Climate model errors over the South Indian Ocean thermocline dome and their effect on the basin mode of interannual variability

TitleClimate model errors over the South Indian Ocean thermocline dome and their effect on the basin mode of interannual variability
Publication TypeJournal Article
Year of Publication2015
AuthorsLi G., Xie SP, Du Y.
JournalJournal of Climate
Volume28
Pagination3093-3098
Date Published2015/04
Type of ArticleArticle
ISBN Number0894-8755
Accession NumberWOS:000352487300010
KeywordsCMIP5; dipole; el-nino; enso; pacific; reanalysis; sea-surface temperature; summer monsoon
Abstract

An open-ocean thermocline dome south of the equator is a striking feature of the Indian Ocean (IO) as a result of equatorial westerly winds. Over the thermocline dome, the El Nino-forced Rossby waves help sustain the IO basin (IOB) mode and offer climate predictability for the IO and surrounding countries. This study shows that a common equatorial easterly wind bias, by forcing a westward-propagating downwelling Rossby wave in the southern IO, induces too deep a thermocline dome over the southwestern IO (SWIO) in state-of-the-art climate models. Such a deep SWIO thermocline weakens the influence of subsurface variability on sea surface temperature (SST), reducing the IOB amplitude and possibly limiting the models' skill of regional climate prediction. To the extent that the equatorial easterly wind bias originates from errors of the South Asian summer monsoon, improving the monsoon simulation can lead to substantial improvements in simulating and predicting interannual variability in the IO.

DOI10.1175/jcli-d-14-00810.1
Student Publication: 
No
sharknado