 12 files, each representing a month http://www.worldclim.org/formats . But I couldn't understand why there are only 12 files if the data is monthly from 1950 to 2000. Is this data only the average of all the Januaries, Februaries....Decembers from 1950 to 2000 ???
Thank you for your help !
Camila
Camila,
You are right, each file contains the values for mean monthly temperature from 1950-2000. (see http://www.worldclim.org/methods). In addition to those, Worldclim also provides 19 bioclimatic variables (e.g. annual mean temperature, min/max temperatures, seasonality, precipitation; see http://www.worldclim.org/bioclim), which are.
Please also note that soon the CHELSA model (http://chelsa-climate.org) will come out. It may have a much better resolution compared to WorldClim.
Hi Camila,
Depending on your model's applications you may also want to investigate using the directly measured data that are available from satellite remote sensing products. Worldclim data tends to contain considerable error in areas with sparse weather stations available due to the shortfalls of the interpolation process.
See: http://onlinelibrary.wiley.com/doi/10.1111/geb.12426/abstract
For details and data availability.
Best,
Alex
For some empirical experience with WorldClim bio-climatic "data" in SDMs please see attached. The issue is that the WorldClim raster maps provide spatial interpolations of double-biased point measurements (meteorological stations). Moreover, it is very difficult to obtain the points used for WorldClim interpolations.
Like Alex implicated already, satellite measured data avoid the above issues. Further, climate proxies measured in all pixels/rasters may also proof superior over point interpolations in SDMs , e.g. elevation in montane environments (see attached 1) or satellite measured seasonal NDVI (attached 2).
Article Where the bears roam in Majella National Park, Italy
Article Transferability of species distribution models: The case of ...
Thank you all for your answers! I'll look deeper into the databases and papers that you suggested me!
Hi everyone,
Can you help me to understand the quarterly categorization of bioclim data? The bioclim data has periods on coldest, warmest and so on. But, which months are coldest or warmest? Is it uniform all over the world? I mean, the months, which are driest in USA, is same in Bangladesh?
Thanks in advance.
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