Distinct quasi-biweekly features of the subtropical East Asian monsoon during early and late summers

Yang, Jing; Bao, Qing; Wang, Bin; Gong, Daoyi; He, Haozhe; Gao, Miaoni

doi:10.1007/s00382-013-1728-6

Cited by 68 publications

(54 citation statements)

References 45 publications

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“…The YHRB rainfall shows obvious 20-50-, 21-30-, and 12-20-day (quasi biweekly) periodical variations as a response to the intraseasonal variations over subtropical and mid-to high-latitude regions Mao et al 2010;Yang et al 2010Yang et al , 2013. In addition, many of the flooding rainfall events over YHRB are associated with the extremely active phase of intraseasonal variations.…”

Section: Introductionmentioning

confidence: 95%

Roles of Synoptic to Quasi-Biweekly Disturbances in Generating the Summer 2003 Heavy Rainfall in East China

Liu

Yang

Zhang

et al. 2014

Monthly Weather Review

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During the mei-yu season of the summer of 2003, the Yangtze and Huai River basin (YHRB) encountered anomalously heavy rainfall, and the northern YHRB (nYHRB) suffered a severe flood because of five continuous extreme rainfall events. A spectral analysis of daily rainfall data over YHRB reveals two dominant frequency modes: one peak on day 14 and the other on day 4 (i.e., the quasi-biweekly and synoptic-scale mode, respectively). Results indicate that the two scales of disturbances contributed southwesterly and northeasterly anomalies, respectively, to the mei-yu frontal convergence over the southern YHRB (sYHRB) at the peak wet phase. An analysis of bandpass-filtered circulations shows that the lower and upper regions of the troposphere were fully coupled at the quasi-biweekly scale, and a lower-level cyclonic anomaly over sYHRB was phase locked with an anticyclonic anomaly over the Philippines. At the synoptic scale, the strong northeasterly components of an anticyclonic anomaly with a deep cold and dry layer helped generate the heavy rainfall over sYHRB. Results also indicate the passages of five synoptic-scale disturbances during the nYHRB rainfall. Like the sYHRB rainfall, these disturbances originated from the periodical generations of cyclonic and anticyclonic anomalies at the downstream of the Tibetan Plateau. The nYHRB rainfalls were generated as these disturbances moved northeastward under the influence of monsoonal flows and higher-latitude eastward-propagating Rossby wave trains. It is concluded that the sYHRB heavy rainfall resulted from the superposition of quasi-biweekly and synoptic-scale disturbances, whereas the intermittent passages of five synoptic-scale disturbances led to the flooding rainfall over nYHRB.

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Section: Introductionmentioning

confidence: 95%

Roles of Synoptic to Quasi-Biweekly Disturbances in Generating the Summer 2003 Heavy Rainfall in East China

Liu

Yang

Zhang

et al. 2014

Monthly Weather Review

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“…They considered the abrupt changes of mean state in mid to late July, which includes the northward migration of westerly jet, South Asia High (SAH) and WPSH, and the weakening and broken of westerly jet, are the root causes of the change in behavior of quasi-biweekly variability (QBV). Yang et al (2014) also indicated that the tropical monsoon trough and midlatitude westerly jet were the possible sources of QBVover subtropical EA in both subseasons and were useful to provide guidance for 2-3-week predictions over the EA. In our study, we have conducted preliminary analysis on how the WPSH influence the QBWO during summer.…”

Section: Preliminary Analysismentioning

confidence: 99%

“…In general, the intensity and coverage of the WPSH may play crucial roles in modulating the occurrence and characteristics of the convection and further impact the evolution and propagation of the QBWO over the SCS. Yang et al (2014) found the differences of quasibiweekly characteristics over EA at early (June 10-July 20) and late (July 21-August 31) summer. They considered the abrupt changes of mean state in mid to late July, which includes the northward migration of westerly jet, South Asia High (SAH) and WPSH, and the weakening and broken of westerly jet, are the root causes of the change in behavior of quasi-biweekly variability (QBV).…”

Section: Preliminary Analysismentioning

confidence: 99%

“…In their study, remarkable differences in mean state and the principal modes of interannual precipitation variability were exhibited during the early and late summer. Later, Yang et al (2014) demonstrated the differences of quasibiweekly characteristics over EA at early and late summer. However, SCS, as a part of the Asia-Pacific, is also a crucial region for QBWO.…”

Section: Introductionmentioning

confidence: 99%

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Different characteristics of the quasi-biweekly oscillation over the South China Sea in two boreal summer stages

