index values: 1-15 land region, 50-61 ocean regions, 100-101 polar regions
  1 = CAN (Canada + Alaska)
  2 = USA (Continental USA)
  3 = CAM (Central America)
  4 = SAM (South America)
  5 = EUR (Europe)
  6 = RUS (Russia)
  7 = CAS (Central Asia)
  8 = MDE (Middle East)
  9 = SAS (South Asia)
 10 = EAS (East Asia)
 11 = SEA (Southeast Asia)
 12 = ANZ (Australia + New Zealand)
 13 = SHR (Sahara)
 14 = SHL (Sahel)
 15 = RAF (Rest of Africa)
 50 = ENP (Eastern North Pacific)
 51 = ECP (Eastern (north) Central Pacific)
 52 = ESP (Eastern South Pacific)
 53 = NAT (North Atlantic)
 54 = CAT (Central (north) Atlantic)
 55 = SAT (South Atlantic)
 56 = NIN (North Indian)
 57 = SIN (South Indian)
 58 = WNP (Western North Pacific)
 59 = WCP (Western Central (north) Pacific)
 60 = WSP (Western South Pacific)
 61 = SOU (Southern Ocean)
100 = ARC (Arctic)
101 = ANT (Antarctic)