fixed variable names and created download script

air temperature and pressure variables were not created properly in the cf compliant ameriflux files, created new variables instead of renaming old ones. Fixed bug in windspeed calculation. Created ameriflux download script for files with gaps.
No, this is something we've been thinking about. Extracting the fluxnet standard name from a site name wouldn't be hard and would just require us to enforce some degree of standardization for those site names. I think the more interesting challenge is how do we flag a site as being an Ameriflux or FLUXNET site and automatically get new sites into our database without having to do that by hand. In particular, given that there are a lot of different plot networks in the world, we don't want these to just be boolean variables in the sites table, since that's not efficient or flexible. We could rely on a naming convention, which is flexible but not efficient. We could also create a new table for site networks, which would need to be a many:many mapping (obviously networks involve many sites, some sites will show up in multiple networks). One thing I like about a sitenetworks table would be that it would make it easier to say that a specific driver becomes an option for any site in that network even if we haven't downloaded that data yet (e.g. in the webpage we could list "Ameriflux" as a met driver for a tower that we've never downloaded the met for since we know that we now have the capacity to get that data).