Wang

Chen

Huang

2015

Theor Appl Climatol

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This study investigates different evolutions and spatial structures of the quasi-biweekly oscillation (QBWO) over the South China Sea (SCS) during the early (May-June, MJ) and late (August-September, AS) summers of 1991-2010. During the MJ stage, a local QBWO in convection is dominant over the SCS, which is strengthened by the southwestward extension of QBWO anomaly from the east of Japan. In contrast, the QBWO during the AS stage originates from the east of the Philippines and propagates northwestward and then westward until attaining maturation over the SCS, followed by a gradual decay while moving westward. Regarding the circulations, the QBWO during the MJ stage is accompanied by a wave train of lower-level circulation anomalies extending from the SCS to the North Pacific. However, it is found that a wave train exists from the equator to the north of the SCS during the AS stage. In the vertical structures, the QBWO exhibits a northeast tilted relative vorticity with height during the MJ stage, while a vorticity anomaly extending from the surface up to near 300 hPa, but with an opposite above during the AS stage. In general, the QBWO active phases during both stages are characterized by the lowlevel convergence and cold anomaly and upper-level divergence and warm anomaly, with a strong upward motion. However, the cold anomaly at the low level is prominent during the MJ stage in contrast to that during the AS stage. And the warm anomaly at the upper level reveals a distinct enhancement from the MJ to AS stage.

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“…As a member of the Asian summer monsoon system, the SAH's spatiotemporal variability and impacts on the weather and climate over Asia and beyond have been investigated (Zhang et al 2002(Zhang et al , 2005(Zhang et al , 2016Liu et al 2004Liu et al , 2007Liu et al , 2013Duan and Wu 2005;Randel and Park 2006;Zarrin et al 2010;Huang et al 2011;Jiang et al 2011;Qu and Huang 2012;Wei et al 2014;Yang et al 2014;Ren et al 2015;Wu et al 2015;Chen and Zhai 2016;Shi and Qian 2016;Yang and Li 2016). Especially, variations of the SAH on subseasonal time scale have attracted more attention in recent years.…”

Section: Introductionmentioning

confidence: 99%

Subseasonal intensity variation of the South Asian high in relationship to diabatic heating: observation and CMIP5 models

et al. 2018

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This study investigates the subseasonal intensity variation of South Asian high (SAH) and the dynamic linkage with precipitation induced diabatic heating during the summer of 1979-2005, based on the observation and 18 models from the Coupled Model Intercomparison Project (CMIP5). The SAH's intensity variation with a period of approximately 10-36 days is identified both in the observation and 18 models, by performing an empirical orthogonal function (EOF) analysis on the standardized subseasonal anomalies in geopotential height at 100 hPa over the SAH's main body region. With the observed strengthening of the SAH, an enhanced rainfall belt between 70°-120°E migrates northward from the equatorial region. The northward propagating rainfall belt occupies almost the whole Indian subcontinent, Indochina Peninsula and subtropical east Asian regions between 20°-40°N when the SAH reaches the strongest. The relative vorticity diagnosis reveals the dynamical linkage between the subseasonal SAH's intensity variation and the precipitation anomalies over the Asian monsoon region: (1) The observed northward propagating rainfall band forms a horizontal gradient of diabatic heating, favoring an enhancement of the SAH over its southern part; (2) When the rainfall band approaches the regions of South and East Asia between 20°-40°N, the increased vertical gradient of diabatic heating in the upper level contributes significantly to the intensification of the SAH; (3) The horizontal advection process favors the westward expansion of the SAH. The observation-to-model comparisons indicate that the model's capacity to reproduce the SAH's intensity variation is highly associated with simulations of the anomalous rainfall band and its northward propagation. A realistic reproduction of precipitation anomalies is fundamental to simulating the dynamical processes related to diabatic heating, and thus the simulation of the SAH's subseasonal intensity variation.

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Distinct quasi-biweekly features of the subtropical East Asian monsoon during early and late summers

Cited by 68 publications

References 45 publications

Roles of Synoptic to Quasi-Biweekly Disturbances in Generating the Summer 2003 Heavy Rainfall in East China

Roles of Synoptic to Quasi-Biweekly Disturbances in Generating the Summer 2003 Heavy Rainfall in East China

Different characteristics of the quasi-biweekly oscillation over the South China Sea in two boreal summer stages

Subseasonal intensity variation of the South Asian high in relationship to diabatic heating: observation and CMIP5 models

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