Abstract
The Madden Julian Oscillation (MJO) is the largest contributor to intraseasonal weather variations in the tropics. It is associated with a broad region of enhanced rainfall that moves slowly eastward over the Indian and western Pacific Oceans, which has global impacts on atmospheric circulations. A number of recent observational and modeling studies have suggested that the MJO is becoming stronger as the oceans warm. In this study, the author explores the sensitivity of the MJO to ocean warming in a recently developed Lagrangian Atmospheric Model (LAM), which has been shown to simulate robust and realistic MJOs in previous work. Numerical simulations suggest that ocean warming leads to more frequent and intense MJOs that propagate more rapidly and cover a larger region of the tropics. The strengthening of the MJO is attributed to enhanced surface fluxes of moisture coming from the warmer ocean waters. While the LAM simulations have a number of limitations owing to idealized physical parameterizations and the use of prescribed sea surface temperatures, they provide additional evidence that the MJO will strengthen if the oceans continue to warm, and they also shed light on the mechanism of this strengthening.
Highlights
The Madden Julian Oscillation (MJO) is a large-scale equatorial convective disturbance that moves slowly eastward over the warmest waters of the Indian and West Pacific Oceans [1,2]
Our previous work [21,22,23,24] established that the Lagrangian Atmospheric Model (LAM) simulates more realistic MJOs than those in a typical CMIP5 model [27], which is one reason why the author elected to use the LAM to study how the MJO will change as the oceans warm
When the LAM is run using unaltered, observed SSTs as a forcing, it generates an MJO with a comparable amplitude, rate of propagation, and zonal extent to those observed in nature (Figure 1a,b)
Summary
The Madden Julian Oscillation (MJO) is a large-scale equatorial convective disturbance that moves slowly eastward over the warmest waters of the Indian and West Pacific Oceans [1,2]. It has a typical period of 45–50 days [3] and a propagation speed of about 5 m/s [4]. There is growing evidence that the MJO is becoming more frequent and intense with time as the oceans warm. Jones and Carvalho [12] examined changes in the MJO starting in
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
