TY - JOUR
T1 - Zonal movement of the Mascarene High in austral summer
AU - Ohishi, Shun
AU - Sugimoto, Shusaku
AU - Hanawa, Kimio
N1 - Funding Information:
The authors express their sincere gratitude to the members of the Physical Oceanography Group at Tohoku University. Numerous comments from and discussions with Dr. Tozuka and Dr. Morioka were very useful and appreciated. We are also grateful to two anonymous reviewers for their constructive comments, which helped improved our manuscript. The first author was financially supported by the Sasakawa Scientific Research Grant from the Japan Science Society.
Publisher Copyright:
© 2014, Springer-Verlag Berlin Heidelberg.
PY - 2015/10/1
Y1 - 2015/10/1
N2 - Temporal variations in the Mascarene High (MH), defined by the sea level pressure (SLP) maximum within the region of [40°–120°E, 50°–10°S] in austral summer (November–January), were investigated using atmospheric reanalysis datasets. The MH longitudinal position has a dominant timescale at about 6 years, which appears to be independent of the MH intensity variation. The MH longitudinal movement is caused by a combination of SLP variations in the eastern South Indian Ocean (ESIO) and in the western South Indian Ocean (WSIO), as follows. (1) Pressure variations in the ESIO region are confined to the lower atmosphere up to the mid-troposphere, and are associated with the El Niño-Southern Oscillation events. (2) Pressure variations in the WSIO region, characterized by a quasi-barotropic structure throughout the troposphere, are related to the meridional movement of storm track. Sea surface temperature anomalies associated with the longitudinal movement of the MH show a southwest–northeast dipole structure, but this is shifted 10° westward in longitude compared with that associated with the MH intensity.
AB - Temporal variations in the Mascarene High (MH), defined by the sea level pressure (SLP) maximum within the region of [40°–120°E, 50°–10°S] in austral summer (November–January), were investigated using atmospheric reanalysis datasets. The MH longitudinal position has a dominant timescale at about 6 years, which appears to be independent of the MH intensity variation. The MH longitudinal movement is caused by a combination of SLP variations in the eastern South Indian Ocean (ESIO) and in the western South Indian Ocean (WSIO), as follows. (1) Pressure variations in the ESIO region are confined to the lower atmosphere up to the mid-troposphere, and are associated with the El Niño-Southern Oscillation events. (2) Pressure variations in the WSIO region, characterized by a quasi-barotropic structure throughout the troposphere, are related to the meridional movement of storm track. Sea surface temperature anomalies associated with the longitudinal movement of the MH show a southwest–northeast dipole structure, but this is shifted 10° westward in longitude compared with that associated with the MH intensity.
KW - El Niño-Southern Oscillation
KW - Indian Ocean Subtropical Dipole
KW - Mascarene High
KW - Southern Annular Mode
KW - Storm track activity
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U2 - 10.1007/s00382-014-2427-7
DO - 10.1007/s00382-014-2427-7
M3 - Article
AN - SCOPUS:84943814585
SN - 0930-7575
VL - 45
SP - 1739
EP - 1745
JO - Climate Dynamics
JF - Climate Dynamics
IS - 7-8
ER -