Citation
========
Cannon, A.J., Köppen versus the computer: an objective comparison between
the Köppen-Geiger climate classification and a multivariate regression tree.
MRT climate classification version 1, Febuary 18, 2011.
(alex.cannon@ec.gc.ca)

Notes
=====
MRT climate classification rules are applied to climate variables derived from
Version 1.4 (release 3) of the 10 arc minute WorldClim 1950-2000 climate
normals (http://www.worldclim.org). Data are in ARC/INFO ASCII grid format
(geographic projection, WGS84 datum). Climate classes are denoted by MRT
node numbers defined below.

Correspondence between node and climate class
=============================================
34=1WW, 33=1WD,
40=1DW, 39=1DD,

26=2Ww, 25=2Wd,
52=2Dh, 51=2Dc, 50=2Dw, 49=2Dd,

42=3hh, 54=3hW, 53=3hD,
36=3cw, 35=3cd,
46=3Hw, 45=3Hd,
56=3CH, 55=3CC,

28=4Ww, 27=4Wd,
38=4HW, 37=4HD,
48=4Ch, 47=4Cc,

58=5hh, 57=5hc, 29=5hC,
44=5cw, 43=5cd

Classification rules
====================
Node 25 (N=11327):
(MAT>=12) & (MAP>=1400) & (Pdry<70) & (MAP>=2200) & (Pswet<590) -> 2Wd

Node 26 (N=2081):
(MAT>=12) & (MAP>=1400) & (Pdry<70) & (MAP>=2200) & (Pswet>=590) -> 2Ww

Node 27 (N=9971):
(MAT<12) & (MAT>=-2) & (Pwwet>=110) & (Pwwet<230) -> 4Wd

Node 28 (N=2758):
(MAT<12) & (MAT>=-2) & (Pwwet>=110) & (Pwwet>=230) -> 4Ww

Node 29 (N=26909):
(MAT<12) & (MAT<-2) & (Thot>=5) & (MAT<-9) -> 5hC

Node 33 (N=9397):
(MAT>=12) & (MAP>=1400) & (Pdry>=70) & (MAP>=2800) & (MAP<3700) -> 1WD

Node 34 (N=2043):
(MAT>=12) & (MAP>=1400) & (Pdry>=70) & (MAP>=2800) & (MAP>=3700) -> 1WW

Node 35 (N=13553):
(MAT>=12) & (MAP<1400) & (MAP>=600) & (Tcold<14) & (Pwdry<40) -> 3cd

Node 36 (N=14406):
(MAT>=12) & (MAP<1400) & (MAP>=600) & (Tcold<14) & (Pwdry>=40) -> 3cw

Node 37 (N=25025):
(MAT<12) & (MAT>=-2) & (Pwwet<110) & (MAT>=5) & (MAP<500) -> 4HD

Node 38 (N=29284):
(MAT<12) & (MAT>=-2) & (Pwwet<110) & (MAT>=5) & (MAP>=500) -> 4HW

Node 39 (N=7554):
(MAT>=12) & (MAP>=1400) & (Pdry>=70) & (MAP<2800) & (MAP<2000) -> 1DD

Node 40 (N=13652):
(MAT>=12) & (MAP>=1400) & (Pdry>=70) & (MAP<2800) & (MAP>=2000) -> 1DW

Node 42 (N=18668):
(MAT>=12) & (MAP<1400) & (MAP>=600) & (Tcold>=14) & (Thot>=30) -> 3hh

Node 43 (N=7831):
(MAT<12) & (MAT<-2) & (Thot<5) & (Pdry<50) -> 5cd

Node 44 (N=3774):
(MAT<12) & (MAT<-2) & (Thot<5) & (Pdry>=50) -> 5cw

Node 45 (N=45637):
(MAT>=12) & (MAP<1400) & (MAP<600) & (MAT>=22) & (Pswet<60) -> 3Hd

Node 46 (N=22851):
(MAT>=12) & (MAP<1400) & (MAP<600) & (MAT>=22) & (Pswet>=60) -> 3Hw

Node 47 (N=18649):
(MAT<12) & (MAT>=-2) & (Pwwet<110) & (MAT<5) & (Thot<16) -> 4Cc

Node 48 (N=38877):
(MAT<12) & (MAT>=-2) & (Pwwet<110) & (MAT<5) & (Thot>=16) -> 4Ch

Node 49 (N=13634):
(MAT>=12) & (MAP>=1400) & (Pdry<70) & (MAP<2200) & (Pdry<30) & (Pwwet<170) -> 2Dd

Node 50 (N=16049):
(MAT>=12) & (MAP>=1400) & (Pdry<70) & (MAP<2200) & (Pdry<30) & (Pwwet>=170) -> 2Dw

Node 51 (N=4601):
(MAT>=12) & (MAP>=1400) & (Pdry<70) & (MAP<2200) & (Pdry>=30) & (Tcold<16) -> 2Dc

Node 52 (N=12845):
(MAT>=12) & (MAP>=1400) & (Pdry<70) & (MAP<2200) & (Pdry>=30) & (Tcold>=16) -> 2Dh

Node 53 (N=17620):
(MAT>=12) & (MAP<1400) & (MAP>=600) & (Tcold>=14) & (Thot<30) & (MAP<1000) -> 3hD

Node 54 (N=26126):
(MAT>=12) & (MAP<1400) & (MAP>=600) & (Tcold>=14) & (Thot<30) & (MAP>=1000) -> 3hW

Node 55 (N=23051):
(MAT>=12) & (MAP<1400) & (MAP<600) & (MAT<22) & (MAT<18) -> 3CC

Node 56 (N=27006):
(MAT>=12) & (MAP<1400) & (MAP<600) & (MAT<22) & (MAT>=18) -> 3CH

Node 57 (N=17495):
(MAT<12) & (MAT<-2) & (Thot>=5) & (MAT>=-9) & (Thot<13) -> 5hc

Node 58 (N=24319):
(MAT<12) & (MAT<-2) & (Thot>=5) & (MAT>=-9) & (Thot>=13) -> 5hh

Climate variable definitions
============================
Temperature variables are measured in °C, precipitation variables are 
measured in mm, and summer/winter is defined as the warmer/cooler of the six 
month period of October-March/April-September. MAP = mean annual 
precipitation; MAT = mean annual temperature; Thot = temperature of the 
hottest month; Tcold = temperature of the coldest month, Tmon10 = number of 
months above 10°C; Pdry = precipitation of the driest month; Psdry = 
precipitation of the driest month in summer; Pwdry = precipitation of the 
driest month in winter; Pswet = precipitation of the wettest month in 
summer; Pwwet = precipitation of the wettest month in winter.
