Previous studies indicate that equatorial zonal winds in the Indian Ocean can significantly influence the Indonesian Throughflow (ITF). During the Cooperative Indian Ocean Experiment on Intraseasonal Variability (CINDY)/Dynamics of the Madden-Julian Oscillation (DYNAMO) field campaign, two strong MJO events were observed within a month without a clear suppressed phase between them, and these events generated exceptionally strong ocean responses. Strong eastward currents along the equator in the Indian Ocean lasted more than one month from late November 2011 to early January 2012. The influence of these unique MJO events during the field campaign on ITF variability is investigated using a high-resolution (1/25°) global ocean general circulation model, the Hybrid Coordinate Ocean Model (HYCOM). The strong westerlies associated with these MJO events, which exceed 10ms-1, generate strong equatorial eastward jets and downwelling near the eastern boundary. The equatorial jets are realistically simulated by the global HYCOM based on the comparison with the data collected during the field campaign. The analysis demonstrates that sea surface height (SSH) and alongshore velocity anomalies at the eastern boundary propagate along the coast of Sumatra and Java as coastal Kelvin waves, significantly reducing the ITF transport at the Makassar Strait during January-early February. The alongshore velocity anomalies associated with the Kelvinwave significantly leads SSHanomalies. The magnitude of the anomalous currents at the Makassar Strait is exceptionally large because of the unique feature of theMJOevents, and thus the typical seasonal cycle of ITF could be significantly altered by strongMJO events such as those observed during the CINDY/DYNAMO field campaign.
资助项目:
NSF, Norwegian Nurses Organisation
; NOAA, National Oceanic and Atmospheric Administration
; NOAA, National Oceanic and Atmospheric Administration
; NSF, Norwegian Nurses Organisation
Texas A and M University-Corpus Christi, Corpus Christi, TX, United States; University of Colorado Boulder, Boulder, CO, United States; Naval Research Laboratory, Stennis Space CenterMS, United States; Florida State University, Tallahassee, FL, United States; Applied Physics Laboratory, University of Washington, Seattle, WA, United States
Recommended Citation:
Shinoda T.,Han W.,Jensen T.G.,et al. Impact of the Madden-Julian Oscillation on the Indonesian throughflow in the makassar strait during the CINDY/DYNAMO field campaign[J]. Journal of Climate,2016-01-01,29(17)