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Wind vector (units: m s −1 ), relative vorticity (contours; units: 10 −5 s −1 ), and vorticity tendency (shaded; units: 10 −10 s −2 ) at 700 hPa associated with the horizontal gradient of total condensation latent heat: (a1-a5) for research area D1; (b1-b3) for research area D2.
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Taking an extratropical cyclone that produced extreme precipitation as the research object, this paper calculates the contribution of condensation latent heat release (LHR) to relative vorticity tendency based on the complete-form vertical vorticity tendency equation. The results show that the heating rate of convectional condensation LHR can reach...
Context in source publication
Context 1
... to the previous analysis, the horizontal gradient of condensation latent heat can also cause a growth in vorticity. Figure 5 shows the vorticity tendency caused by the horizontal gradient of total condensation LHR (the sum of stable condensation LHR and convectional condensation LHR) at 700 hPa. In the formation stage of the '610' cyclone (e.g., from 1200 UTC 8 June 2017 to 1800 UTC 8 June 2017; Figure 5(a1,a2)), there is almost no vorticity generation zone in the circulation center. ...
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Cyclones are a major cause of extreme weather in the extratropics. Projections of future climate change have focussed on extratropical cyclones identified close to the surface, but cyclones identified at multiple levels of the atmosphere (‘deep’ cyclones) make the largest contributions to total and extreme rainfall. Here we use ten CMIP5 models to...
Citations
... The enhanced release of condensation latent heat increases the local vorticity, increases the positive vorticity near the center of the low vortex, and enhances the cyclonic circulation [22]. Shen et al. [23] investigated an extratropical cyclone that produced extreme precipitation, calculated the contribution of condensation latent heat release to the relative vorticity tendency of the cyclone, and found that condensation latent heat release can not only directly induce vorticity tendency but also further cause vorticity tendency by changing the temperature gradient. The vorticity occurrence area is always located directly below the center of latent heat heating. ...
This study utilizes data from national ground meteorological observation stations in Shandong province, Fengyun-4 satellite data, and ERA5 reanalysis data. Through the calculation of atmospheric heat source changes, the role of diabatic heating in the occurrence and development of heavy rainfall is revealed. The widespread heavy-to-torrential rainfall event in Shandong province on 25 June 2018 is analyzed as a case study. It was found that a deep and robust southwest jet stream was the key system for the formation of this rainfall event. Satellite cloud images during the peak rainfall period showed vigorous development in the rainfall cloud region. During the concentrated rainfall period and when the low-altitude jet stream strengthened, there was mostly cold advection overhead at the observation station. The low-altitude jet stream transported moisture, increasing the humidity gradient, thus enhancing frontogenesis. The warm advection in the low-altitude jet stream was not the main energy supplier during heavy rainfall, and local temperature variations were the primary contributors to the thermodynamic conditions during the peak rainfall period. The rate of warming caused by the condensation and release of heat from water vapor significantly increased during the concentrated rainfall period. This warming effect played a heating role in the middle and lower layers, and the positive feedback from the latent heat release of water vapor condensation intensified the weather system affecting the rainfall, providing strong thermodynamic and dynamic conditions for heavy rainfall.
... To measure the latent heating from the phase transformation which is essential for precipitation, . q net is replaced with the latent heating rate Q L = −L v dq dt = −L v Fω following Shen et al. [28], Now the latent heating term F L can be calculated by ...
The heavy precipitation in Northern California—brought about by a landfalling atmospheric river (AR) on 25–27 February 2019—is investigated for an understanding of the underlying dynamical processes. By the peaks in hourly accumulation, this rainstorm can be divided into two stages (Stage I and Stage II). Using a recently developed multiscale analysis methodology, i.e., multiscale window transform (MWT), and the MWT-based theory of canonical transfer, the original fields are reconstructed onto three scale windows, namely, the background flow, synoptic-scale and mesoscale windows, and the interactions among them are henceforth investigated. In both stages, the development of the precipitation is attributed to a vigorous buoyancy conversion and latent heating, and besides, the instability of the background flow. In Stage I, the instability is baroclinic, while in Stage II, it is barotropic. Interestingly, in Stage I, the mesoscale kinetic energy is transferred to the background flow where it is stored, and is released back in Stage II to the mesoscale window again, triggering intense precipitation.
