Probabilistic Climate Change Projections for the Great Lakes Basin Using a High-Resolution Regional Climate Model Ensemble

English Abstract:

Current observations in the Laurentian Great Lakes demonstrate that some changes in climate are already occurring, including increases in surface water and air temperatures and decreases in the extent and duration of ice cover. These changes have a significant influence on the surrounding region by affecting local temperature, precipitation, water vapor, cloud coverage, cyclones and anticyclones, as well as other important aspects of regional climate. Planning of appropriate mitigation and adaptation strategies against these changes in the context of global warming, which requires a better understanding of possible future climate outcomes over the Great Lakes basin, is of great interest to local policy makers, stakeholders, and development practitioners. Therefore, a high-resolution regional climate model ensemble based on the PRECIS regional climate modeling system will be developed in this study to help explore the possible outcomes of future climate over the Great Lakes basin. A Bayesian hierarchical model is then proposed to quantify the uncertain or unknown parameters involved in the modeling results. Probabilistic projections of changes in temperature and precipitation at grid point scales are obtained by feeding the ensemble simulations into the Bayesian model. The high-resolution probabilistic projections developed in this study can provide direct inputs for climate impact researchers to study the possible impacts of global warming on the Great Lakes basin, meanwhile the results are potentially helpful for assessing the risks and costs associated with climatic changes as well as for planning the appropriate mitigation and adaptation strategies.