Quick talks/posters/discussion room links sent each day to participants
Monday September 14, 2020
Warming trends increasingly dominate global ocean: Gregory C. Johnson and John M. Lyman (both NOAA/PMEL)
The ocean takes up about 93% of the global warming heat entering Earth’s climate system. We use gridded ocean heat content maps to examine regional trends in ocean warming for 0–700 m depth from 1993–2019 and 1968–2019, periods based on sampling distributions. We show that use of longer periods results in larger percentages of ocean area with statistically significant warming trends and less ocean area covered by statistically significant cooling trends. We discuss relations of these patterns to climate phenomena, including the Pacific Decadal Oscillation, the Atlantic Meridional Overturning Circulation, and global warming.
Breaking the Bubble of Academia: Introducing the new UW ACORN Program: Tyler Cox, Greta Shum and Lily Hahn (all UW Atmos)
The PCC Graduate Steering Committee (P-GraSC) has launched a new partnership program that will expand PCC graduate and postdoc opportunities to apply subject area expertise and analytical skills by working with local organizations to address community priorities related to climate, energy, and the environment. We have a few projects underway and are excited to increase involvement from within and beyond the PCC community to help the program grow and improve. Recent blog post Introduction ACORN
Reduce App: Bridging the gap between climate science and consumer spending: Billy Henshaw, UW Atmos
Billy shares his experiences working with the Reduce team on developing a suite of fin-tech apps to raise awareness of individual carbon impact. He will also talk about the potential for this app to make a large difference in bridging the gap between science and public knowledge / awareness of the issues of climate change.
BONUS Resource to Share
How Marine Heat Waves are Changing Ocean Ecosystems: What we learned from a massive seabird die-off in the north Pacific: Nina Chambers, National Park Service, Alaska Region. Storyboard Link
Tuesday, September 15, 2020
Seasonal prediction of heatwaves – connections to large-scale atmospheric dynamics: Rachel White (UBC)
Our work helps to better understand the sub-seasonal to seasonal (S2S) predictability of heatwaves from an atmospheric dynamics perspective. Previous work has linked many extreme temperature events to Rossby wave packets in the upper-troposphere, particularly wave packets that amplify and become quasi-stationary, recurrent, or quasi-resonant. It has also been suggested that atmospheric waveguides may play a role in providing favorable conditions and preferred paths for such waves. We study the representation in S2S forecasts, and predictability of: surface heatwaves and atmospheric waveguides and the connections between the two. Focusing on Europe, we find:- There is seasonal predictability of ‘high heatwave summers’ (summers with extensive, persistent, or multiple heatwaves), beyond what can be attributed to soil moisture anomalies
- S2S forecast models reproduce the observed seasonal variability of Rossby wave packets, and the observed connection between Rossby wave packets and surface extremes
- High heatwave summers in Europe are associated with an increased frequency of mid-latitude atmospheric waveguides upstream.
- There is S2S skill, as measured by anomaly correlation, of global waveguide frequency. This may help provide skill in heatwave predictability
An Emergency Medicine Mindset To Guide Climate Action: William Calvin, UW Emeritus
As in emergency medicine’s focus on internal bleeding and preventing shock, climate change has secondary threats such as extreme weather. They may threaten civilization on a much faster time scale than does the underlying overheating. Climate action now requires a different mindset than was needed for attacking the root cause, fossil fuels. The climate emergency is going to require importing some of the mindset taught in emergency medicine…..
Thursday, September 17, 2020
Detecting and projecting changes in U.S. precipitation extremes in the GFDL SPEAR large ensemble: Surabhi Biyani (UW Atmos and ESS)
Extreme precipitation events are predicted to become heavier and more frequent due to climate change, and these changes are an important factor to consider when updating infrastructure. Here, a high-resolution global climate model is used to analyze how U.S. 24-hour precipitation extremes at various return periods change over the 1921-2100 time period. Using the 50-km horizontal atmospheric resolution global GFDL SPEAR 30-member ensemble, we quantify extreme precipitation risks across the U.S. and locally under different climate change scenarios (SSP5-8.5, SSP2-4.5, and natural forcings alone). With the large ensemble, we also quantify the uncertainty of characterizing extreme precipitation risk historically and in future projections.
How regional differences in precipitation minus evaporation shape the ocean circulation: Robert Jnglin Wills (UW Atmos)
Unlike the Pacific Ocean, the Atlantic Ocean is ventilated by high-latitude deep-water formation and exhibits a hemispheric-scale meridional overturning circulation. The asymmetry in ocean circulation between the Pacific and the Atlantic results from differences in their sea-surface salinity. Here, I will discuss the role of the atmospheric hydrological cycle in setting the distribution of precipitation minus evaporation, which is a primary control on the distribution of sea-surface salinity and thus ocean circulation. I will show climate model and proxy-based evidence that the Atlantic-Pacific asymmetry may have weakened at the Last Glacial Maximum and that periods of reduced Atlantic overturning are characterized by strengthened Pacific overturning, as a result of global changes in the hydrological cycle. Read Robb’s recent Research Highlight.