气候变化领域集成服务门户(CCPortal): A skewed perspective of the Indian rainfall-El Niño-Southern Oscillation (ENSO) relationship

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DOI	10.5194/hess-24-5473-2020
	A skewed perspective of the Indian rainfall-El Niño-Southern Oscillation (ENSO) relationship
	Schulte J.; Policielli F.; Zaitchik B.
发表日期	2020
ISSN	1027-5606
起始页码	5473
结束页码	5489
卷号	24 期号:11
英文摘要	Wavelet coherence is a method that is commonly used in hydrology to extract scale-dependent, nonstationary relationships between time series. However, we show that the method cannot always determine why the time-domain correlation between two time series changes in time. We show that, even for stationary coherence, the time-domain correlation between two time series weakens if at least one of the time series has changing skewness. To overcome this drawback, a nonlinear coherence method is proposed to quantify the cross-correlation between nonlinear modes embedded in the time series. It is shown that nonlinear coherence and auto-bicoherence spectra can provide additional insight into changing time-domain correlations. The new method is applied to the El Niño-Southern Oscillation (ENSO) and all- India rainfall (AIR), which is intricately linked to hydrological processes across the Indian subcontinent. The nonlinear coherence analysis showed that the skewness of AIR is weakly correlated with that of two ENSO time series after the 1970s, indicating that increases in ENSO skewness after the 1970s at least partially contributed to the weakening ENSO- AIR relationship in recent decades. The implication of this result is that the intensity of skewed El Niño events is likely to overestimate India's drought severity, which was the case in the 1997 monsoon season, a time point when the nonlinear wavelet coherence between AIR and ENSO reached its lowest value in the 1871-2016 period. We determined that the association between the weakening ENSO-AIR relationship and ENSO nonlinearity could reflect the contribution of different nonlinear ENSO modes to ENSO diversity. © Author(s) 2020.
语种	英语
scopus关键词	Atmospheric pressure; Climatology; Higher order statistics; Rain; Time series; Time series analysis; Cross correlations; Hydrological process; Indian subcontinents; Nonlinear coherence; Nonlinear wavelets; Southern oscillation; Time-domain correlation; Wavelet coherences; Time domain analysis; El Nino-Southern Oscillation; hydrology; rainfall; skewness
来源期刊	Hydrology and Earth System Sciences
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/159253
作者单位	Schulte, J., Science Systems and Applications Inc., Lanham, MD 20706, United States; Policielli, F., NASA Goddard Space Flight Center, Greenbelt, MD 20771, United States; Zaitchik, B., Department of Earth and Planetary Sciences, Johns Hopkins University, Baltimore, MD 21218, United States
推荐引用方式 GB/T 7714	Schulte J.,Policielli F.,Zaitchik B.. A skewed perspective of the Indian rainfall-El Niño-Southern Oscillation (ENSO) relationship[J],2020,24(11).
APA	Schulte J.,Policielli F.,&Zaitchik B..(2020).A skewed perspective of the Indian rainfall-El Niño-Southern Oscillation (ENSO) relationship.Hydrology and Earth System Sciences,24(11).
MLA	Schulte J.,et al."A skewed perspective of the Indian rainfall-El Niño-Southern Oscillation (ENSO) relationship".Hydrology and Earth System Sciences 24.11(2020).