Home > climate models, Statistics > SSES 2012: Warming in North America, 2041-2070

SSES 2012: Warming in North America, 2041-2070

2012 May 16

This Web-Project represents an accounting of temperature change that is projected for North America in 2041-2070. Regional Climate Models (RCMs) are run 60 years into the future for small, 50 km x 50 km regions in North America, and their results are analyzed statistically for all regions and all four Boreal seasons. The preponderance of results throughout all of North America is one of warming, usually more than 2°C (3.6°F). A Bayesian, spatial, two-way analysis of variance (ANOVA) model is used to analyze RCM data from the North American Regional Climate Change Assessment Program (NARCCAP).


We consider current (1971-2000) and future (2041-2070) average seasonal surface temperature elds from two regional climate models (RCMs) driven by the same atmosphere-ocean general circulation model (GCM) in the North American Regional Climate Change Assessment Program (NARCCAP) Phase II experiment. We analyze the di erence between future and current temperature elds for each RCM and include the factor of season, the factor of RCM, and their interaction in a two-way ANOVA model. Noticing that classical ANOVA approaches do not account for spatial dependence, we assume that the main e ects and interactions are spatial processes that follow the Spatial Random E ects (SRE) model. This enables us to model the spatial variability through xed spatial basis functions, and the computations associated with an ANOVA of high-resolution RCM outputs can be carried out without having to resort to approximations. We call the resulting model a spatial two-way ANOVA model. We implement it in a Bayesian framework, and we investigate the variability of climate-change projections over seasons, RCMs, and their interactions. We nd that projected temperatures in North America are credibly higher, that the associated warming e ects di er in spatial areas and in seasons, and that they are of much larger magnitude than the variability between RCMs.

Bayesian hierarchical ANOVA of regional climate-change projections from NARCCAP Phase II, Kang and Cressie (2012)

The paper is behind a paywall. But there is an extensive write up on their website:

Additional information is available in their Tutorial on Bayesian Statistics for Geophysicists

Science Daily: Statistical Analysis Projects Future Temperatures in North America