Seasonal climate summary for the southern hemisphere (summer 2016–17): a season of extremes despite neutral ENSO, IOD

2019 ◽  
Vol 69 (1) ◽  
pp. 290
Author(s):  
Ben Hague
Keyword(s):  
Southern Hemisphere ◽  
Southern Oscillation ◽  
Heavy Rain ◽  
Southern Annular Mode ◽  
Sea Surface ◽  
Madden Julian Oscillation ◽  
Extreme Temperatures ◽  
Atmospheric Circulation Patterns ◽  
Circulation Patterns ◽  
The Indian Ocean

This is a summary of the southern hemisphere atmospheric circulation patterns and meteorological indices for summer 2016–17; an account of seasonal rainfall and temperature for the Australian region is also provided. Although indices for the El Niño–Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) represented typical neutral condition for these drivers, evidence of other climate drivers can be found in the land, ocean and atmosphere data from this time. The Southern Annular Mode appeared to have had some effect on rainfall in the east of Australia, and the Madden–Julian Oscillation active periods produced heavy rain in the tropical north. Despite neutral ENSO and IOD, extreme temperatures, in some areas highest on record, occurred in northern NSW and southern Queensland. High sea-surface temperatures caused further severe bleaching on the Great Barrier Reef.

Seasonal climate summary for the southern hemisphere (winter 2017): exceptionally warm days for Australia

2019 ◽  
Vol 69 (1) ◽  
pp. 331
Author(s):  
David J. Martin ◽  
Skie Tobin
Keyword(s):  
South America ◽  
Southern Hemisphere ◽  
Large Scale ◽  
Southern Oscillation ◽  
Southern Annular Mode ◽  
Austral Winter ◽  
Atmospheric Circulation Patterns ◽  
Circulation Patterns ◽  
The Indian Ocean ◽  
Hemisphere Winter

This is a summary of the southern hemisphere atmospheric circulation patterns and meteorological indices for austral winter 2017; an account of seasonal rainfall and temperature for the Australian region is also provided. The El Niño–Southern Oscillation was neutral during winter 2017, as was the Indian Ocean Dipole. A positive Southern Annular Mode influenced the climates of southern hemisphere countries at times during winter. Despite the lack of large-scale ocean influences, mean temperatures for the season were very much above average across large areas of Australia, New Zealand, southern Africa and South America. Precipitation during the season was below average across much of Australia, South Africa and western areas of Chile and Argentina, but above average in some southern and eastern areas of South America.

scholarly journals Triggering the Indian Ocean Dipole from the Southern Hemisphere

2021 ◽  
Author(s):  
Lian-Yi Zhang ◽  
Yan Du ◽  
Wenju Cai ◽  
Zesheng Chen ◽  
Tomoki Tozuka ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Southern Hemisphere ◽  
Indian Ocean Dipole ◽  
Southern Oscillation ◽  
Southern Annular Mode ◽  
Triggering Mechanism ◽  
Phase Development ◽  
The Indian Ocean ◽  
High System ◽  
The Tropics

<p>This study identifies a new triggering mechanism of the Indian Ocean Dipole (IOD) from the Southern Hemisphere. This mechanism is independent from the El Niño/Southern Oscillation (ENSO) and tends to induce the IOD before its canonical peak season. The joint effects of this mechanism and ENSO may explain different lifetimes and strengths of the IOD. During its positive phase, development of sea surface temperature cold anomalies commences in the southern Indian Ocean, accompanied by an anomalous subtropical high system and anomalous southeasterly winds. The eastward movement of these anomalies enhances the monsoon off Sumatra-Java during May-August, leading to an early positive IOD onset. The pressure variability in the subtropical area is related with the Southern Annular Mode, suggesting a teleconnection between high-latitude and mid-latitude climate that can further affect the tropics. To include the subtropical signals may help model prediction of the IOD event.</p>

scholarly journals Using Indicators of ENSO, IOD, and SAM to Improve Lead Time and Accuracy of Tropical Cyclone Outlooks for Australia

