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Pacific Ocean Contribution to the Asymmetry in Eastern Indian Ocean Variability
Citation
Ummenhoffer, CC and Schwarzkopf, FU and Meyers, GA and Behrens, E and Biastoch, A and Boning, CW, Pacific Ocean Contribution to the Asymmetry in Eastern Indian Ocean Variability, Journal of Climate, 26, (4) pp. 1152-1171. ISSN 0894-8755 (2013) [Refereed Article]
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Copyright Statement
Copyright 2013 American Meteorological Society
DOI: doi:10.1175/JCLI-D-11-00673.1
Abstract
Variations in eastern Indian Ocean upper-ocean thermal properties are assessed for the period 1970–2004,
with a particular focus on asymmetric features related to opposite phases of Indian Ocean dipole events, using
high-resolution ocean model hindcasts. Sensitivity experiments, where interannual atmospheric forcing variability
is restricted to the Indian or Pacific Ocean only, support the interpretation of forcing mechanisms for
large-scale asymmetric behavior in eastern Indian Ocean variability. Years are classified according to eastern
Indian Ocean subsurface heat content (HC) as proxy of thermocline variations. Years characterized by an
anomalous lowHCfeature a zonal gradient in upper-ocean properties near the equator,while high events have a
meridional gradient from the tropics into the subtropics. The spatial and temporal characteristics of the seasonal
evolution of HC anomalies for the two cases is distinct, as is the relative contribution from Indian Ocean
atmospheric forcing versus remote influences from Pacific wind forcing: low events develop rapidly during
austral winter/spring in response to Indian Ocean wind forcing associated with an enhanced southeasterly
monsoon driving coastal upwelling and a shoaling thermocline in the east; in contrast, formation of an anomalous
high eastern Indian Ocean HC is more gradual, with anomalies earlier in the year expanding from the
Indonesian Throughflow(ITF) region, initiated by remote Pacificwind forcing, and transmitted through the ITF
via coastal wave dynamics. Implications for seasonal predictions arise with high HC events offering extended
lead times for predicting thermocline variations and upper-ocean properties across the eastern Indian Ocean.
Item Details
| Item Type: | Refereed Article |
|---|---|
| Research Division: | Earth Sciences |
| Research Group: | Oceanography |
| Research Field: | Oceanography not elsewhere classified |
| Objective Division: | Environment |
| Objective Group: | Physical and Chemical Conditions of Water |
| Objective Field: | Physical and Chemical Conditions of Water in Marine Environments |
| Author: | Meyers, GA (Professor Gary Meyers) |
| ID Code: | 89598 |
| Year Published: | 2013 |
| Web of Science® Times Cited: | 9 |
| Deposited By: | IMAS Research and Education Centre |
| Deposited On: | 2014-03-07 |
| Last Modified: | 2014-06-30 |
| Downloads: | 0 |
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