Science Leads: Melissa Bukovsky (NCAR), Sara C. Pryor (Cornell)
One of the most important ways that climate variability and change impacts society is through the occurrence of climate and weather extremes . Possible evolution in the intensity and morphology of extreme events is very difficult to characterize in long-term low-resolution model simulations, and thus a storyline approach will be adopted . The term “storyline approach” generally refers to research that is conducted within the following framework: First, historically important weather and climate events are identified (e.g., a winter wind storm that caused major economic losses, transportation disruption, or loss of human life) . Then those historically important events are simulated at high resolution using the WRF model and ICs/LBCs from a contemporary reanalysis product. The output is then analyzed to assess fidelity. Once fidelity is demonstrated for a specific event, additional paired simulations will be performed where LBCs will either be perturbed to represent those from future projections of LULC change and/or climate change (using a PGW approach) .
The goal is to examine how the dynamics and thermodynamics of these extreme events may evolve as both LULC and climate evolve and whether societal exposure will change. The science use case will thus benefit directly from the inclusion of both traditional and advanced model diagnostics assessments enabled through the incorporation of the METplus use cases in the containerized end-to-end system. The simulations of each event have limited temporal duration (we envisage 3–5 days) and are manifest at the regional scale. However, relatively high grid spacing (order of 1–2 km) will be needed to characterize both the atmospheric science phenomena of interest and the societal exposure. As such, these simulations are envisaged to be of “moderate scale” and thus to represent a useful test for benchmarking the containers.
In a test case using two winter wind storms that caused substantial economic losses and human mortality and morbidity, we used a simulation domain of 500×400 horizontal grid cells, grid resolution of 2 km, and 57 vertical levels, for a total of approximately 11 million grid cells. Reasonable run times of approximately 9 hours for a 5-day event were achieved using 64 cores. Thus, the use of substantially extended domains to cover a region that includes more upstream influences of the Great Lakes will be entirely achievable. The output from simulations of each storyline will first be subjected to evaluation relative to observations from the contemporary climate, thus demonstrating the model output fidelity toolbox included within the containers.