Diagnosis of the Heavy Rain near a Meiyu Front Using the Wet Q Vector Partitioning Method

Yue, Coijun; Shao-wen, Shou; Lin, Kwei-Jay; Yao, Xin

doi:10.1007/bf03342048

Cited by 9 publications

(4 citation statements)

References 13 publications

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“…Previous studies (Keyser et al, 1988(Keyser et al, , 1992Martin, 1999Martin, , 2007Yue et al, 2003Yue et al, , 2011 have shown that partitioning of the Q Q Q vector can provide useful information about the forcing from multi-scale weather systems. The Q Q Q vector is often decomposed into two components: one along the direction of potential temperature (Q Q Q s ) and the other along the direction of the potential temperature gradient (Q Q Q n ).…”

Section: Q Vector Partitioningmentioning

confidence: 99%

A diagnostic study of the asymmetric distribution of rainfall during the landfall of typhoon Haitang (2005)

et al. 2015

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The precipitation during landfall of typhoon Haitang (2005) showed asymmetric structures (left side/right side of the track). Analysis of Weather Research and Forecasting model simulation data showed that rainfall on the right side was more than 15 times stronger than on the left side. The causes were analyzed by focusing on comparing the water vapor flux, stability and upward motion between the two sides. The major results were as follows: (1) Relative humidity on both sides was over 80%, whereas the convergence of water vapor flux in the lower troposphere was about 10 times larger on the right side than on the left side.(2) Both sides featured conditional symmetric instability [MPV (moist potential vorticity) <0], but the right side was more unstable than the left side. (3) Strong (weak) upward motion occurred throughout the troposphere on the right (left) side. The Q Q Q vector diagnosis suggested that large-scale and mesoscale forcing accounted for the difference in vertical velocity. Orographic lift and surface friction forced the development of the asymmetric precipitation pattern. On the right side, strong upward motion from the forcing of different scale weather systems and topography caused a substantial release of unstable energy and the transportation of water vapor from the lower to the upper troposphere, which produced torrential rainfall. However, the above conditions on the left side were all much weaker, which led to weaker rainfall. This may have been the cause of the asymmetric distribution of rainfall during the landfall of typhoon Haitang.Citation: Yue, C. J., S. T. Gao, L. Liu, and X. F. Li, 2015: A diagnostic study of the asymmetric distribution of rainfall during the landfall of typhoon Haitang (2005).

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Section: Q Vector Partitioningmentioning

confidence: 99%

A diagnostic study of the asymmetric distribution of rainfall during the landfall of typhoon Haitang (2005)

et al. 2015

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“…Heavy rainfall is accompanied by strong vertical motion, which can lift water vapor, momentum, and heat energy from the lower level to the upper level, and thus generate the release of diabatic heating and the conversion of potential energy to kinetic energy. Generally, the atmosphere vertical velocity is hardly measured directly and usually derived by diagnostic method via other physical quantities, such as Q‐vector (Yao et al., 2004; Yue et al., 2003, 2015), helicity (Bogner et al., 2000; Kain et al., 2008), and potential vorticity (Hoskins et al., 1978; X. Wang & Zhang, 2003; D. Zhang & Kieu, 2006). It is worth noting that, by comparison with other methods, the Q ‐vector is known as the best tool for calculating vertical velocity (Dunn, 1991).…”

Section: Introductionmentioning

confidence: 99%

Effects of Typhoon In‐Fa (2021) and the Western Pacific Subtropical High on an Extreme Heavy Rainfall Event in Central China

2023

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Heavy rainfall events (HREs) have great socioeconomic impacts around the world and cause deadly and destructive disasters. China is located in the East Asia monsoon area and frequently susceptible to heavy rainfall and flooding extremes (Cao & Gao, 2007;H. Li et al., 2017). Studies on HREs have always been concerned widely and highly (Chen et al., 2012;Junker et al., 1999).Although HREs generally have a short-lived and localized nature (Jo et al., 2020), they are actually modulated by synoptic-scale systems, such as the western Pacific subtropical high (WPSH, Ding & Chan, 2005), tropical cyclone (TC, also known as typhoon, Ross & Kurihara, 1995), and southeasterly moisture transport produced by their interaction (Y. Nie & Sun, 2022). H. Wang et al. (2021) divided the persistent HREs over the Yangtze-Huaihe River Valley during 1981-2020 into three types according to pattern correlation. They emphasized that the WPSH and TC play significant roles in persistent HREs. Y. Wang et al. ( 2009) performed numerical sensitivity experiments to suggest that Typhoon Songda (2004) enhanced the transport of moisture to the heavy rainfall region through the outer circulation and was responsible for >90% of the precipitation in Japan. Many studies have revealed that when a TC approaches the WPSH, the pressure gradient between them increases rapidly, establishing or strengthening the low-level easterly jet, which is beneficial to transport water vapor toward the heavy rainfall region (Schumacher et al., 2011).

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“…The mei-yu rain belt typically occurs along the Yangtze River in central China from early June to early July, and it stretches farther eastward to southern Japan and the western North Pacific along the northwestern rim of the North Pacific subtropical high (NPSH; Ding 1992;Wang and Lin 2002;Ding 2007;Day et al 2018). Synoptic-scale disturbances, which originate from "southwest vortices" over the eastern flank of the Tibetan Plateau, develop rapidly along the mei-yu front and may cause devastating floods in the region as they propagate eastward (Gao et al 2002;Yue et al 2003;Liu et al 2003).…”

Section: Introductionmentioning

confidence: 99%

Moist Baroclinic Instability along the Subtropical Mei-Yu Front

Yang

2023

Journal of Climate

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Differing from classic midlatitude dry baroclinic instability theory, atmospheric motions over the subtropical mei-yu front in boreal summer are dominated by synoptic-scale disturbances coupled with precipitation and moisture under a weaker background vertical shear. This moisture–precipitation–circulation interactive feature, along with a preferred zonal wavelength of about 3400 km and eastward phase propagation, is explained by a moist baroclinic instability theoretical framework. The new framework is an extension of a traditional two-level baroclinic model by considering a prognostic moisture equation, the moisture–precipitation–circulation feedback, and an interactive planetary boundary layer. An eigenvalue analysis of the model shows that the most unstable mode has a preferred zonal wavelength of 3400 km, a westward-tilted vertical structure, and a phase leading of maximum moisture and precipitation anomalies relative to a lower-tropospheric trough, all of which are in good agreement with observations. Both anomalous horizontal and vertical advection processes contribute to the moisture increase. Further sensitivity tests show that the instability and the zonal-scale selection primarily arise from the moisture–convection–circulation feedback, while the vertical shear provides an additional energy source for the perturbation growth. This moist baroclinic instability theory explains well the observed characteristics of the development of synoptic-scale disturbances along the mei-yu front.

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Diagnosis of the Heavy Rain near a Meiyu Front Using the Wet Q Vector Partitioning Method

Cited by 9 publications

References 13 publications

A diagnostic study of the asymmetric distribution of rainfall during the landfall of typhoon Haitang (2005)

A diagnostic study of the asymmetric distribution of rainfall during the landfall of typhoon Haitang (2005)

Effects of Typhoon In‐Fa (2021) and the Western Pacific Subtropical High on an Extreme Heavy Rainfall Event in Central China

Moist Baroclinic Instability along the Subtropical Mei-Yu Front

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