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Modulation of wet-season rainfall over Iran by the Madden– Julian Oscillation, Indian Ocean Dipole and El Nińo–Southern Oscillation
Citation
Pourasghar, F and Oliver, ECJ and Holbrook, NJ, Modulation of wet-season rainfall over Iran by the Madden- Julian Oscillation, Indian Ocean Dipole and El Nino-Southern Oscillation, International Journal of Climatology, 39, (10) pp. 4029-4040. ISSN 0899-8418 (2019) [Refereed Article]
Copyright Statement
Copyright 2019 Royal Meteorological Society
DOI: doi:10.1002/joc.6057
Abstract
The intra-seasonal variation of precipitation over Iran is examined in terms of the
combined effects of the Madden–Julian Oscillation (MJO), Indian Ocean Dipole
(IOD) and El Nińo–Southern Oscillation (ENSO), using daily observations during
the wet season (October–May) from 1961 to 2015. We have examined how the
probability of daily rainfall above the upper tercile varies across MJO phases during
positive and negative IOD and ENSO states. The results indicate that the
response of Iran’s wet-season rainfall to the MJO is affected more by large-scale
atmospheric variations associated with the IOD than by ENSO. The negative (positive)
IOD strengthens (suppresses) the MJO–rainfall relationship in the wet and dry
MJO phases. The variation in the atmospheric variables (relative humidity and vertical
velocity) indicates more (less) humidity and upwards (downwards) motion
which increases (decreases) precipitation in wet (dry) MJO phases during the negative
IOD. The rainfall relationship with the MJO during the negative IOD is statistically
significant, while the relationship during the positive IOD is weak; and no
significant relationship is found during either phase of ENSO.
Item Details
Item Type: | Refereed Article |
---|---|
Keywords: | Indian Ocean Dipole, intra-seasonal variability, Madden–Julian Oscillation, rainfall probability |
Research Division: | Earth Sciences |
Research Group: | Oceanography |
Research Field: | Physical oceanography |
Objective Division: | Environmental Policy, Climate Change and Natural Hazards |
Objective Group: | Understanding climate change |
Objective Field: | Climate variability (excl. social impacts) |
UTAS Author: | Oliver, ECJ (Dr Eric Oliver) |
UTAS Author: | Holbrook, NJ (Professor Neil Holbrook) |
ID Code: | 133415 |
Year Published: | 2019 |
Web of Science® Times Cited: | 4 |
Deposited By: | Oceans and Cryosphere |
Deposited On: | 2019-06-27 |
Last Modified: | 2020-07-17 |
Downloads: | 0 |
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