scholarly journals Differential Influences of Teleconnections from the Indian and Pacific Oceans on Rainfall Variability in Southeast Asia

Atmosphere ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 886
Author(s):  
Abdul Azim Amirudin ◽  
Ester Salimun ◽  
Fredolin Tangang ◽  
Liew Juneng ◽  
Muhamad Zuhairi
Keyword(s):  
Indian Ocean ◽  
Southeast Asia ◽  
El Niño ◽  
El Nino ◽  
Rainfall Variability ◽  
June July August ◽  
Rainfall Patterns ◽  
Negative Impacts ◽  
The Individual ◽  
June July

This study investigates the individual and combined impacts of El Niño and the positive Indian Ocean Dipole (IOD) on the Southeast Asia (SEA) rainfall variability. Using composite and partial correlation techniques, it is shown that both inter-annual events have individually distinct impacts on the SEA rainfall anomaly distribution. The results showed that the impacts of the co-occurrence of El Niño and IOD events are significant compared to the individual effects of pure El Niño or pure IOD. During June-July-August and September-October-November, the individual impacts of the pure El Niño and IOD events are similar but less significant. Both events caused negative impacts over the southern part of SEA during June-July-August (JJA) and propagated northeastward/eastward during September-October-November (SON). Thus, there are significant negative impacts over the southern part of SEA during the co-occurrence of both events. The differential impacts on the anomalous rainfall patterns are due to the changes in the sea surface temperature (SST) surrounding the region. Additionally, the differences are also related to the anomalous regional atmospheric circulations that interact with the regional SST. The anomalous Walker circulation that connects the Indian Ocean and tropical Pacific Ocean also plays a significant role in determining the regional anomalous rainfall patterns.

scholarly journals Predictable and Unpredictable Aspects of U.S. West Coast Rainfall and El Niño: Understanding the 2015/16 Event

2019 ◽  
Vol 32 (10) ◽  
pp. 2843-2868 ◽  
Author(s):  
Benjamin A. Cash ◽  
Natalie J. Burls
Keyword(s):  
Pacific Northwest ◽  
West Coast ◽  
El Niño ◽  
El Nino ◽  
Rainfall Variability ◽  
Winter Season ◽  
Seasonal Forecasts ◽  
The North ◽  
Dry Conditions ◽  
The Individual

AbstractCalifornia experienced record-setting drought from 2012 to 2017. Based on both seasonal forecast models and historical associations, there was widespread expectation that the major El Niño event of 2015/16 would result in increased winter-season precipitation and break the drought. However, the 2015/16 winter rainy season ultimately resulted in slightly below-average precipitation and the drought continued. In this work we analyze data from both observations and seasonal forecasts made as part of the North American Multi-Model Ensemble (NMME) to better understand the general relationship between El Niño and U.S. West Coast rainfall, focusing on Southern California (SOCAL) rainfall, Pacific Northwest (PNW) rainfall, and the 2015/16 event. We find that while there is a statistically significant positive correlation between El Niño events and the SOCAL and PNW rainfall anomalies, this relationship explains at most one-third of the observed variance. Examination of hindcasts from the NMME demonstrates that the models are capable of accurately reproducing this observed correlation between tropical Pacific sea surface temperatures and California rainfall when information from the individual ensemble members is retained. However, focusing on the multimodel ensemble mean, which deliberately reduces the influence of unpredicted variability, drastically overestimates the strength of this relationship. Our analysis demonstrates that much of the winter rainfall variability along the U.S. West Coast is dominated by unpredicted variations in the 200-hPa height field and that this same unpredicted variability was largely responsible for the unexpectedly dry conditions in 2015/16.

scholarly journals Effects of El-Niño, Indian Ocean Dipole, and Madden-Julian Oscillation on Surface Air Temperature and Rainfall Anomalies over Southeast Asia in 2015

Atmosphere ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 352 ◽  
Author(s):  
M. Islam ◽  
Andy Chan ◽  
Matthew Ashfold ◽  
Chel Ooi ◽  
Majid Azari
Keyword(s):  
Indian Ocean ◽  
Southeast Asia ◽  
Air Temperature ◽  
El Niño ◽  
Indian Ocean Dipole ◽  
El Nino ◽  
Weather Prediction ◽  
Surface Air Temperature ◽  
Madden Julian Oscillation ◽  
Rainfall Anomalies

