Surface heat fluxes and MJO propagation through the Maritime Continent

The 'barrier effect' of the Maritime Continent (MC) is a known hurdle in understanding the propagation of the Madden-Julian Oscillation (MJO). To understand the differing dynamics of MJO events that propagate versus stall over the MC, a new MJO tracking algorithm utilizing 30-96 day filtered NOAA Interpolated OLR anomalies is presented. Using this algorithm, MJO events can be identified, tracked, and described in terms of their propagation characteristics. Latent heat flux from CYGNSS and OAFLUX as well as CYGNSS surface winds are used to compare large-scale patterns for MJO events that do and do not propagate through the MC. Local area-averaged surface fluxes and OLR anomalies are 7-14% and 18-22% of the value of precipitation anomalies, respectively. While differences in these contributions do not change substantially for propagating versus terminating events, precipitation events that successfully propagate through the MC demonstrate surface flux anomalies that are stronger and more spatially-coherent. The spatial scale of precipitation events that propagate through the MC region is also larger than terminating events. It is also shown that large-scale enhancement of latent heat fluxes near and to the east of the Dateline accompanies MJO events that successfully propagate through the MC. This large-scale enhancement of latent heat fluxes to the east of the Dateline is equally driven by dynamic and thermodynamic effects. These findings are placed in the context of recent theoretical models of the MJO in which latent heat fluxes are important for propagation and destabilization. The tracking algorithm is also used to show for historical and greenhouse gas warming scenarios in CESM2 that MJO propagation speed increases and precipitation anomalies propagate further east with warming. However, the CESM2 inadequately represents the 'barrier effect' of the MC region on propagating MJO events.

Name thesis:degree_name

Master of Science (M.S.)

Level thesis:degree_level

Masters

Discipline thesis:degree_discipline

Atmospheric Science

Grantor dc:publisher

Colorado State University. Libraries

Year dc:date.issued

2022

Authors dc:creator

• Hudson, Justin, author
• Maloney, Eric, advisor
• Rasmussen, Kristen, committee member
• Rugenstein, Jeremy, committee member

Statement dc:rights

• Copyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.

Language dc:language.iso

eng, English

Identifier URI

https://doi.org/10.25675/3.02318

OAI identifier oai:identifier

oai:mountainscholar.org:10217/235195