Long-range forecasting of the onset of southwest monsoon winds and waves near the Horn of Africa
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Authors
Vines, Gary M.
Subjects
climate
climate variations
climate analysis
long-range forecasting
subseasonal to seasonal
Horn of Africa
Somali Jet
Indian Ocean
maritime continent
south Asia
southwest monsoon
El Niño
La Niña
Madden-Julian Oscillation
Indian Ocean Dipole
teleconnections
maritime operations
piracy
climate variations
climate analysis
long-range forecasting
subseasonal to seasonal
Horn of Africa
Somali Jet
Indian Ocean
maritime continent
south Asia
southwest monsoon
El Niño
La Niña
Madden-Julian Oscillation
Indian Ocean Dipole
teleconnections
maritime operations
piracy
Advisors
Murphree, Tom
Hutchins, Megan
Date of Issue
2017-12
Date
Dec-17
Publisher
Monterey, California. Naval Postgraduate School
Language
Abstract
The Asian southwest monsoon (SWM) east of the Horn of Africa (HOA) is important in planning and conducting maritime operations in this region. Skillful subseasonal to seasonal (S2S) forecasts of the SWM onset are needed for operational planning but are not yet available. We investigated the potential for S2S forecasting of the onset of SWM surface winds and ocean surface waves off HOA by analyzing global atmospheric and oceanic variables, and three onset states: early, normal, and late. We identified relationships between variables, precursor conditions for each state, and potential predictors for each state. We used the predictors to conduct 48 years of hindcasting. We assessed the skill of the hindcasts and identified two Pacific sea surface temperature (SST) predictors with a high potential to contribute to S2S forecasts of the onset. These results indicate that El Niño / La Niña (ENLN) variations are important in generating early, normal, and late onsets, but are not the only factors. The mechanisms that link remote SSTs to the onset appear to involve anomalous tropical Rossby-Kelvin waves that extend across the western tropical Pacific and the Indian Ocean–south Asian regions.
Type
Thesis
Description
Series/Report No
Department
Meteorology
Organization
Identifiers
NPS Report Number
Sponsors
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Citation
Distribution Statement
Approved for public release; distribution is unlimited.
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.