El Niño Diversity Across Boreal Spring Predictability Barrier

Wang, Bin; Luo, Xiao; Sun, Weiyi; Yang, Young‐Min; Liu, Jian

doi:10.1029/2020gl087354

Cited by 9 publications

(13 citation statements)

References 43 publications

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“…The TCDa_G index, however, does not pass the significance test, meaning that it might be not an effective factor on affecting the ENSO variations over the whole period 1980-2018. Recently, Wang et al (2020) also found that simply using SST and zonal winds before April can successfully predict different types of El Niño, which is consistent with our viewpoint. Besides, the experiment with the preceding ENSO signal removed from the original variables is also conducted, the result of which is nearly identical with Fig.…”

Section: Connection Between the March Information And The Following Esupporting

confidence: 91%

Effect of the air–sea coupled system change on the ENSO evolution from boreal spring

Fang

Zheng

2021

Clim Dyn

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Realistic simulation and accurate prediction of El Niño-Southern Oscillation (ENSO) is still a challenge. One fundamental obstacle is the so-called spring predictability barrier (SPB), which features a low predictive skill of the ENSO with prediction across boreal spring. Our observational analysis shows that the leading empirical orthogonal function mode of the seasonal Niño3.4 index evolution (i.e., from May to the following April) explains nearly 90% of its total variance, and the principle component is almost identical to the Niño3.4 index in the mature phase. This means a good ENSO prediction for a year ranging May-next April can be achieved if the Niño3.4 index in the mature phase is accurately obtained in advance. In this work, by extracting physically oriented variables in the spring, a linear regression approach that can reproduce the mature ENSO phases in observation is firstly proposed. Further investigation indicates that the specific equation, however, is significantly modulated by an interdecadal regime shift in the air–sea coupled system in the tropical Pacific. During 1980–1999, ocean adjustment and vertical processes were dominant, and the recharge oscillator theory was effective to capture the ENSO evolutions. While, during 2000–2018, zonal advection and thermodynamics became important, and successful prediction essentially relies on the wind stress information and their controlled processes, both zonally and meridionally. These results imply that accounting for the interdecadal regime shift of the tropical Pacific coupled system and the dominant processes in spring in modulating the ENSO evolution could reduce the impact of SPB and improve ENSO prediction.

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Section: Connection Between the March Information And The Following Esupporting

confidence: 91%

Effect of the air–sea coupled system change on the ENSO evolution from boreal spring

Fang

Zheng

2021

Clim Dyn

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“…Hereafter, any month in ENSO onset and decay year is denoted by the suffix (0) and (1), respectively. Consistent with Wang et al (2019) and Wang et al (2020a), an El Niño (La Niña) year is identified as that the Niño3.4 index during October-November-December(0)-January-February( 1) is greater (less) than or equals to 0.6 °C (−0.5 °C). As a result, 33 El Niño cases and 36 La Niña cases are identified.…”

Section: Methodssupporting

confidence: 79%

“…Pronounced CEP cooling and western Pacific warming are observed in PC1-regressed SST anomalies, and the PC1-related NWPAC is a direct Rossby wave response to CEP cooling (Figure 1B; Fan et al, 2013;Wang et al, 2013;, Above study is analyzed from the perspective of circulation diversity, and the following analysis is conducted from the perspective of SST diversity to further confirm the importance of El Niño decay pace by an objective method: nonlinear k-means cluster analysis, which is more objective than directly using the El Niño decay rate with some subjective criterions. The 33 El Niño cases can be divided into four categories by a nonlinear k-means cluster analysis of the equatorial SST anomalies averaged between 5 °S and 5 °N over the Pacific from October(0) to October(1), following Wang et al (2020a). The results of k-means cluster analysis depend on the number, k, of clusters chosen.…”

Section: Diverse Enso Decay Pacementioning

confidence: 99%

“…As a result, a robust rainfall response to ENSO has not been fully recognized outside the Asian monsoon researchers, as shown by the schematic diagrams of ENSO impacts on the web pages of National Oceanic and Atmospheric Administration (NOAA), International Research Institute for Climate and Society (IRI), Met Office, and so on. The pronounced rainfall anomalies in summer seem to develop only after a strong ENSO (Wang et al, 2017), leading to the most severe forecast errors during ENSO decay phase (Ham et al, 2019;Wang et al, 2020a). In present study, the diversity of NWP circulation anomalies during post-ENSO summer is explored by using inter-case empirical orthogonal function (EOF) analysis, founding that the diverse circulation anomalies tend to cause the variable rainfall response in the key areas of East and South Asia, i.e., the mountainous central China (Hu et al, 2017;Hu et al, 2020) and western India (Chowdary et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

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Diversity of Northwest Pacific atmospheric circulation anomalies during post-ENSO summer

Tao

Kong

Liu

et al. 2022

Front. Environ. Sci.