2020 ◽  
Vol 59 (11) ◽  
pp. 1901-1917
Author(s):  
Andrew D. Magee ◽  
Anthony S. Kiem
Keyword(s):  
Tropical Cyclone ◽  
Indian Ocean ◽  
Lead Time ◽  
Southern Oscillation ◽  
Pearson Correlation ◽  
Southern Annular Mode ◽  
Sea Surface ◽  
Selection Algorithm ◽  
Statistical Framework ◽  
The Indian Ocean

AbstractCatastrophic impacts associated with tropical cyclone (TC) activity mean that the accurate and timely provision of TC outlooks are important to people, places, and numerous sectors in Australia and beyond. In this study, we apply a Poisson regression statistical framework to predict TC counts in the Australian region (AR; 5°–40°S, 90°–160°E) and its four subregions. We test 10 unique covariate models, each using different representations of the influence of El Niño–Southern Oscillation (ENSO), Indian Ocean dipole (IOD), and southern annular mode (SAM) and use an automated covariate selection algorithm to select the optimum combination of predictors. The performance of preseason TC count outlooks generated between April and October for the AR TC season (November–April) and in-season TC count outlooks generated between November and January for the remaining AR TC season are tested. Results demonstrate that skillful TC count outlooks can be generated in April (i.e., 7 months prior to the start of the AR TC season), with Pearson correlation coefficient values between r = 0.59 and 0.78 and covariates explaining between 35% and 60% of the variance in TC counts. The dependence of models on indices representing Indian Ocean sea surface temperature highlights the importance of the Indian Ocean for TC occurrence in this region. Importantly, generating rolling monthly preseason and in-season outlooks for the AR TC season enables the continuous refinement of expected TC counts in a given season.

scholarly journals Seasonal climate summary for the southern hemisphere (winter 2016): a strong negative Indian Ocean Dipole brings wet conditions to Australia

2018 ◽  
Vol 68 (1) ◽  
pp. 101
Author(s):  
Blair Trewin
Keyword(s):  
Indian Ocean ◽  
Southern Hemisphere ◽  
El Niño ◽  
Indian Ocean Dipole ◽  
El Nino ◽  
Atmospheric Circulation Patterns ◽  
Circulation Patterns ◽  
The Indian Ocean ◽  
Hemisphere Winter ◽  
Neutral Conditions

This is a summary of the southern hemisphere atmospheric circulation patterns and meteorological indices for winter 2016; an account of seasonal rainfall and temperature for the Australian region and the broader southern hemisphere is also provided. One of the strongest negative phases on record of the Indian Ocean Dipole (IOD) developed during the season, contributing to Australia's second wettest winter on record, with rainfall above average over the vast majority of the continent. Neutral conditions prevailed in the tropical Pacific following the end of a strong El Niño event in autumn 2016, but the continuing effect of the 2015-16 El Niño was still evident in southern hemisphere temperatures, which were at or near record high levels.

scholarly journals The Years of El Niño, La Niña, and Interactions with the Tropical Indian Ocean

2007 ◽  
Vol 20 (13) ◽  
pp. 2872-2880 ◽  
Author(s):  
Gary Meyers ◽  
Peter McIntosh ◽  
Lidia Pigot ◽  
Mike Pook
Keyword(s):  
Indian Ocean ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Sea Surface ◽  
El Nino Southern Oscillation ◽  
La Nina ◽  
The Indian Ocean