The Maritime Continent (MC) is positioned between the Asian and Australian summer monsoons zone. The complex topography and shallow seas around it are major challenges for the climate researchers to model and understand it. It is also the centre of the tropical warm pool of Southeast Asia (SEA) and therefore the MC gets extra attention of the researchers. The monsoon in this area is affected by inter-scale ocean-atmospheric interactions such as the El-Niño Southern Oscillation (ENSO), the Indian Ocean Dipole (IOD), and the Madden-Julian Oscillation (MJO). Monsoon rainfall in the MC (especially in Indonesia and Malaysia) profoundly exhibits its variability dependence on ocean-atmospheric phenomena in this region. This monsoon shift often introduces to dreadful events like biomass burning (BB) in Southeast Asia (SEA) in which some led to severe trans-boundary haze pollution events in the past. In this study, the BB episode of 2015 in the MC is highlighted and discussed. Observational satellite datasets are tested by performing simulations with the numerical weather prediction (NWP) model WRF-ARW (Weather Research and Forecast—Advanced research WRF). Observed and model datasets are compared to study the surface air temperature and precipitation (rainfall) anomalies influenced by ENSO, IOD, and MJO. Links amongst these influences have been recognised and the delayed precipitation of the regular monsoon in the MC due to their influence during the 2015 BB episode is explained and accounted for, which eventually led to the intensification of fire and a severe haze.

scholarly journals Interaction between El Niño and Extreme Indian Ocean Dipole

2010 ◽  
Vol 23 (3) ◽  
pp. 726-742 ◽  
Author(s):  
Jing-Jia Luo ◽  
Ruochao Zhang ◽  
Swadhin K. Behera ◽  
Yukio Masumoto ◽  
Fei-Fei Jin ◽  
...  
Keyword(s):  
Indian Ocean ◽  
El Niño ◽  
Indian Ocean Dipole ◽  
El Nino ◽  
Walker Circulation ◽  
Global Ocean ◽  
Tropical Ocean ◽  
The Indian Ocean ◽  
Major Attention ◽  
The Individual

Abstract Climate variability in the tropical Indo-Pacific sector has undergone dramatic changes under global ocean warming. Extreme Indian Ocean dipole (IOD) events occurred repeatedly in recent decades with an unprecedented series of three consecutive episodes during 2006–08, causing vast climate and socioeconomic effects worldwide and weakening the historic El Niño–Indian monsoon relationship. Major attention has been paid to the El Niño influence on the Indian Ocean, but how the IOD influences El Niño and its predictability remained an important issue to be understood. On the basis of various forecast experiments activating and suppressing air–sea coupling in the individual tropical ocean basins using a state-of-the-art coupled ocean–atmosphere model with demonstrated predictive capability, the present study shows that the extreme IOD plays a key role in driving the 1994 pseudo–El Niño, in contrast with traditional El Niño theory. The pseudo–El Niño is more frequently observed in recent decades, coincident with a weakened atmospheric Walker circulation in response to anthropogenic forcing. The study’s results suggest that extreme IOD may significantly enhance El Niño and its onset forecast, which has being a long-standing challenge, and El Niño in turn enhances IOD and its long-range predictability. The intrinsic El Niño–IOD interaction found here provides hope for enhanced prediction skill of both of these climate modes, and it sheds new light on the tropical climate variations and their changes under the influence of global warming.

scholarly journals On the Influence of Enso And IOD on Rainfall Variability Over The Musi Basin, South Sumatra

2018 ◽  
Vol 3 (4) ◽  
pp. 157
Author(s):  
Wijaya Mardiansyah ◽  
Dedi Setiabudidaya ◽  
M. Yusup Nur Khakim ◽  
Indra Yustian ◽  
Zulkifli Dahlan ◽  
...  
Keyword(s):  
Indian Ocean ◽  
El Niño ◽  
Rainy Season ◽  
El Nino ◽  
Monsoon Season ◽  
Rainfall Variability ◽  
Tropical Indian Ocean ◽  
Tropical Pacific ◽  
Indonesian Seas ◽  
Sst Anomalies

