Temporal and spatial characteristics of positive and negative Indian Ocean dipole with and without ENSO

Abstract

[1] The differences in the temporal evolution and spatial characteristics of the Indian Ocean Dipole (IOD) between positive and negative events with and without ENSO have been investigated using observations for the period . To document such differences is particularly important for climate forecasts over far east Asia, since distinctly different monsoon activities over China, Korea, and Japan for different types of IOD are found in the composite maps of precipitation anomalies. The composite map of SST and wind during various stages of IOD and the ocean mixed layer heat budget showed that the IOD with and without ENSO has a large difference in its temporal evolutions and their triggering mechanisms. In both negative and positive IOD events without ENSO, the wind anomaly in the eastern Indian Ocean seems to be responsible for the formation of sea surface temperature anomalies, while the anomaly in the western Indian Ocean seems to be the oceanic dynamical response to the anomaly in the east. During the ENSO years, the temporal and spatial contrast of the asymmetry of the IOD evolution is smaller, and the SST anomaly is driven by the anomalies in incoming radiation due to changes in cloudiness caused by the ENSO associated anomalous atmospheric circulations and not by the local wind anomalies.

Multi-scale meteorological conceptual analysis of observed active fire hotspot activity and smoke optical depth in the Maritime Continent

“…In a personal communication related to the present paper, Field pointed out Hong et al (2008) reported that for the period of 1948-2002 that the strongest negative precipitation anomalies in the MC for June, July, August have occurred during periods of combined positive ENSO and IOD indices. In his own personal communication with Hong (2011), Field reported that the same was true for September, October, and November.…”

The large‐scale circulations and summer drought and wetness on the Tibetan plateau

“…Hong et al (2008) demonstrate that positive events (positive IOD, El Niño, and both combined) reduce the moisture inflow from the southerly moisture origins (Arabian Sea, Bay of Bengal, southeast monsoon) to the Tibetan plateau while these are strengthened during negative episodes (negative IOD, La Niña, and both combined).…”

Robustness of SST teleconnections and precursory patterns associated with the Indian summer monsoon

“…al., 2003;Krishnan and Swapna, 2009;Clark et al, 2000;Terray et al, 2003Terray et al, , 2007Yang et al, 2007;Izumo et al, 2008;Park et al, 2010;Boschat et al, 2010). Although Sea Surface Temperature (SST) anomalies over the equatorial IO are not statistically associated with ISM rainfall (Gadgil et al, 2004(Gadgil et al, , 2005(Gadgil et al, , 2007Ihara et al, 2007), a lot of attention has been paid to the Indian Ocean Dipole (IOD) over the years, with debate regarding its existence as an intrinsic mode of IO variability, its dependence with ENSO (Chang et al, 2006), as well as its relationship with ISM (Ashok et al, 2001(Ashok et al, , 2004Gadgil et al, 2004Gadgil et al, , 2005Gadgil et al, , 2007Loschnigg et al, 2003;Kulkarni et al, 2007;Drbohlav et al, 2007;Hong et al, 2008). However, even the most recent studies have obtained quite contradictory results on this subject.…”