Land and Sea Breeze Characteristics Off the West Coast of Sumatra

The land breeze is a ubiquitous phenomenon along coastal regions of the Maritime Continent Islands. Previous studies have described the land breeze using the temperature difference observed between the ocean and land surface. Other studies have focused on the land breeze behavior during different phases of the Madden-Julian Oscillation (MJO), as well as a means of explaining the dynamics behind the westward propagating diurnal rainfall off western Sumatra. However, detailed and time-evolving characteristics of the land breeze remain unquantified for this region. Utilizing hourly 10-m wind observations from the Bengkulu Airport on the west coast of Sumatra, characteristics such as the frequency, timing, duration, maximum wind speed, and seasonality of the land breeze are investigated. For 2018, a land breeze was detected at Bengkulu every day. The land breeze events had a median start time of 19 LST, a duration of roughly 14 hours, and a median maximum wind speed of 1.78 ms⁻¹ obtained near 02 LST. These characteristics were also investigated across the phases of MJO and the Asian and Australian Monsoons. To evaluate the effects of the MJO, land breeze events were separated into nine categories corresponding to the eight phases of the MJO and a weak phase (i.e., when RMM<1). Significance tests were then conducted for each variable, of which every variable returned a significant result at the 95% interval. Unlike with the phases of the MJO, only the onset time and the maximum speed showed a statistically significant difference by monsoon phase. Additionally, a comparison between the airport observations and ERA5 reanalysis surface winds is provided to ensure that ERA5 can adequately resolve the diurnal cycle of winds, justifying its use where observations are unavailable. Overall, ERA5 can accurately represent the onset time and duration of land breezes at Bengkulu but struggles with regards to the maximum speed and the timing of the maximum speed.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

Masters

Discipline thesis:degree_discipline

Atmospheric Sciences

Grantor

Texas A&M University

Year dc:date.issued

2023

Author dc:creator

• North, Ryan T.

Advisors dc:contributor.advisor

• Epifanio, Craig
• Schumacher, Courtney

Committee member dc:contributor.committeemember

• Potter, Henry

• diurnal cycle
• tropical meteorology
• land breeze
• sea breeze
• maritime continent
• Sumatra
• diurnal
• semidiurnal tide
• Madden-Julian Oscillation
• monsoon

Language dc:language.iso

en

Handle dc:identifier.uri

https://hdl.handle.net/1969.1/203008

OAI record oai:identifier

https://oaktrust.library.tamu.edu/server/oai/request?verb=GetRecord&metadataPrefix=dim&identifier=oai%3Aoaktrust.library.tamu.edu%3A1969.1%2F203008