Investigation of the mei-yu front using a new deformation frontogenesis function

Gao, Shouting; Lu, Chungu

doi:10.1007/s00376-014-4147-7

Cited by 11 publications

(10 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The deformation term also intensifies the Mei-yu front in the developing stage as shown by previous studies (Ninomiya 1984;Zhou et al 2004;Gao et al 2008;Yang et al 2014Yang et al , 2015. However, the deformation frontogenesis is in general less important compared to effects of diabatic heating and titling as demonstrated here.…”

Section: Discussionsupporting

confidence: 79%

“…Ninomiya (1984) put forward the Mei-yu/ Baiu front frontogenesis function using equivalent potential temperature e gradient to define the front intensity and it was shown that deformation is the predominant frontogenesis term. The importance of deformation flow was highlighted later by more studies where the large-scale flow associated with Mei-yu fronts were found to exhibit a deformation pattern favoring frontogenesis (Zhou et al 2004;Gao et al 2008;Yang et al 2014;Yang et al 2015).…”

Section: Introductionmentioning

confidence: 96%

“…Since total diabatic heating was considered in earlier studies (e.g., Ninomiya 1984;Zhou et al 2004), the effect of latent heating alone has yet to be explicitly evaluated in terms of a classic Mei-yu frontogenesis function. The most recent work on the development of Mei-yu fronts and Meiyu rainfall also tend to focus on dry dynamical processes (e.g., Gao et al 2008;Yang et al 2014Yang et al , 2015. Therefore, it remains unclear how diabatic heating, especially latent heating, contributes to the spatiotemporal morphology of Mei-yu front throughout its lifecycle and what is the relative importance of diabatic heating compared to other dynamical and thermodynamical processes in determining the evolution of a Mei-yu front.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Dynamics of the spatiotemporal morphology of Mei-yu fronts: an initial survey

et al. 2021

View full text Add to dashboard Cite

Mei-yu fronts are often accompanied with prominent diabatic heating due to the development of frontal clouds and rain bands. The direct effect and relative importance of diabatic heating on the spatiotemporal morphology of Mei-yu fronts however remain unclear. Here a new frontogenesis function is derived to isolate the effect of diabatic heating and this function is then applied to the latest high resolution reanalysis product ERA5 to conduct an initial survey of dynamic and thermodynamic processes driving the intensity and structure evolutions of three typical Mei-yu fronts. It is found that the direct effect of latent heating (moisture depletion) is always frontogenetical (frontolytical) in the pre-frontal and frontal zone throughout the lifecycle of the front with latent heating (moisture depletion) in general dominates the front intensification (dissipation). Tilting is another critical process that turns the vertical gradient of equivalent potential temperature into horizontal gradient leading to frontogenesis during the front development stage, and, after the release of convective instability ahead of the front, flattens the front surface leading to frontolysis during the front decaying stage. Therefore titling maintains consistently positive contributions to the evolution of a Mei-yu front and its importance depends highly on the convective intensity near the front. The deformation effect appears frontogenetical but carries a much smaller weight compared to diabatic heating, moisture depletion and tilting. The structure evolutions of the three Mei-yu fronts studied here exhibit two distinct patterns: “bending and breaking”, and “moving and rotating”. Both patterns are dominated by the front propagation (i.e., frontogenesis through air parcels), further highlighting the critical roles played by diabatic heating, moisture depletion and titling in determining the spatiotemporal characteristics of Mei-yu fronts. As these three processes are all closely tied to updrafts, clouds and precipitation near the fronts, improved representations of clouds and convection are needed to accurately depict their feedbacks to frontal evolutions and ultimately achieve better predictions of heavy rainfall and floods associated with Mei-yu fronts.