Abstract The Indian Ocean zonal dipole is a mode of variability in sea surface temperature that seriously affects the climate of many nations around the Indian Ocean rim, as well as the global climate system. It has been the subject of increasing research, and sometimes of scientific debate concerning its existence/nonexistence and dependence/independence on/from the El Niño–Southern Oscillation, since it was first clearly identified in Nature in 1999. Much of the debate occurred because people did not agree on what years are the El Niño or La Niña years, not to mention the newly defined years of the positive or negative dipole. A method that identifies when the positive or negative extrema of the El Niño–Southern Oscillation and Indian Ocean dipole occur is proposed, and this method is used to classify each year from 1876 to 1999. The method is statistical in nature, but has a strong basis on the oceanic physical mechanisms that control the variability of the near-equatorial Indo-Pacific basin. Early in the study it was found that some years could not be clearly classified due to strong decadal variation; these years also must be recognized, along with the reason for their ambiguity. The sensitivity of the classification of years is tested by calculating composite maps of the Indo-Pacific sea surface temperature anomaly and the probability of below median Australian rainfall for different categories of the El Niño–Indian Ocean relationship.

Influence of the Madden-Julian Oscillation on sea surface salinity in the Indian Ocean

2011 ◽  
Vol 38 (17) ◽  
pp. n/a-n/a ◽  
Author(s):  
Gary Grunseich ◽  
Bulusu Subrahmanyam ◽  
Anthony Arguez
Keyword(s):  
Indian Ocean ◽  
Sea Surface ◽  
Sea Surface Salinity ◽  
Madden Julian Oscillation ◽  
Surface Salinity ◽  
The Indian Ocean

Seasonal climate summary for the southern hemisphere (summer 2017–18): an exceptionally warm season for Australia – a short-lived and weak La Niña

2019 ◽  
Vol 69 (1) ◽  
pp. 351
Author(s):  
Tamika Tihema
Keyword(s):  
Southern Hemisphere ◽  
Warm Season ◽  
Summer Rainfall ◽  
La Niña ◽  
Atmospheric Circulation Patterns ◽  
La Nina ◽  
Circulation Patterns ◽  
Tasman Sea ◽  
Average Rainfall

This is a summary of the southern hemisphere atmospheric circulation patterns and meteorological indices for summer 2017–18; an account of seasonal rainfall and temperature for the Australian region is also provided. A short-lived and weak La Niña developed but decayed by the end of February 2018. Sea-surface temperatures were exceptionally warm in the Tasman Sea from late 2017 to early 2018. It was an exceptionally warm summer for Australia, and the third-warmest mean temperature on record for the nation. Summer rainfall was close to the long-term average for Australia, with aboveaverage rainfall in west and below-average rainfall in the east.

scholarly journals Northern and southern hemisphere controls on seasonal sea surface temperatures in the Indian Ocean during the last deglaciation

2013 ◽  
Vol 28 (4) ◽  
pp. 619-632 ◽  
Author(s):  
Yiming V. Wang ◽  
Guillaume Leduc ◽  
Marcus Regenberg ◽  
Nils Andersen ◽  
Thomas Larsen ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Southern Hemisphere ◽  
Sea Surface ◽  
Sea Surface Temperatures ◽  
Last Deglaciation ◽  
Surface Temperatures ◽  
The Indian Ocean ◽  
The Last Deglaciation

The relationship between Indian Ocean sea–surface temperature and East African rainfall

2005 ◽  
Vol 363 (1826) ◽  
pp. 43-47 ◽  
Author(s):  
Emily Black
Keyword(s):  
Indian Ocean ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Southern Oscillation ◽  
Sea Surface ◽  
East African ◽  
African Rainfall ◽  
The Pacific ◽  
The Indian Ocean ◽  
The Relationship

Knowledge of the processes that control East African rainfall is essential for the development of seasonal forecasting systems, which may mitigate the effects of flood and drought. This study uses observational data to unravel the relationship between the Indian Ocean Dipole (IOD), the El Niño Southern Oscillation (ENSO) and rainy autumns in East Africa. Analysis of sea–surface temperature data shows that strong East African rainfall is associated with warming in the Pacific and Western Indian Oceans and cooling in the Eastern Indian Ocean. The resemblance of this pattern to that which develops during IOD events implies a link between the IOD and strong East African rainfall. Further investigation suggests that the observed teleconnection between East African rainfall and ENSO is a manifestation of a link between ENSO and the IOD.

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