A possible cause of the AO polarity reversal from winter to summer in 2010 and its relation to hemispheric extreme summer weather

Otomi, Yuriko; Tachibana, Yukio; Nakamura, Tetsu

doi:10.1007/s00382-012-1386-0

Cited by 34 publications

(38 citation statements)

References 27 publications

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“…Because chaotic phase variations of the Silk Road pattern are not strongly tied to SST forcing, it limits the predictability at monthly and longer leads over East Asia even though the PJ pattern transmits predictable tropical influences. Some recent studies, however, suggest an association of the Silk Road pattern with Atlantic SST (Wu et al, 2009b;Yamaura and Tomita, 2011;Otomi et al, 2013). This is a potential source of predictability that can benefit midlatitude Asian countries.…”

Section: Midlatitudesmentioning

confidence: 99%

Indo-western Pacific ocean capacitor and coherent climate anomalies in post-ENSO summer: A review

et al. 2016

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ENSO induces coherent climate anomalies over the Indo-western Pacific, but these anomalies outlast SST anomalies of the equatorial Pacific by a season, with major effects on the Asian summer monsoon. This review provides historical accounts of major milestones and synthesizes recent advances in the endeavor to understand summer variability over the Indo-Northwest Pacific region. Specifically, a large-scale anomalous anticyclone (AAC) is a recurrent pattern in post-El Niño summers, spanning the tropical Northwest Pacific and North Indian oceans. Regarding the ocean memory that anchors the summer AAC, competing hypotheses emphasize either SST cooling in the easterly trade wind regime of the Northwest Pacific or SST warming in the westerly monsoon regime of the North Indian Ocean. Our synthesis reveals a coupled oceanatmosphere mode that builds on both mechanisms in a two-stage evolution. In spring, when the northeast trades prevail, the AAC and Northwest Pacific cooling are coupled via wind-evaporation-SST feedback. The Northwest Pacific cooling persists to trigger a summer feedback that arises from the interaction of the AAC and North Indian Ocean warming, enabled by the westerly monsoon wind regime. This Indo-western Pacific ocean capacitor (IPOC) effect explains why El Niño stages its last act over the monsoonal Indo-Northwest Pacific and casts the Indian Ocean warming and AAC in leading roles. The IPOC displays interdecadal modulations by the ENSO variance cycle, significantly correlated with ENSO at the turn of the 20th century and after the 1970s, but not in between. Outstanding issues, including future climate projections, are also discussed.

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Section: Midlatitudesmentioning

confidence: 99%

Indo-western Pacific ocean capacitor and coherent climate anomalies in post-ENSO summer: A review

et al. 2016

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“…Kosaka et al (2012) showed that, in summer 2010, many coupled seasonal forecast models predicted a cool summer in developing La Niña conditions. Yet, they missed the interfering role of the S-R WT, which brought a record-high hot summer over the Far East (Kosaka et al, 2012;Otomi et al, 2013). From the two above-mentioned factors influencing the summer climate over the Far East, the PJ teleconnection appears to some extent (but not entirely) predictable on the seasonal time-scale, through its link with ENSO.…”

Section: Introductionmentioning

confidence: 99%

Extreme precipitation events over north China in August 2010 and their link to eastward‐propagating wave‐trains across Eurasia: observations and monthly forecasting

Orsolini

Zhang

Peters

et al. 2015

Quart J Royal Meteoro Soc

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Over the Far East in summer, climate is strongly influenced by the fluctuating Western Pacific Subtropical High (WPSH), and strong precipitation is often associated with southeasterly low-level wind that brings moist air from the southern China seas. The WPSH intraseasonal variability is partly influenced by quasi-stationary wave-trains propagating eastwards from Europe across Asia along the two westerly jets: the Silk-Road wave-train along the Asian jet at midlatitudes and the polar wave-train along the sub-polar jet. In the unusual summer of 2010, northeast China experienced its worst seasonal flooding for a decade, triggered by unusually severe precipitation. That summer was also characterized by a record-breaking heat wave over eastern Europe and Russia, whose impact on the precipitation further east over China has been little explored. Here, we examine the role of the Silk-Road and polar wave-trains, and their impact on precipitation over northeast China throughout August 2010, using station precipitation data and re-analyses. We found that there is a strong link between the Silk-Road wave-train and extreme precipitation events.Forecasting such regional precipitation events at the monthly time-scale remains a big challenge for operational global prediction systems. In this study, we use simulations with the atmospheric model of the European Centre for Medium-range Weather Forecasts (ECMWF) to highlight the key role of the Silk-Road and polar wave-trains in modulating extreme precipitation over north and northeast China in August 2010. While the ensemble-mean of the forecasts fails to predict the pulses of the Silk-Road wave-train, some model members show a high spatial correlation in upper-level meridional winds with re-analyses. Similarly, there is high spatial correlation between model meridional winds and precipitation. These results highlight the importance of better representing the intraseasonal evolution of the Silk-Road wave-train in order to improve the monthly prediction of summer precipitation over the Far East.