show abstract

Section: Discussionsupporting

confidence: 79%

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Dynamics of the spatiotemporal morphology of Mei-yu fronts: an initial survey

et al. 2021

View full text Add to dashboard Cite

show abstract

“…In meteorology, deformation is mostly applied to the frontogenesis process (Petterssen, 1956;Yang et al, 2014;Yang et al, 2015). However, many observations and a number of clear and simple theories show that deformation also plays important roles in other physical processes, such as stormtrack dynamics, the formation and maintenance of the moat structure in tropical cyclones, symmetric instability, blocking onset, and so on (e.g., Whitaker and Dole, 1995;Elhmaidi et al, 2004;Rivière and Joly, 2006a, b;Gao et al, 2008;Wang, 2008;Thomas, 2012;Moon and Nolan, 2015).…”

Section: Introductionmentioning

confidence: 96%

The impact of deformation on vortex development in a baroclinic moist atmosphere

Ran

Gao

2015

Adv. Atmos. Sci.

Self Cite

View full text Add to dashboard Cite

A mathematical relation between deformation and vertical vorticity tendency is built by introducing the frontogenesis function and the complete vertical vorticity equation, which is derived by virtue of moist potential vorticity. From the mathematical relation, it is shown that properly configured atmospheric conditions can make deformation exert a positive contribution to vortex development at rates comparable to other favorable factors. The effect of deformation on vortex development is not only related to the deformation itself, but also depends on the current thermodynamic and dynamic structures of the atmosphere, such as the convective stability, moist baroclinicity and vertical wind shear (or horizontal vorticity). A diagnostic study of a heavy-rainfall case that occurred during 20-22 July 2012 shows that deformation has the most remarkable effect on the increase in vertical vorticity during the rapid development stage of the low vortex during its whole life cycle. This feature is mainly due to the existence of an approximate neutral layer (about 700 hPa) in the atmosphere where the convective stability tends to be zero. The neutral layer makes the effect of deformation on the vertical vorticity increase significantly during the vortex development stage, and thus drives the vertical vorticity to increase.

show abstract

“…Li et al (2011) studied a blizzard due to a cold front in Wuhan, and revealed that the elongated axis of deformation and the great-value divergence field were coincident with a cold front, keeping in step with the appearance and ending of the snowfall. Yang (2007) proposed a generalized scalar frontogenesis function (Yang, Gao, and Lu 2014) and an inhomogeneous saturated moist atmospheric frontogenesis function by the local change in the deformation gradient (Yang, Gao, and Lu 2015). The frontogenesis process and dynamic process of torrential rainfall in North China have been investigated in detail.…”

Section: Introductionmentioning

confidence: 99%

Deformation characteristics of the ‘7.20’ heavy rainfall event in North China

Ran

Jiao³

et al. 2018

Atmospheric and Oceanic Science Letters

View full text Add to dashboard Cite

A heavy-rainfall event that occurred in North China during 19-20 July 2016, resulting in severe flooding, was investigated in this study. In this event, high-value total deformation overlapped the precipitation region, implying a close relationship between them. By deriving the nongeostrophic ω equation in a non-uniformly saturated moist atmosphere, the relation between vertical velocity and deformation was diagnosed. The Q-vector divergence on the right-hand side of the new ω equation was divided into three compositions, associated with horizontal divergence, vertical vorticity, and horizontal-wind deformation, respectively. It was found that the deformation component of Q-vector divergence contributed most to the negative Q-vector divergence in the precipitation region, implying an important role of deformation forcing in facilitating the vertical motion. In order to track the precipitation on the basis of deformation, potential deformation was proposed by virtue of the generalized potential temperature. The high-value potential deformation and precipitation were always overlapping, and shared an analogous temporal trend. This means that potential deformation can reflect the variation of heavy precipitation to a certain extent, and can serve as a tracker of the precipitation region.

show abstract

Investigation of the mei-yu front using a new deformation frontogenesis function

Cited by 11 publications

References 22 publications

Dynamics of the spatiotemporal morphology of Mei-yu fronts: an initial survey

Dynamics of the spatiotemporal morphology of Mei-yu fronts: an initial survey

The impact of deformation on vortex development in a baroclinic moist atmosphere

Deformation characteristics of the ‘7.20’ heavy rainfall event in North China

Contact Info

Product

Resources

About