The southern Sumatera region experiences one rainy season and one dry season in a year associated with seasonal change in monsoonal winds. The peak of rainy season is occurring in November-December-January during the northwest monsoon season, while the dry season comes in June-July-August during the southeast monsoon season. This study is designed to evaluate possible influence of the coupled ocean-atmospheric modes in the tropical Indo-Pacific region, namely the El Niño-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) on the rainfall variability over the catchment area of the Music Basin, South Sumatera. The ENSO and IOD occurrences were reflected by the variability of sea surface temperature (SST) in the tropical Pacific and Indian Ocean, respectively. During El Niño and/or positive IOD episode, negative SST anomalies cover the eastern tropical Indian Ocean and western tropical Pacific including the Indonesian seas, leading to suppress convective activities that result in reduce precipitation over the maritime continent. The situation is reversed during La Niña and/or negative IOD event. The results revealed that the high topography area (e.g. Bukit Barisan) was shown to be instrumental to the pattern of rainfall variability. During the 2010 negative IOD co-occurring with La Niña event, the rainfall was significantly increase over the region. This excess rainfall was associated with warm SST anomaly over the eastern tropical Indian Ocean and the Indonesian seas. On the other hand, extreme drought event tends to occur during the 2015 positive IOD simultaneously with the occurrence of the El Niño events Investigation on the SST patterns revealed that cold SST anomalies covered the Indonesian seas during the peak phase of the 2015 positive IOD and El Niño event.

scholarly journals Identification of Hotspots of Rainfall Variation Sensitive to Indian Ocean Dipole Mode through Intentional Statistical Simulations

2019 ◽  
Author(s):  
Jong-Suk Kim ◽  
Phetlamphanh Xaiyaseng ◽  
Lihua Xiong ◽  
Sun-Kwon Yoon ◽  
Taesam Lee
Keyword(s):  
Indian Ocean ◽  
El Niño ◽  
Indian Ocean Dipole ◽  
El Nino ◽  
Clear Understanding ◽  
Indian Ocean Dipole Mode ◽  
The Indian Ocean ◽  
Dry Seasons ◽  
Rainfall Patterns ◽  
Wet And Dry Seasons

Abstract. This study analyzed the sensitivity of rainfall patterns over the Indochina Peninsula (ICP) to sea surface temperature in the Indian Ocean based on statistical simulations of observational data. Quantitative changes in rainfall patterns over the ICP were examined for both wet and dry seasons to identify hotspots sensitive to ocean warming in the Indo-Pacific sector. Rainfall variability across the ICP was confirmed amplified by combined and/or independent effects of the El Niño–Southern Oscillation and the Indian Ocean Dipole (IOD). During the years of El Niño and a positive phase of the IOD, rainfall is less than usual in Thailand, Cambodia, southern Laos, and Vietnam. Conversely, during the years of La Niña and a negative phase of the IOD, rainfall throughout the ICP is above normal, except in parts of central Laos and northern Vietnam. This study also simulated the change of ICP rainfall in the wet and dry seasons according to intentional IOD changes, and IOD-sensitive hotspots were verified through quantitative analysis. The results of this study provide clear understanding both of the sensitivity of regional precipitation to the IOD and of the potential future impact of statistical changes regarding the IOD in terms of understanding regional impacts associated with precipitation in a changing climate.

scholarly journals Remote Sensing-Based Rainfall Variability for Warming and Cooling in Indo-Pacific Ocean with Intentional Statistical Simulations

2020 ◽  
Vol 12 (9) ◽  
pp. 1458
Author(s):  
Jong-Suk Kim ◽  
Phetlamphanh Xaiyaseng ◽  
Lihua Xiong ◽  
Sun-Kwon Yoon ◽  
Taesam Lee
Keyword(s):  
South China ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Rainfall Variability ◽  
Clear Understanding ◽  
Dry Seasons ◽  
Rainfall Patterns ◽  
Independent Effects ◽  
Wet And Dry Seasons

This study analyzed the sensitivity of rainfall patterns in South China and the Indochina Peninsula (ICP) using statistical simulations of observational data. Quantitative changes in rainfall patterns over the ICP were examined for both wet and dry seasons to identify hotspots sensitive to ocean warming in the Indo-Pacific sector. The rainfall variability was amplified by combined and/or independent effects of the El Niño–Southern Oscillation and the Indian Ocean Dipole (IOD). During the years of El Niño and a positive phase of the IOD, rainfall is less than usual in Thailand, Cambodia, southern Laos, and Vietnam. Conversely, during the years of La Niña and a negative phase of the IOD, rainfall throughout the ICP is above normal, except in parts of central Laos, northern Vietnam, and South China. This study also simulated the change of ICP rainfall in the wet and dry seasons with intentional IOD changes and verified IOD-sensitive hotspots through quantitative analysis. The results of this study provide a clear understanding both of the sensitivity of regional precipitation to the IOD and of the potential future impact of statistical changes regarding the IOD in terms of understanding regional impacts associated with precipitation in changing climates.

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