Calendar

Dear all,

We are fortunate to have Gokhan Danabasoglu (NCAR) and Jon Robson (NCAS/U. Reading) visiting next week, and they will be giving back-to-back seminars on Friday 2nd October, BCCR seminar room 4020.

10:00 - 10:50, High-Resolution Simulations with the Community Earth System Model (CESM), Gokhan Danabasoglu

As impacts of climate change are being felt by the society through sea level rise, increased intensity and occurrences of heat waves, droughts, extreme rainfall events, and tropical cyclones (TCs), decision makers and stakeholders need reliable weather and climate information at increasingly finer spatial and temporal scales. There are also numerous science questions regarding representation of and changes in importance of various processes with increased model resolution. It is generally anticipated that with less reliance on uncertain parameterizations and their parameter choices, high-resolution (HR) models will represent various processes and coupled interactions of the Earth system with increased fidelity. To address these needs and challenges, we have made significant advances in HR global Earth system modeling and predictions. Specifically, we have performed an unprecedented set of simulations at a TC-permitting (0.25°) and ocean-eddy-rich (0.1°) horizontal resolution using the Community Earth System Model (CESM-HR). The presentation will introduce these simulations and provide a few highlights from our extensive analysis. While not a panacea to address all model biases, the HR simulations certainly offer promising improvements with reduced biases in comparison with their low-resolution counterparts and advance our understanding of processes. 

11:00 - 11:50 Understanding model uncertainty in North Atlantic multi-decadal variability and change,  Jon Robson

Changes in the North Atlantic Ocean play an important role in shaping regional weather and climate. Yet climate models differ widely in how they represent both the response to external forcing and internal variability on multi-decadal timescales. These differences contribute to substantial uncertainty in how we might expect the North Atlantic to evolve in the coming decades. In this talk, I will highlight key uncertainties in our understanding of variability and change in the region. Focusing on two central issues—the Atlantic Meridional Overturning Circulation (AMOC) and multi-decadal variability in the tropical North Atlantic—I will discuss some ongoing efforts to untangle the underlying processes and make progress toward reducing uncertainty.