Free Modes and Low-frequency Variability in the Atmosphere
Prof. Peili Wu
Met Office Hadley Centre, UK
Peili Wu is an expert scientist at the Met Office Hadley Centre in the UK and a fellow of the Royal Meteorological Society. He obtained a PhD in atmospheric dynamics and a Diploma in Physics from Imperial College London. He spent seven years at Edinburgh University developing ocean models and researching in physical oceanography before he joined the Hadley Centre in January 1999. His research covers a broad range of climate dynamics focusing on air–sea interactions through the global water cycle. He is currently the science coordinator of UK–China Climate Science for Services Partnership (CSSP) supported by the Newton Fund and Work Package3 lead on East Asia climate variability and extremes. His current research also includes drought and extreme precipitation.
Atmospheric circulation fluctuates around a number of quasi-steady states generating a rich spectrum of low-frequency variability. There are very few known exact solutions to the governing equations of the atmosphere. I will introduce a set of finite amplitude large-scale exact solutions to the barotropic vorticity equation. The resonant excitation and instability of these steady states solutions are suggested as a fundamental process for low-frequency atmospheric variability. As global warming continues to strengthen land-sea thermal contrasts, this process may become even more relevant to interactions between the high and the low latitudes.