Dr. Aaron (Ari) Preston, Visiting Assistant Professor of Atmospheric Sciences, recently defended his Ph.D. research on the transport of chemical species to the upper troposphere/lower stratosphere (UTLS) by tropical cyclones. Species such as carbon monoxide, nitrogen oxide, and ozone have been found to exert a greater influence on climate change at these high altitudes than if remaining near the surface. Typhoon Mireille (1991) was examined in the western North Pacific Ocean basin using in situ aircraft-derived chemical data from NASA’s Pacific Exploratory Mission-West A field project.
The Weather Research and Forecasting (WRF) model was used with chemistry (WRF-Chem) at an innermost grid spacing of 3 km. This grid spacing explicitly resolved the convection being studied. Results show that pollution from distant sources were ingested by Mireille and subsequently lofted by eyewall convection to the UTLS, enhancing concentrations in this region. Flux calculations suggested that a strong tropical cyclone, such as Mireille, can impact UTLS chemistry as much as a continental middle latitude cyclone. Furthermore, overshooting cells in Mireille produced chemical flux density values at the tropopause level as much as 10-20 times greater than that of the tropical cyclone as a whole. Thus, although the overshooting tops comprised only a small area of the total tropical cyclone, they transport large quantities of gaseous species to the UTLS because of their very strong updrafts. Results also suggested that millions of cars would need to be hypothetically placed in the upper troposphere to have the same impact on chemical concentrations as Mireille. This demonstrated the transport strength of the tropical cyclone as a whole.
Improved understanding of atmospheric chemistry in the western North Pacific basin is important, especially in the context of increasing Asian emissions and a changing climate. Furthermore, since it has been hypothesized that global warming will lead to more intense storms, it is important to understand tropical cyclones’ role in chemical transport.
Dr. Janel Hanrahan, Assistant Professor of Atmospheric Sciences at Lyndon, and two student members from Lyndon’s Climate Change Communication group, Jonathan Hutchinson and Francis Tarasiewicz, were three of several speakers at the event. This was an excellent opportunity for them to practice communicating about climate change science and to share their personal climate change stories.
Fall 2017 Climate Change Communication
Throughout the fall of 2017, Atmospheric Sciences and Climate Change Science students practiced informal communication skills in various settings. They discussed climate change science with local middle and high school students at the Youth Environmental Summit and the Burke Community Fair, and presented fundamental climate change concepts at Springfield College. Some students took the initiative to visit their former high schools to stress the need for climate change action. In addition, the Climate Change Communication group hosted a campus-wide movie screening, attended a Vermont Climate Action Commission scoping meeting, and created new blog posts for www.theclimateconsensus.com.
Our own Dr. Jay Shafer was a guest on Vermont Public Radio’s Vermont Edition on January 22, 2018, along with the Vermont State Climatologist Lesley-Ann Dupigny-Giroux. They answered listener questions about winter weather phenomena in Vermont, including:
Why does it get quieter when it snows? Can there actually be thunder and lightning during a snow storm? How can smog and flooding happen in the dead of winter?