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In present study, the diversity of summertime Northwest Pacific (NWP) atmospheric circulation anomalies following El Niño-Southern Oscillation is investigated by performing the inter-case empirical orthogonal function (EOF) analysis among 33 El Niño cases and 36 La Niña cases, respectively. Although an anomalous anticyclone is observed over the NWP for all El Niño cases’ composite, the circulation anomalies there vary from one case to another for each case. The EOF1 mode of NWP circulation anomalies explains 39.8% of inter-case variance, and its positive phase features an anomalous anticyclone and cyclone at south and north of 25°N, respectively. Therefore, the positive first principal component (PC1) corresponds to the anomalous NWP anticyclone, while the anticyclone shifts more northeastward and a cyclone appears at its south side for negative PC1. The PC1-related NWP circulation anomalies are largely controlled by the pronounced central and eastern Pacific sea surface temperature cooling, which indicates the diverse El Niño decay rate. Furthermore, four categories are obtained according to the El Niño decay rate by the nonlinear k-means cluster analysis, and the results further confirm that the close relationship between NWP circulation anomalies and El Niño decay rate. The PC1-regressed land rainfall anomalies highly resembles the composite results in the key areas of Asian monsoon region: the central China and South Asia, indicating variable rainfall anomalies in these areas during post-El Niño summer. The conclusion obtained from La Niña cases are generally same to El Niño.

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“…Based on this criterion, the two types of El Niño events that were determined using detrended monthly HadISST from 1891-2020 are as follows: • CT El Niño: 1896, 1899, 1902, 1905, 1911, 1913, 1918, 1925, 1930, 1940, 1941, 1951, 1957, 1965, 1972, 1976, 1982, 1986, 1991, 1997• WP El Niño: 1900, 1940, 1941, 1957, 1958, 1968, 1977, 1986, 1987, 1990, 1991, 1992, 1993, 1994, 2002, 2004, 2006, 2014 It can be seen that several events (1940,1941,1957,1986,1991,2009,2015) are defined as both CT and WP El Niño events based on this determination criterion, which is due to the fact that these events show significant warming in both Niño3 and Niño4 regions and are basin-wide warm events. Therefore, some studies also refer to these events as "strong basin-wide" events and do not regard them as a regular CT or WP El Niño (Wang et al, 2019;Wang et al, 2020). In following analyses, we still keep these events in their respective categories.…”

Section: Precipitation Anomaly Patterns Associated With Two Types Of ...mentioning

confidence: 99%

Different Seasonal Precipitation Anomaly Patterns in Central Asia Associated With Two Types of El Niño During 1891–2016

et al. 2022

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In this study, we examine the different seasonal precipitation anomaly patterns in Central Asia associated with the cold-tongue (CT) El Niño and warm-pool (WP) El Niño from the El Niño developing autumn to the decaying spring based on the Global Precipitation Climatology Centre (GPCC) full data reanalysis version 2018 (GPCC V2018) data set. Overall, El Niño are associated with more precipitations over Central Asia, but significant discrepancies can be found in the precipitation anomaly spatial patterns associated with the two types of El Niño from the El Niño developing autumn to the decaying spring. The precipitation associated with CT El Niño is mostly concentrated in the plains and hilly areas of Central Asia and is more dispersed in space. Whereas the precipitation associated with WP El Niño is mostly concentrated along Pamirs and Tian Shan Mountains with consistency throughout the autumn before El Niño peaks to the spring when El Niño decays. Also, the strength of the positive precipitation anomaly associated with WP El Niño is significantly stronger than that of CT El Niño. The analysis of anomalous atmospheric circulation caused by two types of El Niño shows that the interconfiguration of anomalous high pressure in the south side of Central Asia at low and middle latitudes and anomalous low pressure and anomalous high pressure in the high latitudes of Eurasia affects the southwest water vapor flux and north side water vapor flux in Central Asia, thus causing different effects of different types of El Niño on precipitation in Central Asia at different stages. The spatial consistency of the WP El Niño effect on precipitation in Central Asia over three seasons may be related to the upward branch of the anomalous Walker circulation over the Indian Ocean induced by it.

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El Niño Diversity Across Boreal Spring Predictability Barrier

Cited by 9 publications

References 43 publications

Effect of the air–sea coupled system change on the ENSO evolution from boreal spring

Effect of the air–sea coupled system change on the ENSO evolution from boreal spring

Diversity of Northwest Pacific atmospheric circulation anomalies during post-ENSO summer

Different Seasonal Precipitation Anomaly Patterns in Central Asia Associated With Two Types of El Niño During 1891–2016

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