Friday, June 16, 2017 | 2pm, 417 Akasofu Toshiki Iwasaki, Tohuku University Polar cold air outbreaks are studied with a definition of cold air mass below a threshold potential temperature of 280K. It allows us to treat the cold air mass as an adiabatically conservative material localized in the extratropical troposphere. There are two distinct cold streams in the northern hemispheric winter, namely, the East Asian and North American streams. The equatorward cold air mass flux consists of outbreak events that intermittently occur under favorable synoptic situations. In East Asia, cold air outbreaks show interannual variability associated with the El Niño and the Southern Oscillation. For more information, contact Nate Bauer (email@example.com).