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“…Comparisons with reconstructed AO or NAO index may provide new information for interdecadal variability in the spring AO-EASM relationship over the past few centuries, which appears to be effected by SST in the North Pacific (e.g., Gong et al, 2011), the Indian (e.g., Gao et al, 2014), and the North Atlantic Oceans (e.g., Otomi et al, 2013). Comparisons with reconstructed AO or NAO index may provide new information for interdecadal variability in the spring AO-EASM relationship over the past few centuries, which appears to be effected by SST in the North Pacific (e.g., Gong et al, 2011), the Indian (e.g., Gao et al, 2014), and the North Atlantic Oceans (e.g., Otomi et al, 2013).…”

Section: Comparison With Reconstructed Naomentioning

confidence: 99%

“…In future work, we will extend hydroclimate reconstructions using tree-ring δ 18 O in northeastern Japan. Comparisons with reconstructed AO or NAO index may provide new information for interdecadal variability in the spring AO-EASM relationship over the past few centuries, which appears to be effected by SST in the North Pacific (e.g., Gong et al, 2011), the Indian (e.g., Gao et al, 2014), and the North Atlantic Oceans (e.g., Otomi et al, 2013). Additional comparisons with reconstructed other climate parameters (e.g., SST in the North Pacific, the Indian, and North Atlantic Oceans) also may allow us to consider whether the spatial change in spring AO-associated signals is a recent phenomenon or a more persistent characteristic of this teleconnection.…”

Section: 1029/2018gc007634mentioning

confidence: 99%

Assessment of Northeastern Japan Tree‐Ring Oxygen Isotopes for Reconstructing Early Summer Hydroclimate and Spring Arctic Oscillation

Sakashita

Yokoyama

Miyahara

et al. 2018

Geochem Geophys Geosyst

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The spring Arctic Oscillation (AO) significantly affects the subsequent summer rainfall in the East Asian summer monsoon (EASM) region, and analysis of meteorological data indicates this teleconnection strength varied on interdecadal timescales during the late 20th century. Tree‐ring records may be able to extend the relatively short observational record, but the extent to which these proxy reconstructions correspond to AO variability has yet to be explored in this region. Therefore, we present new tree‐ring cellulose oxygen isotope (δ18O) records from northeastern Japan (Akita, northern limit of EASM), spanning a.d. 1950 to 2003 which overlaps with the instrumental record. Tree‐ring δ18O is used for reconstructing the past hydroclimate variability and allows us to consider whether tree‐ring δ18O has the potential to clarify the longer‐term interdecadal changes in the spring AO‐EASM relationship. Measurements and analyses show that our tree‐ring δ18O data sets have a significant negative correlation with May‐June‐July relative humidity, and the tree‐ring δ18O in northeastern Japan also significantly correlates with the summer EASM index. Temporal comparisons between our record and observed monthly AO index indicate that reconstructed following early summer relative humidity significantly correlates to the previous March‐April‐May AO. This linkage changes on interdecadal timescales, and the linkage is relatively strong during early 1970s through early 1990s. Similar results are also obtained using a separate tree‐ring δ18O record from a separate location about 200 km to the southeast, suggesting that tree‐ring cellulose δ18O in northeastern Japan is indeed useful for better understanding the long‐term teleconnection between the spring AO and EASM.

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A possible cause of the AO polarity reversal from winter to summer in 2010 and its relation to hemispheric extreme summer weather

Cited by 34 publications

References 27 publications

Indo-western Pacific ocean capacitor and coherent climate anomalies in post-ENSO summer: A review

Indo-western Pacific ocean capacitor and coherent climate anomalies in post-ENSO summer: A review

Extreme precipitation events over north China in August 2010 and their link to eastward‐propagating wave‐trains across Eurasia: observations and monthly forecasting

Assessment of Northeastern Japan Tree‐Ring Oxygen Isotopes for Reconstructing Early Summer Hydroclimate and Spring Arctic Oscillation

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