The models and scenarios include:

IEM Generation 1, AR4/CMIP3:

CCCMA-CGCM3.1(T47)

MPI-ECHAM5/MPI-OM

under the A1B emission scenario

IEM Generation 2, AR5/CMIP5:

NCAR-CCSM4

MRI-CGCM3

under RCP 8.5 emission scenario

Relative vegetation change was defined as the likelihood of a pixel to transition to a different dominant vegetation type. These parameters were assessed throughout the full spatial domain and 3 temporal domains of the simulations (1900-1999, 2000-2099, and 1900-2099) across all 200 model replicates. We calculated the proportion of years among all the simulations (200 replicate runs x number of years per simulation) that each individual pixel transitioned.

Relative Vegetation Change counts the number of times a pixel transitions through all replicates and time and divides that value by the total number of layers (replicates * years)

A transition is defined as a pixel changing to a different dominant vegetation type. Transitions occur under several circumstances:

A pixel can burn and be reset to an early successional type.(ie. spruce pixel burning and then becoming deciduous).

A pixel becomes old enough to transition from an early successional type to a later successional type (ie. deciduous to spruce)

Graminoid tundra pixels that are subjected to warming conditions for long periods of time can transition to shrub tundra types.

Both graminoid and shrub tundra pixels can become populated by spruce stems and if the spruce basal area accumulation is high enough, it can transition to a spruce type.

There are several example map layouts for specific Landscape Conservation Cooperatives in Alaska for for IEM Generation 1 outputs only.

For background on ALFRESCO, please refer to the following references:

Daniel H. Mann, T. Scott Rupp, Mark A. Olson, and Paul A. Duffy (YEAR) Is Alaska's Boreal Forest Now Crossing a Major Ecological Threshold?

Arctic, Antarctic, and Alpine Research 2012 44 (3), 319-331