Abstract
The seasonal variability in volume transport of the South Indian Ocean subtropical gyre is characterized for the first time. Only three complete hydrographic crossings of the gyre have been conducted over a 22-year period, with an upcoming repeat in 2019. Changes to geostrophic transport and thermocline properties imply a strengthening of the gyre from 1987 to 2002. However, some of this strengthening could result from aliasing of seasonal variability. We use data from Argo, satellite altimetry, and an Agulhas Current transport proxy at 34∘S to quantify the seasonal variability of the upper 2,000-m volume transport. A semiannual cycle is revealed, with peak-to-peak amplitude of 6.4 ± 3.1 Sv(1Sv = 106 m3 s−1) and dominated by annual anomalies in quadrature near the eastern and western boundaries. Seasonal aliasing does not account for the observed gyre strengthening.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 9034-9041 |
| Number of pages | 8 |
| Journal | Geophysical Research Letters |
| Volume | 45 |
| Issue number | 17 |
| DOIs | |
| State | Published - Sep 16 2018 |
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ASJC Scopus subject areas
- Geophysics
- Earth and Planetary Sciences(all)
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The Seasonal Cycle of the South Indian Ocean Subtropical Gyre Circulation as Revealed by Argo and Satellite Data. / McMonigal, K.; Beal, Lisa; Willis, Josh K.
In: Geophysical Research Letters, Vol. 45, No. 17, 16.09.2018, p. 9034-9041.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - The Seasonal Cycle of the South Indian Ocean Subtropical Gyre Circulation as Revealed by Argo and Satellite Data
AU - McMonigal, K.
AU - Beal, Lisa
AU - Willis, Josh K.
PY - 2018/9/16
Y1 - 2018/9/16
N2 - The seasonal variability in volume transport of the South Indian Ocean subtropical gyre is characterized for the first time. Only three complete hydrographic crossings of the gyre have been conducted over a 22-year period, with an upcoming repeat in 2019. Changes to geostrophic transport and thermocline properties imply a strengthening of the gyre from 1987 to 2002. However, some of this strengthening could result from aliasing of seasonal variability. We use data from Argo, satellite altimetry, and an Agulhas Current transport proxy at 34∘S to quantify the seasonal variability of the upper 2,000-m volume transport. A semiannual cycle is revealed, with peak-to-peak amplitude of 6.4 ± 3.1 Sv(1Sv = 106 m3 s−1) and dominated by annual anomalies in quadrature near the eastern and western boundaries. Seasonal aliasing does not account for the observed gyre strengthening.
AB - The seasonal variability in volume transport of the South Indian Ocean subtropical gyre is characterized for the first time. Only three complete hydrographic crossings of the gyre have been conducted over a 22-year period, with an upcoming repeat in 2019. Changes to geostrophic transport and thermocline properties imply a strengthening of the gyre from 1987 to 2002. However, some of this strengthening could result from aliasing of seasonal variability. We use data from Argo, satellite altimetry, and an Agulhas Current transport proxy at 34∘S to quantify the seasonal variability of the upper 2,000-m volume transport. A semiannual cycle is revealed, with peak-to-peak amplitude of 6.4 ± 3.1 Sv(1Sv = 106 m3 s−1) and dominated by annual anomalies in quadrature near the eastern and western boundaries. Seasonal aliasing does not account for the observed gyre strengthening.
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U2 - 10.1029/2018GL078420
DO - 10.1029/2018GL078420
M3 - Article
VL - 45
SP - 9034
EP - 9041
JO - Geophysical Research Letters
JF - Geophysical Research Letters
SN - 0094-8276
IS - 17
ER -