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.

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 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 Teleconnections between Monthly Rainfall Variability and Large-Scale Climate Indices in Southwestern Colombia

Water ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1863 ◽  
Author(s):  
Teresita Canchala ◽  
Wilfredo Alfonso-Morales ◽  
Wilmar Loaiza Cerón ◽  
Yesid Carvajal-Escobar ◽  
Eduardo Caicedo-Bravo
Keyword(s):  
Water Resources ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Rainfall Variability ◽  
Monthly Rainfall ◽  
Wavelet Coherence ◽  
Climate Indices ◽  
Annual Scale ◽  
Wavelet Coherence Analysis

Given that the analysis of past monthly rainfall variability is highly relevant for the adequate management of water resources, the relationship between the climate-oceanographic indices, and the variability of monthly rainfall in Southwestern Colombia at different time scales was chosen as the research topic. It should also be noted that little-to-no research has been carried out on this topic before. For the purpose of conducting this research, we identified homogeneous rainfall regions while using Non-Linear Principal Component Analysis (NLPCA) and Self-Organizing Maps (SOM). The rainfall variability modes were obtained from the NLPCA, while their teleconnection in relation to the climate indices was obtained from Pearson’s Correlations and Wavelet Transform. The regionalization process clarified that Nariño has two regions: the Andean Region (AR) and the Pacific Region (PR). The NLPCA showed two modes for the AR, and one for the PR, with an explained variance of 75% and 48%, respectively. The correlation analyses between the first nonlinear components of AR and PR regarding climate indices showed AR high significant positive correlations with Southern Oscillation Index (SOI) index and negative correlations with El Niño/Southern Oscillation (ENSO) indices. PR showed positive ones with Niño1 + 2, and Niño3, and negative correlations with Niño3.4 and Niño4, although their synchronous relationships were not statistically significant. The Wavelet Coherence analysis showed that the variability of the AR rainfall was influenced principally by the Niño3.4 index on the 3–7-year inter-annual scale, while PR rainfall were influenced by the Niño3 index on the 1.5–3-year inter-annual scale. The El Niño (EN) events lead to a decrease and increase in the monthly rainfall on AR and PR, respectively, while, in the La Niña (LN) events, the opposite occurred. These results that are not documented in previous studies are useful for the forecasting of monthly rainfall and the planning of water resources in the area of study.

scholarly journals The influence of El Niño–Southern Oscillation regimes on eastern African vegetation and its future implications under the RCP8.5 warming scenario

2017 ◽  
Vol 14 (18) ◽  
pp. 4355-4374 ◽  
Author(s):  
Istem Fer ◽  
Britta Tietjen ◽  
Florian Jeltsch ◽  
Christian Wolff
Keyword(s):  
Climate Change ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Rainfall Variability ◽  
Future Climate ◽  
Future Climate Change ◽  
El Nino Southern Oscillation ◽  
Vegetation Response ◽  
African Rainfall

Abstract. The El Niño–Southern Oscillation (ENSO) is the main driver of the interannual variability in eastern African rainfall, with a significant impact on vegetation and agriculture and dire consequences for food and social security. In this study, we identify and quantify the ENSO contribution to the eastern African rainfall variability to forecast future eastern African vegetation response to rainfall variability related to a predicted intensified ENSO. To differentiate the vegetation variability due to ENSO, we removed the ENSO signal from the climate data using empirical orthogonal teleconnection (EOT) analysis. Then, we simulated the ecosystem carbon and water fluxes under the historical climate without components related to ENSO teleconnections. We found ENSO-driven patterns in vegetation response and confirmed that EOT analysis can successfully produce coupled tropical Pacific sea surface temperature–eastern African rainfall teleconnection from observed datasets. We further simulated eastern African vegetation response under future climate change as it is projected by climate models and under future climate change combined with a predicted increased ENSO intensity. Our EOT analysis highlights that climate simulations are still not good at capturing rainfall variability due to ENSO, and as we show here the future vegetation would be different from what is simulated under these climate model outputs lacking accurate ENSO contribution. We simulated considerable differences in eastern African vegetation growth under the influence of an intensified ENSO regime which will bring further environmental stress to a region with a reduced capacity to adapt effects of global climate change and food security.

scholarly journals Simulated enhancement of ENSO-related rainfall variability due to Australian dust

2011 ◽  
Vol 11 (1) ◽  
pp. 1595-1639 ◽  
Author(s):  
L. D. Rotstayn ◽  
M. A. Collier ◽  
R. M. Mitchell ◽  
Y. Qin ◽  
S. K. Campbell
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Rainfall Variability ◽  
La Niña ◽  
Climate Feedback ◽  
Surface Cooling ◽  
Atmospheric Heating ◽  
La Nina ◽  
Eastern Australia

Abstract. Average dust emissions from Australia are small compared to those from the major sources in the Northern Hemisphere. However, they are highly episodic, and this may increase the importance of Australian dust as a climate feedback agent. We compare two 160-year coupled atmosphere-ocean simulations of modern-day climate using the CSIRO Mark 3.6 global climate model (GCM). The first run (DUST) includes an interactive treatment of mineral dust and its direct radiative effects. The second run (NODUST) is otherwise identical, but has the Australian dust source set to zero. We focus on the austral spring season, when the correlation between rainfall and the El Niño Southern Oscillation (ENSO) is strongest over Australia. We find that the ENSO-rainfall relationship over eastern Australia is stronger in the DUST run: dry (El Niño) years tend to be drier, and wet (La Niña) years wetter. The ENSO-rainfall relationship is also weaker over north-western Australia in the DUST run. The amplification of ENSO-related rainfall variability over eastern Australia and the weaker ENSO-rainfall relationship over the north-west both represent an improvement relative to observations. The suggested mechanism over eastern Australia involves stabilisation of the surface layer due to enhanced atmospheric heating and surface cooling in El Niño years, and enhanced ascent and moisture convergence driven by atmospheric heating in La Niña years. The results suggest that (1) a realistic treatment of Australian dust may be necessary for accurate simulation of the ENSO-rainfall relationship over Australia, and (2) radiative feedbacks involving dust may be important for understanding natural rainfall variability over Australia.

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