Abstract. Given the increasing use of climate projections and multi-model
ensemble weighting for a diverse array of applications, this project
assesses the sensitivities of climate model weighting strategies and their
resulting ensemble means to multiple components, such as the weighting
schemes, climate variables, or spatial domains of interest. The purpose of
this study is to assess the sensitivities associated with multi-model
weighting strategies. The analysis makes use of global climate models from
the Coupled Model Intercomparison Project Phase 5 (CMIP5) and their
statistically downscaled counterparts created with the localized constructed
analogs (LOCA) method. This work focuses on historical and projected future
mean precipitation and daily high temperatures of the south-central United
States. Results suggest that the model weights and the corresponding
weighted model means can be sensitive to the weighting strategy that is
applied. For instance, when estimating model weights based on Louisiana
precipitation, the weighted projections show a wetter and cooler
south-central domain in the future compared to other weighting strategies.
Alternatively, for example, when estimating model weights based on New
Mexico temperature, the weighted projections show a drier and warmer
south-central domain in the future. However, when considering the entire
south-central domain in estimating the model weights, the weighted future
projections show a compromise in the precipitation and temperature
estimates. As for uncertainty, our matrix of results provided a more certain
picture of future climate compared to the spread in the original model
ensemble. If future impact assessments utilize weighting strategies, then
our findings suggest that how the specific weighting strategy is used with
climate projections may depend on the needs of an impact assessment or
adaptation plan.