Table 1. List of 21 regions.
| ID | Region | Abbreviation |
| 1 | Australia | AUS |
| 2 | Amazon basin | AMZ |
| 3 | southern South America | SSA |
| 4 | Central America | CAM |
| 5 | western North America | WNA |
| 6 | central North America | CNA |
| 7 | eastern North America | ENA |
| 8 | Alaska | ALA |
| 9 | Greenland | GRL |
| 10 | Mediterranean basin | MED |
| 11 | northern Europe | NEU |
| 12 | western Africa | WAF |
| 13 | eastern Africa | EAF |
| 14 | southern Africa | SAF |
| 15 | Sahara | SAH |
| 16 | southeastern Asia | SEA |
| 17 | eastern Asia | EAS |
| 18 | southern Asia | SAS |
| 19 | central Asia | CAS |
| 20 | Tibet | TIB |
| 21 | northern Asia | NAS |