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contributor authorMiyamoto, Ayumu
contributor authorNakamura, Hisashi
contributor authorMiyasaka, Takafumi
date accessioned2019-09-19T10:08:42Z
date available2019-09-19T10:08:42Z
date copyright3/2/2018 12:00:00 AM
date issued2018
identifier otherjcli-d-17-0229.1.pdf
identifier urihttp://yetl.yabesh.ir/yetl1/handle/yetl/4262039
description abstractAbstractThe south Indian Ocean is characterized by enhanced midlatitude storm-track activity around a prominent sea surface temperature (SST) front and unique seasonality of the surface subtropical Mascarene high. The present study investigates the climatological distribution of low-cloud fraction (LCF) and its seasonality by using satellite data, in order to elucidate the role of the storm-track activity and subtropical high. On the equatorward flank of the SST front, summertime LCF is locally maximized despite small estimated inversion strength (EIS) and high SST. This is attributable to locally augmented sensible heat flux (SHF) from the ocean under the enhanced storm-track activity, which gives rise to strong instantaneous wind speed while acting to relax the meridional gradient of surface air temperature. In the subtropics, summertime LCF is maximized off the west coast of Australia, while wintertime LCF is distributed more zonally across the basin unlike in other subtropical ocean basins. Although its zonally extended distribution is correspondent with that of LCF, EIS alone cannot explain the wintertime LCF enhancement, which precedes the EIS maximum under continuous lowering of SST and enhanced SHF in winter. Basinwide cold advection associated with the wintertime westward shift of the subtropical high contributes to the enhancement of SHF, especially around 15°?25°S, while seasonally enhanced storm-track activity augments SHF around 30°S. The analysis highlights the significance of large-scale controls, particularly through SHF, on the seasonality of the climatological LCF distribution over the south Indian Ocean, which reflect the seasonality of the Mascarene high and storm-track activity.
publisherAmerican Meteorological Society
titleInfluence of the Subtropical High and Storm Track on Low-Cloud Fraction and Its Seasonality over the South Indian Ocean
typeJournal Paper
journal volume31
journal issue10
journal titleJournal of Climate
identifier doi10.1175/JCLI-D-17-0229.1
journal fristpage4017
journal lastpage4039
treeJournal of Climate:;2018:;volume 031:;issue 010
contenttypeFulltext


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