Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA 99352
Abstract. Pattern scaling is used to explore the uncertainty in future forcing scenarios. Of the possible techniques used for pattern scaling, the two most prominent are the delta and least squared regression methods. Both methods assume that local climate changes scale with globally averaged temperature increase, allowing for spatial patterns to be generated for multiple models for any future emission scenario. We explore this assumption by using different time periods and scenarios, and examine the differences and the statistical significance between patterns generated by each method. Regardless of epoch chosen, the relationship between globally averaged temperature increase and local temperature are similar. Temperature patterns generated by the linear regression method show a better fit to global mean temperature change than the delta method. Differences in pat- terns between methods and epochs are largest in high latitudes (60–90 degrees N/S). Error terms in the least squared regression method are higher in lower forcing scenarios, and global mean temperature sensitivity is higher. These patterns will be used to examine feedbacks and uncertainty in the climate system.
How to cite. Lynch, C., Hartin, C., Bond-Lamberty, B., and Kravitz, B.: Exploring global surface temperature pattern scaling methodologies and assumptions from a CMIP5 model ensemble, Geosci. Model Dev. Discuss. [preprint], https://doi.org/10.5194/gmd-2016-170, 2016.
Pattern scaling is used to explore uncertainty in future forcing scenarios and assess local climate sensitivity to global temperature change. This paper examines the two dominant pattern scaling methods using a multi-model ensemble with two future socio-economic storylines. We find that high latitudes show the strongest sensitivity to global temperature change and that the simple least squared regression approach to generation of patterns is a better fit to projected global temperature.
Pattern scaling is used to explore uncertainty in future forcing scenarios and assess local...