Andrew Berrington- Nov 13

Name:     Andrew Berrington Title:    How Does the Madden-Julian Oscillation Circulation Affect its Propagation? Location: NWC 5930 Date:     2019/11/13 Time:     3:00 PM Series:   Weather and Climate Systems Abstract: The Madden-Julian Oscillation (MJO) is one of the key links between global weather and climate, yet operational forecasts of the MJO continue to have

Start

November 13, 2019 - 3:00 pm

End

November 13, 2019 - 4:00 pm

Address

120 David L Boren Blvd, Norman, OK 73072   View map
Name:     Andrew Berrington
Title:    How Does the Madden-Julian Oscillation Circulation Affect its Propagation?
Location: NWC 5930
Date:     2019/11/13
Time:     3:00 PM
Series:   Weather and Climate Systems
Abstract: The Madden-Julian Oscillation (MJO) is one of the key links between global weather and climate, yet operational forecasts of the MJO continue to have shortcomings, especially pertaining to the speed and extent of eastward propagation of the disturbance over the Maritime Continent. The MJO is the dominant intraseasonal mode of variability in the tropics, consisting of a planetary scale coupling of convection and circulation that influence global circulation. Accurate depiction of MJO propagation in numerical models is therefore viewed as crucial in subseasonal to seasonal forecasts of a variety of hazardous weather events.
While a number of studies have attempted to understand the general mechanisms of MJO propagation, its variations in propagation extent and duration between MJO events are not well understood. Specifically, over the Maritime Continent, the propagation characteristics and structure of the MJO change, with some events terminating and others continuing into the West Pacific. MJO convection is often thought to be coupled with Rossby-Kelvin circulation response, which is thought to be important in determining whether the MJO survives across the Maritime Continent. However, the variations of the conventional structure of MJO circulation and their role on MJO propagation have not been examined in details. To better understand the role of the Rossby-Kelvin circulation on MJO propagation, this study aims to address following two questions: 1) how does the coupled Rossby-Kelvin wave response change as it moves from west to east, and 2) how does the strength of the Rossby-Kelvin response influence the eastward propagation of MJO convection? This talk will present our preliminary results and discuss ongoing development of a method to quantitatively assess the strength of the Rossby-Kelvin circulation.