Appendix 1:
         Regional climates, based on the Koppen system of classification
         (1931), as modified by G. T. Trewartha (1968) and Trewartha and
         others (1967).
         Koppen group and types            Ecoregion equivalents
         A--Tropical Humid Climates        Humid Tropical Domain (400)
            Tropical wet (Ar)              Rainforest Division (420)
            Tropical wet-dry (Aw)          Savanna division (410)
         B--Dry Climates                   Dry Domain (300)
            Tropical/subtropical           Tropical/subtropical steppe
              semiarid (BSh)                 division (310)
            Tropical/subtropical           Tropical/subtropical desert
              arid (BWk)                     division (320)
            Temperate semiarid (BSk)       Temperate Steppe Division (330)
            Temperate arid (BWk)           Temperate Desert Division (340)
         C--Subtropical Climates           Humid Temperate Domain (200)
            Subtropical dry summer (Cs)    Mediterranean Division (260)
            Humid subtropical (Cf)         Subtropical Division (230)
                                           Prairie Division (250)*
         D--Temperate climates
            Temperate oceanic (Do)         Marine Division (240)
            Temperate continental, warm    Hot Continental Division (220)
              summer (Dca)                 Prairie Division (250)*
            Temperate continental, cool    Warm Continental Division (210)
              summer (Dcb)                 Prairie Division (250)*
         E--Boreal climates                Polar domain (100)
            Subarctic (E)                  Subarctic Division (130)
         F--Polar Climates   
            Tundra (Ft)                    Tundra Division (120)
            Ice cap (Fi) 
         *Koppen did not recognize the Prairie as a distinct climatic type.
         The ecoregion classification system represents it at the arid
         sides of the Cf, Dca, and Dcb types. 

         Definitions and Boundaries of Koppen-Trewartha System
         Ar    All months above 64F (18C) and no dry season.
         Aw    Same as Ar, but with 2 months dry in winter.
         BSh   Potential evaporation exceeds precipitation, and all months
               above 32F (0C).
         BWh   One-half the precipitation of BSh, and all months above 32F
         BSk   Same as BSh, but with at least 1 month below 32F (0C).
         BWk   Same as BWh, but with at least 1 month below 32F (0C).
         Cs    8 months 50F (10C) or more, coldest month below 64F
               (18C), and summer dry.
         Cf    Same as Cs, but no dry season.
         Do    4 to 7 months above 50F (10C), coldest month above 32F
         Dca   4 to 7 months above 50F (10C), coldest month below 32F
               (0C), and warmest month above 72F (22C).
         Dcb   Same as Dca, but warmest month below 72F (22C).
         E     Up to 3 months above 50F (10C).
         Ft    All months below 50F (10C).
         Fi    All months below 32F (0C).
         A/C boundary = Equatorial limits of frost; in marine locations,
                        the isotherm of 64F (18C) for coolest month.
         C/D boundary = 8 months 50F (10C).
         D/E boundary = 4 months 50F (10C).
         E/F boundary = 50F (10C) for warmest month.
         B/A, B/C, B/D, B/E boundary = Potential evaporation equals